Got my R about 6 months ago and now after the initial woody has subsided I'm starting to think about modding it. The car right now is bone stock and I'm leaning towards a 4-1 header w/ a high flow carsound cat. I love the look, fit, and sound of the stock R exhaust, so I don't want to mod it all just yet. My question is, will say a toda header and carsound cat bolt up to my stock cat-back?? I know about the 2.5" vs. 2.25" difference between the two, but is there any way around this?? Any suggestions are appreciated in advance :lol:

 

Also, what type of Intake would be best suited for this setup?? Icebox's seem to be popular, but I've heard they're of shitty construction for what you get. I've also been looking into a J's Carbon Fiber, although I can't really get a decent opinion on that either, too many mixed emotions. Wanna do as much research as I can BEFORE I go out and possibly waste my money. Thanks!

 

So search previous topics here and on Honda-Tech.com

 

I'm no noob to this process, I spent my whole morning going through old posts both on itrca and honda-tech..................anyone have an answer to this question???

 

The worst thing you can do bro is to change diameters within an exhaust system from one size to another , which ever size you go with it should be the same size all the way back. A big header with the small stock exhaust will yield minimal gains you might get a few hp with tuning. Best bet is to find specs on exhaust and headers and cats, and try to find a combo that has the same diameter.

 

Not completely true Jan. The 2.5" to 2.25" trasnition on the R with a JDM collector header is not all that detrimental. you will see a slight gain to use 2.5" all the way through but nothig to write home about 1-2 hp. he stock ITR exhaust will make all motor power up to 190 with stock cams (Has been done).

You CAN get an adapter that you weld into your b'pips that bolts to a 2.5" collector and that trasnsitons down to 2.25" but if a 2.5" exhaust makes a couple HP expect this to make les than 1.

The Toda header is a great choice. I made 180 whp on stock cams and stock exhaust with the OEM JDM 4-1 and a toda should make a bit more.

Trey

 

A bone stock R runs about 160 at the wheels, give or take a a few hp. George knighton has a dyno where he got 180 whp from a sms header, cat , and 2.5 cat back. http://members.aol.com/_ht_a/georgek...ages/dyno1.jpg
Trey, you say a full 2.5" exhaust makes a couple horsepower, how is this possible while people such as George are making 20+ at the wheels w/ intake and exhaust?

 

first, a 1997/1998 ITR might make 160 ish but more so 163-165. a Bone stock 2000/2001 ITR driven hard (This is the harder you drive it the power it makes therory, not that George does) makes more like 169-171. My 1998 R was weak at first making 159-161 depending on dyno. My 2000 R I had first made 169.5. The intake cam is the big factor here.

I went from 159 to 180 going from Bone stock to 2000 Intake cam, Icebox, JDM 4-1 and Stock exhaust with a power FC.

George has an SMSP header and the car is tuned (Hondata) by one of the best. THere was a guy Mike K that made 192 with a stock exhaust and stock cams. Not sure the rest of the details but with stock cams nothing compression wise is too radical.

It is all in the parts of the system and the state of tune. ALso like I mentioned I firmly belive crs that are driven hard tend to make a bit more power

 

If you read my post again, you'll see that I said you might gain a few hp with tuning. I'm talking about a header with stock exhaust. Are you guys talking about aftermarket catback?

The point is, exhaust pulses like equal diameter tubing, whenever you change sizes you stagnate, especially going from large to small, going from small to large is less detrimental.

 

I am talking about a JDM (2.5") header and stock exhaust and the fact you can easily make 15-20 HP over stock form with stock cams and stock exhaust.

Tuning will net more like 25% of that power if not more. Tuning is the key even in stock form and the transition from 2.5" to 2.25" isn't nearly what you make me feel like you think it is (Not sure I worded that right but based on all the tuning and work I have done on my 4 different integras (2 R's) I just don't agree and feel you have some theories that are amiss)


Read: Who cares about pulsation or stagnation if the car makes power? And the R with a 2.5" collector to stock 2.25" exhaust does.

Trey