Carb Swap, Race Prep and talkin about the Launch 🚀 1968 Dodge Dart drag car
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- Опубликовано: 1 окт 2024
- You just can beat a Holley 750 double pumper. I swap out my Holley 950 xp and go back to my classic Holley 750. A quick oil change and opening g the oil filter for inspection and we talk about last race and launch issues.
Sometimes it seems the new generation of carbs are more marketing than engineering. The vintage double pumpers are hard to beat!
I agree theres nothing like rejetting a quadrajet carb if you need more fuel put two quads and the throttle response is accurate
You said it best!
How much air pressure in the slicks?
Have you tightened the shocks up, both front and rear aren't controlling the suspension. Need stiffer extension on all 4 shocks.
joey- if you don’t have 90/10 shocks in the front . get them and set to easiest extension, hardest compression. i think you have ranchos on the back ? set 2-3 clucks back from stiffest. cal trac front end link in the lower hole and try some preload. 1/2 turn, then increase. first work on traction without using the Tbrake. launch from just above idle, about 1,000 rpm and WHACK the throttle on the bottom bulb. that will flash the converter . if it hooks, you’ll get some daylight under the tires. you need to watch your launch in slow motion again. it’s most certainly not compressing and then launching. it’s going to full extension. front & rear, then unloading the tires causing spin, then settling and trying to hook.
I agree the rear shock extension is too loose.
I'd fill it up with new oil and filter. Next time you make a few runs, I'd be dropping the oil again and inspect for debris for sure.
The reason the car is bouncing is because the shocks are probably extended to the max. I use a 1050 dominator. But i only footbrake at 2500. My dart is 3100 lb and 4.10s. It 60 ft 1.26 on a average. Definitely drop the stall down about 3400.
Is that on a small block or big block?
@@ArthurSperotto a stock 360 block stroke to 414 cubic inches. Small block
AWSOME CONTENT AWSOME cars MAHALO from HONOLULU MANOA VALLEY
With covid. Im finding many quality control aspects being over looked. Suppliers are rushing everything and skipping quality
I'm a biker guy, but the bottom line is, CARBS SUCK. The best thing I've ever done was switch over to EFI. Just go with a late technology crate and be done with it.....lol
I ran Sharpe roller rockers on my 340 Super Stock and those damn rockers were always shedding tiny flakes. Never effected the bearings. Always in the filter.
I ran a dual carb setup on a 406 sbf, two 600 holleys. We didn't have the electronics back then so it was tune by sound, plugs, smell. Third time changing due to day into evening I said to hell with this. Back on with the tried and true 750, spark work, and actually ran 0.07 faster the next day.
After commenting on the last vid about climbing your sidewalls to quickly it dawned on me you said you were leaving on your torque converter. Your eating the R's to your converter should allow you to walk up your sidewalls instead of climbing them doing the dbl loading.
Bigger isn't always better. That's what she said!😂 Seriously that carb is probably too big for your dual purpose motor street/strip combo. Dyno tuning only gets you so far. The time slips don't lie. Keep up the great videos and you'll get it figured out.
Can’t beat a tried and true carb, nothing wrong with going back to what you know. I suspect we’ll see the 950 again soon!
I had a holley 700 double pumper on my old 69 gts worked well but it was a stock 383 magnum not really anything special other than now it is and wish I still had the car.
My bronze distributor gear in my big block Chrysler sheds material constantly which is annoying but it would be brass particles
750 double pumper is old school very reliable used across the spectrum of mopars, chevys and fords...looks great on that cool port matched manifold...you can use some Moroso high temp wrap on those headers to keep your tranny cooler...
You think Holly carburetors after being in business for 50 60 70 years would have it figured out by now but they never seem to be quite right no matter what
I don't know about the small block but my big block loved the tunnel ram with two 4-barrels. Initially I ran two Holley 450's and later ran two 660 center squirters and they ran about the same. But several times I tried different single plane intake manifolds, and different carburetors, 750 DP, 800 DP, 850 DP but nothing came close to the tunnel ram! You should give one a try, at least in my opinion. Anyways, absolutely gorgeous car! I sure miss mine every time I see your videos! Thanks for sharing and best of luck with it! I hope you and yours have a great holiday season, man!
I think you will get better response from the 750
Dont need to back down on launch power you need to fix you suspension. All your doing is slowing the car down to mask other issues
Are You using the same ignition kit on the car that You used on the dyno ?
Got a AED 850 on my 408 and love that carb
Looking good! I’d bet that you’re probably gonna end up with the 750 on the car permanently.
I was using larger carburetors on a brand X 468 big block I have and eventually ended up with a QuickFuel SQ 750 mechanical secondary. It’s a fantastic carburetor even on the bigger cubes.
At 3,900 pounds the car has run 11.8’s on pump gas. That alone speaks for the carburetor.
Best of luck, I’ll be waiting for the next video 😉👍
Usually a sign that a carb might be too big if it takes really big jetting to get the afr right. My brother's big block 468 ran 1/2 second faster with a 750 dp compared to a 1050 dominator. It's hard to beat a well tuned 750 for sure. I'd say it's normal to have a little metal in the oil on a brand new engine.. still breaking in. Do you have a pinion snubber on the rear end? That could make the rear of the car jump up on launch. I know a lot of Mopars had them.
Yes for sure, over carbing is often an issue. The correct air flow velocity through the carb is critical for proper atomization so that fuel does not fall out of suspension. Sometimes less is more, especially on a street/strip combo.
Full cal track set up
Y’all ant wrong for sure. They were big droplets of fuel when you would hold it open. Small carb better atomization is very true
Need a thumper carb.
I love mopar i have an old school 426 industrial hemi im try to work on them are the rarest mopar engines their is it litterally has industrial on the heads in huge letters factory tunnel ram etc this is a bad boy
850 DP annular discharge boosters. Best carb ever.
slow down the rear shock. The tire is unloading. Lowering the launch RPM will hit the tire harder because you are allowing the converters stored energy to make a run at the tire.
Sounds good but your back up lights don't work
Have you mounted your windscreen fluid reservoir under the dash?
No. Deleted it.
Super nice car bro I've always been a chevy guy but i did a full resto on a 69 barracuda and 66 dart GT convertible and submersed myself in mopar history while doing so cuz i love all classic cars and the history. Good shit
Sounds sweet! 👍🏻👍🏻👍🏻
What about a FI tech throttle body?
Ya sure Ill try it. Send one.
If I had to make a wild guess you probably have to much emulsion on the xp.
if your wanting to tune yourself it's cheaper to buy a box of 6/32 brass set screws and a pin drill set and then you can make your own pvcr, ifr, and e- bleeds to tune the metering blocks then just buy air bleed kits close to what the xp has in it to tune those aswell
Like I said before you have to let it flash give it room !!!! My 8 inch was 5200 rpm with a 6300 flash !!! I left @ 3000 rpm and it launched !!!! Low 1.40 - 60 fts. !! A stock converter works best at idle ! You ft brake it and raise the rpm at all it falls on its face !!! You MUST have room for the stall flash !!!! Carb sounds too small !!!! Try a progressive carb with multi stages of flow !! I had a BG stage 3 750 that flowed 1040 CFM at the top end !! Crisp off the bottom along with flow for top end !! When that car is right it probably could be a 10.90 car in the quarter !!!! A custom converter the only way to go or will keep chasing that proverbial tail !!! Been there done that !!!! Proper combination is EVERYTHING !!!! I was a private consultant for years just helping guys understand it's not about big it's about the RIGHT combo !!!!! Your close but still off !!! I would LOVE to know your engine specs gears car weight whose converter !!! Love to help if I could !!!
A way to explain this is: Take a bull and put his chest against a split rail fence, then shoot him in the ass with a pellet gun. He will just bump the fence and lay down. Stand him 3 feet from the fence and shoot him in the ass, and he'll make toothpicks from that fence wood!! lol
Yes goin to flash converter and it’s a custom. Yes whole combo had to work together and yes 750 is small but need something that works right now.
@@SimpsonsSpeedShop what company is the converter from ??? Torqueflight ??? Coil suspension ??? Ladder bars ??? Just my 2 cents I like details !
@@circletrack7538 all details on are the channel. Local custom converter, 727, full cal track suspension with there shocks.
He needs a J turbo action opel style converter & a 800hp!
I think I'd only use the air/fuel meter for reference. Try reading the plugs, too. Remember center porcelain for mixture, ground strap for timing.
I would add a secondary idle speed bracket, then you don't need to open the primary side too much, exposing too much transfer slot. I put them on every double pumper I set up.
Honestly, sell that 950XP. It will never be exactly right. If you recall, I mentioned I had helped someone set one up, but it still wasn't quite right. And that was on a 650 hp 496.
How many filters does this make? Thats piston & rings! All you need is a hp center section for your 750 & make a 800 out of it wt bleeds! Better get one while you can though! They are wanderful & cheap! One dude maybe right about stiffening the shocks up 50/50 on rear & 75/25 on front! Or just the rear first! The break in material will clear up after 500 miles
Do you think possibly you need to adjust the air pressure in the slicks?
Had at 10 if you watch the slow mo it crushes the tire and it looks good, I could go down to like 8 tho
@@SimpsonsSpeedShop I was thinking more pressure. This is a little blurb on tire pressure. Just throwing out suggestions. Wheel spin loses races, and if you have too much air pressure, your tires can’t react (wrinkle), and your tires will encounter what is called initial spin. Initial spin is when the tires spin almost immediately when you are trying to launch the car. Another type of spin is called reaction spin. Reaction spin usually occurs when the tire is underinflated. What happens is the underinflated tire reacts (wrinkles), but the lack of proper air pressure allows it to overreact, and that force releases itself with a suspension-overcoming force. In other words, it initially hooks, but then bounces as they unload.
Agreed, I would try more pressure. I was having traction issues years ago. I was advised to increase the pressure in my slicks by an older gentleman at the track. My Duster immediately responded well to the increased air pressure. I have been running 18 psi since and it consistently goes 1.56-1.58 in the 60 foot.
Converter is too big.....Not enough gear or motor.
i had one of those Xp950 on my 408 when they came out, these new 950 XP are much larger than the older 950's. The throttle bore sizes are much closer to a 1050. I did all the tuning possible and it was able to improve it, but was still a slug out of the hole. Properly sized carb woke it right up. ✌
i would hold off on 850 until all else is ready, converter Launch Suspension tweaks, shifting "at ease" besides 750 or 850 might be quicker without taller spacer...and there are squirter sizing for the launch. you tuning the car will make interesting theory vs reality stories to come. best of luck
Exactly correct get everything else in line before you start the real tuning of the engine because sometimes you will end up going back and forth with it all then get all messed up and lost.
Watching your launch. Doesn't really seem there's enough transfer of weight. Have u considered a softer rear spring and or softer shocks all around?
Car has a full cal track set up in clouding mono leafs amd adjust shocks played with it on race day not much difference with shock adjustment
@@SimpsonsSpeedShop Go to 1:17.
ruclips.net/video/R1jKotYw06E/видео.html
@@SimpsonsSpeedShop You need to slow the extension down or change the fulcrum on the caltrac bar. Its hitting the tire too hard and causing it to bounce. Also lowering the nose of the car will gain front end travel.This will allow the rear tire to hook a little harder because when the front tire tries to leave the ground it puts a tremendous strain on the rear tire.
I’d check with your local speed shop to see if they offer oil analysis. If not your local Caterpillar tractor dealership certainly does! It will tell you exactly what that is and how much of it there is!
The big chunks that you can see don’t tell the whole story.
Ya I don’t have access to ether of those.
Cut a section of your foyer material out and squeeze it in your vice to remove most of the oil then inspect the pleat, it will give you way more information than looking in the bottom of the filter can.
Filter not foyer, fen auto correct!
At first, I was going to applaud your cutting the filter apart, but I was disappointed you kinda half-assed it. I thought you were going to inspect the oil filter? You never examined, on camera anyway, the filter element media. You need to check the pleats in the filter media, too.
I'm a firm believer in spin-on oil filter magnets. With a brand new engine ($$)rebuild, I'm surprised you didn't opt for filter magnets. I use FilterMags, for the convenience, but you can get some bulk neodymium strip magnets off Amazon that can function nearly as well, but they're kinda more of a hassle to use. Not that the FilterMags are troublesome at all. I've even used them on my riding mower, and the difference in the clarity of the oil at oil change is like night vs day.
Awesome Joe《☆》Good plan Brother👍Hopefully you can get the parts & take advantage of 950 CFM. I think that's break in metal👁So RockOn. Good Luck at the Track🖖😎☮
👍🏻👍🏻👍🏻
Was there any gas smell in the oil with the bigger carb?
Now I don't have the knowledge that well... anyone does. But quite awhile ago Nicks garage stated using a Thumper carb that he had received from Thumper.
Again... I know nothing but my own experience and I don't like holleys. They always seemed finicky like a Ferrari. You gotta stay on top of them. No thank you.
That being said I plan on using either a Thumper or two on a recently bought 413. Unless I can find a couple of predators. Just sayin.
And I pray the shavings aren't anything major.
You got this.
You do a bunch of work to swap from street to race, why not include swapping the carb at the track as well? We've used probably a dozen of the 950's over the past 5 years, yes they tend to be chunky on a cruise. I'm not sure why you struggled on the dyno, at least in terms of WOT, from engines as small as 302's and as large as 565's, including running Q-16 oxygenated fuel, I've never had to venture more than 5 sizes from the stock 92's, and 5 sizes on the bleeds.
If the bores weren't chamfered on the bottoms the sharp edges will shave some of the skirt material that's exposed at BDC.
Those little flakes on a new motor are normal also the oil filter believe it or not isn't the best one to use. Wix or Purolator in extensive testing worked out to be the better ones K&N isnt what it is cracked up to be. Also did you try taking off the carb spacer and checking your mixture or even try adding another spacer that can make a huge difference depending on the intake manifold and engine combo.
What is your gear ratio ? Do you know you can change your gear ratio with out changing your rear gear. Your 4.10 or 4.11 may have been perfect the car now with a lower gear and power peaks 6,000 rpm and 5,000 stall well not a lot of room to play with. Find what gear ratio they used in big mobile homes ?
Sounds bad ass. Everything today is a lesser quality by design.
I would tend to agree with a previous poster, that sometimes these new "race only" carbs are more complicated than they need to be for a stout street/strip car. Unless you have all the bleeds, jets, cams for the race only carb....your better off with an old-fashioned Holley double pumper. You seem to have a definite handle on the 750. As for the particles in the oil pan, that's something you might want to keep an eye on. Hopefully, you won't have to pull the oil pan to investigate further. Good luck on your racing season!
Im with blood sweat & gears. New oil & filter put some miles/runs on it and check again. Put a camera on oil pressure gauge? see if you have adequate pressure at the end of a run? Just spit balling.
What is the size and thread pitch on the bigger fitting right below the water neck?
Normal debris in the filter.
Looks like standard break in material in the filter, just bearings setting in
Makes sense what your trying out.working out the new combo nice
Looks good man I hope you get her all sorted out....I know you will your mopar
The motor sounds real good!
I know you will find the "sweet spot" Joey, it just takes time and testing which you are doing very well. Thank you for sharing that gorgeous Dart with us. I remember when the '68 Hemi dart came out back in the day. It made mincemeat out of everything in it's class.
Thank you Mike for watching 👍🏻
Oil didn't look too bad
I have a 850xp on my small block. it is not even close to how it left the factory. I changed the emulsion all around. it has 50cc pumps, no power valves. It works well now.
I did swap metering blocks with my 750 but it didn’t seem to change anything
@@SimpsonsSpeedShop it was a lot more to it. I followed the reconditions of mark from lightning carbs with all the changes to the metering blocks. It changed the amount and size of the emulsion jets and the high speed air blead.
@@okoko47 hmmm interesting. I have change high speeds already to get rid of the lean upper rpm problem but ya prob in them emulation jet area is prob
@@SimpsonsSpeedShop if you look up the 850 xp all the problems show up that are common with the 850 and 950 ultra xp Holley carbs.
There where a lot of posts years ago on yellow bullet trying to fix the poor booster signal they have.
Don't at all costs... listen to a Chevy or Ford guy's advice .
That’s the best advise I have ever heard lol
coming from a background of chevys, i cant agree more lol good advise is far and few between