Hey all, I was wondering if there are any companies out thier that make high compression rotors for the 13B. Or do you just have to use the S5 rotors?

 

I believe pineappleracing.com may offer them. I know they offer lightened rotors. The S5 rotors would be a cheaper solution.

 

no, no one really makes them. When the RX-8 comes out it should have 10:1 compression rotors, hopefully theyll be compatible with other 13B engines.

 

Sorry Node, but your wrong. They are made.
Downing Atlanta runs 12:1 rotors in their 4 rotor. Custom made. They will sell them to you - but you won't be able to afford it. I asked Jim Downing what he would sell a used 4 rotor for. His answer - $50,000.

 

David, are the rotors machined from scratch or are they modified stock rotors?

 

Not sure. They have the facility to do either, and Mr. Downing didn't say. (I didn't ask.)

 

I wouldn't be suprised if they created them from scratch. My guess is that the only way to modify stock rotors to run 12:1 compression would be to fill in the combustion recessions on the rotor. I don't think that would be the best or even easiest way to go.

 

I wonder if any of the guys in the na class are running the high comp rotors... It would be funny if there not... 9.7:1 and still kicking every one elses A$$

 

you can fill the stock ones in and then CNC machine the pocket out for any ratio you want!!!!


MWW

 

Really? Never heard of custom rotors.
Interesting.
Do you have any more information on them?

 

are they not just 787b rotors?

mike

 

Nope. I could go by there and ask though sometime. His shop is 5 min from my house.

 

lucky

mike

 

I am planning to fill the combustion chamber with a trick alu insert to get a higher c:r. Plan to go all out PP and methanol. What kind of c:r should i use for a NA 13B?
Any inputs?

 

Stock rotors are steel right? Don't steel and aluminum have different expansion characteristics under high heat? If so, then your aluminum inserts would crack off. I'm probably waaay off on that one though.

 

That's what I was thinking (aluminum / steel)

I always wanted to compare a series5 na engine with the same compression as a renesis (10.0?) and streetported intake and enlarged exhaust ports to a stock renesis engine in terms of power output and shape of power curve.

Fun Dream: NA 13B in go-kart with 12.5:1 rotors and peripherial ports.

 

Bridgeported's Fun Dream = Grim Reaper on wheels!

 

Sounds like a expensive way to blow up a motor go to a machine shop have them make you new rotors and fill the dish in a little....

 

Wouldnt you have to get them heat treated so they dont fail? Or is that even done?

Can you simply just fill them in and how do you fill them in?

 

I am gonna use 7075T6 heat treated alluminium block which i think gonna cope with the heat in the combustion when it occurs,it's only a very little time when the alu maybe expands a little. I also gonna use some paint on heat barrier from Powerhouse. I have plans to dyno this engine this winter with lot of power tricks for a N/A PP, hoping for 350hp or more!

 

Good luck! In the in it might be better/cheaper to go with completely custom rotors machined from a block of heat treated aluminum--or whatever other material your heart desires. It might also give you the potential to make even more power.

 

I was thinking the samething...how much do you guys think it would actually cost to get to brand new machined rotors???

 

He used to own his own foundery. So i am pretty sure they were actualy cast. He casted his own AL housings also.

CJG

 

i am a machinist and i can tell you that it would not be cheap to make new rotors. at a quantity of two it would be around 1200.00 each. dont forget that all of the apex,side,corner seal slots are wire EDM'd and that is not cheap!! as far as using aluminum inserts go, there is no way that is going to work you have 1700+ degrees in the cumbustion chamber and the rate of expansion and the cast rotors is way off the mark. you would be better of plasma spraying the CC and CNC grinding the surface to a specific compression. i have access to all of the equipment to do this but it would have to be a SERIOUS group effort to make it affordable. i run methanol and would like to have 10:1 and i bet 12:1 on a NA would be beastly!!


MWW

 

In piston engines... does anyone have an example of how much power rasing the compression makes?