anyone know or have experience as to about how much power can be made through the stock manifold before needing to upgrade to something better?

 

definitely won't exceed what your irons will handle so I wouldn't worry about unless you upgrade to s5 irons...

 

don't bet on it... i was more than impressed with the port flow on another car i built which was still raking in power at 9k RPMs@17psi@450WHP where i had to shut it down due to electronic limitations(on this engine i beveled the bridge as close as i could to the water jacket, even destroyed one iron in the process). there's only minimal difference between S4 and S5 irons at the port opening(LIM side), maybe 1mm larger which the S4 ports were already opened up that much more during cleanup, the intake manifolds are just only slightly smaller on the S4 which can only be extrude honed out or logically swap to an FD UIM and modify either the stock LIM or fabricate the FD LIM to fit the S4 block. none of which is realistic until you start pushing around 600WHP.

there really is no limit though but it will be a bottleneck after about 500WHP where switching to an FD UIM/TB will help. in n/a's it is more critical as it will halt your progress completely, in forced induction applications it just limits power exponentially after a certain amount of air is trying to be forced through it. with a big enough turbo for example even the S4 intake can handle 1000HP but a tuned intake with larger runners could probably do 25-30% more.

you can find an S5 LIM/UIM, it will help a little and can be found cheap and port match them, since that doesn't require much effort. but in the end it will probably only net maybe 1-2% hp. so i guess the question is is 5-10whp worth a couple hundred bucks for the work parts and effort finding the S5 UIM/LIM or a couple hundred more for the FD UIM to double that figure? i'm not sure.

 

upgrading(replacing) the manifold can be benefial on anything over 300. but 450+ can, and has, been made on the stockers. this is one of those things that don't really have a limit. like stock ports.... you can street port/bridge port for more power, but you can leave them alone and still throw down plenty. infact, this a moot question all togather if you think about it.

 

how much power were you thinking, or is this just a trivia question?

 

Hijack alert!

FD manifold and throttle body, is this doable on an S4 or 5? I think for FMIC, the S4 and S5 go like a snake before the original IC, so a FMIC would slow the air down even more.

 

with his current setup it is good for about 500WHP before the hybrid gives up, then onto a bigger turbo.

since he doesn't like to give specifics it is a full bridge S4 running 9.4:1 CR rotors, undivided tubular exhaust manifold with stage 4.5 BNR hybrid turbo, 3" full open exhaust, microtech LT8, overdriven modified supra TT pump and progressive methanol/water injection.

the FD UIM can fit with either a bit of modification or an adapter plate, which iirc japan2la sells for about a buck fitty.

 

hahahahah why you say i dont like giving my specs?
answer your phone fool!!!
or call me!
and yes i will go with a much bigger turbo but was just wondering if that manifold is gonna hurt me if i go to 600whp or a little above that

 

oh and its a Microtech lt10s not lt8, come on you should know!!

 

well the motor is getting pinned so i dont think i should have a problem there

 

oops, LT8s are more common so i forgot you had a 10.

i did call you back but you didn't pick up!

 

it never rang, i must have had bad reception so it never rang to my phone, try again fool

 

I did 386rwhp uncorrected (dynojet) on my old s4 irons and s4 manifolds

 

then changed the setup or did it pop?

 

^ changed the setup. I decided to tear it down for inspection after a detonation event. All seals were intact but I used the opportunity to switch to s5 irons and manifolds, as well as enlarge the exhaust ports further.

 

nice, good luck with the new setup.
are you going for bigger power now?