I have searched and read almost every thread I still can't find what im looking for so here it goes. Does anyone know if there is a difference between catback exhaust systems for the H23 and the H22 engines or the Si and VTEC models? Is it a difference in chassis or the engine you are hooking the exhaust to? I have a 93 Si im swapping an H22a into and im wondering if i need to change exhaust systems or not

 

The cats on the si and vtec are different, so the flanges on the exhaust is different as well. You can still use your si exhaust and cat with the h22a since the down pipe side of the cat is the same for both.

 

different catalytic converters, Vtec model is longer....and Flang different on exhaust side..

 

So would the Si cat reach the down pipe on the H22? since it the VTEC one is supposed to be longer?

 

yes

 

Sweet saves me money so i can fix what the *** that had the car before me did and tried to cover up with side skirts. dented the door jamb and quarter panel and its rusting out.

 

I have a VTEC swap in my Si. I am using the "H23" cat-back without ANY problems.

People say the VTEC cat is longer. I have yet to see proof. Until I actually see it, I would have to believe that they are the same.

 

just a correction...the cat isnt longer, the bolt pattern is just slightly different on the cats. when i put an h22 catback on an h23, i just used a drill and enlarged the cat holes a bit

 

VTEC and Si exhausts are EXACTLY the same....

the flange where the header meets the CAT is different

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95greenlude &raquo;</TD></TR><TR><TD CLASS="quote">VTEC and Si exhausts are EXACTLY the same....

the flange where the header meets the CAT is different</TD></TR></TABLE>

Jared you're wrong. The flange on the cat where it meets the header down pipe is the same on the s, si and vtec. The outlet side of the cat is different on the vtec. The s and si are the same. This makes the flange on the exhaust where they meet the cat different as well. When I did a engine swap I ran a h22a with a si cat and si exhaust. Before the swap I ran a Greddy SP (which was only made for vtec models) the exhaust flange bolt holes wouldn't line up with the ones on the si cat. All you had to do was enlarge one of the holes on the exhaust flange so the bolts on the cat would line up. Multiple people have done this with vtec exhausts to fit them on s and si preludes.

 

well when i ordered my Apexi WS. When i recieved my package it was labeled for the VTEC model. it bolted right up to my SI cat.......

 

huh....i guess they are different....


Majestic Honda has 2 different part numbers for the B pipe....

 

I know they're different for sure though. As for the exhaust ftting I've heard stories that some people had no problems bolting up certain vtec exhausts to an si cat. My guess is when the exhaust is manufactured the holes for the flange have some tolerance which allows it to fit on to the si cat. You don't have to remove very much on the flange to make it fit.