I have not flow tested the manifolds yet, but plan to do so. In addition, I will also be making some additional testing with some modified S1 exhaust manifolds and as we speak, I am having some S1 flanges being made.

I still believe that ported manis is a good way to go and I don't think this info discredits that belief. The discussion here is just about the extent of improvement you get and the relative flow rates, front-to-back. I think that if you ask anyone here who has PEMs, they will tell you the improvement is significant.

I'm sure that I will be ordering ported manis, but not for a year or so. My own reasons.

difference between headers and tubular mani'* are?

Headers share a common collection point. Manifolds dump into a common tube, but not at the same point.

You'd be looking at a BIG cost I'd bet to have tubulars made.

First a question...on flowing the rear SI and SII manifold was air flowed through the ports with the crosover blocked, or was the crosover and the ports fed air?
if this is the case then it may be a more cost effective mod to just get a rear header and utilize the factory front/crossover without the added cost of also getting a front header manufactured.

on that topic i will be taking the SII flanges and modfying the SI manifolds (tubing and log) to use the larger id SI tubing with the SII port flanges on my SI/SII Hybrid...
of course the main reason i am doing this is because it'* getting turbocharged and with deleting the stock dump i will be changing the angle of a couple of the tubes where they dump into the log, and i want to see how that works before i go making the 304 stainless one'* in the future (as i may make a manifold type with a stepped "log" at that point vs headers (too much thermal loss with all the extra surface area)

nice work fella'*, nice to see this stuff is getting sorted out

Regards, James

Seems worthwhile dusting this off. Marty...I found something interesting. I went to swap my rear manifold finally ... Looking at the new versus old, I think I see why the flow tests you had done yielded the results they did.

Travis from Hulkspeed personally pulled the new one off a 97 Bonne, my original came off my 97 Bonne. Unfortunately I do not have the original drivers door on my car and don't know my production date. The manifolds seem the same except port size, outlet size and the collar that sticks out of the new manifold. Otherwise..the bends and things look identical.
Take a look at the differences..




I'm working with Travis at Hulkspeed to get the problem remedied.

nice socks.....

and its interesting......he says they were off a 97eh??? maybe it was a early or late production vehicle that had a different set of manis on it all together??? cause I know the PN'* were different for the different years

Jr's3800 mentioned offline to me that they look like 95-96'*.

Which brings up my point of neither Travis or I knowing the production dates of the 97'* we are dealing with. His was probably an early 97 wearing 96 manis before they made the change over.