Hi guys,
My friend has a lotus7 with n/a 13b in it. It's street ported, and has fuel inj. along with a few other good mods. He is a big time perfectionist and does things properly and knows a lot about rotaries.

He is looking around for a 2-piece eccentric shaft and carbon seals. This setup aparantly gives potential for 12,000rpm!
Can anyone direct me to where I could buy these parts?

Thanks, help is much apreciated

 

Grannies Speed Shop

Pineapple Racing

Atkins Rotary

I'm sure there are more, but if high revolutions is the goal, wouldn't you want ceramic seals?

 

kiwi re in NZ

 

Apprently he doesn't know that much j/k

Most likely if he's looking for ceramic seals, he's looking for Ianetti seals.

I haven't heard of 2 piece eshaft for 2 rotor engine. I also don't see a point of having 2 piece eshaft for 2 rotor just to spin higher (12k+). 20B eshaft is 2 piece to handle higher HP and torque.. and 26B is 3 piece for similar reason. Tell your friend to stop wasting time and just stick with factory eshaft.. not that he has much choice.

 

Or get one from the Rx-8 maybe

 

the guru (aka xtreme rotories) eshaft is some high end ****. this is for the person who revs for no good reason or needs to handle alot of boost. the reason why it is 2 piece is to allow for a center support bearing to eliminate vibration 8000+ rpms. the crappy thing is, if you are running high boost, a reason why you are getting an eshaft from guru, then you are looking at pitting the rotors. if you really want the bad *** of the bad ***, get nrs ceramic coated rotor housings, nrs 3mm 1 piece gray apex seals, guru e-shaft, xtreme rotories stud kit, guru stationary gears and the racing beat cnc rotors that have not even hit the market yet.

 

The 2-piece shaft allows for a bearing to be inserted into the center iron, which supports the shaft in the middle. You would never be able to snake a regular shaft through the smaller opening created by the bearing assy.

 

why would anyone want to spin to 12k rpms?

 

Why wouldnt you?! it's non-turbo too...

Thanks for all the feedback guys.

So ceramic seals are better than carbon for those sort of revs?

 

That too!! Just in case, he's talking about for 20B. LOL!

James81... Unless he's building a race car, ceramic seals are waste of money.

 

It is a sorta street legalish car only driven to races, raced and then back home again, it's got a race clutch and really is not pleasant to drive already so...

He drives it hard too, so what is the estimate price of the 2piece E-shaft?
How much do ceramic seals cost opposed to carbon?

 

The e-shaft is about $2500 i think, ceramics from NRS are in the $1,500 range. Carbon seals are cheap, about $240 a set. Big price difference. Carbon and ceramic both handle extreme rpms, however carbon doesn't seal as well at low rpms, and wears fast.

 

I have one in my motor ! https://www.rx7club.com/rotary-car-performance-77/two-piece-guru-type-e-shaft-635143/

 

WOW! I learned something new!

 

[QUOTE=james81;7488089]Why wouldnt you?! it's non-turbo too...

QUOTE]



Unless you could actually make some hp gains up there, then I wouldn't want to spin that high. Just because an engine can rev high doesn't mean it's making more hp. Hondas spin high b/c it takes that to make power with Vtec. Do you think Supras that have near 1,000 hp are spinning 12k?!? Not even.

And this is a non-turbo engine.. so the argument that you have a large turbo and need the rpms to get it boosted to max is not applicable.

So I'll say it again, why would you even want to spin to 12k?

 

Look at bikes..look how much power they make for their displacement..and they rev to 13k ranges. Example Yamaha R1 - 1000cc making 180 hp NA at 10K+ rpm

 

Because the number of power strokes per unit of time is one factor in calculating power.

 

Two piece e-shaft here:

http://www.rotorsportsracing.com/per...torclearancing

 

yeah i know that. but engines have a peak for their horsepower gains. After a certain point the rpm to hp/torque falls off. Just because you spin to 12k does NOT mean you will be making additional horsepower with each increase of increment in rpms. At some point the positive correlation between the two becomes a negative correlation. Engines don't just keep making power as rpms go up.

The argument could be made that if you run a large enough turbo you would need additional rpms to produce the force to properly spool the large turbo. However, he said it was a NA engine. I guess i'm just a little puzzled on the rational for spinning a NA engine to 12k with no explination.

 

A street port will be nowhere near enough to make power at 12k rpm's, you'd need something more along the lines of a J-bridge or a peripheral port to actually flow enough to make it worthwhile. Then you'd also need manifolds and exhaust to flow enough at those speeds. Friction is higher the faster you spin, and it'll wear faster too. You'd definetely need to underdrive all the accessories so that they can withstand the high rpm's so you don't kill the WP and alternator, and then the oil pump might explode, because you can't really underdrive it as far as I'm aware (I've heard of this happening). Is the clutch and flywheel rated for those speeds? No, so factor in racing flywheel, a 5.5" clutch and a scatter shield too. Now how about the tranny, can it take those speeds? Now add a racing tranny into the budget and it all really starts to look like a bad idea. At that point it'll be stupid expensive and totally un-streetable.

With some clearancing of the rotor tips and a good build with a normal e-shaft there's no reason he can't rev it untill the power drops off and there's no point in revving it any more anyway (9-10k).

 

 

the e-shaft is pointless. only certain people will be able to utilize is actual potential (IE:lupe's old car, ernie or whoever). but even then, they dont use this. the only need for this is if you have a 3 rotor or something. ****, i cant think, but everything has been covered already.

 

There are lots of rotors revving to 10K+ , it can be done . Saying that a 2 piece shaft is useless is an inaccurate statement. James81 , at some point in time you will have to make up your own mind and do what you want to do, you will also see that there are a lot of mis-informed opinions on here. I would also consider using the RX8 stationary gears .

 

Then why are they in such high demand? These aren't stock REW's we're talking about here...

 

B/c people think that revving to 12k makes instant extra horsepower power? Just because something sells doesn't mean it's worthwhile. Spice Girls sold over 7 million albums. That make them a good? The 12k rpm shafts sell because people want to use larger turbos and those take rpms to spool. Heck if that's your goal then go rpm crazy! But for a NA rotary engine there is ZERO reason.


I just read the statement way up top comparing a car engine to that of a sportsbike. I'll ask you this. What kind of torque/hp do those bikes run under 4-5k rpms. Not much. The engine is set up to produce hp at higher rpms. Cruising bikes have much more low end torque and rarely reach 5k rpms. Just because 1 engine does it does not mean it's valid across the board. ENGINE DESIGN.