Yellow Bullet Forums banner

1 - 20 of 49 Posts

·
Registered
Joined
·
180 Posts
Discussion Starter #1
Looking for dyno Graphs of cars with a stock style intake Fast 90 92 102 you get the point making powe past 7000 Rpm. And any info on if it really can or has been done?
 

·
Registered
Joined
·
49,465 Posts
Theres a reason it sounds like crickets in this thread.
 

·
Registered
Joined
·
110 Posts
like I said bud you aren't going to find many...I am sure a 102 would put me a hair higher...

6750 rpms 239/243 lsl 110+3, a4, ported fast 92

I think the only way to get there would be a larger cam, solid roller setup, ported fast 102 will help...and even then probably only 7000...

you need a sheetmetal or Vic intake to let her breathe but needs a good cam to match with a tighter lsa
 

·
Registered
Joined
·
3,049 Posts
Ive done some stuff with FAST manifolds that peaked 6600-6900 range, and carried to 7500 give or take a couple hundred. But forcing the manifold to run upstairs where it aint happy isnt good either. Dyno graphs on our dyno, but that thing is whacked right now
 

·
Registered
Joined
·
3,049 Posts
like I said bud you aren't going to find many...I am sure a 102 would put me a hair higher...

6750 rpms 239/243 lsl 110+3, a4, ported fast 92

I think the only way to get there would be a larger cam, solid roller setup, ported fast 102 will help...and even then probably only 7000...

you need a sheetmetal or Vic intake to let her breathe but needs a good cam to match with a tighter lsa
A 370 inch or smaller engine can peak a good bit higher with those manifolds, hair over 7 some of the setups weve done, but the bigger stuff wont peak all that high, but can still be happy turning some RPM. Some 400+ inch stuff weve done peak at 6600 say, but isnt laying down hard enough to shift it until 7500. Just cuts the tip of the curve off so to speak

Alot of time what people see is valvestrain instability on top of manifold quitting, alot of the new flavor of the week cam lobes are the culprit, might be good with <6500 stuff and light valvetrains, but 7000+ stability comes first before valve accel to me
Valvetrain stability has a lot to do with it as well as the manifold.
 

·
Registered
Joined
·
110 Posts
A 370 inch or smaller engine can peak a good bit higher with those manifolds, hair over 7 some of the setups weve done, but the bigger stuff wont peak all that high, but can still be happy turning some RPM. Some 400+ inch stuff weve done peak at 6600 say, but isnt laying down hard enough to shift it until 7500. Just cuts the tip of the curve off so to speak

Alot of time what people see is valvestrain instability on top of manifold quitting, alot of the new flavor of the week cam lobes are the culprit, might be good with <6500 stuff and light valvetrains, but 7000+ stability comes first before valve accel to me
Valvetrain stability has a lot to do with it as well as the manifold.
yeah I definitely agree if you have a built, lightened bottom end with well controlled valvetrain, it will carry higher and hold longer...

rob should have said "stock bottom end" 346 that makes peak power over 7k

I haven't seen many that have is all...I am sure there might be a few...some have guessed they would be over 7k but actually peak at 6700ish
 

·
Registered
Joined
·
180 Posts
Discussion Starter #12
A 370 inch or smaller engine can peak a good bit higher with those manifolds, hair over 7 some of the setups weve done, but the bigger stuff wont peak all that high, but can still be happy turning some RPM. Some 400+ inch stuff weve done peak at 6600 say, but isnt laying down hard enough to shift it until 7500. Just cuts the tip of the curve off so to speak

Alot of time what people see is valvestrain instability on top of manifold quitting, alot of the new flavor of the week cam lobes are the culprit, might be good with <6500 stuff and light valvetrains, but 7000+ stability comes first before valve accel to me
Valvetrain stability has a lot to do with it as well as the manifold.
At max i will be spinning to 7400rpm in good air on a stock 346 thats max. Me and Geoff talked and the cam should peak 7200 to 7300. Geoff said he setup the cam for stock style intake so i just want to see if its worth it to run the fast or upgrade.
 

·
LSXTTFMF
Joined
·
927 Posts
The only way I can see it carrying up any higher is to increase the section width of the current intake runner to effectively tune the resonant frequency higher or shorten the runner up some. I could see you going with a Fast102 and finding a happy medium between a fast and a carb style by slightly shortening the runners a hair.

My ported 90 fell off pretty good at 6500 on my 403 with a cam that was more geared for 7500rpm. Valvetrain was stable as well.
 

·
Registered
Joined
·
180 Posts
Discussion Starter #17
The only way I can see it carrying up any higher is to increase the section width of the current intake runner to effectively tune the resonant frequency higher or shorten the runner up some. I could see you going with a Fast102 and finding a happy medium between a fast and a carb style by slightly shortening the runners a hair.
Yes i have read about this but about how much is needed to be cut out of the runner you think?
 

·
LSXTTFMF
Joined
·
927 Posts
It takes alot of trial and error. I've never done it personally but if I was in your situation I would pull the intake off and cut a little out at a time and put it on the dyno to see the results. It 'should' bump the power curve up slightly each time. I don't have the resources for such testing so I just went carb intake on my personal setup with a much better cam from Geoff and it picked up from 10.7 to 10.3
 

·
Registered
Joined
·
1,134 Posts
We have some that peak at 7000 or so and pull to 7500 rpm. Larger cam 347s. They just flat line to 7500 or so.

Our 445 still pulled to 7500 with a FAST 92 and a 96mm TB and went low mid nines in the 14x mph range.

Of course the SV will go another 1000 rpm higher and pick up a lot. The fast usually peaks at most in the upper 6XXX area in general.
 

·
Registered
Joined
·
715 Posts
We did a lot of back to back testing on porting a Fast 92 starting with simple stuff like port matching and light work, all the way up to putting epoxy on the outside of the upper shell to increase cross section, and shortening the runners. The testing was done on the TFS 440 on the engine dyno. The simple stuff worked well, the additional work decreased the torque and never raised the horsepower.

If this type of work hurt the torque on a 440, I wouldn't even attempt to do that on a LS1.
 
1 - 20 of 49 Posts
Top