Cattman's new header/y-pipe appears to make 17 hp more than a stock y-pipe (184 vs 167 hp), so maybe 5-6 hp more than just an aftermarket y-pipe alone. That's on a NA Maxima.

Anyone want to hazard a guess as to gains (compared to an aftermarket y-pipe) on a boosted, MEVI'd Maxima that's flowing significantly more exhaust?

 

Just for fun, I'll take a stab....

Cattman headers with 17hp over 167hp is a gain of about %10, whereas the aftermarket y's gain of 12hp over 167hp is a gain of about %7. So take a sc/turbo car making 300hp, 10% would get you 330 whereas 7% would get you 321. So maybe ~10hp? Of course that's assuming the effects are linear...

 

The effects are non-linear, actually...

Exhaust changes to forced induction engines can yield exponentiol gains as compared to N/A engines. It takes more than just a few bolt on parts for a N/A engine to really make significant gains. If you replaced/modded the entire intake and exhaust system of any N/A engine, then you would get the gains...but this is porting/polishing heads, switching to larger valves/better springs, true high flow headers, crossover X pipe, and true duals...

That's a lot of work for 35-50 HP when changing the exhaust alone on some boosted application can easily yield that much of a gain.

 

Soo....what your sayin' is that if I get rid of my WSP downpipe for Cattman Longtubes, that I will gain an extra 30+hp on top of what I already have?? Quicksilver, i'm holdin' ya to that!!!!

 

Read the rest of my post...

On the VQ30 I said that porting/polishing the heads and installing larger valves/better springs + a CAI + the headers + better exhaust would get you the 30 HP you're looking for. All that for only $3000 or so...

What I'm trying to point out is that at that point, it's cheaper to boost your car than to try and make it a beast (N/A).

EDIT-- Whoops...forgot you are boosted! The entire exhaust replacement (along with the headers) could get you that 30 HP, yes. Try porting the stock heads (if you can afford to do it). You'll be amazed by the difference with just that mod alone...it's costly, though.

 

I'm pretty sure he installed them on his personal vehicle....so don't forget Cattman has 1xx,xxx miles, however he also has a PR CAI, rims, and a catback exhaust. He might also have a RT cat, but I'm not sure.

 

Craig, if I can gain 40fwhp from a b-pipe & test pipe, ~30fwhp off a set of headers isn't completely out of the ballpark.

I'd expect more like 15-20, but that's still not a bad gain.

 

Ereet, are you talking 15-20hp *more* than an aftermarket Y-pipe, or 15-20whp total?

 

Here's a graph of what Cattman's headers can do, based on information in a different thread over in the 4th gen forum. It looks like the gains want to take off at about 5000 rpm, and then the intake starts to choke. It would be interesting to see what a boosted, MEVI'd VQ would do out to about 7200 rpm.

 

Craig -- I'd say 15-20 MORE than a y-pipe. Again, I could be wrong here since we've all assumed that the stock headers aren't that badly designed up until this point. If emax95 took essentially the same headers and gained what .. 5-7hp on them? Expecting double that on a heavily boosted car isn't that far off.

The y-pipe alone on a boosted car should provide nearly double the gains as it would on an NA car. Now, what I'd REALLY like to see is:

Cattman headers bolting up to a 3" y-pipe. Now THAT'd be sweet

 

Ethans were shorty headers, these are LONG-tube(all the way back to the cat) headers, so definitely going to have better gains then Ethan's 1-2hp gains.


Cattmans' headers include the "y-pipe", so that's not possible. Unless you mean a dyno of headers vs. 3" y-pipe?

 

Anybody know what diameter Cattman's collector is? I've asked several times and never got an answer.