T4 exhaust ports
 

Hello,

I have a T4 question:
Which type of exhaust ports are more desireable in the T4 engine, the oval ones that requre a special copper gasket, or the later vanagon square port heads?

I am building a T4 and I have acess to both styles of cylinder heads, just wondering about the pros and cons of each style, this will be a turbo motor also.

thanks, Bry

hi
use the sqr port heads if your doing a turbo motor they seal better the oval port heads with copper rings leak at the best of times if the flange is not flat. also the sqr port heads flow better thru the exhaust port as well if you want to work them there more there to start with as well.

Neil,
Any flow data to back this up?
Also consider the availability of exhaust systems when deciding for which port you choose.
Also the sealing problem is rarely a head problem, more often a header problem, since the sealing surface of the header will not lie at the same level as the head level: imitation heater boxes or bad quality header.
Greetings,
Walter

The header I intend to use will be custom made stainless steel, and the flanges will be thick (1/2"). So I dont think header availability is a problem, nor are heater boxes, as I dont intend to use them.
This engine will be a replacement engine for my ghia, and eventually replace my T1 turbo with a larger displacement T4 with a T04 turbo.
Yes, I have seen the light, T4s all the way baby!
Bry:D

hi
i have not one bit of proof to back up the fact that sqr ports flow more im only going on what ive read on the net wally even jake says its true these days and well remmele uses the sqrs and so do most other german tuners dont they all that initially set me off that they must flow more is just the x-section compared to oval ports they have more!

sorry if im a disapointment in my lack of proof but its obvious or?

Hi Neil,
All true, but for the x-section, of which I'am not sure. They look about the same to me and is difficult to measure for a difference.
Don't deduct from the fact that square ports are used more by well known tuners that they flow more! After all it could just be a matter of availibility! Remmele's supplier AMC only makes the squareports, so he cannot use another head for extreme porting, because max porting is only (well, preferably) done by high end tuners with new heads and there are no more new oval ports heads availible anywhere anymore.
The reason that AMC only makes the squareports could also just be the fact that they originally were meant to repair T25 (Type3)buses.

In reality, I think the early part of the ports are virtually the same for both type of heads and only the last part is different. Therefore stock flow will probably not differ much either.

Greetings,
Walter

If you have a look on laperformance.co.uk and look at engine section then go to the cylinder heads section all thier heads are square port jobbies as these flow better according to lee.

hi
now i did for some reason think that amc make the oval heads as well! i might be wron im getting on dont ya know .

with the sqr port heads i think theres more meat in the port wall this was done to stop problems here as well.

i wonder what leads lee to that conclusion as well?

the x-section is definately bigger if you chop the end bits of an oval port exhausts they fit a sqr port head the width and length of the oval is the same as sqr port heads but sqr is sqr there is more area in a sqr than an oval with a proper gasket as well you can open them up easier as well.