That's horseshit, what kind of applications do they claim they "break all the time" in?

 

I think you may also be missing one point..



on very high HP, high boost applications you will encounter a large amount of eshaft flex, which just as it sounds, does bad things.



If the rotors are more stable in their orbit, perhaps this flex will be cut down a small amount.



Remember how close the tolerances are in this engine, It doesent take much to make a difference...



I agree that the stock ones are fine for anyone running a sane amount of HP and RPM, but mabye they do some good...

 

That sounds a bit backwards to me, the eccentric shaft flexing being due to the uneven way the weight on it is counterbalanced. The rotors "get unstable" because of the e-shaft, not the other way around.



Find a way to mount the counterweights in the middle of the rotors and flex will be all but gone.

 

The most important factor in performance of a gear train is how the gears are matched to each other.



A dirty gear box with unmatched gears due to slight difference in size caused by tolerances will cause certain teeth to be loaded more than others. The accuracy and precision of each tooth will also determine how the gears will mesh and how the load is distributor on the individual tooths.



For me if I had the money I would by 100 sets of mazda stat gears and rotor gears and try to make 20 or so matched pairs. With the other ones going into the scrapper or used in less demanding applications.

 

Those guys are all running IPRA bridgeports insanely high I want to say BP's with 300+ hp running up to like 12.500RPM.

 

they should design a new center housing with a stationary gear and put a gear on both side of the rotor

 

that what i was thincking extremerotaries alredy do a centre bearing.

this is what guru said about the centre bearing



GURU Racing can supply a two piece eccentric shaft for a 13B engine that substantially reduces eccentric shaft flex as well as providing extra bearing surface area. The end result is increased horsepower with substantially increased reliability!



The unit is especially designed for exceptionally high horse-powered and high revving engines, where bearing fatigue and crank flex is detrimental to engine reliability.



Technical Specifications:



Applications:



Currently delivered for all 13B Mazda engines

Suits Mazda RX7 models (Generation 1 - 3, Series I - VI)

Suitable for road and race applications



[attachment=37372:attachment][attachment=37371:attachment][attachment=37370:attachment]

General:



30% more bearing surface area than a standard 13B Shaft

Helps reduce bearing failure & fatigue on high boosted turbo engines

Helps eliminate crankshaft flex at high rpms

Reduces crankshaft flex therefore rotor clearance can be set to a minimum and seal clearances can be set tighter for increased horsepower

Stronger

1.2kg lighter than a "standard" eccentric shaft

Kit supplied with all components (including needle roller bearing) and specifications for centre housing machining to fit the centre bearing.

13B 2 piece eccentric shaft with centre bearing $2750.00 + GST

 

yes but we're not there yet

 

I did some reading on the IPRA bridgeports, and it seems that a number of racers preferred the early 13B cranks over the 2 piece ones.

 

because they are way cheaper?