The 500hp Gen2 Question

[Bonkers]

I know what I want, and what to expect from the dyno with it, but I figured it would be prudent to ask before starting this little project. Maybe one of you has a neater/cheaper method.

If I wanted my 99 GTS to kiss the 500-550rwhp range on the dyno what would be the best route to go? I'm looking for motor reliablity and long life, not easy numbers. Since she's basically a DD I would like to avoid SC/TT/NOS and keep it as simple as possible.

 

[Dimitrios]

some ported heads, cam, rockers, headers, and catback will give you an easy 500+rwhp

 

[Vic]

Headers, Corsa cat back with hi-flow cats, cam+heads? That should bump ya up a bit. Maybe you don't need your cats in Delawere?

 

[Bonkers]

Yup cats are a must - while others have passed through without problem I'd rather take the path of least resistance (oxymoron unintended.)

 

[hemibeep]

I went the ported heads,
stock exhaust manifolds, stock rockers, stock PCM, JonB's high flow cats, corsa cat back.,k/n filters and stock tubes.

On the track trapped at 122mph, which is identical to SRT coupe trap of 122mph that day. SO, I am assuming that we should be at/around the same 500hp numbers.

I am sure much could be gained with other bolt ons, just haven't got there yet. The motor was rebuilt and uses Ross pistons and file fit rings, (balanced). but is really stock and completely reliable and simple.

 

[Bonkers]

Could ported heads provide that kind of HP gain? I haven't seen gains like that since the vipair thread! Actually I think trap speed is a little to unreliable a guide here, but I already see the pattern setup.

Since everyone seems to like the ported head route, what's the best way to go with ported heads? I guess what I mean is, should I pay Heff or another like viper tuner for one of theirs, or can any competent builder be able to do it?

 

[Bob K]

My '96 just dynoed at 467 hp and 507 torq. with the following mods: henne$$ey air box, K&Ns, smooth tubes, SVP headers, no cats and old style Borla cat back. I am considering adding a VEC2 which could put me over 500/550 if some of the claims I have read are true.

Bob K

 

[Vic]

Bob K,
Are you talking rear wheel figures? If so, that sounds great.

 

[Bob K]

Yes - rear wheel figures! I was very surprised.

Bob K

 

[RedEnuf93]

Good heads 4K
Headers 1.8K
Cam + Rockers 1.8K
Gaskets, Labor etc 2K

Now you've spent 8-9.000 dollars for a NA car. You'll get the 500-500. I dont think big lift cam is much more better for long life than supercharger, they are today quite reliable, besides you dont have to boost the crap out of it.

Why not simply put a ROE or PAXTON on it for 7,500?

Or get a bottle?

 

[joe117]

Bonk,
I know you said you wanted to go with NA.
But for a street car, that just doesn't make sense.

As RedEnuf93 said. Go with the supercharger.

I think that if you were to look at the curves for a 500hp na engine against a 500hp sc engine,
there probably would be more area under the curve with sc.

What I mean is the sc would give more "street power". Th ena engine would probably have all of it's power at higher rpm.

 

[Steve 00RT/10]

I agree with Joe and RedEnuf93. I just put a Roe on and am now getting ready for the tuning part....if it ever stops snowing. Total cost will be around $8,400. This includes a new (older) computer which you won't need--$454, all the VEC2 software/card reader stuff, WBO sensor and meter, new OEM O2s, new crankcase breather system, and a new fuel filter. I will likely never see a dyno as the closest one is over 400 miles away. I'll just tune with log files and help from Sean. I guess another reason to go the SC route and do it myself is that there's not a Viper Tech do a NA job within 400 miles of here. It's my guess that going the NA route, by the time the smoke cleared, would have me well above $8,400 dollars to achieve the same power. Even with a 5 pound pulley, Sean says 500 pounds of torque at 2000 RPM. I felt that power in my first little test ride between the snowflakes this past week end. Big power down low! Perfect for what I was looking for. Optimistically, I'll be in the 550-560 range for HP with big torque down low.

Steve

 

[hemibeep]

Don't know about the heads from a tuner, I'm sure that a viper tuner may be able to extract more than the person I used. But my guy is charging $1600 for stage II.

As far as the MPH being a HP guide, I don't know. I was always told that MPH tells about horsepower. And if I am running same MPH and a .1 faster than SRTC in the lane next to me, then power must be pretty close.

Also I only did the heads first as motor was already apart. I can do bolt on stuff later.

So my cost was $1600(heads) + $1400 (corsa) +($300)cats + $60 (k/n's) so far $3360 not including motor rebuild ($2900).

 

[Bonkers]

I haven't entirely ruled out a SC, but my biggest concern is the additional stress caused by the FI leading to failure in certain components. Specifically those components that normally would be upgraded in a NA buildup anyway. Its one thing to do one or another, but it would be a very bad thing to be forced into both.

 

[rcdice]

Bonkers, I've been wrestling with this issue myself. I'd like to get my car up to 600 hp (540 rwhp) without FI or juice. Perhaps I'm being unrealistic in that a reasonable heads/cam package can provide that. Like you, I'm concerned with traveling too far down the mod route because of reliability issues, etc.

Here's a question I haven't been able to get a solid answer to: Mopar produced two version of performance heads. "Street Performance" and "GTS-R Performance". The GTS-R version are CNC ported with 269cc intake and 76cc exhaust. They also feature a 64cc combustion chamber (vs. 74cc stock) which will have the effect of raising compression. Both these heads are supposed to be direct bolt on. So, here is the question: If we take a basically stock car (tubes/filters/exhaust mods) and bolt on a set of the GTS-R heads with Mopar (T&D) roller rockers could we expect a 50 hp gain? Say 20 from the RR's and 30 from the heads? I'm talking without any further modifications such as the PCM, VEC, fuel pump, nothing else. Opinions?

 

[Jack B]

There is one item that is being forgotten relative to costs, you still need the headers, exhaust and cat delete to get all the power under the curve. Our cars are very responsive to the exhaust mods, without them the dyno curve is very typical, with torque peaking early and declining quickly. Peak hp numbers are just that - hp at one point. With a good exhaust system the power is opened up under the whole curve, this is even more so on nitrous.

 

[joe117]

Heads and cam designed for a race car may not be very good for a street car.
The street exhaust system, as mentioned above, might limit what you get from race porting.

The compression that you can use with street gas is probably going to top out at about 10.5 or so.
A race car is going to use CAM2 or something like it and with that, higher compression is possible.

The cam that you find in a race car is probably going to be set up to get all the power it can at high RPM with no thought given to low rpm.
A race car with a hot cam will seem to "kick in" at some point. Below that point, you might have less power than a stock cam.

What I'm saying is, if there were some magic something for nothing power that you could get with the big heads, they probably would have come stock on the car.
I can't believe it would cost more to make them if all the cars used them.

 

[hemibeep]

The stage II heads I installed were done with future upgrades in mind. I did not want to go through the hassle and expense of pulling them back off. I realize that with so many stock components that I have, they really aren't being utilized.

But, these heads with just cats and cat backs are even up with GEN III on the track(MPH). AND are used as Daily dirver without any side effects.

As I add performance later, they will make a more substantial difference. I feel it was the best $1600. spent.

 

[HARDVIPER]

Paxton Supercharger adds 150+