rmayton

ok ive never said i was a master mechanic, a decent paint and body man ok but not a master mechanic.

i hade a major discovery today.

asuming my rotary motor is 1.2 liters, and running correctly, it should make approx 100 hp right?

if you put this in perspective a normal production 5.0 v8 should produce about 416 hp, which it doesn't come close to making.

therefore the rotary is extremey efficient at making power in its stock form. Although it is cheaper to gain a high hp number in a v8, the power to weight ratio should be a lot less.

someone told me a rotary weighs approx 80lbs
if this is correct, and all my calculations are right, i have gained more respect for these motors in 3 months than i have for anything else in 18 years

this is another reason i love my rex

pls correct me if im wrong on anything.

1rx7owner

Sounds good to me.

wwilliam54

my 12a weighted 220lbs dry and stiped


the end and center pales weight alot for there size

wwilliam54

my 12a weighted 220lbs dry and stipped


the end and center plates weight alot for there size

Pittdp

You can buy the aluminum once the lighten the load, but they cost so much.

gamble302

normal production 302 wont make 416 hp no way no how.......
waitin for cloud to chime in, maybe youre talkin about the stock bottom end heads/can/intake in mm&ff or whatever magazine did somethin like 400hp. not cheap though, heads are like $1500 alone

vipernicus42

iTrader: (4)

Then again..

There has always been that debate about how to tell the displacement in a rotary engine.. Whether it's actually 1.2, or if it should be doubled to 2.4...

2.4 = 100hp
5 = 200hp

That sounds more realistic now.

Jon

mar3

iTrader: (8)

Displacement is displacement...there are engineering standards the OEMs has to go by to determine engine statistics that get reported to various gov't agencies, and Mazda called it at 1.1/1.2 L, so that's what it is. And I wouldn't say it's more efficient (look at the gas mileage as a true indicator of efficiency...) but it doesn't have any "down" time like a boinger, so it gets more power per pulley rotation. Each time the "chamber" passes by, it pulls an intake charge whereas in a 4 stroke, that only happens every 3rd time the intake valve sees the piston visit...

JALVORD_2003_68

The method of determinding the displacement of a rotary is not so cut and dry, many consider it 2 stroke and therefore should be measured out to be a 1.3L, some don't consider it to be a 2 stroke but a 4 stroke, don't ask me how they came to this conclusion, so the displacement should be 2.6, or somewhere in that area. I tend to agree with the people who measure it as a 4 stroke of sorts. anyway, just my 2 cent

REVHED

It's pretty simple. Mazda says the 12A is 1.2l. But, because rotaries work on a two-stroke principal of one combustion event per rotor per revolution it actually displaces the same amount as a 2.4litre four-stroke piston engine. That's the figure you need to use when doing calculations of any sort. It's also the figure most racing organisations use to achieve parity with other cars.

Swolbynos

The renisis makes 250hp so that is still more efficient than a reciprocating engine, and gets way better gas mileage. I think it has a 4.44 rear axle so if it had a 4.10 like other 7's the mileage would be even better

MikeLMR

the displacement of a 12a is 1146cc's but because its rotary (its not a 4 stroke or a 2 stroke ... how can it be a stroke is piston engine term ) running on the otto cycle this means that it is for comparisons sake similar to a 4 stroke piston engine of twice the size.

This is due to the 4 stroke cycle "wasting" one crank rev inducting and exhausting the charge

Its a complicated one as its not easy to compare the rotary to a piston engine and the "double" capacity rule does not account for the fact that the power stroke has a different duration to that of a piston engine too