Exhaust question. - Honda Prelude Forum

epicblue · 02-03-2009, 03:05 PM

I'm about to buy a Hi Flow Cat, and a Greddy Ti-C catback.

If the cat pipesize is 2.25" will it fit the greddy?

Let's say if the greddy is 2.75", will the flanges bolt on without any issue?

The cat is carsound and has no flanges yet.

I have no idea what size is the size the greddy is. Tried searching all over.

spin_r_g · 02-03-2009, 03:19 PM

If the cat has no flanges then it won't bolt to anything. You have to have a flange welded on that match the the flange of the Greddy.

Solid · 02-03-2009, 03:30 PM

I looked up that exhaust and the diameter varies from 50mm to 100mm depending on the car and application. Turbo exhausts will be much wider than N/A exhausts.

Best bet is to either call someone that sells them, or buy flanges after you buy the exhaust.

silver5g · 02-03-2009, 04:07 PM

it needs flanges to bolt to anything, make your own. also if say you did get a 2.25 cat and 2.75 cat back you're robbing power with that restriction, it will also sound a little goofy. with exhaust you have to try to stay equal the whole way back. just a suggestion even though it sounds as if you've already bought them

epicblue · 02-03-2009, 05:24 PM

What's the stock cat size for the prelude?

Solid · 02-03-2009, 07:39 PM

Quote:

Originally Posted by silver5g

it needs flanges to bolt to anything, make your own. also if say you did get a 2.25 cat and 2.75 cat back you're robbing power with that restriction, it will also sound a little goofy. with exhaust you have to try to stay equal the whole way back. just a suggestion even though it sounds as if you've already bought them

Actually you won't for a few reasons.
-2.75" is far more than needed for a stock engine, so you are actually getting more volume than needed
-This isn't a bottleneck, so again it opens up not restricts.

2.25" to 2.75" is a bad idea, but not due to the cat. Due to the 2.75" which would be for a good turbo build.

So you are going to lose power, but this would be due to having a 2.75" and low velocity. A 2.75" would be extremely un-restrictive, but still poor on power.

epicblue · 02-03-2009, 09:31 PM

hmm. Whats the stock Inlet diameter for the a 98 ludes stock exhaust.

silver5g · 02-03-2009, 10:37 PM

Quote:

Originally Posted by Solid

Actually you won't for a few reasons.
-2.75" is far more than needed for a stock engine, so you are actually getting more volume than needed
-This isn't a bottleneck, so again it opens up not restricts.

2.25" to 2.75" is a bad idea, but not due to the cat. Due to the 2.75" which would be for a good turbo build.

So you are going to lose power, but this would be due to having a 2.75" and low velocity. A 2.75" would be extremely un-restrictive, but still poor on power.

you're right, for some reason i was assuming he was going to have a larger diameter collector also

Lude Acts · 02-07-2009, 04:05 AM

I think all the Greddys for Preludes are 60mm---2.36" . There shouldn't be a problem.

rayslude · 02-07-2009, 05:19 AM

I wouldn't go any larger than a 2.5" exhaust on a n/a prelude motor.