DC350

Come on guys give me some insite on why they are better, i know they are unique, and they give more power per litre. But whats so great about them

HWO

3 moving parts means WAYYYYYYY less internal resistance
simplicity - once you get your head around the idea
small and light for the HP they are capable of.

niner

you can build them in your garage and they rev high as the sky

supergoat

But RX-7s still have a HUGE driveline loss percentage.

RETed

Huh???


-Ted

Felix Wankel

Um, show me a car that DOESN'T lose power through the drivetrain....

Grizzly

We aint talking drive loss all cars loss power through the Tranny?

The Rotary engine is compleatly diffrent in every aspect the only thing they share is the Fuel and air they both need.

U show me a car you can dubble the Bhp out put without any problem, it can be rebuilt in a weekend (if you know your way around one), 3 moving parts,very Light and very interchangable.

They are alot stronger than people give them credit for.

All i can say is DRIVE a tuned RX7 then come back hear and start again?

NZConvertible

Driveline loss is just that, loss through the driveline (gearbox back), it is nothing to do with engine. An since all the RX-7 driveline components are quite conventional, there's no more loss than a similar car.

To answer the original question, the main advantages are:

• fewer moving parts means less frictional losses
• no mechanical losses to drive valvtrain
• no pumping losses caused by valves in the air path
• lack of reciprocating parts means higher revs easier to obtain and the engine is smoother
• much less height than a piston motor, fits under a lower bonnet line

There's more but these are the biggies

BhamBill

I'm not knocking the rotary, but any engine can be rebuilt in a weekend if you know what you're doing. Ever watch them tear down an engine and "freshen" it in 45 minutes at the drag strip?

supergoat

Um, that's not what I implied at all.

I just meant that the RX-7 seems to have a higher driveline loss than most other cars I've seen. I've seen a stock 88 non-turbo register 115 at the wheels. that's 20% loss. Same with the 89-91 registering 125. Also a 20% loss. That's higher than any stock other car I've seen dyno'd. I usually see 15-17%

supergoat

Grizzly

BhamBill ? You try taking an engine out of a car replacing ALL the bearings, seals and gaskets put it back and set it up in Two days?

drag people do not pull there engines apart at the strip! they may take the heads off to cheak for damage but i have never seen a racer replace a piston or change all the bearings at the track. i know a Top Fuel Funny car owner and he would be P****d if his engine was thrown together. Changing and engine in the car is diffrent that is done alot at the track.

We are talking about an engine that you can take out your self with little experiance armed with a Haynes manual rebuild it in no time at all. remember 3 moving parts compared to how many in your stock v8.

RX-7Impreza

the only way i can see a larger loss of power through the driveline would be that there is less rotational inertia in the engine. but any loss there would be gained in other areas

justin

Grizzly

SuperGoat the Rollers are only a rough figure at the Flywheel, you can't say its defanatly 20% loss with out pulling the engine and geting it riged up to a Dyno. That is the only acurate way of geting the Flywheel figures.

BhamBill

I'm not looking for a big argument. I pulled the engine (327) from my 65 Corvette on a Friday night, tore it down on Saturday morning, cleaned everything and put the short block together by evening. Sunday finished the engine and put in back in the car. Running before midnight. It's not unique.

fastrotaries

Ok how about this reason: It is posssible to get 550 HP out of a rotary and still be STREETABLE. If anybody denies this talk to Pluto of call Ari or something. That HP leads to 6.875 Horses per cubic inch. IF your standard 350 V8 like lets say on a Camaro Z-28 produced that same amount of HP per Cubic Inch it would be about a 2,406.25 HP motor. I have 207 HP out of my 89TII with simple bolt on's. Z-28 would have to produce 905.625 HP to produce that same type of displacement efficiency. there's a reason for you!!

swoop

Rotaries are better at being drag race motors too.
No valves to adjust--No tear down between runs.

Node

iTrader: (1)

We have two big triangles that spin in circles in a little double circle oval looking things, one big stick, 4-6 holes, and a shitload of air and fuel

Poindexter10thae

iTrader: (2)

I have to agree with Fastrotaries. I have built up 3 chevy small block engines(one for all nitrous, 383 stroker, and a 410 stroker). These engines I had in my cars/trucks in high school, they lasted a little while, I still love chevy, but I could NEVER leave it alone, it was always something. And every single one of those engines threw a rod,one time 3 rods.

Rotaries have never let me down in that manner.

repuguru

Circular motion as opposed to Linear Motion is why the rotary is always smooth feeling and powerful for its size. Your never off of the power stroke.Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmnnn

2DoritosOnAStick

It's not circular motion, more like wobbling, although more efficient that pistons going up and down. And remember, if the eccentric is moving at 9k, the rotors are only moving at 3k.

Felix Wankel

Actually, its 6-8 holes. You forgot the exhaust ports.

repuguru

The rotors spin from tip to tip in their motion of going around, It may not be a circular pattern the crank forces them to travel, but I dont think it Wobbly Motion

mazdaspeed7

FWD, by its nature has a lower drivetrain losses from a simpler drivetrain. Most front engine, rwd cars lose 15-20% in the drivetrain, and Im sure some cars lose even more.

DriftFC

Because rotory engines rarely last more than 90K miles... d'oh!