RS-R exhaust diameter size????

[linksys42]

OK I just bought this exhaust from a guy of the classifieds and its only reading out too 2.25” inside diameter (see pics below)! Did RS-R make an exhaust for the N/A motors? Because I thought the inside diameter would read out to 2 ½”. did I get ripped off?

 

[RamenPride]

Did you just get the cat-back or a turbo-back? I was thinking if that was the downpipe in the first pic that would make sense. Anyway, here's mine....

 

[95blackGsTurbo]

Did you read the inside diameter of the part where it bolts to the cat. Usually exhuast are a little smaller where they connect to the o2 housing, then get larger.

 

[linksys42]

I just got the cat back, and the pic with the measurement is the connection before the muffler, where the two pieces of the cat back exhaust system bolt up to one another. Did I get ripped off??? “Ramenpride” is that a pic of the RS-R 70mm cat back system for the 95-99 DSM FWD? thanks

 

[daren_p]

If thats the connection before the muffler, I would say its for a N/A. While I don't personally have the RSR their system, if the turbo system is listed at 70mm thats ~2.75", my buddy has one & the diameter of the pipe is much larger then what you've shown (like the second pic). I'd say if it was sold as the turbo exhaust, you got ripped off.

 

[JOEY A]

All cat backs bottle neck down in certain areas, unless you go custom there is no true full 3inch on the market.




I highly Doubt RSR even made a NA exhaust, I was under the impression they only made FWD and AWD turbo exhausts.......

 

[staticbrainwash]

Um. . . i think thats an uneducated statment. Because there are PLEANTY of systems that are full 3" or 2.5". It's the catbacks or dp's that are designed to work WITH a stock cat that will narrow down.

 

[linksys42]

All cat backs bottle neck down in certain areas, unless you go custom there is no true full 3inch on the market.

The exhaust is supposed to be a FWD 2 ½” inside diameter and it reads 2 ¼ inside diameter all the way thru from the cat all the way thru at every connection. Im just wondering if I can meet my goal of 300 wheel HP with this exhaust.

 

[staticbrainwash]

I'm sure it's possible, but it would be MUCH easier with a 2.5 or 3" system. Because really, 2.25" is just stock exhaust with maybe a straight through muffler.

 

[daren_p]

All cat backs bottle neck down in certain areas, unless you go custom there is no true full 3inch on the market.




I highly Doubt RSR even made a NA exhaust, I was under the impression they only made FWD and AWD turbo exhausts.......

That is a very general statement, which happens to not be true. I know many cat back that don't "neck down". If they do its usually on at the point where they start so they can connect to the factory cat if need be & in alot of cases the necked down area is an adapter that can be removed when you are running a larger cat or straight pipe. Such is the case with my Apexi N1, it is 3" from the cat all the way back until a few feet before the muffler where is actually expands to over 3".

You can probably hit your goal with that exhaust but it will make things harder. With turbo basically the less the restriction the better. Smaller diameters will hurt your top end and take longer to spool the turbo. Personally I would want something larger, 3" defently isn't overkill even for a t25. You may think .25" in diameter doesn't make much of a difference but look at the actual area difference in the different diameters, 3" has over twice the area of 2.25":

2": 3.142
2.5": 4.909
3": 7.069

2.25" will be an improvement over stock but not by much as they pipeing is pretty much the same size, you will gain the mandrel bends for better flow and a straight through muffler.

 

[daren_p]

Here are a couple pics I could find, you can tell the pipeing is much larger then yours, as is my buddies fwd system.

 

[linksys42]

I spoke with a guy over at road race eng. And he said that I prob have the old design of the RS-R and that it is 2.1/2" he said that exhaust are sized on the outside diameter of the exhaust piping. So the outside diameter is 2 ½" the inside is 2 ¼ (im guessing that the outside diameter of the stock exhaust is 2 ¼") and that would be fine for my goals he said the only time you need a 3" is if you are shooting for over 600hp. Said it was unnecessary. Also im guessing that the outside diameter of the stock exhaust is 2 ¼". So I guess im going to go with it.

daren p, thoes pics you posted are of an AWD 3" RS-R. thats why they look so big

 

[RamenPride]

“Ramenpride” is that a pic of the RS-R 70mm cat back system for the 95-99 DSM FWD? thanks

Yes it is.

he said that I prob have the old design of the RS-R and that it is 2.1/2”

This is probably correct, as the muffler on mine looks different than yours. I got one of the last ones available from turboimport.com about 2 years ago.