im getting one in 10min, and i was wondering, is this something i can do? if so, how? can i port the runners all the way top to bottom? TIA

I've never tried it, but I would think for the top part of the exhaust manifold, with a dremmel and a flex extension you could do it. But, it is cast iron so it should take more effort as compared to the aluminum intake manifold.

I have no idea what kind of improvement you would see from porting the exhaust manifold. I don't think it would be very much, but that is just a guess.

But since it is the exhaust manifold and not intake, I would say you could really open it up (without weaking it). I am guessing you don't have to be as careful with porting the exhaust manifold as you would have to be with the intake manifold or (especially) the head.

well considering a header makes approximately 0hp over the stock manifold on a near stock motor i would say that unless you have heavy engine mods (cams/bottom end) that it wouldn't be worth the time.

I used a Dremel w/flex - oarnge stone. It took a LONG time cause it's cast iron. Stock, the inlets go from oval to square in about a half an inch. I was able to port about 3-4 inches in on the runners - making the transition from oval to square smoother than it was. You can NOT port the entire runner length for the outer cylinders. you could probably do it for one of the inner cylinders. You should be able to get rid of all of the visible casting snarbles. In the collector I just hogged out as much as I could - making the + as thin as possible. I also ported the collector outlet to remove that step - and made the outside wall angles much less steep.

I noticed a small gain...with a ram intake, Jeep TB, Gude cams, no cat, and GS-T exhaust to support the port job.


95 Eclipse RS : 5 speed
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

there is a pretty good wrie-up for the turbo dsm's on the vfaq

http://www.vfaq.com/mods/porting-exhman.html

thanx evry1 woohoo 700th post

Whore! :P

>well considering a header makes approximately 0hp over the
>stock manifold on a near stock motor i would say that unless
>you have heavy engine mods (cams/bottom end) that it wouldn't
>be worth the time.

Well, He has a CAI, catback and built bottom end with high comp. pistons. I think It'll help a little bit

hahaha 792 posts, take that :P
oh and thanks for the shift nob Chris :thumbsup