Well, I let myself get talked into (again :(), a new header/cat system against my better judgement, and I have proved to myself, my first extinct is usually better. Here it is:

On a 2002 Z06, only performance mods are Blackwing and air bridge (that means everything else is stock, the way it comes from the factory).

We installed TPIS headers with Random Technology's new system.
Here's their description: "C5 Corvette--Add 10 horsepower and 14 lbs./ft. of torque with our complete all-stainless steel high flow converter/X-pipe assembly. Available in 2-3/4" and 3" diameters, it's a direct fit, bolt-in replacement." BTW, I had the 3".

After a few days of driving, I just didn't like it, and the car just didn't seem to be responding the way I expected. After 1000 miles (try to give the PCM plenty of learning time), I dynoed the car: 373 rwhp 364 rwtq. A/F ratio was off a little, but not much. Probably could have gained another 6-8 with LS Edit.

I knew deep down, this wasn't what I wanted, so I decided, screw it, I'm going to take my losses and do what I wanted to in the first place. So I worked a deal, and had it done. I replaced the TPIS with Belangers, and replaced the Random system with my stock setup and added an x-pipe. So now, my only mods are Blackwing, air bridge, Belangers and a Magna-flo x-pipe. Results (same dyno): 382rwhp 373rwtq About the same relearn mileage, and no PCM work, and better yet, no A/F ratio issues. Car feels good (ask RAT ;)).

Anyway, not trying to bash anyone's products or service here, just posting back results. I want to thank Paul at Corvette's of Houston for working with me in swapping out to what I wanted. You have to give them credit for trying new things, this one just didn't work for me. :cheers:

Short version:

Blackwing, air bridge, TPIS LT headers, Random Tech system w/x-pipe: 373 rwhp 364 rwtq

Blackwing, air bridge, Belanger LT headers, stock cats, Magna-flo x-pipe: 382rwhp 373rwtq

Both dynoed on the same dyno SAE correction at 0.98. 1/4 mile results in my sig were with TPIS/Random system (only about 100 miles of relearn).
:cheers:


[Modified by JWSchmidt3, 10:29 AM 12/11/2002]

 

Interesting, JW. From all the enthusiasm about TPIS, I would've thought the diff would be minimal. Why didn't you leave the hi-flo cats in? The Belangers are the tri-y design, correct?

:cheers:

 

What did you do with the Random Tech cats? If they are available, I would be interested.

Greg
:cool:

 

That 's great improvement! Do they sound different?

 

I've never had Belangers, but I'm told the Belangers are very good for mid RPM power. So it's not surprising that they perform well on a stock motor. I would think that with heads and cam, the TPIS would have fared better.

 

Great news, JW! BTW, can you snap some more pics of that hood for me????

 

I'm not a big fan of TPIS, but I think most people are becasue they are readily available and cheaper, and have fared decent in results. I researched the hi-flo cat scenario, and found that I had pretty good cats already. Plus, the cat on the random system is welded in place to the pipe, part of the system. You kinda have to see it to understand. The cats are only about 5" long, and about 4" in diameter. I also think the cats were causing the A/F ratio to be out of whack. Yes, the Belangers are Tri-y design. :cheers:

 

As I stated in my post, I worked out a deal with COH and they sold them. :cheers:

 

The Random system definately put out more sound, but was higher pitched, kinda "lean" sounding. They also vibrated the floor board, especially when cold. Only between 1800-2200 rpm did the system sound any good. The Belangers are obviously quiter because I put the stock cats back on, but at WOT, they have a nice sound, deeper than stock (with the Ti exhaust). :cheers:

 

Actually, they don't. Without getting into that whole "other header" conversation, I saw significant results over TPIS with the Belangers, with a pretty aggressive H/C package which put down 44x/43x hp/tq. In fact, the Belangers hung quite well on that package with the much longer, true LT header design. IMO, the Belangers give you the most bang for the buck on the market. While there are cheaper headers, and more hp producing headers, the Belangers give that perfect dollar to performance ratio. I haven't tried every header on the market, so this is only my opinion, based on my experiences and what other people say, particulalrly on this forum. :cheers:

 

Just click the link in the bottom of my sig, plenty of pics. :cheers: Let's just not get into the whole pic fiasco again. ;) :cheers:

 

JW......do your Belangers have a diffuser in them ?( a cone like thing-a-ma-bob) I have the Belangers but never got a chance to dyno yet.

 

Yes, I believe so. I think that may be called a "collector" :confused: but I like "thing-a-ma-bob" too. :lol: :cheers:

 

Well whatever they call it.....I'm glad you're happy :cheers:

 

JW, where did you get that hood? How much was it? How does it fit on the car? Was much work needed to get it to mate up with the lines of the C5? I LOVE that hood man. It looks KILLER!

 

Thanks dude. Got the hood thru Eckler's. The fit is in line with most after market hoods. The underneath looks like crap, but I had holes drilled, and just put the hood blanket over it. Problem solved. :cheers:

 

Did you just use the hoodliner as a template for the holes and drill them that way?

 

Heh :D .. the thing-a-ma-bob... is a "pickle"... straight from Jerry's mouth :yesnod: ... designed for exhaust scavenging.

:cheers:

 

Glad to hear you're happy with the new setup. Looking forward to putting the set I've had sitting in the garage on in the next couple of weeks.

GT

 

It's hard to know without A/F data for each run. Did you record that on a wideband by chance? If you were too rich with the TPIS and the Belangers flow more and leaned you back down to optimal, that may or may not have been part of the gains.