SoloII///M

iTrader: (13)

Apologies if this has been asked before.

The S5 NA motor I built a couple months ago is my second ever rebuild. I rebuilt an S5 TII motor about 10 years ago but didn't know anything about the NA motor differences until I went to build this new motor. Comparing photos I could not help but notice how tiny the primary intake ports were on the NA motors, and how restrictive the baffles on the NA housings were.

Would there be any performance improvement to building an NA motor with 6-port end plates, a TII intermediate and TII rotor housings? I figure someone here has done it.

Thanks!

lastphaseofthis

iTrader: (8)

manytimes.. but more commonly to just swap the sleeves from a turbo housing to a na. and or port the middle.

SoloII///M

iTrader: (13)

Can you point me to any threads where the performance improvement (if any) is discussed? I have not found anything in searching here.

From searching I see that the turbo primary intake ports are indeed larger but I don't see where anyone has quantified the improvement between using the stock NA intermediate housing and a turbo one.

Thanks

j9fd3s

iTrader: (3)

i have heard the na vs t2 rotor housings = about 3hp

ive built a couple of turbo center iron motors (one stock, one ported na) and i didn't really see a power difference, although one engine was setup poorly on the stock ecu, and the other had a rotor gear come out.

so i could be wrong there.

peejay

I don't quite see the point of using the TII center if you're using a 6 port intake manifold.

Yet, if you're not using a stock intake manifold, I don't see the point of using 6 port end housings...

It's not really that difficult to remove the diffuser from FC N/A exhaust sleeves, about an hour per sleeve with not-quite-proper tools.

SoloII///M

iTrader: (13)

All I was asking was that if you wanted to keep a 6 port motor, it looked like you could get a little larger primary port by using a TII housing. Didn't think it would be worth the effort, but thought that somebody must have tried it along the way.

gawdodirt

There is a Lucas Off Road Racing Series class , Super Lite that uses a spec rotary engine. It is a 13B using 6 port intermediate plate and TII outer plates. It has a 45 DCOE sied draft and makes a spec 225 hp. I do not know what rotor housings or rotors it uses.

On another topic. Why do you guys use the exhaust insert at all? The MFR PP housing do not have an insert and they work well. I remove mine in most cases. Nothing I have drives on the street though.

gd

TonyD89

iTrader: (10)

Correct me if I'm wrong but, I don't think there is any real difference in the TII center plate and the six port when it comes to porting. Yeah, the original machined port in the face of the plate is smaller on the six port but isn't the casting the pretty much the same? I mean, I think a six port center plate can be ported as much as a TII center plate. I have both and they sure feel the same feeling inside the water jacket.

peejay

I'll have to go back and check when I get my engine apart, but I recall that there really isn't very much material for making the port runner larger on the 6 port center housing.

Note that my TII and my 6 port stuff is all Series 4. Series 5 6-port may be different.

diabolical1

iTrader: (3)

well, i've never had T2 intermediate housings and i still haven't pulled my REW apart yet, so i can't speak on the turbo intermeidates. however, i can speak on the 6-port intermediates and i'll say this ... you can port them just fine, just don't get greedy. i used the Pineapple REW streetport on mine and it worked just fine, but in an attempt to solve a problem i wasn't sure i had, i tried to revise it with my own template and i hit water jacket.

personally, i would advise just using the side housings you have. the rotor housings are different between N/A and T2/REW, but it's exhaust timing. i'm not sure i'd even worry about the sound diffuser. sure it's not best for flow, but i'm not sure how worth it it is to change if you're on a budget.

SoloII///M

iTrader: (13)

When I built my motor I did use the housings I had. But again, when I looked at the primary ports they looked smaller than I had remembered. So I dug out the pictures of my TII rebuild from around 1999 and it looked like the TII primary ports were indeed bigger than the NA primaries.

It sounds like the answer is yes, they're bigger, but not enough to make a difference on an otherwise stock NA build.