bcmzr23

Is'nt the Renesis basically a race motor, or an application from Mazda's racing cars? Besides being a rotary, this is why it loves to be beat on and rev'd all the time correct? Also would explain some of the lackluster MPG. Looking at that and then having the 350Z drivers laugh at the lack of torque, another bragging right 8 drivers have is they have an actual racing motor in their daily driver 'Cause basically the Z is the same VQ found in the Altima/Maxima, just tweeked a little bit. Just some stuff I was thinkin about

Rhawb

Yes, this motor is used in the Star Mazda series. Most other series use 3-rotors, though.

chickenwafer

iTrader: (9)

the Renny used in the Star Mazda's isn't stock, but not too far from it. As far as I know they have custom PCM's, tweaked intakes and exhaust- but that's about it. They claim 250-whp which isn't too far off with their sequential transmissions and short power delivery path.

Most other Mazda racing vehicles, however, use a 3-rotor 20B or the new 4-cylinder MZR engine.

Rhawb

Just realized I've owned two of Mazda's race engines! ^_^

First with the 8, now with my Speed 3.

bcmzr23

Lucky

rotarygod

Your engine has nothing in common with the MZR race engine. It's an AER designed and built 4 cylinder. It is basically one half of their V8 race engine which shares nothing in common with the Mazda engine. It was also designed for direct injection too which again is not a Mazda design. When the direct injection finally gets put on the race car, it will be basically the direct injection system from the street car with some tweaking but that's it. That's akin to a race car using the same fule injectors and claiming it's a shared platform. Nope. Totally different animal.

At least the 3 rotor that was in last years Courage had Renesis rotors in it so it did share something. The Speedsource 3 rotor engines use 9.7:1 RX-7 rotors. They may have changed to the Renesis rotors but when they talked about the details of that engine at last years Sevenstock, it had no Renesis components in it either. Basically you have none of their race engines.

The Star Mazda cars use stock Renesis engines. We don't have race engines adapted for the street. They use street engines set up for the track. New intakes and exhausts are used which doesn't amount to much. They do run Motec ecus though. Basically it's no more than anything anyone else can do to their street engine.

Raptor75

One thing you can brag about is the advantage of racing in the Mazda Star is that the rotary engines run for the whole season without a tear down. Piston engines would need at least one tear down and probably more. The engines hold up very well which lowers the cost of operation.

Rhawb

Dear RG,

Please stop tearing down and subsequently crapping on my dreams.

Love,
Rob

machfive

I have but one thing to say:

Rotarygod has spoken!

Bastage

iTrader: (1)

and he did it without insulting anyone. All hail RG!

Razz1

^ ^ What does a cave man know anyhow?

8 Maniac

iTrader: (1)

kinda on topic question: what's the highest revving rotary that's been used? and what was it's rev limit?

swoope

iTrader: (5)

dont quote me, but i think it was the 4 rotor le mans engine.

14k rings a loud bell...

beers

DMRH

I cant see how MSP rotors would work in a non-MSP engine. Dont they have additional O-rings to prevent gas leakage.

Traditionally, the series-5 (89-91) N/A rotors have been the go with their 9.7 compression but the 10.0 compression of the MSP rotors would be enticing......

REgards

MazdaManiac

iTrader: (3)

I was deeply insulted. I am going to put RG in the hospital next time I see him. His head is too large.
Something like that.

Fred - have you any info on the Motec setup as it is employed in the Star cars?

8 Maniac

iTrader: (1)

oops

cool, thanks. I figured it would have to have been a race built engine (or someone with a lot of money and time on their hands). Not to go off topic too much, but would a 13B have more potential or less for rpms? I thought with more rotors the eccentric shaft loses reliability? or is it just more difficult to design, but still as reliable?

rotarygod

The R26B in the 787B was shifted at 9000 rpm. There was a comment made that if they could have revved it up higher, they would have seen more power. They held the rpm's down for reliability reasons. Bearing stress goes up with the square of rpm and after 7000 rpm, it really starts to take off. You'll do your bearings a favor by keeping rpms down and concentrating on making more power lower down. Most bearing stress is rpm related. Most seal stress is combustion pressure related. When you design around helping one, you usually end up doing the opposite for the other.

The Renesis rotors physically fit in the 13B. Yes they have an additional seal called the cutoff seal. This is there to protect the oil control rings from the hot exhaust gasses in the Renesis. When running Renesis rotors in older engines, you don't necessarily need to use the cutoff seals. However the race teams that do run the Renesis rotors do use the cutoff seals in the 13B. This is because it actually helps in an unexpected way. It also cuts off any carbon from having a path to the oil control rings. It also helps with blowby so it does do more than just merely cutoff a path for hot gasses.

If using Renesis rotors in a 13B, it is advisable to also use Renesis stationary gears and eccentric shaft as well as the tolerances are slightly different. The eccentric shafts aren't even the same between the 4 port and 6 port Renesis engines. Someone at Mazda must have been bored.

The early attempts at using Renesis rotors in 13B engines showed no improvement in power over the 9.7:1 RX-7 rotors. This was due to the overly excessive side seal clearances that the Renesis uses to account for thermal expansion from the hot exhaust gasses. Now you can buy oversized side seals for the Renesis and clearance them to earlier tolerances which should help them seal better. I've seen no definitive proof that they work any better though. Speedsource was running RX-7 rotors and the Courage ran Renesis rotors so go figure.

Ben98gs

But most of the high revving ones like that are in Drag Racing applications and I guarantee they do not last that long at that high and RPM.

baseballgenius80

In the words of Ricky Bobby, "I wanna go fast!"

Rootski

iTrader: (1)

How the hell do you know so much? Teach me your ways.

RoXanneBlack8

the star mazda 13b msp also have larger throttle bodies and a dry sump (no oil pan underneath the engine) and its 250 crank hp, not wheel.