Anyone care to explain the principle here?

 

Mazdas new RX-8 seems to develop ridiculous HP from its 1.3 litre rotary engine.

 

Seems good to me...

 

 

comments?

1300cc of combustion space - but because it doesn't waste loads of energy through the recipricol motion of a 4 stroke piston engine it produces loads of power for its size.

http://auto.howstuffworks.com/rotary-engine.htm

 

Damn good design IMO. RX7 engine has a 3-rotor engine I believe - so each must be about 433cc?

2 rotor engine, the MAzda cosmo came out with both 2 and 3 rotor engines.

Is there still a load of controversy about how they measure the capacity? I remember years ago when Norton had a rotary engined superbike that used to win all the time. It was entered as a 600cc, but loads of people were saying it was really over 1 litre. Wicked bike though, very very fast, and bloody deafening!:) :D

Originally posted by x-biker

Is there still a load of controversy about how they measure the capacity? I remember years ago when Norton had a rotary engined superbike that used to win all the time. It was entered as a 600cc, but loads of people were saying it was really over 1 litre. Wicked bike though, very very fast, and bloody deafening!:) :D

 

Always wanted one of those :)

A mate of mine (who raced against the Norton) used to refer to it as an 1800cc single stroke motor.

He only says that because he probably lost to it ;)

 

Its an amazing engine.

the RX-8 in the adds looks cool - wish I cud afford 1:(

Originally posted by SRRAE

He only says that because he probably lost to it ;)

 

Its an amazing engine.

 

 

Everybody lost to it, even the alleged 600cc rating against 1000cc bikes it still won - helped a little by the professional rider of course.

 

Actually, I think it holds the record as the fastest British bike ever at the IOM TT.

 

 

Anyway, interesting info here :- http://auto.howstuffworks.com/rotary-engine.htm

Pretty pic

and another ...

I wonder why people debate the size of the engine. I have heard people say you double it or something so I have seen the engine written down as 1300cc x2, 650cc x 2, 2600cc.

 

 

I went watching the old Norton bike at Oulton Park a few years ago. Quite a few now. The bike was out doing a final lap of Oulton after the death of Steve Hislop.

I had an rx7 turbo11, its a 2.3 twin rotar, loved it!

The last rx7 has a 2.6 twin rotary engine (2 x 1.3)

Does the rx8 only have a 1.3 then? sure its not a 2.6?

Anyone interested in buying an rx7, make sure its very low mileage or had a recon engine because the tips of the rotors do wear out usually around 70 to 100k miles. Recon is about 2k.

I also hear that you should red line a RX7 every now and then to get rid of the carbon deposits at the end of the rotary.

Various specs for the Mazdas rotary's but essentialy they have one combustion chamber of approx 0.65L capacity per rotor, usually two rotors hence 1.3L, but each combustion chamber fires once per rev as opposed to a four stroke 'boinger' engine which fires once per two rev's. Hence to compare engine capacity in a realistic way the rotary engine capacity is doubled to give 2.6L. If you think the Zed's fuel consumption is high try an RX7 it virtually throws fuel out the exhaust. Nice interesting car though.

The problem is because capacity in a 4 or 2 stroke is based on swept volume. Since a rotary engine don't go up and down, how can you have swept volume?

 

If you interpret the ****el (oo- er I always wanted to say that) in one way, you can say the swept volume is (say) 588. But this gives you many more power impulses (look at the anims posted earlier) for a single turn of the crank than the equivalent single cylinder 600cc.

 

So given that the old rule was 500cc 2 stroke = 1000cc 4 stroke, how do you rate the ****el?

 

Cheers - Gio

LOL... can't say w-a-n-k-e-l here without censorship! ****el? ****EL?! :)

 

Interesting engines, but why are they in a minority?

i would say servicing cost and reliability is the major concerns, but in terms of efficiency they are able to produce a lot of power from a small capacity, but they are very thirsty in the process.

I had an RX7 for many years,brilliant car,it could rev to infinity.But I must admit it was the fastest thing between two petrol stations.Did you know that at the Bonniville Salt Flats they managed to get one to do 246 MPH,now that is quick!

I used to work with a guy who worked for a place rebuilding rx7's when i asked him if they had to be rebuilt at 60k, and he said that he fad seen many in for rebuilds as low as 12k, having said that hes seen them running strong with over 100k on them and no rebuild, suppose alot of it is down to how you drive it same as other cars.

 

Still cant get my head round an "engine" with no pistons???:confused:

The major problem with rotary (since I can't say ****el hehehe) engines is tip wear. The rotor tip is in constant scraping contact with the chamber wall and they had to develop all sorts of clever sintered materials which cost a fortune.

 

Also, they are a nightmare to get through emission standards as they chuck out all sorts of unburnt hydrocarbons. And drink a lot of fuel.

 

That's why - although they are nice lightweight and very smooth, the first ones were not a success (kept having problems with the tips) and it took a manufacturer with deep pockets to get it a success - eg Mazda.

 

First production car IIRC was NSU ro80 in 67 http://www.motorbase.com/vehicle/8/9/0/primary.html

Went for a drive in one of these back in the 70s and very smooth - but on its second engine.

 

Because it was so light, a lot of bike factories went for it - Suzuki, Van Veen and most famously Norton. The Norton F1 http://www.jpsnorton.com/start.asp was an absolute stonker with a rasping roar which made your hair stand on end. And it won!

 

Norton also did a small range of Classic, Interplod and Commander. I rode a Commander once and parked it on a Range Rover (tho that's another story). Great engine - really turbine like.

 

In looking up these links, I just found a very very sad bit of news http://www.andrew-grant.co.uk/fineart.htm

Norton has been put into receivership and is being sold off at auction:cry:

 

God, I dunno - first Concorde, now Norton.