393 Windsor Build Part 8 Picking a Camshaft Part II Dyno Graph of F4TE, HO, Trick Flow and E303
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- Опубликовано: 10 май 2023
- Picking a camshaft is one of the most important and one of the more confusing parts of an engine build. The attributes of a camshaft have more effect on the performance of a motor than any other part. In this video I begin looking at cam specs and discuss my thought process as I picked a cam for this build. I also used Desktop Dyno the graph pout the 4 camshafts in the running and compared them.
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The video has a very good & easy to follow presentation. Most of us enthusiasts / hobbyists can enjoy videos like this, because we may be building or planning engine/car builds similar as such...That being said - the only thing I would have considered in the camshaft timing, would have been to entertained more exhaust duration. This is due to the fact that a SBF head has a weak design(to small & to low of a floor). The revised design of your Thumper head exhaust port may help, however the increase in cubic inches suggests more exhaust scavenging could be a plus benefit. Tri-Y 1.5" primary headers will also help with the given weight of the vehicle & desired operating range...Lets not forget that this is a DRIVER - not a race car...I just built a 302 engine for a 1965 Mustang 2+2 - with a similar Lunati hydraulic roller cam & its a BLAST to drive!! Its like driving two different cars. Down low at 1300-1500 RPM w/ a 5spd & 3.40 gears, very smooth & well behaved...Jump on it with the double pumper carb - and it lights up the car with a very satisfying rush of acceleration! That was the goal...I'm sure that you have the same objective in mind...So enjoy it!!
That is fantastic information and lots of good things to consider. The biggest problem I had was finding something ready made for a roller block. There were tons of retrofit cams, and there were tons of flat tappet cams, but when I went to an OEM roller cam that was not retrofit there were only about 10 or so non stock grinds to choose from. A better option would have been a custom grind but I found the trick flow cam was close enough. The Howard's cam I was originally looking at did have a little more exhaust duration and I probably should have done that, but I didn't want to wait for it when the trick flow was "close enough". Glad you liked my video and thank you so much for the insightful comment!
Glad you explained that a wider LSA dont mean you sacrifice HP. If you watch Engine Masters they have tested multiple cams with just a change in LSA and have proven a wider LSA can produce more HP in the upper RPM range but it takes the right duration to do it.
yep. people talk about LSA and duration as individual specs but they are totally related
@@dazecars Absolutely. I learned a ton on Grumpy's Performance web pages. Another thing most people dont understand is the how the ramp angle effects valve train. I have seen test of Race cams VS Street cams VS the new soft ramps and its unbelievable what the spring goes through at RPM.
I received an email saying you made a post on my new video but when I went to respond to it your comment was gone.
@@dazecars Huh, thats weird. I commentated on your EFI & intake selection.
@@440cubicinch I could see that it was on the new video but It was no longer there for me to reply to, thanks for reposting.
1- Camshafts are about maximizing cylinder filling (air/fuel volume)
2- each engine configuration is different. (Intake runners on a 351w are longer than a 302. Some exh ports don't flow as well etc etc)
3- LSA is the first spec in selecting a cam to maximize cylinder filling and overall engine output.
4- Overlap is the second spec to determine where you want the engine peaks to be.
5- Duration is the "byproduct" of the first two selections. It is the result of choosing the first two specs correctly.
6- Lift, tied to Duration, is related to valve speed, ramp rate, etc. Higher ratio rockers are effective moreso because they lift to a higher point faster, not so much because they increase total lift.
Then there are other factors that must be taken into account too like idle with A/C, brake power booster, static compression/cranking psi, etc.
If you select accordingly you will have driveability you desire while your engine maximizes it's output potential. Intake charge that never makes it into the cylinder, gets bled out the exhaust, or results in detonation is all a fail.
This is why pros get paid to spec a cam for you. If you don't know what you're doing it's worth it to pay to get the most output for your money. My two cents. Cheers ~
Thanks for the lengthy and well thought out response. Everything you have said is correct, with one exception, using this software like I do in this video is much like asking the experts BUT you have the freedom to compare camshafts across different makers. Each "expert" is only going to provide a selection for the the company they work for. You can't get dyno200 anymore but the latest version of the software, dyno5, can be purchased and used to eliminate the "cam expert" In fact the virtual dyno is better because you can put in head flow numbers. The cam expert isn't even going to look at that. I would much rather have the tools to make my own choices than to trust that the guy on the phone really knows what he is doing and has all the info he needs to make the correct decision.
ruclips.net/video/rML9EJEe3dY/видео.htmlsi=ElFeSNLZLJl0aSnV
@@dazecars My comment was a general statement for all, not directed at you. While I agree there is some help from using simulation software, there are unforeseen variables too.... For example, one head may flow 300cfm, and another 270cfm. By flow input alone, the "superior" head will make more power on a simulator. But what we've experienced in real life Dyno sessions is not always the case. Often, far too often, we are where a block is capable of using every bit of a "300cfm head", but will make better overall and better peak power with the "inferior" 270cfm head. Why do these anomalies occur? Because sometimes one cam and supporting combo favors the "lessor" head. Sometimes the lessor head does a better job of swirl and tumble with the air/fuel it provides the cylinder, better dispersing the charge in the cylinder. Sometimes the "restrictive" head had a better chamber design, and better quench areas.
I'm just saying there are many factors, and most OTS cams work well and "good enough" for most people. You put a combo together and wow, it makes 400hp/tq to the tires. Well.... What if a different grind cam made 440 to the tires, in the same RPM spread, making noticeable improvements everywhere across that spread? Wouldn't that be worth $100 to ya?
I'm not saying every "pro" is a pro.... But those that are, truly know their stuff, and earn every dollar they make doing what they do. Cam company xyz is probably going to hand you cam with 112° LSA for a 393w, because it'll "idle better".... Rather than toning down the overlap and duration.
If a cam has 100° of LSA and only 10° of overlap.... How exactly does that kill your idle vacuum? Excessive overlap kills idle... Not the LSA.
If you have 120° LSA and 100° of overlap, I guarantee your idle is going to suck!
I guess ultimately people misunderstand much about cams. The LSA is getting the exhaust to draw on the intake port at the right time relative to how columns of air move in a given combo.... with all factors varying that. For example, a 2.08 valve will require less LSA (higher number) than a 1.94 valve will. 12:1 less than 10:1, etc. Many factors in optimizing a choice of valve event timing.
@@dazecars PS - I'm sorry I don't know your combo of parts, but I know a 393w is big block cubes and can use big block sized heads and big block cam specs and still be very stout down low and make a broad curve. I think you'll find that small TFS cam is going to leave a lot of potential on the table and you might have to retard it some for cylinder pressure/detonation depending on your heads/intake?
Let me know how it goes. Cheers ~
once again fantastic info and I do apprecite the coment@@richdouche8253
The intake is a work in progress (see some of my other videos in the series) as to the heads its flotek thumper. I agree that given the limitations of the 302 designed parts now at 393 cubes a bigger cam would be in order for max power but I am not going for max power. This engine is being built for 1500 to 5000 RPMs so it should flow enough.. I'm hoping. all in all I'm after lots of low end torque and a generally mild build thats why the 393 and the flotek cam. Thanks again for the input @@richdouche8253
I have the trickflow stage 1 cam for my roller 351w, I want to upgrade but I’m not sure what fits with my sbe and old trickflow 170s. Cam would have to be bought and installed to even check ptv clearance.
I would think you could measure PTV and calaculate exactly how much lift you could have.
What happened to video number 9?.
its "EFI 3 options" I quit numbering at that point