Porting fast with stock ls1?

[LS1TOY]

I have a 2003 holden ute with a 346cui LS1, its internals are stock inc cam etc, its got a fast 90/90 setup on it will it make any gains anywhere if the manifold is ported? i dont care about cost vs gain, i need every bit of grunt i can get. thanks currently runs 118-119mph.
Jake,

[INMY01TA]

My guess maybe like 10hp. You know you could have got a whole cam kit for the same $$ and got alot more hp.

[kev70ss]

I would spend the money elsewhere, that is a big manifold for your engine being stock. IMO porting it without heads and a cam would be overkill

[LS1TOY]

Thanks for the replies but cost is not a factor, i am trying to go as fast as possible with stock internals and not Forced induction. the goal is 11.3 at around 122mph to beat a mate of mines time. So even 3hp is a gain as the class has a weight limit of 1400kg.
Jake,

[Mr. Luos]

Very little power to be gained.

As I understand it...a stock 90mm FAST flows 285cfm or so. Ported FAST will flow 295cfm.
Stock LS1 heads won't really outflow the ported FAST.

[LS1TOY]

so i wont lose power but maybe gain a tiny bit?
Jake,

[Mr. Luos]

so i wont lose power but maybe gain a tiny bit?
Jake,
That would be my best guess.

Maybe a slight power loss in the low, low RPM range.

[LS1TOY]

Thats cool, thanks for that.
Jake,

[mark21742]

That would be my best guess.

Maybe a slight power loss in the low, low RPM range.

I don't know what class restrictions he is limited to but how about porting and polishing his stock heads. with the stock cam would that help or hurt him?

[Mr. Luos]

I don't know what class restrictions he is limited to but how about porting and polishing his stock heads. with the stock cam would that help or hurt him?
It would help...but that is also quite a bit more work.

Depends on what he wants to get into I guess.

[LS1TOY]

heads need to remain as they left the factory.
Jake,

[Midnight02]

If you're looking to stick with stock internals, there isn't much of a benefit to come from porting the FAST. Are there any other bolt-ons that you could pick up? Underdrive pulley, electric water pump, etc? If you're at 119mph with stock internals, it sounds like you're already squeezing out about all you're going to get with bolt-ons.

How's your suspension setup? Might be able to squeeze more out of it by running a better tire for traction, better suspension setup (if traction is an issue) or better gear or stall (if your car is an A4) for your powerband.

[LS1TOY]

If you're looking to stick with stock internals, there isn't much of a benefit to come from porting the FAST. Are there any other bolt-ons that you could pick up? Underdrive pulley, electric water pump, etc? If you're at 119mph with stock internals, it sounds like you're already squeezing out about all you're going to get with bolt-ons.

How's your suspension setup? Might be able to squeeze more out of it by running a better tire for traction, better suspension setup (if traction is an issue) or better gear or stall (if your car is an A4) for your powerband.

Ive done or am doing every bolt-on allowed, if there is even 2 hp to be gained by porting the manifold, it will be done. suspension setup is about as good as it will get. the target is about 122mph which has been done in my class, i ran 119 with a bit of excess weight and 3.9 gears so 4.11's with a spool are going in. just seeing how far we can go with boltons prior to the next step. thanks.
Jake,

[squee]

I wonder what kind of differences you would see with a ported 92/92 instead of 90/90 since you want absolutely every bit of power possible with the stock internals? What all have you done?

[tonyjnjz]

what kind of gains could i see from a 90/90 fast set up??? my stock manifold was ported by lpe and i still have stock exhaust manifolds...ive seen some huge numbers on here with a 90/90 set up......bolt on only car in for sale section with a 90/90 set up pushing 383 rwhp...im only at 400 with my 383...and there was that car that put down 500 rwhp at stock cubes and no power adders..he had a 90/90 set up........im really wondering what long tubes PLUS a 90/90 would give me

[squee]

I'd say if you went with something like Kooks 1 7/8th with something like the Bassani TD setup and a Fast 92/92 would probably net around 450 or more. Of course it all depends. I've seen the Bassani alone net 15hp more than the Borla adjustable at the rear wheels.

[mark21742]

ls1toy are you allowed to do any weight reduction? the less weight you have to push down the track the less power you need to go faster. seats, carpet, extra brackets, tow hitch mount, spare tire and jack, a couple of pounds here and there can really add up

[LS1TOY]

We are allowed to get down to 1400kg not including driver. i think i have a bit more weight to pull out before the next run. i might try and borrow a ported manifold and see if the dyno shows any differences.
Jake,