Nah, I never liked the stock intake pipe on those things.
For some reason 3" sounds kinda small.
I might look into making a 3.5" adapter for it, since the motor has the potential to do over 700hp...


-Ted

 

Ted,

When you can, let's see the dynos! I would LOVE to have them for my dyno collection at www.catenet.net/dyno.php

 

its the one kurgan made, it looks like the one you guys made for pauls car

 

Crap, it's been a long time...
Got a pic handy?


-Ted

 

Yeah, I'll definitely get them pulled off the box.
I think the easiest way is to use a USB jump drive.
That should be pretty harmless at this point.


-Ted

 

Ted,

Are you running 9:1 rotors? If the owners dedicated to staying N/A, Rennesis rotors can be swapped in with some modest mill-work (Bruce Turrentine has done this). Nonetheless, for a basically block 20B to put out ~280bhp WITHOUT turbos is an sweet accomplishment . Good street porting (aren't 20B ports smallish?) + higher comp rotors =Perfect Street Car.

 

There are no Renesis counterweights for a 20B.

Het Ted, I got mine to fire up. It would idle, but wouldn't rev (dellorto). At least the ignition works. It sounded kinda like yours but a bit different. Kinda like going from stock FB ignition to some sort of simultaneous firing direct fire igniton (smoother sounding).

Sorry, no sound clips for now. I'll get a better intake setup and try again.

 

No, but if you can balance a rotary, all you'd need to do is grind down the 20B's counterweights until they balance the assembly properly.

You could do the same in reverse if you were putting heavier rotors in an engine (add metal, either welding or using Mallory metal slugs, to the counterweights) but the question remains: why would you put heavier rotors in an engine?

(unless maybe you *really* wanted a 8.5:1 (or lower: see below) 20B, in which case you might be better off milling material from the rotors to make them the same weight as the 20B rotors, maybe even milling the dishes out to get even lower compression)

When you're doing custom engines, there is no such thing as "won't work" or "doesn't fit".

 

I had mine milled. Mazda Comp was nice enough to send the spec sheet along with the flywheel.

 

Yep, stock 9.0:1 Cosmo rotors.
Nah, I don't want to mess with the Renesis stuff - did you read the Mazdatrix experience with trying to run the Renesis rotors in an earlier 13B?  It wasn't positive.

Thanks for the congrads.  I was hoping for a little more (over 250hp), but after finding out the restriction was the air filter, it was pretty much game over.

-Ted

 

Hey, how about some pictures of the header?

 

It's in the other thread I've posted in here.

-Ted

 

would be nice to see what kind of power you would get
with 90 N/A rotors and some porting, not much porting
would be needed intake ports are big enough, just
remove the cosmo exhaust sleeves and put in turbo ones .
a 20b N/A project might be some thing to think about,
judging by the numbers you got and what a motor
built for N/A use motor could do it might be an option.

matt

 

Especially when the stock twins add so little.

 

Ted! Where on Mazda trix homepage did you find the negative info on RX-8 rotors in an earlier 13B? Reason i asked is that i am gonna dyno a 13B PP with RX-8 rotors on Sunday. I have milled the apex slots to proper depth (9.8mm) and i am using 2 mm Hurley race apex seals. I dyno'd a similar engine last year w/ 9.0 c:r rotors and it made 276 hp @8100 rpm. Hope to have another 10 hp w/ proper timing. Anyone have any suggestions on max safe L and T timing w/ 10.0 c:r rotors?

 

Someone mentioned it somewhere in here...try do a search?
I dunno where the info came from, but it was definitely from Dave Lemon.


-Ted

 

The main problem MazdaTrix had with the Renesis rotors in the older 13b was that they used the stock Renesis apex seals & corner seals. The thinner seals actually warped because of the extra heat and them not being designed to travel over the peripheral exhaust port. Others have milled the renesis rotor seal grooves to use regular 2mm apex seals as you have and are having great results. You should be fine. Here is the actual Dave Lemon info.....read the very last post:

http://www.coloradoscca.org/prodcar/...pic.php?t=2096

Also some info from ausrotary:

http://ausrotary.dntinternet.com/for...263&highlight=

Hope these help!

 

Damn! You beat me to the punch!

I was looking into building A P-Ported 13B towards the end of this summer. I figure it should be more or less equal to the 13B P-Port that Mazda used in its factory race cars in the mid-80's. If I remember right, those motors had 10:1 cr's.... I figure the motor should be good for 275RWHP with conservative port timing and reasonable drivability (at least for a Peripheral Port).

As for your question, you'll be fine if you you milled the rotor to the proper depth. The rotor is now the dimensional equivalent of all 85-93 rotors. In fact, my engine builder (Bruce Turrentine) uses modified Renesis rotors in his aircraft motors.

~Hakan

 

Lasse Wankel,

Please don't forget to post your dyno results on the forum. Are you using a chassis or brake dyno??

 

I am using a brake dyno corrected to SAE hp. Last engine i dyno'd was 313 hp on alcohol 13B PP rectangular port.

 

Update on dyno day Sunday. I didn't finished to get every small parts in place so i hope i can dyno on Monday if the dynooperator can and will. i'll keep you posted!

 

Hi Ted,

My local workshop has built an NA 20B to fit into a first gen rx7. It's running a PP with a very huge custom trottle body, and microtech MT-8. Dynoed about 300@wheels. We've been using PP 13b's, but were no matched to the NA civic that were producing 300@wheels too. And these piston guys had the ratio's to play with. But finally we've gotten fastest NA with the 20B 1st gen rx7, and fastest 2wd turbo with a 20B GT42 fd. Even the Silivia's running RB27(HKS Stroke-up to2.7ltr) and T88@2bar boost was not up to the FD's 20B which is only boosting at 1bar.

 

Got any direct info on this 20b w/GT-42 boosting 1 bar? I would love to see some numbers.

 

You should make way more power than 300rwhp with a PP 20B.

 

A PP NA 20B should be around 400hp on a chassis dyno.