Cam Testing: Tighter LSA, Less Intake/Exhaust Split
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- Опубликовано: 11 сен 2024
- I show the dyno results of testing two different cams on the Ls Dyno mule.
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Both Holdner (RUclips) & Brule (Engine Masters show) did a similar test, one on a LS, the other on a 440. The tests used same lobe profiles and duration, but different LSA. Interesting dyno results. Keep up the good work, Eric! This is fun stuff!
Richard Holdner also promotes procomp/speedmaster junk, so I lost all respect for him. His cam test went crazy as hell. He should have went with normal shit people actually use, 106, 108, 110 and 12 or 114. He went crazy wide with around 4° between each cam. I think he ended up with a 128 or 120 lsa as his wisest on a SBC. That's retarded
man need to get out of the arm chair do something to get credit, when you have a dyno and 10002 of results let me know
@inscoredbz bet you can't take me out and I got some of those procomps on my Windsor. But those procomps can look and perform very well with someone who's knows heads
I know that we built a 1030 hp 433, ls based, 9800 rpm and we used around a 118 lsa and some engines we used tight lsa. It's all dependent on everything else lol. We had a 400 sbf with 114 and 116 on the end lobes. But, I've personally had my hands on 6 engine masters engines that won and placed in top 5, all of them. Camshaft and people talkin about them is comical sometimes. Keep on building and racin!
@@inscoredbz all the respect to richard holdener. He has done great for the youtube engine performance testing community.
I ran a 236/248 111+3 in a 380” ls3 years ago. It had my ported 243 heads and 13.7:1 compression, worked victor jr. this was 2015 or so not as many options back then. 665hp on engine dyno and 540whp in my 2600# fb rx7. It was a great cam setup and street drove great on e85! I put thousands of miles on that setup and the t was incredibly fast. The ls3 heads are an odd duck when it comes to cams, you basically have a great BBC rec port on the intake side and a SBC exhaust port. On stock heads you will always see a large split due to the essentially having 2 different style of ports
665hp is pretty serious for ported 243s. Impressive.
I am pretty sure you are onto the LSA and comp. ratio. problem. I have been specing cams for my own builds for years and use Vizard s formula for up to 11-1 for every point over increase LSA by 1 degree also for every step up in valve size increase your LSA 1 degree. Richard Holldiner did a test on a junkyard LS and for every cam with a tighter LSA it made more low down torque and more HP than the previous. Keep up the videos Eric they are all good.
The Comp Cam had less cylinder pressure due to having over double the overlap. So the tighter LSA didn’t work as typically seen in testing.
TS cam = IVC- 43.5, Overlap-12.5
Since we don’t know the intake centerline, I’m guessing the cam is advanced 2 degrees on the Comp Cam.
Comp cam- IVC- 47, Overlap- 28
The LSA on the Comp (108) should be about right if the duration is matched to maintain the same cylinder pressure.
235/239 @ .050 on a 108 LSA, 106 ICL, 43.5 IVC, 21 degrees of overlap.
This should lose nothing at the bottom and gain at the top.
Exactly without calculating the dynamic compression ratio and valve overlap the test is not informative by just slapping parts in an engine and running it.
I think the tight LSA cam is beyond the point of diminishing returns for intake duration, Richard Holdner did a teat with a 240 and a 246 deg intake duration cam, the bigger cam lost tq and made no more Hp. It's called Stroker LS Cam Swaps: When is Bigger Not Better? The test engine was a 408 with AFR 245cc heads so it has just about the best as cast cathedral port heads available and it didnt benefit with more than 240° int duration.
Good test and evaluation Eric.
This is certainly a very fair and honest comparison.
Thanks for the great Tech.
Have a great day.👍👍
Sweet, I’ve been sticking with 112 lsa for my LS builds for about 8 years now. No surprises. Keep racing! Great video.
One thing I noticed is that the 112 camshaft has 12.5 degrees of overlap and the 108 camshaft has 28.5 degrees of overlap. I'd be curious to see how the engine would respond to a tighter 108 LSA with the same amount of overlap. So, the .050" duration numbers would be 221/236. This would at least keep the dynamic compression a constant in the test.
The dynamic compression could be increased by sciencing out the ICL and advancing it to the point where it adds as much cylinder pressure as possible while still being able to pull to the necessary rpms for the best peak HP.
13:1 Compression and heads and intake that flow very good numbers require less overlap (wider lobe sep) More overlap will help in a lower flowing intake port to scavenge more flow into the cylinder by the exhaust charge exiting. That gives you increased cylinder pressure.
Compression ratio has a big influence on LSA, I would imagine the higher the CR the wider you'd typically want to go with LSA, as a general rule of thumb. With a 10.5:1 the tighter angle may have been more appropriate. Still a great test that shows some interesting things.
Thank you for the information. Even this old guy learned something new today. I always thought the same way. Tighter lobe separation meant more horsepower.
Wow. I was not expecting that.
I have a pair of Promaxx cnc shocker 185 heads for my 360LA. It's good to see their Chevy heads doing so well.
Don’t mean to get off topic. But I was watching a video of David Wolf and he made 630hp and 625 ft lbs of torque with a 7.3 Godzilla for under $5,000. BTR camshaft, forged rods and pistons, aftermarket intake, and Ls7 lifters. He paid $1500.00 for the engine core. I know they’re hard to find because of being such a new engine. It would be awesome to see what you could do with one of these Ford engines.
Too much intake Duration is why the 108 split loses power under the curve. Great test though. Would love to see a cam with similiar duration on the intake but the same 108 lsa.
There are a lot of factors that determine camshaft selection, the higher the compression the wider the LSA, more low lift flow and higher port energy the wider the LSA and there is much more!!!
This. There are many factors to take into account, most here are trying to oversimplify
Richard Holder did a LSA test on Chevy LS with 108/112/120 LSA. The 108 made more peak and average torque and even more peak HP. It's on youtube somewhere.
Yes on THAT PARTICULAR ENGINE
@@dennisrobinson8008 another interesting point, they used the same intake and exhaust lobe, so it was a pretty apples to apples comparison. I'm just a keyboard warrior, but the comparison should be much closer the more I think about it.
@CK-mf6du it surprised me because the assumption would be the tighter lsa would fall off earlier. In that test it did not.
@@dennisrobinson8008 same here, I remember too when I first saw that. We have good information here, but it's honestly not discrediting vizards formula, not yet anyway. We would have to see a cam with same intake and exhaust lobe as Texas speed on a 108 lsa.
He did another test with AFR 245s on a 408 and it didnt make any more hp and less tq with a 246 vs a 240 deg int cam, so, I believe this cam is too big and is beyond the point of diminishing returns making 680hp on a 408 which is a lot for a 408 over 100hp/L, that article is called Stroker LS Cam Swaps: When is Bigger Not Better?
These LS engines sure do have some funny quirks . It seems each different style head brings its own set of rules too . Its hard to understand just why they hit a certain power level and Bam a brick wall is there ?? Especially NA ?? So much power comes so easy that this is truly baffleing !!! Ive run a big inch mouse for years and i just dont get it . I dont think the LS has truly been unlocked yet . This sure is a head scratcher !!
perhaps a better way to compare LSA effects is to have custom cams ground with the EXACT same lobe just at different angles. I know on all MY SBC and BBC engines I always get better results with tighter LSA's than similar cams with wider LSA's.
Yes, absolutely, I think that this cam had more duration than would be beneficial. Look at this test done by Richard Holdner with a 408 with AFR 245cc heads, 246 deg int made less tq and no more hp than a 240 deg cam, its called Stroker LS Cam Swaps: When is Bigger Not Better?
I dabble in engines but one of my passions is reloading pistol ammunition for shooting Cowboy action. That statement about testing and knowing is important. But even testing and knowing will still make you wrong on the internet. I've almost stopped posting, far too many theoretical experts out there. And as you also indicated, the best LSA and split are tied with the compression ratio as well. Any racing organization that lowered CR to limit HP quickly found out that the good teams could tune around that limitation and gain most of the lost HP back in. Back in the day I was hired to help on a late model dirt racer, with a 030 over 400 SBC, to do the engine work. Yes, I was working way above my pay grade. Therefore I went back about 5 years and went with the combinations that were proven winners five years back. IOW, I selected a combo where I could go to just about anyone and get tuning tips. Winning was what happens, not dominating, but if the driver had a good day, he had enough car to get it done. Thanks for posting the video.
Lots of information here. But I’m still not switching from my gen 1 small block.
youll always finish last too. Im certain my unported '87 305 makes more power than your small block does.
@@MasterWitchDoctor All the LS guys think burnouts and donuts mean fast. Most of the cars on RUclips don’t show time slips, and we don’t race dynos.
And there is always someone faster.
Still not sure why no one spins their LS engines past 7k when my flat tapped hydraulic cam sees 7400, And sustained 6500 rpm operation. Think if I ran some Erics promaxx or dragon slayer with shaft rockers. While you can have your opinion, I’m not basing my builds and wants off what others think. Plenty of really powerful high rpm gen 1 small blocks out there. The LS does not have the monopoly on horsepower.
And these videos have proved you don’t get the magic big hp with just a cam change, cause the stock heads flow decent but not enough to make the amazing hp fiction even one believes, you have to have the aftermarket heads to make the big numbers.
And this dyno engine has a 4.00 stroke. No stock production, LS other than the 7.0 427 LS has a 4.00 stroke.
@@MasterWitchDoctor I like 87 Irocs but the 305 was not really what I would call fast. Past few years circle track engines have gone this way with the 305. They said it was for cost and a saved many race series with these engines.
Production wise, the 305 was a bandaid for emissions. When in reality they could have kept the 350 and done much better. Even the 302 ford engines of the day were making the same hp as the tpi corvette 350. That’s really embarrassing for gm. And why would gm even put the 305 or the 4.3 in obs trucks that weigh in at 4200 plus pounds. At least the aftermarket was there to save us. And once Dart and World came along in the late 80’s with better cast iron heads it got better. Be glad we have so many choices of good cylinder heads today. In the 80’s we had nothing. Good thing we figured how to port the factory heads of the day.
@@DavidB7474 I beg to differ, I race an NHRA K Stock Automatic 87 Monte Carlo SS with 081 centerbolt 305 heads making 419 hp @ 6700 RPM and 407 torque 4100 rpm. This is a factory stock class that allows zero work to the heads (stock valve sizes and no porting including gasket matching or removal of slag) other than cutting the valve seat. It requires the stock intake manifold and carb (again no modifications), stock cam lift, 100% stock body including hood, and full interior. The Stock / Super Stock corrected horsepower of my L69 is rated at 248 from the NHRA which is what my 305 got on Carlisle Racings dyno (it was actually 246). The NHRA weight break is 13.25 lbs per claimed horsepower = my car must weigh in on the scale 3286 lbs. The NHRA stock classes are more about tuning the engine and making the modifications that are allowed and beating the opponent in a bracket race. My car runs a consistent 11.60s @ 118 mph and Ill put it against any 305 powered car in an NHRA Stock eliminator class. Ive thumped every one ive been on the starting line against. A well tuned 305 is every bit as fast as a 350 and i have proven it time and time again. My 305 has more small blocks, big blocks, and LS on the trailer than i care to remember. The only thing that beats me in K/SA are the 383 Mopars because its a heads up race and they have 100+ more horsepower. Those who think a 305 is a dog Im at Memphis International Raceway every weekend and my NHRA district track is Gainesville Florida. Come see me my Monte Carlo is the factory Burgundy and Ill show you what a 305 in the right hands can do.
@@DavidB7474 I beg to differ, I race an NHRA K Stock Automatic 87 Monte Carlo SS with 081 centerbolt 305 heads making 419 hp @ 6700 RPM and 407 torque 4100 rpm. This is a factory stock class that allows zero work to the heads (stock valve sizes and no porting including gasket matching or removal of slag) other than cutting the valve seat. It requires the stock intake manifold and carb (again no modifications), stock cam lift, 100% stock body including hood, and full interior. The Stock / Super Stock corrected horsepower of my L69 is rated at 248 from the NHRA which is what my 305 got on Carlisle Racings dyno (it was actually 246). The NHRA weight break is 13.25 lbs per claimed horsepower = my car must weigh in on the scale 3286 lbs. The NHRA stock classes are more about tuning the engine and making the modifications that are allowed and beating the opponent in a bracket race. My car runs a consistent 11.60s @ 118 mph and Ill put it against any 305 powered car in an NHRA Stock eliminator class. Ive thumped every one ive been on the starting line against. A well tuned 305 is every bit as fast as a 350 and i have proven it time and time again. My 305 has more small blocks, big blocks, and LS on the trailer than i care to remember. The only thing that beats me in K/SA are the 383 Mopars because its a heads up race and they have 100+ more horsepower. Those who think a 305 is a dog Im at Memphis International Raceway every weekend and my NHRA district track is Gainesville Florida. Come see me my Monte Carlo is the factory Burgundy and Ill show you what a 305 in the right hands can do.
Higher compression = wider LSA. Lower compression, restricted flow benefits more from the tighter LSA. Your real world testing proves this out. Looking forward to the next test.
IMO those heads are SO GOOD that on a 4" bore basically anything thats not 420+cuin that even an small cam is able to meet the airflow demands. So adding more cam is no different than adding more head, it simply doesnt need it! Sure it will make a few more hp but making BIG gains isnt going to happen
I don't completely agree yet, because until a "big" high lift cam is tested, we won't know what it's truly capable of. I'd like to see something in the .670" - .690" lift 112-115 LSA .256/.272 @ .050 on the 13:1 setup to REALLY max em out. I feel like the slightly bigger dur cam would've done better on a wider LSA but it didn’t have enough lift if it did to go 715ish HP
this 408 with those ProMaxx heads is probably not benefitting because the intake duration is too big, here is a test Richard Holdner did with a 408 with 245cc AFRs that made no extra hp and less tq with a 246° int duration than it did with 240° int duration its called Stroker LS Cam Swaps: When is Bigger Not Better?
I love this. Thanks for the data eric. IDK what LS people were saying to get the intake and duration split to be minimized but theyre clearly wrong lmao. Ive always seen a lot more duration on the exhaust than intake for N/A stuff.
Cylinder head flow is so good it doesnt require nearlybas much cam to get huge gains !!!!
With good flowing heads and bigger compression, less duration and overlap is needed, pretty evident of that here
It's not what I would have guess ed. Thanks for showing this
A wasted 2c, but I will pay.
I will point to the intake closing being some +10° later for the 108lsa vrs the 112, thats assuming the 108 was not advanced? If the 108 was put at +4-6° (intake centerline of 102-104), then low rpm might come back. The reasoning is that this would put the intake valve closing event closer to the 112 helping restore torque in the lower rpm. However, I doubt that will fix the top end. To fix that, more head cfm is needed. 680 hp is around the "calculated" 340cfm requirements.
Thank you for sharing your knowledge.
In my opinion it seems like lower compression 9-11:1 like the tighter lsa and 11:1 and higher do better with a wider lsa... Can't wait to see what happens with the next set of heads
I'm lov'n this testing work. Keep the good stuff coming !!
Try both cams at 108 and 112 with the same specs and see what numbers it gives.
frieburger did this on engine masters also
Holdener also did an LSA test 108,112 and 120 and the 108 made better TQ and hp with same duration and lift ... every combo is different
i think the 13:1 compression made the 112 lsa cam the right choice. if it had 10:1 , i would go with 109 lsa.
Talking with Herb Gebler many years ago (RIP), he would always talk about signal. A tight lobe separation angle would give better signal (better scavaging) assuming everything else was tuned. Gebler was a header guy (for the likes of Warren Johnson) and all about tuning headers.
Still waiting for the someone on youtube to make a video comparing cams that all have the same over lap but different lsa/duration. (108lsa 224/228 and 112lsa 232/236) Both cams have 10° overlap at .050. I would love to see a test like this please
All the most powerful LS engines I see tested always have a 10-15 degree intake to exhaust split and the LSA is always around 112-114..........just seems to be what those engines want....they don't respond well to cams that would normally work well for gen 1 small blocks or even Ford Windsor engines.....
Exactly
Depends alot if the engine has Cathedral or Rec port heads. Cathedrial ports will perform well with tighter a duration split and LSA than rec ports that are bandaiding the huge difference in flow Int vs Ex.
So the cam I specd for an LS 3 that made that made 550 tire through a dog box and quick change with only an 8* split must be fake news
Love some tight LSA videos great info thanks.
If I was to guess, I would have thought the bigger cam would have traded more torque for a little more top end, makes me wonder if that intake is holding it back now, I haven’t seen many high rpm carbed ls setups, but with those heads, a cam that size would be in the 7500 rpm range with a holley high ram or low ram, with wayyyy less torque, wish I could afford to send you a holley setup with a carb adaptor
It would be fun to see what DV would come up with on his cam program, feed him some numbers
That was great hope you do more of this stuff
you're only spinning the motor to 6700. it only needs 224 intake duration to do that. any more and you're just bleeding off cylinder pressure. imo, the 243 intake duration is too much area under the valve for that rpm and is more suited for 7-8000rpm. vizard is gonna say it's too much duration using his 108 lsa formula. if the comp cam had less intake duration it's gonna pick up more mid range torque. i actually don't know what the intended use this motor is designed for, tbh.
Testing is the science behind it, I look forward to seeing the lower compression with the 108! I think speculation is based on people’s guess and lack of evidence. You go Eric always enjoy your work!
Real life testing hurting feelings, i love it!
Several observations, hopefully no parroting. That said it’s info from dyno results published by other folks. First, the BTR Truck Norris cam is tiny. The only way you’d want that in a 408 is for towing (obviously my opinion). The Texas Speed stage 2 is probably intended for a 6.2 (376 cu in), not so much a 408. It does very well, though. Holdener’s many tests show that LSes like big splits between intake and exhaust duration. The two “big” Comp cams Richard often uses, one cathedral and one rectangular port, have the same intake duration at 0.050, but the rec port one has more exhaust duration. Comparing the two cams on the same combo, usually a 6.2 but sometimes a 6.0, the rec port cam loses a bit at rpm below the torque peak and gains a bit above. As I recall all these variations are single digits. When Richard put the big Comp cam in a 5.3 with good heads and intake, he got a power peak at 7700. I would think the right cam would peak higher than 6600 or so in yours. Another “well understood rule” (parroting?) is that higher compression generally likes wider LSAs. My two cents would be none of the cams tested so far are really optimized for your 408. In spite of that, you’re doing the testing and that’s the only way to get real answers. Thanks, Eric.
@EricWeingartner- ❤ your testing. We all have our best bench dyno thoughts, in our heads😉 I really enjoy actual data. Im really looking forward to seeing the test difference, with lower compression. I have always thought that 8 to 9 to 1 comp., regular/average type "street" engines, that use 87, or 89 octane, would benefit the most from tighter LSA's. I also think that "Any" engine, that responds well to a lot of timing= is not very eff., would benefit more from a tighter LSA. Since LS engines are typically very eff.= most run well with low timing, i feel they don't respond well to tighter LSA's. I also feel if a engine is limited in RPM capability, it may favor tighter LSA, especially if it responds well to high timing. Your thoughts would be very much appreciated. Im a former drag racer, that had a 9 to 1 comp., solid roller cammed 406 cu. In engine, cam was Comp 300 AR= street roller series ( 255° @ .050, .575 Lift 110° LSA +4°adv. ), in a "91" S-10(race wt. 3400Lbs. Im very Big, & it had a heavy ford 9" rear end w/3.50 gears), 28" drag D.O.Ts, it had average, unported, Iron Eagle 200cc cast iron heads, Edlebrock Rpm Air-Gap intake, 750 holley Dp, w/notched floats & jet extensions, blocked off power valve(buddy talked me into doing this= great throttle response, but sucked for cruising! Had 80 jets front & rear), 1" 5/8 shorty headman headers= way to small, w/manual exh. Blockoffs, w/3" dual exh., with 2 chamber flows( they dont flow but they sounded mean ), & about a 100 shot of Nitrous. 11.50s @ 115 Mph, on engine & 10s in the 120s w/the little Nitrous wiff! Im disabled now, & have not been outside in Almost 5 years now, so youtube videos help make my life much more enjoyable, so thank you sooo much, Eric. I Really Appreciate you. Thank you, for taking Your valuable time, to make these videos💖
Pretty much most of the Ls cams I've seen seem to be 112, 113,114 and 115 LSA. Great info brother.
A closer result than I was expecting. The difference in duration may have been mitigated to some degree - from an IVC perspective - by the difference in LSA. In other words the IVC figures are closer than what you'd expect from a first-glance look at the duration figures. I love what you're doing here; one good test is worth a million internet opinions.
486 average HP will walk away from the 431 cam all day. Most manufacturers lean towards a wider LSA to avoid “Low manifold vacuum”. BTR has used the tighter LSA in the smaller cams with success.
NA Race applications like the tighter LSA cams.
Application specific LSA depending on where in the RPM range you want to optimize power.
I was wondering why this wasn't mentioned, 50+ more average?
Because it wasn’t 50 average better. One pull started later so you are not comparing same range.
Maybe that mystery cam needed to be more in the 238 intake and 246 exhaust neighborhood, .620/.620 lift 107 or 109 lsa maybe it got to the point where more intake duration wasnt helping and didnt have enough exhaust duration and lift and maybe it needed to go a degree up or down on LSA. Maybe the Summit Single Plane would be better 240/252 .569/.569 106 then maybe run it with 1.8 rockers to get .604/.604 lift or 1.85 to get .620/.620 lift. That is crazy impressive power from a 408 680hp is serious, that Super Victor is impressing me, those ProMaxx heads too. Here I was thinking that a basic bish 600hp if I was lucky 408 was stroker might not be worth my time, I was thinking about trying a 7.3 Godzilla or GenV L8T bored to 4.125" with a 4.125" stroke 441ci build to get 650-700hp. Super impressive test engine no doubt. You ever know what you are going to happen until you test the engine like you say. When it's a custom combination you never know exactly what can happen there can be idiosyncracies and something that people think will work might not.
Thanks for putting out this info. I'm glad I waited till the end to comment. You cleared up questions that came to my head during the vid.
Hey Eric,
Tim here, yea, i tire of i-net warriors.....who REALLY dont know crap.......i think u said it best, when you said...."well did u watch him race??....oh, it was SO fast, u didnt even see him"......yep.....i was VERY surprised at the cam swap outcome......i wudda thunk the tighter LSA, and less spread wudda netted more.......each motor is its own dude......12° of seperation in common in an LS....i'm a Pontiac guy, i need a 6-8 spread, and like a 108-110 LSA for my shi% to perform, but each engine has its own thing.....i think ur MASSIVE testing proves certain i-net "GOTTA BE's" false/garbage, unless you've dyno'd it urself......i enjoyed my brother, and KEEP TESTING PLEASE!!!..i'm a gear head nerd.....i will trust ur testing, and #'s, b4 i wud blab, and say i-net garbage, as to what to do, again, EACH ENGINE is its own animal.......you are KICKIN BUTT!!!!...i am VERY proud i sub'd so long ago........PROVE IT THRU TESTING!!!....like Vizard preaches!!!...yep, enjoyed, TY sir, PEACE to you!!
I believe chamber and port position effect desired lobe seperation more. Low port sbc will need to be cammed differently then a high port LS at a 15 or less angle.
Great channel!!! Ok you HOOKED me!!! FINALLY, a No b/s channel, refreshing, with Intelligence, keep en’ coming!!
Opinion: A couple flaws in the 108 cam.
1) the higher compression ratio needs a wider LSA.
2) The greater flow of the LS head needs a wider LSA.
3) The longer exhaust duration may help the the engine lengthen the over rev time which may improve the average power output.
I think you are wrong, I think the intake duration is beyond the point of diminishing returns. Look at this test Righard Holdner did with a 240 and a 246 cam in a 408 with AFR 245s, the smaller heads made more tq and the same hp. Its called Stroker LS Cam Swaps: When is Bigger Not Better?
Richard Holdener did a LSA vid with a LS. He ordered 4 cams from BT. Lift and duration exactley the same all run in the same motor. He only recieved 3 of them from BT and without exception the engine picked up HP & Torque through most of the whole sweep.The only variable was the LSA. There sees to be some variables at times you don`t concider or don`t recognize but for the most part most and I say most of my engines that I do dyno support the tighter LSA thinking. Good Video none the less. Any Info is good Info
This engine is 13:1 though
@@ezmny1387 My dirt motors were 14.75 on a 106LSA with conciderable more duration and turn right at 8000rpm, as I said we engine builders may not recognize or concider all variables. In fact all my compression motors are at 106, ICL 102 or 3. None were LS motors that might be a varible I was talking about.
I think alot of the tight LSA guys are coming from the DV camp.
The duration and I to E ratio theories are what was pounded into us from the magazine days imo.
From the testing you've done and what has been done on LSs, they seem to need less timing from an efficiency standpoint.
So funny reading the comments and so many people believed they would have predicted the results. Next time Eric, do a summary video with the all the information before testing, and see most the predictions be wrong in the comments. I'll be honest, I would have predicted wrong. If it was an EFI with factory style intake manifold, I would have chosen the Texas speed camshaft, but being carburetor, I would have predicted the comp cam to be the winner. Goes to show, every combo is different.
Guts are telling me, when you get near 700 HP, you are into 2" dia, or larger, header territory. Also, a lot bigger carb. Did you record manifold vacuum during the tests?
I wonder how the different lobe shapes of the cam changes things.
A test with two different duration/split but the same lobe shape would be interesting.
Good test! How about getting Texas Speed to send you identical cams other than lobe separation angles? Is that doable?
Magnificent. I was here for the rant . Great factual analysis
LOL Eric, people are giving advice to the guy that competed in Engine Masters.😂
Yes the LS don’t need as much cam as guys think cause they flow better. I would like to see the data down to 2500 RPM’s. Coming off a street light it would be interesting to see. SBC and LS are different animals as you show. Nice😊and better for power brakes vacuum.
I Was Bummed When I Saw The 108 Cam With A 243 Intake Duration lmao. That Things Got Ridiculous Overlap Too. I Thought The Power Would Shift Near 7K But I Think That Intake Duration Is Past The Point Of "Demimishing Returns." On That Engine. I Would Have Tried A 229/229 108 So It Had Similar Overlap As The 112 And Then Maybe A 229/246 108 So It Would Have Alot More Overlap To See If It Would Make More Peak Power Around Similar RPM As The 112. Id Like To Disqualify Myself As Knowing What Im Talking About Tho. Ive Only Test 2 Camshafts Personally And It Was On My V6 Turbo 3800. I Had A "Turbo" 230/224 117 Camshaft Then I Did A Crap Ton Of Personal Research With Tons Of Yourube Videos, Dyno Graphs etc I Made The Determination Of 210/212 110 (orginally wanted a 108 with slightly tweak durations but comp cams wont grind you anything tighter than 110). Anyway It Didnt Feel Any Faster Or Slower Up Around 6000 But God Damn When It Grabs The Next Gear It Felt Like It Was Freighttraining. I Basically Put The Power Where I Use It. Next Im Gonna Try 9.9 CR On That Camshaft Shaft Which Is What The "On Paper" LSA Should Be For My Combo. I Had 8.0 CR An On Paper The 108 Was The Target. Its A Daily Driver So Im Excited To Test Out The 9.9 Compression. I Try And Make The Best And Test Different Things When My Engine Has To Come Apart LMAO.
I am mechanic and bench racer, I lost a 327 because the biggest Crane econo power hydraulic it was 2 degrees advanced from the factory, I didn't know it and just lined up the timing chain marks and put it together and I used tin shim head gasket all exhaust valves hit pistons until one broke a lifter. The only camshafts that come "straight up" are Factory, blueprint grinds or Lunati. Lesson learned, read the cam card, put it together no head gasket on one side w/clay on piston top check it. With that said were these cams. Factory advanced 2 degrees, did you advance or retard them and with the 0.6 something lift did you do any piston fly cutting or anything to prevent piston valve contact? That Texas can,I can see it inching a similar car on the track, but they were so close, you got Dyno, little things like advancing/retarding cam can make difference and comp cams are not straight up from factory, did you use it as is or did you center it, same goes for Texas cam? Both cams have outstanding performance either way, love the video!
One more thing, I am not accusing anyone of Anything, bench racing is just chatting, I am learning,I mean no offence!
It would be interesting, to fill out a couple a spec sheets and order 2 or 3 cams from people who do spec (chris padget at bullet, mike jones at jones cam) cams and see which one works the best.
There's more to a cam than the general specs
Yep
@@WeingartnerRacingI do not understand them beyond the general stuff, but I'm fascinated with it, you would think the bigger cam would've pulled away as rpm rose. Thank you for testing all this and showing us the results
I like it. Anymore though, I think there is such a large aftermarket for LS motors, one cam/head combo is going to do something completely different than the other.
Good information! Thanks for sharing.
Ls engines deffintly seem to love 1 7/8" headers as aposed to 1 3/4". Doesn't hurt them down low either from my experience. Would be interested to see a back to back in your setting compared to chassis dyno/hub dyno. I'd be inclined to say you will see a big gain from 1 7/8 and possibly a different result with 1 7/8. Just what I've found. Love your work and videos.
I can’t wait to see that solid roller in it
Cool video. The only problem I see is with a 13:1 compression ratio you need a bigger LSA. That's why the 112 LSA dis so much better. It made its power through the trapping efficiency. In a higher compression big block. Like this 114 or 115 LSA is where you would want to be. I know this is an LS motor but power is power. And torque is torque. The bigger LSA under high compression confirms my favorite camshaft Guru's statements and builds. Love it great video.
I’m no expert honestly.. but I’ve always seen a split make more power.. my Experience seems like in a good engine combination… according to cubic inches and compression ratio the duration @50 is where the magic is.. I had an old 355 with 58 cc heads and a 248/254 @50 hydraulic they said it wouldn’t be streetable but it was in a Silverado with 355 gear and it had some 140s 60’ and I drove it about every day..
Take a cam like david vizard or smokey yunick say works on a small block chevy because of intake to exhaust ratio... While smokey didn't profess a cam rule on lsa and duration and his power secrets book makes it sound like voodoo he did have an opinion on single pattern cams being good for a chevy and for engines with poor exhaust ports a dual pattern might be worth any extra cost (remember he was a big deal in the 1950's to the 1980's cams weren't that available in 31 flavors like baskin robins icecream, a dual pattern cam may have been premium during his lifetime). Take that cam, lets go by davids lsa rule (rule of thumb really) and grind up a 109 lsa (probably) cam and lets guess 230 degrees of duration @.050 and max lift for the valve springs, gind the cam to be installed straight up, no advance... Now watch some darin morgan videos about the importance of blowdown time for high rpm... Take the cam specs you just ground into cam A and advance the exhaust opening time 8 cranshaft degrees... Now you have a cam with the same intake open time, the same exhaust close time and the same intake close time. What's the lsa? Whats the advance? The cam spins half speed and the lsa is cam degrees. You move the exhaust centerline 4 crank degrees or 2 cam degrees. Now it's 111 lsa but it's still 109 icl. 3 out of 4 timing events are the same you you just increased power area above peak hp, you have exactly the same overlap and exactly the same intake closing time for the low speed "true compression" the engine idles almost exactly the same but perhaps the exhaust note is a little more lively as the gasses are buring a little more in the pipe. You may have reduced wot torque at the bottom of the curve slightly but it didn't necessarily decrease peak torque. I used to play with desktop dyno 2000 as a simulator when i was a kid reading magazines. It had an iterator feature where you would let it run hundreds or thousands of simplulation and it would keep the best few for you to see at the end. No matter what the parameter was, peak hp peak torque, best area under curve in your specified range, It always ended up with huge duration splits, advanced instalation sometimes 6 degrees or more and an lsa around 112 degrees. But you could manipulate the numbers and get really close with single patter cams and narrow lsa. Davids rule of thumb works well enough, but people fail to see where different cams are similar when you look at the open and closing events. I know a simulator is not a dyno. Im not saying people should have 25 degrees of lobe split and install their cams 7 degrees advanced. Im saying that sometimes we argue and don't even know that we aren't that far apart on things. Davids formula was derived from a lot of factors and somewhere in the reality of things the derivative of a curve lined up. The formula imputs are displacement and valve diameter. Well the funny thing about valve diameter is it defermines maximum flow area as long as the valve opens 25%+ its diameter long enough this gives you an area number. And the other input is the engine size. You basically have and area/volume here. Well valve packing in a cylinder can only get so big untill you splay the valves. A racing engine should always have as much valve to bore that's practical. The funny thing about this is that you end up with a lot of the volume calculation and the valve diameter both attached to the bore diameter. The only other thing is the stroke. In a well enough developed engine you could in theory guess the lsa based on the stroke length alone. This and blow down and lobe splits is part of why a prostock or a nascar cup engine use an lsa closer to 115 degrees flying in the face of hotrodder logic but in a street engine it wouldn't make a ton of torque. They have strokes less that 3.4" and they are at the pinacle of cylinder head development and may even have valve cant or splay. Get it close and let the dyno tell the rest!
So... tight lobe angles makes for a peakier motor. And a more sensitive motor to tuning.
In system engineering we call this a high Q system. If your racing dynos, obviously not the way you want to go.
There are reasons for picking one over the other. Wide lobe separation tend to be easier to tune (esp with EFI - well, if your not using a MAF) - but from my very limited experience, the motor seems to rev a bit more lazy (this could all be bas seat of the pants results).
Now you must play with cam timing and header tuning..... arguably stuff that the normal guy cannot afford.
I thought that was a general understanding. Wider LSA shifts the power band up top at the expense of some low end power.
Thanks for the info.Sounds about right.I have been playing with different cams in this 408 sbc.Went from a 240-248 on a 110.Reground it to a 244 straight up on a 108.It felt more snappy.Less on top end but more grunt down low.More UFH.I then put another split cam in it. similar specs 244-252 on a 112 and it had it pulled to 7500 but less down low.Less responsive but it screamed up high.This motor 10.8-1 with AFR 195’s.This motor by switching cams out 4 times playing with lobe and duration I am going with A cam this is split 240-244 on a 107 lobe with 550-580 lift.I definitely think you are correct.
@@JohnZornAscendedgo watch Richard holdeners LSA test 108,112,120 very interesting
@@lukesimeon5756 Rich is how I found that out. Bought his book for the Ford Focus and have been watching his channel for years.
It still boils down to the combination you have whether or not this or that cam will optimize more power! This is why you can customize your camshaft and Taylor it to your combination!! Trial and error my friend!!
Proving all the time how 1 test is worth 100 opinions
The LS head design uses wider lsa then small block as the intake port doesn't need to be tugged on by the increased overlap timing event
Great video as always!!!!! Have you ever flowed the GMPP LS3 cnc heads? I searched you're videos but didn't see them. Just wondering because I have a set on a 6.0 with a magnuson supercharger. Thanks!!
I had my cam reground and installed because I was curious about this from DV cam chart.I went from a 110 to a 107 in my 406 sbc.same lift and duration just changed the lobe.I did notice a little bit of a difference down low.Little more ufh.
Good testing, and i look forward to the lower compression test results.
I always thought a decent split on the exhaust duration helps the engine to carry out farther. (more gradual fall off past peak HP.) As an afterthought, when most of the big LS cam suppliers have wide separation angles and big exhaust splits, it's reasonable to assume they've done testing and their final grinds produce favorable results. I had a customer bring in a bone stock 2006 6.0 out of a truck, cam was something like 23x on the intake, and with the rocker fulcrum kit, a set of springs, and a carb/Victor Jr single plane the engine belted out 475 HP. I'm sure the engine had 100K original miles, and it belted out impressive numbers (to me) for minimal investment.
This is why the 383 SBC I built accidentally made unbelievable power. 230/244 114lobe sep. made 447hp 479tq at the tires through an auto. Was in a 92 rs camaro that ran 11.40’s @122mph on nitto 555r’s.
Imo, until a "big" high lift cam is tested, we won't know what it's truly capable of, .630ish cams are "small" these days. I'd like to see something in the .670" - .690" lift 112-115 LSA .256/.272 @ .050 on the 13:1 setup to REALLY max em out. I feel like the slightly bigger dur cam would've done better on a wider LSA but it didn’t have enough lift if it did to go 715+ HP.
You Rt. I run Grudge race these LS motors and its like some people like to fight for the small cams myths vs Big cam facts . Like ron from vengeance re racing explain to me, JR i don't care what nobody says bout Ls its a reason why we make max effort, nitrous, turbo cams yes we have small also for a different type of coustmer but for what you are doing and it you want to get the max HP Numbers that can be made like 80-129Hp you have to go big even a 408 cubic inch motor will soke up theses 220is - duration and low lift stage 1,2 cams . Its a reason why in the LS world you have such a thing as a cam only Ls1 max effort build. And the lope lsa on matters to how you gonna run that motor, NA , nitrous, force induction. NA 108-111, nitrous 112+4 through 114 max but better at a 112+ or turbo 113-116 . So I'm with you on that and i really just believe instead of getting the max HP people just really want to prove why your point is false. A 408 LS already made 730 hp no problem way years ago on RUclips. I just don't understand no my point is rt or no your point is wrong vs well lets really see what have been proven facts time after time after time dealing with LS and this decades old debate.
The correct way to use flow between In and Ex, is you look at the intake flow at peak flow demand and then the Exhaust flow at BDC. That is the ratio that you design the camshaft around. Not peak lift flow. 70% at these points is what you look for.
Just like most things with engine building there’s NO one size fits all it all comes down to your power goals and most importantly where you want that power to be at in the RPM range and LSA is just a small piece of the puzzle but still a pretty important piece in my experience with dirt track racing we tended to stay around 108 lsa but we didn’t venture much lower that 106 or higher than 112 we wanted that midrange grunt to help come off the turns and the engine still pulled hard down the straights but if I being completely honest we could’ve had it all wrong 🤷🏼♂️
That promaxx seems To be an excellent head
Not trying to bash or or hash up any conflictions, but even vizard said, the better the combination, the less need for a small lsa. Primarily by means of compression ratio. So when it gets flip flopped in your next text, I think you will be correct in your hypothesis.
Do you run a map sensor on the dyno ? I am pretty sure at this point you have run out of carb size and need a higher flow carb
I thought we learned in the early 90's that better flowing heads like a wider LSA.
What about an LS motor would change that?
Eric, great test and info. It still comes down to combo, as you know, but I can't believe all of the people in the comments. I would not want one touching my sbc or bbc, and I'm old school SBC and BBC to the end.
Interesting stuff. Always love good data. Always wonder about the combo too. Changing more than one variable is always sketchy but...The TS cam looks to be peaking about where'd I'd expect based on past experience, but the Comp wasn't really any higher. Normally on LS stuff with a duration that big on the intake the power peak will move up the rev range, unless you're sticking with a stock/stock like intake mani, then the peak just hangs on forever, but doesn't really climb. Never did a Victor on the LS though so don't know where that thing does its best work. Keep posting!!
Here is the problem with Eric Weingartner’s videos.
It makes me suspect of every article from the 80’s to present, and now I question every RUclips video with the high hp claims.
This is not the first time I’ve question magazine article.
When you hear stories from engine builders that articles are based on who supplied parts or who they want editors to say have more power.
It’s all the same.
Everyone has been preaching that you can make so much power with the stock LS with just a cam change. These dyno tests prove that stock bore and stroke engines with stock heads are not making the big power. You are not making the big power without stroke cranks and after market heads.
Now BTR is testing the new LT1 and LT4 direct injection engines, they claim really high power numbers with just a cam change. But can you really trust those numbers?
Theres a test that Holdner did a while back called. Stroker LS Cam Swaps: When is Bigger Not Better? That shows a 240 and a 246 cam and there was almost no power gain and lost tq. That was a 408 with AFR 245cc heads, I think this engine is the same deal, I dont think the tighter LSA was able to help if it was going too because I think that the duration went past the point of diminishing returns on size. If the intake duration was more in the 238-242 range, I think it might have helped, even if the exhaust split was sorta tight 2 to 4 extra degrees duration split, .600"-.625" lift on both sides with a 106-108 LSA I suspect it would have ran better as long as the ICL was set to the point it produced cylinder pressure close to what the smaller TSP cam has.
The design of the Gen III and IV heads can achieve very high volumetric efficiency, if the setup can support it. The 108 lobe separation angle sacrifices some VE in comparison to a wider lsa. That shows in the power curve. I tried looking at the dyno sheet, did you track VE?
His air hat has issues with accuracy, so probably not.
Morning E. Love the camshaft stuff.
I have Greg Good ls7 heads and Erik Koenig spec the cam and valve train on mine after much research. The cam specs from guys like Erik and likely how you spec them as well Eric are polar opposite from what someone like David Vizard would say (yes I looked heavily into that as well). The conclusion I came to is if you want a strong street car you could probably use David’s advise, but the guys making 700/800/900 wheel are running cams specd completely different from what the internet says and what David says. No disrespect at all, I think he is a genius and watch a lot of his stuff, but the cam stuff just doesn’t seem to work in the high na power Ls world.
I know that the racing side people dont care about the emissions part but it would be helpful for the street guys to know how lsa affects that part, thanks for any advice/knowledge you could bestow on the average person
This test isn't apples to apples, but it is close. I think this engine with this displacement and valve size needs a 106. Not a 108. I'd be curious what a single pattern cam would do in this engine. What's the DCR?
I'm the best I've ever been. Lol
Thank you for what you do! 😊
You makin me wanna start puttin up vids on my channel again! Im a cylinder head guy as well, also engine builder, but i love cylinder heads and cams. I could talk with anyone on these subjects. But you are correct everyone is a cam expert, lol
Also, I'm gonna sub I've been seeing you a while. But what S&G machine do you have or use?
I had a Rottler’s sg7 I now have a Robbins sg8. Both are good but the robins is better.
For that carb'd 408, I wish I could send you the Summit Single Plane 240/252 .569/.569 106lsa cam I would probably want to run it with 1.8 or 1.85 rockers to get the lift at the valve up to .604/.604 or .620/.620 and I kind of do wish the exhaust duration was lower but, it's only like a $300 cam. If I could have one made for a 408, like the one I want to build with an old LQ4 block I have for my '04 GTO T-56 with either ported, milled down 241s or 823s I would probably have it made with like 238/242 .595/.595 106 that way if I wanted to run 1.8 rockers it would effectively become 242/246 .630/.630 106 at the valve or I could try 1.8 on either the intake or exhaust separately, I doubt I would want too but, I could always try 1.85s and have effectively 244/248 .646/.646 106. I think that with the right quench, 11.0-12.0:1 compression, the right cam timing, the right intake, possibly a high rise single plane with a big carb or Holley Sniper, a cam like that could really shine, might have to run E85 if I make the cylinder pressure too spicy but, I would imagine that with a set of heads that can manage at least 300cfm on the intake at .600-.650 lift it should be a very torquey, punchy, responsive engine that makes an easy 600-625hp at 6700-7000. I am tempted to run a scienced out souped up 800cfm Qjet on it just to replicate that old school Pontiac V8 induction sound since a newer GTO is stuck with an LS. I would imagine that if it is tuned well I might manage decent fuel economy too on the front barrels of that Qjet.
You have to test to know, when the 502 crate engine came out two bracket racer guys used it in similar cars one guy used a strip dominator one guy used a dart intake they traded intakes and both cars lost a tenth
The LS3 style heads with a huge split in valve sizes needs the exhaust duration more than conventional heads.