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Hello all, I’m new to the forum here, and I’ve been researching rotaries for a while now.



I’ve got a few questions that may be new-b type of questions but I haven’t seen anything discussing them despite my searches and it may be because it is not feasible.



So here goes….



Has anyone used a set of 6 port end housings for a turbo application ported by making the separate ports into one large port and then using a ported turbo intermediate plate? I know the intermediate plate on the 6-port engines can not be ported as large as the turbo plate can due to the water jacket, but I understand that the intake port timing on the end plates would be later on opening than a peripheral port, but roughly equal to intake closing on a peripheral port. This seems like it would work good for a turbo application since I don’t believe you would see the exhaust/intake overlap that you would see in a P-port, but you would have great flow. So would the 6-port end housings flow more than the turbo housings when ported in this manner? This setup would probably require some type of manifold fabrication of course.



And while I’m at it, has anyone used the 89-92 non-turbo rotors (9.7:1 CR) and what kind of boost could be reached assuming good intercooler efficiency and proper fuel air ratio was maintained with no less than 98 octane but more likely 105 octane or better before detonation?



I’m obviously not speaking of a daily driver street engine, but not a full out race engine either.



I’m sure other people have thought of these things, I’m just curious what the feeling is on this type of set up.



Thanks for any comments you guys have.

diabolical1

i've seen it done on a non-turbo Gen II that my friend had years ago. to be honest, the car was an animal! i'm guessing a turbo would just make it moreso. however, i don't know how it would fare against a ported original 13B-T in terms of flow, reliability and numbers.

slash

Yea, I would say it would really hit a big powerband at 4k or so on an NA engine with so much duration, but the low rpm would suffer badly.



It just seems like someone would have tried this on a turbo in the past, especially one of the rotor heads that have plenty of parts to play with in their shop (Like Judge Ito or someone).



I think there must be another reason not to do it??

diabolical1

yeah, i'm willing to bet that there are reasons NOT to do it, but like i said, it is effective. Very effective! and even if it's just for the weekend mechanic that doesn't have the money to throw at a project and has to work with what he's got, it's quite a payoff - in my opinion. like i said, my friend's car was a freakin' ANIMAL! the only car that i knew ran harder, was another friend's T2 (with some modest mods).

White_FC

Wrong!



The low RPM part is really quite strong. Much stronger than a similarly modded low-comp turbo motor.



I've played with two different turbo setups on a stock '86 N/A block.

First was with a stock S4 turbo.. was ok, but ran out of boost higher up in the revs.



Second was with a pretty custom T3/T4 turbo, basically equivilent to a high-flowed S5 turbo.

This was a much better setup. Never got to fully test it before the wategate line fell off, 18psi + stock 460cc injectors = bang.

slash

White_FC,



Yea, I was saying that a NA engine with the 2 ports connected would have a pretty bad low rpm power, but you say it was pretty good as a turbo huh?



Did you get a chance to take it to the track or compare it with a regular turbo at the high rpm range at all before you blew it? (you are speaking of the aux port mod I was talking of and not just the high comp rotors right?)

White_FC

Well I didn't combine the aux ports, no, sorry didn't see that bit of your post



You'd be a fool to do that IMHO, don't gain much (if any) port timing but you'd loose a hell of a lot of port velocity.



But I can tell you with totally stock porting with the same turbo and other supporting mods, the 6-port motor(with sleeves removed) would own a 4 port motor.



and no, i never got to do a proper circuit or drag race with the setup before I blew it unfortunatly.

slash

diabolical1,



That sounds promising! Maybe it is worth a shot.











I mean, the aux port on the NA engine if combined and opened up compared to a street port seems like it could could just blow the street port away in a turbo app (no pun intended)



And like I said in my first post, you wouldn't have the overlap you would with a p-port, but you would have the port open longer to get more fuel/air into the combustion chamber.



Sure seems like it would work pretty good....