Robinson.R

What horsepower is the 12a, can't find it anywhere

MattG

iTrader: (2)

100 hp. Thats flywheel, not the rear wheels by the way!

PS. Love your sig! makes me laugh just like the real thread lol

Snapshot

I think it was 98 -I have a manual somewhere. However a RB head to tail job increased it significantly w/ little effort. 1st thing I did w/ both 7s.

trochoid

iTrader: (6)

101 hp, 105 lb.ft. torque, asked and answered in the last 2 weeks.

MattG

iTrader: (2)

WOoT I was only off by 1 hp!

Dr_Jeff

So then what is the rear wheel horsepower, is it differant with 4 speed, 5 speed, & auto, if so what ?

jeff

rx7owner

probably only around 89 rwhp

81gsl12a

iTrader: (1)

lol dr. jeff your location is grate hahaha

Dom

It actually depends on the size of the turbo

AcidAngel7477

iTrader: (16)

damn, i always wanted to know that....i knew it was 100hp, wow!! thats kinda weak....but it still seems fast..i dont think they changed the hp just cause it was auto, 4spd or 5spd right? i mean why would they? that would be kinda stupid but then again.....damn i have to get to upgrading that 12a engine....lol

BTW all:

whats the max hp you can reach with the 12a....??

MattG

iTrader: (2)

Rotary shack has a 680 RWHP 12a

He is a member on this forum. His Id is 680RWHP12A also lol

I think you can see all the details @ www.rotaryshack.com

85rotarypower

The hp doesn't change at the flywheel weather you have 4 speed, 5 speed or an auto, but the rear wheel hp will change slightly. I read a thread a long time ago when people were posting their STOCK rear wheel hp numbers and it was quite sad to see. Most were in the high 70's to low 80's range. You'll see even less with an auto as they eat up a lot of power on any car. With a full set of bolt on power upgrades on a 12A, they generally dyno in the low to mid 120's. Full set of bolt ons includes an aftermarket carb and intake, exhaust and removal of any unnessesary items from the engine.

Oh ya, forgot to mention that they do change the flywheel power output on some cars weather its auto or manual. The RX-8 is a perfect example. The auto RX-8 puts out 196 hp or something like that, while the manual RX-8 puts out 238 hp or something. This could be due to the decreased redline, but I'm sure there are other things involved.

fcdrifter13

Not enough.............never enough.

nick1

OH my god, you have no idea how much i just laughed my *** off!!!!

OPENSHOT RULES

hahahaahahhaa oh man this is too much.....ahhhhhhhh for the love of ALL THAT IS SACRED IN THE WORLD!!! GOOD LORD

fcdrifter13

I just saw sig with the accual guy in it. OMG that is so funny.

steve84GS TII

101HP might not seem like much,but compare a piston engine with the same HP and I garuantee it wont have 100+lbft of torque. A 100HP 4 cylinder will typically make only 60-70lbft of torque.That large,smooth,even torque curve is what allows that little 1.1L engine to push the 1G around with little effort.
The same is true of the SE's engine.Its a torque monster,with peak torque availlible all the way down at 2500RPM!

misterstyx69

iTrader: (142)

haha..sorry couldn't help it..like a supliminal massage or sumthin..speekin to me?..(boy needs two days of hands on training)...back to subject..wow 101 hp..but are the 12a's more durable compared to the 13b?..meaning forgiving if you decide to add turbo ..(turbo N/A)?..kinda related to thread ..apologies to starter..

dufourmike

iTrader: (1)

ive always wondered, shouldnt a 12a rev higher as the rotors weigh a pound less than s4's?

steve84GS TII

There are no bearings in the middle of a rotary,so the 12A has a natural advantage over the longer 13B in respects to high RPM operation.Since the rotors are on eccentrics,at high enough speeds the Eshaft will "whip" in the center,allowing the rotors to strike the housings.
Lighter rotors and hardened statinary gears will help,but having a shorter Eshaft makes the whole thing more stout,without the detriment or cost of the previous mods.That said,the S5 N/A 13B and the Renesis 13B rev to 8000 and 9000RPM factory redlines,respectively.The 12A unfortunately didnt gain any support from Mazda after 86' or else it could easily be a factory 10,000RPM engine with todays technology.
If you wanna make a high RPM 12A you have to build it yourself and incur costs and comprimises in the process.Carbon apex seals allow high RPMS but seal poorly at low speeds and are fragile.Hardened gears and race bearings are costly and extend break-in time.Porting will be required to actually make power way up high,but unfortunately it kills what little lowend torque the 12A has already....(yea,105lbft isnt much,even though it is a fair amount for a 1.1L)
In regard to turbocharging,you can turbo any rotary.Boost creates torque where it never used to be,and you usually dont have to rev the hell out of a turbo engine to go fast,so high RPM peration isnt a big concern.
Keeping the engine in one piece is a BIG concern.The 12A is not factory designed to be turbocharged,so the compression ratio and internal durability arent the same as the factory turbo engines.
You run a higher chance of failure if you boost an N/A engine,everything from detonation failure of the apex seals,rear plate cracking and so on.For reliability,its best to choose a strong platform and none are better than Mazda factory turbo engines,be it a J-spec 12AT,13BT or an REW engine.

Nitro789

hey i dont mean to rain on your example here but i have a 84 RX-7 with a 12a and i also have a 92 corolla with a 4A-FE, my 7 has 101hp and 103 lbs of torque while my corolla (at stock) has 103hp @5600rpm with 101 lbs of torque!!! now correct me if im wrong but that sound to me like similar hp with similar torque even though the RX-7 has less weight and RWD, right?

Anthrax Mike

It often appears that less powerful engines make simular hp and torque figures. But as the numbers start to climb it often looks like there is a trade off, though this isn't always true. Examples the new F430 makes 490 hp but "only" 343 lb-ft. Other cars like the Ford GT make 550 hp and 500-some lb-ft.

The new Mazdaspeed 6 in my garage has 274 hp and 280 lb-ft. So its never given that hp and lb-ft valves will conicide.

There are no blanket statements.

Excempt that Anthrax Mike rocks.

renagade_rotary

85.85 bhp

Directfreak

iTrader: (2)

You got one of those?!!

Lots of Pics, and tell me all about it. I am looking for a new DD.

steve84GS TII

Sorry,that original statement wasnt quite what I meant,I should have proof read it a little better.
What I was leaning towards was the observation that 4 cylinder engines of equal size and output(such as smaller Honda engines) are not able to match a rotaries torque output,even if they make an even 100hp.The problem with that statement is that it drags up the old rotary displacement arguement,which I didnt want to do.
Its true, there are plenty or 100HP 4 bangers that make lots of torque,take the good ol' dinosaur Ford 2.3L....In N/A guise it can barely pump out 100HP,but it makes respectable torque due to its large displacement.Displacement will almost always glean you more torque...The 4A-FE is 1.6L...not huge,but larger than a 12A and it likely has a longish stroke.

inuissus_cendi

whats interesting though, is that the two examples you used both take advantage of forced induction. The GT has a blower on it and the Mazdaspeed 6 a turbo.

I get your point though. an example of high horsepower AND lots of torque would be the Dodge Viper, with just over 500hp AND 500lb-ft. But how does it do this? an 8.3 liter V10 is how. Thats a hell of a lot of displacement.

All in all, for naturally aspirated engines, large displacement=lots of torque. Smaller engines with high horsepower have a lack of torque.

Ferrari engines are a good example, like you said about the F430. They almost ALWAYS post extremely high horsepower numbers, but significantly lower torque figures. You have to realise that all that power is coming out of a 4.3liter naturally aspirated engine. The Ford GT beats it with larger displacement and a supercharger.

This is just because to squeeze lots of horsepower out of a small engine (forced induction aside) you have to trade off low-end torque.