SoloIIdrift

I can get the diffuser out to port it, but mazdatrix says: Here's mazdatrix website on it

Anyone ported the stock n/a housing and left the diffuser out? I'm thinking it would flow more, but I'm afraid from what mazdatrix says that it wont flow as good. Any comments?

jimmyv13

PM hypntyz7. He's building me a SP for my 86 in a few weeks & he's removing the diffuser on it.

RB told me the engine would be unecessarily loud w/o the diffuser. Who knows, everybody has their own opinion on the subject.

Felix Wankel

I've heard you can remove the sleeve and put a TII sleeve in the housing that has no diffuser. I can see how its possible (they're just pinned in), but I don't know if it will actually work or not.

SoloIIdrift

I can get the diffuser out no problem from the stock NA housing, by drilling the pin that holds it in, the question is, should I put it back in after I port the housing, or leave it out.

mazdaspeed7

Mazdatrix's site isnt very clear about it. You can grind the diffuser out, and all will be good. But the sleeve itself must remain for a street ported motor.

"unnecesarily loud"? Doesnt the describe EVERY n/a rotary? Seriously though. If youre street porting a n/a, you probably could care les show loud it is. And I think theyre sense of "too loud" is a little more skewed than 9 out of 10 RX7 drivers. What a lot of people like, sound-wise, they say is way too loud.

TII sleeves will work.

SoloIIdrift

Yeah I could care less about loudness, I want to know will it flow as well WITHOUT the TII sleeves, using just the stock NA housing, and the diffuser out, should I leave it out, or do you think it'll disrupt the flow?

mazdaspeed7

You dont want to remove the sleeves. Your low end will really suffer, and you wont gain any top end. It is very bad for power on a street ported n/a. You need a PP or big bridge port to be able to use that much exhaust porting.

Use TII sleeves, or grind the diffuser out of yours, and put the sleeves back in. Youll be happier.

jimmyv13

Are the TII sleeves the same as NA sleeves just w/o the diffuser?

SoloIIdrift

So if am using the all stock N/A stuff, and I remove the diffuser only to port the exhaust, and leave the sleeves stock in place, should I put the diffuser back in after the porting?

I have a way of getting the diffuser out without grinding it out permantly, just the pins so I can put it back in i think....

mazdaspeed7

The diffuser is PART of the sleeve. You wont be able to get it back in, it mush be grinded out. Do not get rid of the sleeve. You will regret it.

The TII sleeves are the same as the n/a minus the diffusers. Definately worth the effort/cost.

Angel Guard Racing Team

Remove the sleeves like I did. Forget about the low end BOOK B.S. I have not lost any kind of power at all. Remove the sleeves, port the SOB and you will feel the diffrence. I am running with no sleeves and race intake and exhaust ports. Just in case somebody says something: My cousin is running no sleeves and no intake port. REMOVE THE SLEEVES YOU WILL NOT REGRET IT!!!!! I KNOW WHAT I"M TALKING ABOUT!!!!!

easy p-cheesy

you could always email them asking why they say that. just a thought.

SoloIIdrift

hmmm....i guess i could email them, but they do go by the nick name of "mazdaprix" for a reason

Bambam7

Well, my sleeves are removed, and it is a bit louder, though not terribly.
I have to say, my engine is pretty strong for an street ported N/A.
My low end is easily drivable, and it starts making real power at 4000.
The only problem is that the exhaust flange for the manifold will have to be port matched (bigger) to mate up with the bigger exhaust ports. (That's what I did)
Don't worry about too much of a loss of low end tourque... If you have a normal sized exhaust, and regular 2" headers, the flow velocity in the exhaust won't really be compromised... The diameter of the port is only bigger for less than 1" of distance! It just may introduce a bit of turbulance... hence the smooth port matching... problem solved (99%)!


Disclaimer- I don't ahave a ported engine with an intact sleeve/no diffuser to compare it too, but my low end torque is currently not THAT much less than when my car was stock.... though it may be down a tad. (port work, VDI in high, no 6p sleeves...)

Bambam7

Oh, and "Mazdapricks"?
I have gotten a lot of great tech support from them, they've answered a lot of questions I have emailed them even though they had nothing to do with them selling me anything- I think that's pretty good.
I did get one wierd anwser though- I asked if I should be worried about my N/A tranny holding the power of my new engine- The reply?
"Worrying won't help it, just replace it when it breaks."
That was the whole reply.
Oh well.

mazdaspeed7

In defense of Mazdatrix, they spend more time than you could possibly imagine on their OWN engine dyno, and lots of time on chassis dynoes. I resect their opinions, b/c they have more experience than most people. Drivability is relative, and they do seem to be a bit more picky about noise, and general drivability. But is that really a bad thing? They cant go around telling everybody PP engiens make good street cars, because the simple fact is they dont. Sure, it can easily be driven on the street, but sacrifices always need to be made.

Felix Wankel

I've talked with Dave Lemon before, he was very nice.

Mazdatrix

iTrader: (1)

Information for those interested:
(Looks like not everyone on this thread is in that group?)

SCCA E/Production 6-port (currently on the dyno),
52mm IDA, race exhaust, etc:
Best power: Turbo sleeves
2nd best: Sleeves cut to outer ring only
Next: no sleeves (bad enough I did not record the numbers)
Worst: any type of 6-port sleeve

mazdaspeed7

If you dont mind me asking, what kind of power are you making on that engine?

Liquid Anarchy

iTrader: (2)

I hate to bring an old thread out of the graveyard, but... what did Mazdatrix mean by "Sleeves cut to outer-ring only"?

I've run into the problem of Streetporting my N/A and must do something about the exhaust sleeves. My options at this point are... #1 Grinding out the Diffuser, #2 Having my friends @ a machine shop fabricate some sleeves, or #3 finding some people with blown TII engines, that are willing to sell their sleeves for a DECENT price.

so, just out of curiousity... what was he talking about?

Liquid Anarchy

iTrader: (2)

^BUMP^ From Evil Pentagram Goat-head

Bambam7

Meana just the diffuser ground out- and the sleeve itelf left in place...
That's what I'd recommend too.

Strange, that's identical to the turbo sleeve.. wonder why it's less power?

Liquid Anarchy

iTrader: (2)

It's only identical if you can match the walls as well as a cast that's accurate down to .01 millimeters. Well, I'm happy to know that's what they ment. I was getting nervous.