non-droning exhaust that can make 300rwhp ?
 

After my tuning with Steve Kan @ Pettit, we stopped at 273 rwhp due to exhaust flow restrictions. In fact, Steve said 300+ rwhp is possible, but I need to uncork the exhaust.

Now, while I'd like to get to 300+ rwhp with my current mods (see below), I just don't want to have that dreaded highway drone @ 3K rpm, stinky exhuast, or a super loud exhuast just crusing down my neighborhood.

My search has indicated I should:

1) get a real 3-inch downpipe (I have the JDM one that is only 2.25" OD);
2) keep my HF metallic-cat and 3-inch Magnaflow resonator;
3) and replace my old (I'm the 3rd owner) TRUST muffler which sounds like the Racing Beat one.

Any recommendations for number #1 and #3 ?

Can I make 300+rwhp with a Racing Beat cat-back muffler ?

TIA,
:-) neil

(4) 850cc injectors
PFC tuned by Steve Kan
ARC SMIC
Spec '99 airbox & airbox diverter

yes, I made 301rwhp seq. with the main cat and racing beat dual tip...but I had an open intake with heat shield

i'd start with the DP. Get a used name brand one off the FS section here.
Maxcooper made good results with the same cat/resonator setup.
I doubt the cat back is an issue, but I could be wrong.


what intake do you have?
how much boost were you running to make 273HP?
running sequentially?

Stock airbox, but with the Spec '99 diverter that does NOT share air with intercooler.
That was 273 at 12 psi.
Yes, turbos are sequential.

:-) neil

12 psi with these mods?

(4) 850cc injectors
PFC tuned by Steve Kan
ARC SMIC
Spec '99 airbox & airbox diverter...

273 rwhp is good number...I hope to see 300 when Steve tuned mine. It is pegging at 12 - 12.5 psi so aint boosting it until she is tuned.

HKS DP, Apexi Intakes, Greddy SMIC, RB Dual Tip catback, & PFC.

I'm in the same boat amigo. I'm looking at the racing beat duals, the greddy SP, and the RSR single tip. they all should be good for 300hp. Your downpipe is whats stopping you.

Hmm, interesting. I'm running an Ebay downpipe, stock main cat, and HKS Hiper cat-back (which looks like the Apexi N1) and it's VERY docile - no highway drone, not bad around town, etc. Not sure what it would be like with a high-flow cat, though.

I do know a number of people have had very good numbers with the Racing Beat cat-backs. Also, if you stay sequential, that will help with idle and cruise noise a LOT.

You've bigtime got a restriction with the stock airbox, even with the later air intake. Unless you've hacked it up or something - the funnel air is drawn through is VERY small.

Anyhow, everything sounds good and I'm glad to hear your car is doing well!

Dale

I make that at 12 psi with the Racing beat dual tip (its RSR actually), downpipe, M2, intake, medium IC, power fc and stock injectors

M104-AMG I PMed you about a downpipe that I have for sale :)

I am making about 300 rwhp with a modified stock airbox, and a stock main cat. Click the link in my sig for info on the airbox mod.

I made 315whp on stock injectors at 13 psi with a 3" DP, stock cat, and RB Duals, M2 ECU, Airbox and Large SMIC and HKS TwinPower.

I now run a high flow metal core cat with magnaflow resonator but haven't dynoed yet

i hage a greddy sp exhaust for sale one of the most quietest ..pm me if interested

You might wanna upgrade your fuel system dude or you will start messing up your engine.

I think you should hit up any 3in downpipe. They are pretty much all the same, some harder to instal than others but just make sure it is stainless steel. I have a generic 3" DP, Stock Cat, Blitz Nur Spec, and running non-seq. I love it. Its not even that loud. Very deep though. I should be hitting about 300rwhp by now. I just gotta finish the tuning on my PFC because I had to get new tires (last ones were old and dry rotting).

He is perfectly safe running right where he is. Don't know where you got your info from.

One other suggestion that I dont think has beed mentioned, is replace the main cat with a resonator. It will offer some restriction in the system (more than a stright pipe) and get rid of the droning. Rx-7store sells a MP with a large resonator, for like $250, I think. won't do much for the smell though, with the main cat gone. You can probibly get an exhaust shop to make you one for half the price.

As one of my reliability mods, I'm already running a Supra Twin-Turbo fuel-pump.

The TRUST cat-back muffler I have is the original TRUST/Greddy SP.

:-) neil

PS: I just got a used HKS downpipe on ebay for $77.

The HKS is the one that DOESN'T maintain a 3" downpipe -- it's crushed to clear the steering for RHD! :doh:

So, how much would that cost in HP vs a full 3" DP, assuming the stock main cat and a hi-flow cat-back?

I was going to get the Gotham, but I like the build and casting of the HKS better.

Is the Gotham fairly good ?

:-) neil

Probably not enough to poke a mole with :molepoke:

Very true but fitment was perfect...at least for mine.

Yep. Before I installed mine, I had read the horror stories about installing the DP. When I did my HKS, I couldn't understand why everyone had so much trouble... probably cause they didn't buy an HKS.

Thanks - I already have an HKS (my mods are below in my sig), but I was curious.

That casting is the problem though... it's all convoluted up at the top like the stock precat, and you'll prolly be in the same boat. Get a real 3" stainless mandrel bent DP with ceramic coating.

I can't imagine the GReddy exhaust is that restrictive compared to a Racing Beat (which isn't exactly the free-est flowing)... but let me get this straight, you've got a cat AND another resonator on there?

I don't know if the jury is in yet on those metalic cats, but if you get a good quality high-flo cat (like a bonez or something), ditch whatever extra resonator you have on there, run a regular DP, and whatever catback you like, you'll probably be fine.

I think the "drone" is a fact of life and something you'll have to live with... opening up the exhaust makes the car louder, that's just the deal.

i made 373 whp with the stock catback before :D