Club 80-90 Forums

I may be completely off beam here but is there any reason why a Mazda rotary engine would be unsuitable, aside from the fear of the unknown? That and rotor tip wear. They do seem to be very powerful for their physical size and the noise is awesome!
Are there particular problems associated with their fitment in a T25?
Brooky.

mpg......

they are rev happy..

the turbo ones are better....

Quite thirsty as well.

Are they any worse on fuel than my DG at 22mpg around town and absolute maximum of 30mpg on a run? Admittedly it would be shoving a whole lot more weight than it would normally be used to but the same can be said of most of the engines discussed on this forum couldn't it?
Brooky.

worse???



I reckon you would be lucky to see 25 out of the car it came out of...

LPG the DG... dont know of any LPG'd wankles though...

I knew someone with a 54 plate and it did 20-25 in the mazda car, it got sold, but yes it did sound nice and it spooled up well.

Hmmm. Yeah but what a gorgeous noise! A bus that sounds like an F1 car!
There are other considerations. Only 3 moving parts; crank and two rotors, no valves, no camshaft, no cambelt or chains, virtually no constraints at all on revs and as every trainee mechanic is taught, making an engine rev faster is one of the four ways to increase power output. The others are; make it run hotter (better thermal efficiency), fill the cylinder better (better volumetric efficiency) and.....I can't remember the fourth!
So a turbo'd rotary engine fulfills two of those criteria. I'll have to try and find out how tall they are from centreline to top of plenum chamber.
Brooky.

Well.. expect about 15mpg if you are lucky.. a good bit of hasle and a bus that sounds and goes like stink...

the fourth?? "no excuse for cc's"...... ?

i own a rx8 and its not a nice car to drive slowly in. 231 bhp and revs past 9000rpm very good fun cross country but couldn`t think of a worse engine for a t25.

also very thirsty cost me £10 more in fuel to drive from leeds to swansea than it cost my brother in his high top westy 65/70mph.

So a turbo'd rotary engine fulfills two of those criteria.

Very poor in basic thermodynamic cycle, in some respects worse than a reciprocating engine, the way it compresses gas, the 'lost volume', high surface area to volume ratio, and lack of full gas expansion...

Horrendously complex way of making a rotary engine though, took nearly 50 years for Wankel to get it working then another what, 20 or 30 for Mazda, a big shame, if Mazda had chosen a rotary with a better gas cycle to start with, having their great engineering abilities, might be throwing all our piston engines away now.

but yes, they rev well of course, their saving grace

Oh porting limitations too... limiting volumetric efficiency

Also, don't rotary engines lack torque? You would have to rev the nuts off it to get it moving off the lights. Nice idea, but not suited to a bus. I still reckon the new Scooby boxer diesel engne is the way forward....

Slam

Also, don't rotary engines lack torque? You would have to rev the nuts off it to get it moving off the lights. Nice idea, but not suited to a bus. I still reckon the new Scooby boxer diesel engne is the way forward....

Couldn't agree more slamdunk, though if someone got their act together and developed the quasi-turbine it'd have so much torque you'd only need about 2 gears - that would be a proper rotary engine!

Ive owned a few rx7 s and disagree with most of your opinions,i found that the engine is very torquey even at low revs very quiet and the newer rx7 twin turbo very powerfull and reliable and costing under a thousand pounds for a full engine rebuild... I think it would make a good transplant engine and prefer the Type rb from the rx7 which produces more torque and bhp per cc compared with the factory restricted rx8 unit.
I think the only gripe would be mpg generally producing 25mpg on a carefull run but under 10mpg when your having fun......but just think 300 bhp standard what a smile....