Hey its me again i wanted to know if once I bought that 914 if it would be worth the time and money to put a 13B Rotary engine into a 914. there wouldn't be too much remodfeling if I put the radiator right in front of the rotary and I would have 200 HP on tap. So what do you guys think? Yah or nah?

Been done - several times

http://web2.airmail.net/atl/Rotary.html

been done a few times...do a search here....pictures and everything else you want to know...

radiator in front of motor = bad idea, too much heat, not enough airflow

did you buy that car yet? I would worry about buying it first, getting it driveable, then dealing with a new engine swap. Its fun to think about new more powerful drivetrains, I do it every day, but it doesn't make sense (at least for me) to spend money on something that I can't use until the car is back on its feet.

But yes a rotary can be put into a 914, someone on the board is doing (I think) a 3 rotor swap which should be really kickass when he is done. I don't think you have the airflow to put radiators in the engine compartment too though, maybe with some creative ductwork and some powerful fans . . .

I met a guy who did one but he put a custom 4-row in the front trunk. It STILL overheated. Those things need a good oil cooler too. I think they'd make a good conversion but you have to really sort out the cooling issues.

They have overheating problems in the Mazadas, but they sure kick ass. It would never work to have the radiator in the engine compartment and upfront you have to plumb it right to get enough cooling.

Geoff

Look dude--your young---are you REALLY ready for your first ride to NOT have any room to put that coleman cooler at????????? What about the hibache and coals???? What about space for that young sweet something by your side to put her (his) spare change of clothes???


Live life first---then when your in your 20's and can afford the time and money for a swap like that---then do it!!!!

Trust me--a radiator will NOT fit directly in front of the engine, ( well, it CAN, but that is another story)

I think Wankel did something like this. But wait till you've driven the car as is for a while. So at least you know what will be different

In my opinion, putting an NA rotary in a 914 is not worth it unless you turbo the rotary (not easy, for details check out the first-gen forum on rx7club.com). And if you turbo an NA rotary engine or use a Turbo II rotary engine, then engine-bay heat is the big issue for the engine to have any longevity.

Just FYI -- I drove my RX-7 GSL-SE during our 914club cruise down to Portland this year, and though my stock 13B engine has about 130 flywheel horsepower and my RX-7 only weighs 2425 lbs, once those stock 914 2.0's shifted into 2nd gear, they effortlessly walked away from me every single time, even when I anticipated it. It was a humbling lesson in the value of torque.

Wow! That surprises me. Cool. (for the 914 2.0)
I estimate the 'average' power to weight ratio of the 2.0's @ 22:1 and yours @ 18:1. Obviously there's more to this than meets the eye.

-Ben M.

Yeah, it surprised me, too! I figured I could take 'em with the 130hp (or that it would be relatively even given the RX-7's extra weight). But after those 2.0's shifted into 2nd gear they walked away. Their torque advantage at low-to-midrange rpm's was impressive. It wasn't even a contest. With every gear shift they increased their lead, and even by the time they hit midrange in 3rd gear, they were already well ahead of me. It was nice of them to slow down and let me catch up, about a mile down the highway. Of course, by then I was eating humble pie..

Roger
1976 914 2.0
1984 RX-7 GSL-SE daily driver

this is why a lot of times the /4 cars dominate the auto-x courses

Weight by itself should never be discounted. It makes an big difference. The best example I ever saw was when a friend of mine and I took two similar bikes out and did roll-on acceleration tests (about 20-60mph). At the time, he was about 30lbs heavier than I was, and I was dramatically walking away faster than he was no matter which bike I rode. Just 30lbs difference, or about 5% of the total weight. We repeated this several times and were quite suprised at how big the gap was.

Now, I'm about as heavy as he is, maybe more so. He's one of those types that exercises regularly...

Taking that one step further I rode in David's NA 13B 914 (the one at http://web2.airmail.net/atl/Rotary.html ) and it would definitely get up and run away from any 2.0 914. He did have cooling issues until he put in the Renegade V8 cooling system. Unfortunately, as conversion logic would dictate, having that coolng system already in the car made the step up to a bare knuckles SBC so easy that the rotary had to go. I'll tell you what though, except for the unnatural sound of the rotary's exhaust that was a really nice conversion. Very fast and light, a nice match for the car.

I'm doing a 3 rotor conversion on my car. I purchased the Renegade Hybrids radiator setup after listening to club members here talk about cooling problems. I'll be sure to start a build thread as soon as I get everything I need to start putting things together. I just moved to a new place in the country with a 2400 square foot shop so my time has been spent getting my act together. The shop isn't heated - but is set up for in floor heat - and it still needs to have all the electrical, insulation and sheet rock put in. Definately a project that will consume most of my time the next while. The latest -20 cold spell hasn't helped any either.

where then do they put the radiator when they do V-8 conversions? up front from what I have seen. As far as hp from the rotary, we have one of the top rotary engine builders about 10 minutes down the road. A friend of my dad's has a hillclimb car that use a 13B with an Eaton supercharger, it dynoed at over 350 hp and still can take more boost.

in the front, where radiators belong


do a search for "Chevy AND conversions" on this site, tons of info and basicly it's the same way to do a rotary

Which shop is near you? Mazdatrix? Very few people are using superchargers on rotaries. Most use turbo's because of the flexibility and efficiency of them. Also, a rotary has a really strong and hot exhaust pulse both of which suit a turbo application. I would think a supercharger would be a step backwards from a turbo. Just my $0.02

My dad dosn't know if it has a name he just said that that was all he does is rebuild rotorys. he said he was rebuilding a triple rotor the other day.

If he was one of the top rotary engine builders I would think he would be known in the rotary community.

Daryl Drummond of Drummund Enterprises; I had to dig the card out. I have heard he does a lot of Formula Mazda stuff. You are right, he does a lot of turbo engines and the supercharged isn't one of his, but is helping the guy out. I don't know if I would say the supercharger is a step back, as there are benefits to the supercharger, too; it wouldn't be my choice, but it does make instant power. We plan on going by Daryl's shop next week; we have to soon, as he is moving North to a new shop. Once the electrical and dyno cell are operational, I heard he's outta here.

supercharger is perfect for a rotary...the compression sucks big time in a wankle, the supercharger will help that right off the bat.....a perfect system would be supercharger at low rpm with a turbo for high rpms

that would just make it too complicated for me! although it probably would work!

Yeah, but complicated is a relative thing. Road and Track a few years back did a piece on a big pumper truck that has (no I'm not kidding) a

Twin turbo
Supercharged
2-stroke
overhead valve (yes, ohv 2-stroke)
diesel

-Ben M.

I can't imagine anyone driving these things much different than me... all kinds of things can kick a 914s ass.. but in certain situations..

If you are finding the upper revs often, you are moving. I just use 1st to get into the middle of second.

Wuudddnn! Wuuuuuuuuuuuuud! Wuuuuuuuuuuuuuuuuuuuuud! <-- 914 sound, yo.



M

Love driving a turbo2 Mazda, its more like WwuuuuuuuuUUUUUUU(9000rpms)shift, wwwWWUUUUUUUUUUUU(holyshit)shift.......hehehe
would be wicked in a 914.

There is no such thing as a 2-stroke having valves, it uses a completly differnt system for fuel dilivery and exaust. It uses ports -like the rotary- to run and the valves would have to be really light weight becuase the 2-stroke engine does 2 operation in one stroke (up and down) when the 4-stroke does 1 operation for every stroke. And from what i hear Madzatrix ain't that special either. This Daryl does racing rotarys. Gets flown all over the US to help diagnois racing rotorys. And gets payed big bucks to do it.

2 Stroke Detroit Diesels, which have been around for years. Have normal type OHV on exhaust side only. Intake ports are down in cylinder wall.

Walt

I agree that the supercharger/turbo combination (which has been done) for a rotary would be an attractive package. Pretty complex to set up though.

Not at all true.

If you ran the camshaft(s) at crank speed instead of 1/2 crank speed and changed the ignition system to suit, you'd have an engine that had a power stroke on every down stroke. You'd have serious problems with getting enough mixture into the cylinder w/o all of it going out the exhaust (Toyota and Chrysler used a positive displacement blower in their engines to make up for this).

The fact that the common two-stroke design is to use in-wall ports and run the intake into the crankcase hardly means that's the ONLY way to do it.

Also, nearly every two-stroke engine made now for non-industrial purposes has reed-valves on the intake. Many also have a valve on the exhaust to change port timing. These devices have been used for 30 years or more, now, and no one refers to the engines as anything but two-strokes. Disc valves were also used in place of reeds for awhile. These were shutters in the intake stream timed to only allow induction into the crankcase in a particular time window. They were a bit for flexible in their timing adjustments, and certainly less restrictive than reeds, but both do the same thing conceptually. Both are certainly valves.

Very few poppet valve'd spark-ignition two-strokes have made it past the research stage, since they have all the complexity of four-strokes and many of the emissions problems of two-strokes. However, quite a few poppet valve'd two-stroke DIESELS (which the original quote was referring to) have made it into produciton, since a diesel inducts only air, and the fuel is injected directly into the cylinder under very high pressure after the exhaust valve has closed, just before the piston reaches TDC, thus solving many of the emissions concerns. Many of these engines are turbocharged for more volumetric efficiency, and forced induction very difficult to do with conventional piston-port or reed-valved two-strokes.

Regarding the original question, people have put 12A and 13B rotary engines in Volkswagens with good results. The ones in VWs are not turbo'd or supercharged, because running a carb and high-flow exhaust gives plenty of hp and the acceleration is fantastic, the Type I VW transmission (reinforced) will be at its limit, and there's already lots of heat (that cooling issue again) to deal with. Also, the aftermarket-turbo and supercharged rotaries seem to require a lot of initial adjustments and tuning, and that's no fun when the car is needed as a daily driver. I would suggest starting with a reliable carb'd setup and see how happy you are with that, before deciding to use forced induction.

One reason carbs are favored is the OEM injection setups on most of the RX-7s were evil. Very complex pneumatic systems with a zillion vacuum hoses and electric solenoid valves. They frequently don't work in the RX-7, let alone in an engine swap. Aftermarket EFI can do a great job, but they're a lot more expensive than a single Weber and manifold. You'd have a hard time even getting Megasquirt to be as cheap as a carb setup on these engines.

The big downside to rotaries is that rebuilding one yourself is almost entirely out of the question, and there are only a couple of shops in the country that can do a proper rebuild on one.

I knew a guy in STL with a tube-framed AX car with a Spridget fiberglass body on it, powered by a supercharged 13B. Rumored to make about 400hp.

That's what I used to think too. Then I learned that was one more to add to the list of things I've been wrong about.

-Ben M.

Not true at all. Rebuilding a rotary engine is actually less complicated than a piston engine. Once you know what you are doing that is. If your rotors are assembled with their seals you can button up the keg of a rotary engine in less than an hour. Try that with a piston engine. I have friends who rebuild them all the time in their garage and this was a major consideration in what engine to put in my 914. For about $1000 in parts I can have my 3 rotor back on the road if she blows.

I was under the impression that a very common problem was the endplates were no longer flat, and fixing that required machine work that wasn't likely to be handled by the corner machinists. If it's just a case of replacing the apex seals, that's certainly easy. Perhaps I was just drinking too much of Mazdatrix' kool-aid...

Just to clarify my earlier post, it's my impression that "engine heat" per se is not a problem with normally-aspirated rotary engines.. the problem is the exhaust heat, and the need to route the exhaust system well away from lines containing fuel or other flammables, and also well away from painted body panels and such. And doing that while constructing an exhaust system that meets street-legal decibel levels.

I'm not sure whether "engine heat" is a problem with turbo'd rotaries, but I know a gal with a supercharged carb'd 12A RX-7 (Code Blue 2 on rx7club.com, she's very fast) and she hasn't reported any heat-related problems in the 2 months she's had that setup.
But that might be too much power for a reinforced VW Type I trans..

OK maybe i will, exept the fact that I am wrong partly, maybe, kinda. I asked my dad about the detroit diesels and he said that the engine used a blower to force the exuast out. The valves were just to stop and start the process. anyway I think that eventually I will try to put a rotary in the 914. I found this old water cooled flat four that I will clean up and hopefully trade for a 13B at John's wreckers. If he doesn't want to trade i will throw in some torque converters and transmissions from my auto shop that we will never use.