Tiger Stripes

I have a stock '06 GTO A4, and my goal is 550-600 rwhp.

My dream would be to do so n/a. Can this be safely achieved with a 402ci-406ci stroker kit + cam swap + intake swap + heads swap + headers swap + etc.?

Or would the safer bet be fi(s/c or turbo?) + cam swap + intake swap + heads swap + headers swap + etc.?

I would prefer to keep my ls2.

& Money is not the issue.

Any constructive criticism about my goal would be greatly appreciated, because I'm not too sure how much my car can handle, from my research I've found that 550-600 is about the A4's limit.

Thanks!

chevyrunner

iTrader: (4)

gonna be tough to get that out of a stroker from a aluminum block 6.0 as you cant bore it out as much as a iron block.... most ive seen out of an auto stroker is 530 rwhp.... 600 probly not gonna happen.... is this going to be a daily driver still?

you can go with a big stroke like 4.125 or bigger but would not recommend this as a daily driver at all, but thats how your gonna be able to get high hp numbers

Tiger Stripes

Yes that was another concern, it will be my daily driver, at least temporarily.

chevyrunner

iTrader: (4)

yea man without nos, or a power adder i dont see it happening through an auto, keep in mind the bigger the motor, the bigger the stall your probably going to need as the bigger strokers usually run big cams that need big stalls, thus more power being eatin up through the drive train.... is 550 your goal just to have or are you going to be racing at all? a stroker with 460-500 rwhp is still making a boat load at the crank but the drive train loss eats up anywhere from 23-28%.... ive heard things about the small bore ls7 heads being a step up from ls3 stuff(which is better than cathedral port) but still, 550+ from a 6.0 i have not seen done yet n/a

newschool72

iTrader: (12)

Yea, that's a ton to ask, especially from a driver. Money will have to be thrown at the trans and the IRS, too. On street tires, 450 RWHP is a hoot and is more than enough to get you in all the trouble you can take, LOL.

Tiger Stripes

I more or less just want to see 550 rwhp on the dyno more than anything. She won't be seeing too much of the drag strip, at least until I slap a mini tube and some fatter wheels on her. Any racing will more than likely be from a roll (20mph-60mph) for now.

It is sounding like fi + everything else is my best bet? Are the ls2's happier with s/c or turbo? Or is it just preference?

Tiger Stripes

True, I know I'm asking a whoooole lot. I may end up deciding that something around 450 rwhp will make me happy. From my understanding this can be achieved without fi or a stroker kit, pretty much with just bolt ons and a sweet tune? I may be wrong.

chevyrunner

iTrader: (4)

can i ask why your wanting to keep the aluminum 6.0? for the amount of money your going to spend on either a sc/ or turbo car you can get a motor that makes 600 to the wheels n/a...

the issue i have with the aluminum blocks are that they are not as strong as iron blocks, thus in any fi set up id suggest forging everything. you can just throw a pro charger on there but how long the motor will last idk...

in regards to your question super or turbo charged id go sc just for the simple fact they have kits that are pretty much bolt on, while the same is true with turbo 9/10 your gonna end up have to custom fab a few things.... i think sc is also less of a hassle with instal/tune.... just my .02

newschool72

iTrader: (12)

A healthy cam and a quality set of heads, along with the standard bolt on goodies (headers, intake, UDP) will get you all over the 450 mark. Don't make the mistake of thinking a long duration cam is needed to get great numbers. You can run a well mapped out smaller cam and hang on to the low end torque you have now, maybe plus some, and still get the HP . Im from the school of thought that Id gladly hang on to 25 ft lbs of torque than pick up 15 HP up top. If its a DD, you will appreciate the TQ every time you leave a light. The extra HP up top only shows up on those back roads, late at night when you go for a glory run, LOL. Just my opinion.
FI would be the way to , if you want to keep the engine intact and get 450+. A nice Maggie would fit under a stock hood and run as seamless as the stocker, but roll on when you nail it. A few companies offer the Maggie in a turn key package for the GTO. I almost did that with my 05 before I sold it. FYI, through an M6 my 05 made 376RWHP with a cat delete, cheap pace setter LTs and a cold air intake, so the little LS2 makes some good steam with just more in ,more out on a stock long block. Your auto will be closer to 320ish.

UGotBeaT

Imo 550rwhp isn't out of the question n/a. A stroker kit and a nice set of aftermarket castings for a small bore along with a fast manifold and properly specced cam will get you there.

JakeFusion

iTrader: (7)

550 is still tough in a 402. LS3 based 418 is easier. LS7 based 427 is no problem.

What I would do is look at TFS 245s and a fairly large cam. 251/259 114 or so. FAST 102, 1-7/8" headers, and 12:1 CR. 550 could happen even with a high stall A4.

Other options would be to look at Chris Frank ported TFS bare castings (Frankenstein Racing). I believe someone here hit 580 with a 402 with those heads through an M6.

redtan

iTrader: (5)

A mild turbo/supercharged LS2 will make a lot more usable power than any N/A engine making the same 600rwhp. Plus an engine big enough for that kinda stuff will be more expensive than a basic FI setup.

Aluminum blocks are strong enough for upwards of 1000rwhp with forced induction, so for his needs there's no need for an iron block.

newschool72

iTrader: (12)

Id have to see it. Through an auto, stalled to the cam, 550 at the wheels is a lot. Not saying its impossible, but IDK ? I do know pretty confidently he wont do 550 NA at the wheels with something he would want to drive everyday unless driving to work is a 10 mile or less daily deal.

Unreal

Blower and headers would do it easy and drive 10x better. No need for cam or anything else.

UGotBeaT

A ls7 based casting would do it easier imo as long as its a small bore head.

chevyrunner

iTrader: (4)

450 and 550 rwhp are two completely different ball parks

newschool72

iTrader: (12)

Yea, earlier in the conversation, I made a point that 450 would be enough to get plenty of giggles, and just continued to go that direction. Big dyno #s get thrown around on the forums all the time and a lot of people don't realize that 550RWHP is a tremendous amount of power to try and control on the street. Its a numbers game to many, and noobies look in on the sites and think, yea, Id like to have xxxxxHP, but don't realize exactly what that means. Its just a number that looks impressive on paper. After 1000s of dollars are spent, they wind up with a car that's useless for anything but blowing tires off, then get their butts handed to them by someone with 375RWHP that can actually use all the power they have. Spinnin aint winnin !

lil john

6.0 block+4.0 crank,AFR or TFS Cathedral heads,ported FAST intake,11.5+ comp / Manual trans and a Cam from Greg Good you'll be pretty close how about settling for 525+rwhp.

lil john

I couldn't think of the article but it's in my file:
Look @ the people & parts

403 LS2 / AFR 205’s lays down 550+ RWHP!!
________________________________________
It was a typical late night for me working in my shop at the house when my cell phone rang just after 10 PM yesterday evening. Turns out it was a phone call from my friend George Lara, a respected tuner in the So Cal area and an all around good guy. I had been waiting for this call for a few weeks, not to mention this project originated almost 6 months ago, but isn’t that par for these types of things anyway.

Back in April I had gotten involved with a C6 project belonging to Greg Schult….seems Greg and his brother Alex are somewhat competitive and with the two of them recently purchasing C6 Corvettes, the stage was set for some power mods to up the ante. Alex went the Magnuson forced induction route and put down some respectable numbers with basically the stock C6 short (490 RWHP / 490 RWTQ thru an A4) and Greg contacted me inquiring whether we could come close or possibly beat those figures with an N/A build. Initially we had moved forward with a package designed to optimize the stock 6 litre block in his car but somewhere between the start of this project and his brother on the dyno….LOL, Greg decided to get with LME on a 403 stroker to make things more interesting. Besides spec’ing a larger cam, most of the work on my end remained the same. We used a set of 205’s that I opened up the chambers and did some light porting work to optimize their small efficient ports (like I helped Pat G. and a few others with), ported a FAST and an LS2 TB, and sent him shopping with a list of the other supporting mods in the recipe (Yella Terra rockers, EWP, lightweight clutch, etc. etc.).

I was hoping to see around 525 RWHP with 500 TQ, and felt if everything really came together there was a chance it might make a little more. BTW, with a set of 1.875 Kooks headers already installed on the car (and a CAI as well I believe), on the same Dynopack wheel dyno over at Haddad Motorsports where the tune and the install was performed, the car put down 375/375 as a baseline prior to the engine swap. Pretty much solid textbook numbers for 364 CID engine and an M6 driveline with those mods (similar to others I have seen). The baseline dyno graph is included below to compare the data and shape of both curves….

Here are the final results….



I was especially surprised and pleased at how well the TQ curve carried without the band-aid of a monster sized cam which would have obliterated the bottom end and hurt drivability, essentially getting away from the well rounded package I was shooting for. While this technically isn’t an out of the box 205, the finished port volume is within a couple of cc’s of that showing once again that “area under the curve” flow coupled with good port velocity and a well thought out combination is more powerful than most realize. Picture the throttle response this animal has with all that power and a tiny 205cc intake port….its a lethal street combination.

This car made over 550 RWHP on five consecutive back to back runs (500-503 TQ) with the best registering 558 at an A/F ration George felt was a touch aggressive (13.7-13.8 over 6K), so he fattened it up a bit to give Greg a little more hip room on the street. Down in the low 13's the car still rolled 552/500 with a much more conservative A/F across the curve.

For those interested here is the flow data from Greg’s 205 heads tested on a 4” bore (on May 2nd no less!....lol)

Intake
Lift…..CFM
.200…..151
.300…..220
.400…..266
.500…..293
.550…..302 (peaked at .575 @ 306 CFM)
.600…..301

Exhaust (w/ 1.875 pipe)

.200…..129
.300…..190
.400…..228
.500…..242
.600…..248

Note how strong the exhaust port flows after the chamber and light porting work….It’s close to 200 CFM (more than a stock head’s peak flow) by .300 and as early as .400 matches a lot of aftermarket heads average .600 number at 228 CFM. Due to this situation and the very high overall exhaust to intake ratio (82%) a single pattern cam (244/244) was obviously a good choice here and proved effective on the dyno.

A quick summary of this combination is as follows because I know a lot of you will be asking…

403 Shortblock (built by LME)
11.6 CR
AFR 205’s with reworked 4” bore chambers and some light porting in key areas
Ported FAST 90 / Ported GM LS2 TB
Custom Comp Cam 244/244 XER lobes 113 LSA
ASP Underdrive pulley
Mezeirre EWP
Kooks 1.875 headers (with Cats btw!)
QuarterMaster clutch/flywheel assembly
M6 driveline with stock rear gears (3.42)
SVO “green top” 42” injectors
Vortex Ram air CAI (85 mm)
Nology ignition wires

Thanks to LME for all their hard work on the short….Mike and crew @ Haddad Motorsports for the install and “storage”….LOL, and George Lara who put all the pieces together with a killer tune. Look for some idle clips and video footage of this combination in the near future as well as an article in one of the Vette specific Mags….

Regards,
Tony Mamo
__________________
Anything worth doing is worth doing well. Build it right the first time....its alot cheaper than building it twice!!
________________________________________
Last edited by Tony Mamo @ AFR; 10-23-2007 at 07:18 PM..

JakeFusion

iTrader: (7)

550 through an M6 is much easier than through a stalled A4. You really need to be in the 580-600rwhp range through an M6 to see 550 with an A4...

That's a beastly engine. And very hard to do with a 402.