Flashy

Well car is finally in the repair stages....so now I want to think about some Spring engine performance mods...

Car: '04 GTO 6 Speed
Current Mods:
K&N FIPK
Kooks 1 7/8" Headers And Catless Midpipes
SLP Loudmouth 2 Exhaust
HPTuners Software
Monster Stage 3 Clutch Kit/Flywheel/Tick Master
Short Throw Shifter
Texas Speed TorquerV3 Cam
Texas Speed Stage 2.5 CNC Ported LS6 Heads
Ported LS6 Oil Pump, LS7 Lifters

With that setup car put down 423whp on pump....

I'm wondering what mods you guys can recommend next for me...really want to get around 475whp..

I've heard conflicting stories...but here is what I was kind of thinking...although I'm looking for advice from people who were in my shoes in the past.

-Larger Throttle Body (Which one should I run????)
-Larger MAF (Which one????)
-Svedespeed Intake
-Larger Injectors (What size????)
-Larger Fuel Pump (Which one???)

I'm also thinking of running a 75-100hp plate system this year....so keep that in mind with the mods above so they can work together and have enough fuel.

I'd obviously get a new tune with any of these mods...feel free to add suggestions or tell me which/where I should source the above mods...

Thanks guys!

James@ShorTuning

To get up from where you are isn't gonna be easy without changing a few current mods to more a more tasteful variety. To get there you'll need:

TEA or AI ported 243/799's
Better camshaft
Fast102 ported to whichever heads above with a matching TB
Injectors to support the extra power (I recommend Bosch pencil injectors white 36lb or green 42's)

If staying NA save the money on fuel rails and pickup a set of LS2 rails.

That setup has proven time and time again to make the best power on a 346 bottom end.

I've got a porter here locally that graduated from SAM that has picked your particular type head up 30cfm with some of his tricks.

Flashy

So you are saying my PRC Stage 2.5s LS6 heads won't flow enough???? I've been told they will have no problem which is why I went with those...I know the cam wasn't very aggressive, but was looking for nice street cam.

From what I have heard the '04 GTO intake manifold is the LS6 intake manifold...

I will looks for a set of LS2 rails...can I run the LS2 injectors (are those 32 pound ones....someone local told me that...otherwise I'd look for some stock LS7 would be nice upgrade...like 40 lb/hr) and MAF as well?

I forgot I also have 1.750 Texas Speed pushrods as well....it was a complete heads/cam package from them.

James@ShorTuning

There are decent results on here but unfortuneatly of all the PRC LS6 heads I've had on my machine, they are sub par at best. The just do not compare to the AI or TEA ported castings.

A FAST intake is def a good move on whichever head you have. You could run the LS2 injectors but could potentially be pushing those to the limit as well. They do flow 33lb @ 4bar/58psi. LS3/7 injectors flow nearly the same as the older white 36lb @ 3bar I mensioned above, which is right at 41.7lb @ 58psi. They will support more than you'll ever be able to push out of an NA 346.

BrntWS6

iTrader: (7)

FAST intake for sure and more cam. No way I'd swap out those heads for another set of 243's. Big waste of time and money....go aftermarket castings if you do that.

Check Fuel injection connection for injectors and get at least 42lb, price difference isn't much over 36lb. They have rebuilt stock ones that are much cheaper.

GM 85mm MAF on E-bay for $50 all day
Racetronix fuel pump with hotwire kit
FTP lid

Flashy

Thanks!

Thanks!

Grr

iTrader: (2)

Fast 102 intake and bigger injectors
Walbro 255 pump
Polluter v.2 cam

James@ShorTuning

If your goal is 470rwhp+ you'll need to ditch the current heads and cam for what I mensioned. On my machine there hasn't been a single PRC head outperform any of the AI or TEA castings.

One setup comes to mind was some PRC 243 heads with an EPS 226/230 cam with some nice ARH LT's and stock LS6 intake this setup made 352rwhp on my dyno dynamics. The average cam only LS1 cars make between 340-350rwhp. I've just not been impressed with those heads or the AFR heads from what I've seen on my machine. There may be some really great results out there with them however I only use what is tried and true in my shop.

bene

iTrader: (16)

H/C and bolt ons putting down 350 RWHP? I would be pissed however being a dyno dynamics machine, your dyno machine (brand) is one of the stingiest or the stingiest roller known on earth. Have any of your customers with AI headed car ran against with PRC headed car, on the street or at the track? Dyno machines are just tools.

99Bluz28

iTrader: (35)

FAST intake(ported 102 or 92) and mill the heads to get the compression up, 42lb injectors, Racetronix F99 Fuel Pump Kit.

James@ShorTuning

You are exactly right! The highest 346 H/C/I car thats been on my machine is my test car which has TEA St2 heads FAST102 and one of my custom grinds which made 418rwhp. Full weight the car has been almost 124mph in the 1/4 through a 4L60E.

It's really hard to compare dyno numbers on the internet and it seems everyone is looking for a dyno number but like you said it is only a tool. I chose this machine for tuneability rather than inflated numbers. I have done some comparisons from my machine to others and the average differnece seems to be around 10% lower than a dynojet.

Flashy

Thanks for the suggestions guys....So Fast 92 or 102? I don't plan on going forced induction or stoker motor....probably a throttle body plate spray kit will be about it.

James@ShorTuning

If you want a more bolt on setup the 92 works the best because you can reuse your stock fuel rails and the injectors are setup for the stock LS1 style as well. The 102 requires LS2 rails or aftermarket rails and will need to be shimmed up for LS1 length injectors.

Power wise the 102 is superior in all respects but once the 92 is ported theres not a huge difference in power between the two.

Being a GTO I would def look into an Edelbrock Pro-flow intake as well!

Flashy

Thanks for all of your suggestions James! If I wanted to stay away from porting myself would you say the following would be ok:

FAST 102mm Intake Mani
Nick Williams 102mm TB w/ Adpater Harness
FAST Fuel Rail Kit
FAST, FIC, or RaceTronix 36-37 lb/hr injectors LS2 style
Walbro 255 Pump

I'd also like to add a Nitrous Outlet TB Plate Wet Kit and spray around 100hp shot to it.

After all of that stuff I would obviously get a tune...I don't want to mess with these heads and cam yet...but then over summer that would be next step and prolly forged bottom end just so I can spray a big shot...

MikeWS6

Its funny when you see a 224R cammed car throw down 415 then if you do a search you can find plenty in the 360hp range. You're right its just a tool.

garygnu

maybe get a fast 92 mm intake ,and a fast 92mm TB.consider a 383 stroker using your current block ,or get a 402 or bigger short block based on a ls2 block .look at 100mm MAF and a bigger lid.