But it does allow for much easier ingress of the intake charge and while the ultimate point of sealing does take place at the side seal, a square, flat shoulder doesn't exactly promote flow now does it? It you really want to nit pick, it doesn't change port timing but it'll have the same effect!

 

the rotor mod looks very interesting to me..

less weight
lower compression
IMO, a significant step forward in charge flow.

while Scott's points as to port timing are correct as to the seals being the ultimate arbitrer of timing Cheesy did say "effective" port timing and it is difficult to disagree with his conclusion.

as to what the effect is quantitatively, that's a hard call to make without testing. as one who used to own a flow bench i think that these flow ramps could be quite beneficial, but that's my own opinion.

it would be interesting to pursue this rotor mod. i sure would put them in my motor.

howard coleman

 

so the top of the face is machined to give better flow, lower compression and less weight right. now why don't they machine the bottom also. would that cause to low of a compression? and do the rotor have balanced after machining?

 

Sorry, but that is not the case. The port timing on a side port is affected by the *rotor* edge, not where the seal is. This is because there is only .004"-ish clearance between the side of the rotor and the side housing. You are NOT going to get any kind of airflow through a crack that thin. The effective port opening is done by the edge of the rotor, so relieving the rotor in that manner allows the intake port to open (FLOW!!) that many degrees sooner. It's actually quite a lot of degrees, since the face in question is moving "up" so it takes a lot more degrees of shaft motion to move the rotor face that few mm to the side to open the port.

 

Picking up my engine on Tuesday night from CLR so I'll try and nail down some definite CFM improvements using these rotors for you guys...or you could just call them yourselves. Not too many phone calls though, I want Carlos to get the engine back together! Maybe he'll let me take a few pics. We'll see. I'm very very anxious to see how this engine is going to run and just how it'll improve my spool times vs. the old engine. Should be night and day.

 

Hey, I hate to ask but what does CLR Motorsports charge to do up a set of rotors like what you posted in the pics?? I am building a 20B motor and think I could benefit power wise to have my rotors lightened.. I have seen many different approaches to making the rotors lighter but was really impressed with what CLR did to your rotors.. BIG question how much per rotor and I am sure wou need to balance the entire rotating assembly after he is done hoging them out.. right????I tried to call the number listed in this thread but was unsuccessful in getting intouch.. So again, how much and what is the turnaround time???

Maybe there is an email address I can get so that I can make contact via email..
Please advise...

 

clrotary@bellsouth.net

He may be a bit busy at the moment (building a few engines including mine, and was VERY ill earlier in the week) but usually answers e-mails late at night within a day or two. He's also on the forum (GT1 20B or something like that).

As for prices, not exactly sure, you'll have to get a quote from him. It's NOT inexpensive but for reliability's sake, worth every penny IMHO. It's probably somewhere around $1,000 for a 2-rotor setup if he supplies the rotors. Don't quote me though!

 

HEY when is someone going to make some TITANIUM rotors.

 

That'll never happen. We'd have more luck with beryllium.

 

LOL you think those things are lighter - they are NOTHING.

the lightest i know of are the prototype aluminim/ceramic insert rotors used for the re10x engine weighing in at about 40% lighter then cast iron rotors (engine designed to hit 10,00rpm - i will psot pics once i get acess to my camera agian.

I also believe the renesis rotors are simlar as in beign a lot lot lighter.

 

Which are you referring to as being nothing? CLR's? Beryllium? Titanium? Let's see, we can actually get our hands on the CLR rotors...so they're something. Beryllium is one of the lightest of all metals (atomic weight of 9.012) and has one of the highest melting points of all of the light metals. Supposedly, F1 teams during the height of the turbo days used pistons made out of the stuff. Problem is, it's very toxic. And the properties of titanium would never allow it to work. And the prototype ceramic/aluminum rotors would probably still be heavier than beryllium but unfortunately, you, I, nor anyone else will get our hands on a set of those :-) So what's nothing again? All relative, isn't it!

 

ok what is the re10x engine i've never heard of that
and i'm guessing u have access to these rotors and engine you're talking about because you said you will take pics of them with your camera right? please more info

 

Talked to Carlos about the CFM improvements with these rotors...too difficult to nail down an accurate number like it would be on a piston motor with cams/valves determining the start/stop of the intake phase. Just too many variables with a rotary. What it does do is expose the intake ports for an additional 140 degrees of rotation. Essentially it makes quite a big difference. The engine he's built for me will support 600 horsepower (I'm assuming rear wheel) and that's with a big street port (Cosmo).

 

so is that around 45 degrees for each rotor face adding up to 140 degrees total for each rotor or how did he come up with 140? also are u using a 13btt or 13b-rew engine?

 

i think i'll have to give this CLR Motorsports a call when it comes time to build my turbo engine.

 

RE motor actually, but it should be the same on an REW if the ports are as large.

 

i totally agree. the seals are most effective for compression and power strokes. BUT, on a forced induction engine that tiny clearance would let some air pass by i guess.

 

Actually, they were using AlBeMet pistons (or Mercedes/Ilmor was anyway) until around 2000 when they were banned. Elastic modulus was one of the big concerns; one of the failure modes was tearing the centers out of the pistons at high RPM. Resistance to heat wasn't that big a deal in comparison. They were supposedly banned for cost and toxicity reasons, but like everything else in F-1, the FIA did it the dumbest way possible; by specifying that the elastic modulus of pistons couldn't be higher than (off the top of my head) 40MPa... which of course, led to a whole new generation of metallurgy where everyone's cooking up alloys at that specific stiffness that are far far more expensive and toxic than AlBeMet.

Look up Duralcan... it's a castable Al-Si metal matrix composite. I was semi-seriously doing some research on it as an attainable exotic rotor material. Thermal expansion, strength, and modulus for some formulations are about equivalent to the cast iron we have and tolerate, but density is far far less. The Si particles mandate diamond tooling to machine it though, as it'll eat anything else. There's companies out there that'll do low production runs of castings in it (or all *SORTS* of other fun stuff) from CAD files for reasonable costs... the word "reasonable" of course being relative to what it would cost to do it yourself, and not relative to the cost of buying Mazda's rotors. Still, I'd love to see what would happen...

 

Ok I have some q's First are the rotors all aluminum minus the gear inserts? After lightening do they have to be re-balanced? What is the purpose of the material removal from the face of the rotor rx7tt95 posted. Also is the compression ratio difference between the different model rotors purely generated by the size of the divet on the face? I have access to cnc equipment and knowledge of machining surfaces like that so I was thinking it might be fun to pick up some high compression rotors and make low compression rotors out of them. Can someone point me in the direction of some helpful info or lend some wisdom?