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rotary z


Guest Anonymous

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Guest Anonymous

I have been thinking about this for a while. I try looking through all the forum but came out short. I was thinking if anybody had thought about swapping in one of Mazada rotary engine into a Z. The motor is small enough, have a good power to weight ratio, and it got twin turbos. A light car + a light motor = a very fast Z. Should't be that bad of a swap.

 

An other idea. Imagine swapping a three rotary motor into a Z?

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Torque is the downside of the rotary - even boosted. High powered turbo rotaries usually dump the twin turbo setup and go single turbo - more power and you lose about 35FEET+ of vacuum hose icon_eek.gif Look at the single turbo Miata pics I put up for Scottie awhile back to see what I mean. To make up for the lower torque RX7 have 4:11 rear gears or lower. A 3rotor engine would be a monster though - not cheap however as it would have to be imported from Japan. It's a COSMO motor only I believe. You can find them on the WEB for sale in the US if you look hard enough, shop in Texaas sells them I think.

 

Honestly, if that's what you want I think it would be easier to simply buy a FD3 RX7. It weighs close to what a Z does, already has modern brakes, looks great IMO, and handles like a dream. Climbing into the RX7 from the Z is a REALLY weird experience. It RPMs MUCH faster but the sensation of speed is 100% different - it feels like the clutch is slipping icon_eek.gif That is until you note that the speedo' is moving right along!

 

The Z on the other hand throws you back in the seat and goes RIGHT NOW and it's always weird to see the RPMs so much lower. I throw shifts at 7K or more in the RX7, the Z seldom sees 6K but has come close to 7K once or twice with no sign of letting up icon_biggrin.gif It's really hard to explain but if the Z felt like the RX7 I don't know if I'd be happy or not.

 

You might want to try test driving an RX7 FD3 before you get too set on the rotary motor. A roatry in a lighter 510 - now THAT'S sick! icon_biggrin.gif I want one. Now! HeHe...

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Guest Anonymous

Even of the low torque that the rotaries are know for. You should't need much of it to get a 2355 lbs car moving. Even in stock form, the third gen RX-7 with a curb weight of 2700 lbs and a twinturbo 13b rotary can kill just about anything on the road.

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Umm, I drive an RX7 TT - modded somewhat heavily with bolt-ons. It's quick but a Vette will likely take you off the line due to superior torque production. Top end I've had a late model Vette keep up with me - but barely. Light weight really helps - I'd actually be surprised if an FD3 weighed as much as 2700, more like 2500lbs I think. In a Z you would indeed save some weight and beat that Vette icon_biggrin.gif With th eaddition of a mod or two recently i could probably do it now.

 

I guess you could run an R180 Subaru rear to get the gearing down which would help. With porting and no emissions the power would climb a great deal too.It would be an interesting experiment but I think a Miata is a better candidate.

 

Hrm, I might add that I've have a modded 300ZX TT keep up with me (mostly) and that a somewhat modded Mustang creamed me - off the button. The Mustang had plenty more to give if he needed too and was running a junkyard motor with heads that had 100K on the shortblock. Again, it's torque off the line that did me in icon_rolleyes.gif

 

The RX7 is a point and squirt bundle of fun but a "muscle car" it's not (shrug)...

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  • 2 weeks later...
Guest Anonymous

I have a 3rd gen rx7 as well, modded pretty heavily but i must say that i am going single soon on mine. Anywhere that I can put a rotary in my 240z though? I am thinking of it as a possibility, because I like rotaries and z's but i thought people used the turbo 2 motor more often because it is more simple?

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in aus we have so many rotarys RX3's and RX4s and RX7 in the 10s here, ausrotary.com has some info there about rotarys... rotarys are great, if u can afford the upkeep, have the money to get it worked enough... and u love that rotary sound go for it...

 

its up to you, i havn't seen or heard of anyone with a rotary Z, there is prolly someone out there who has done it

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Never heard of it being done but it's certainly small enough that room won't be an issue. If you're really seriously maybe hunt aoround for a 3rotor and get a REAL thrill icon_smile.gif Even a 2rotor in a Z would be interesting and I'd certianly go single turbo for that. I'm just not sure how much torque it would make off the line. Once moving though it would be pretty sick icon_wink.gif If you're already tinkering with them you know what sorts of issues they can have. I'm thinking mine will never be a single though, way too much work for a daily driver and emission would kill me here.

 

Hrm, an RX3 or a 510 would be sweet. Even lighter than a Z and hwo would evensee it ocming? Harder to swap maybe with the smaller engine bay but.... RX3s and whatnot are next to impossible to find around here, a shame too because I'd LOVE to own one!!!

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Fastest Non-V8Zcar I have ever gone for a ride in was a Turbo Rotary RX7 powered ZCar from ZDr. in Roanoke Va. The car was owned by Rob, one of the mechanics at Zdr. and then Bought by Doc's brother. It was SCARRY fast at ANY Speed.

 

Mike Kelly

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Guest Anonymous

Don't some people change to single turbo's because the twin turbo is known to crack the housing (like alot, finding a used uncracked or broken one is a stroke of luck)?

 

The only thing that concerns me with rotaries is they're easy to overrev (ok, a rev limiter would fix), and you have to be pretty carefull about the mixture. Get it lean and detonating at all, and after you load it up on the tow truck, find someone to fix the Apex seals and who knows what else that will have grenaded in your engine. They're a bit fragile IMHO.

 

That said, would I want one in a Z? Probably not, powerwise would be fine, torque, um no, not for me anyway, I like stepping on it at 2k and getting major thrust, not having to row the shifter trying to keep an engine singing. Depends on what you like I guess.

 

Regards,

 

Lone

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Havent looked at this one for a while but theres a sight called 3rotor.com. Guy put a 3 rotot in a early maxda capella. It had sound of the engine and everything. 3 rotors shouldnt be that hard to get hold of. the big hassel seems to be the electonic engine controls. Check out racing beat as well. I think they used the 3 rotot in there land speed record cars.

 

Douglas

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Guest Anonymous

Hey guys, how much does the rotary wiegh? I had dinner with some local SCCA/Autocross guys last night and one guy has a Lotus Europa with an RX-7 rotary and he said that it was actually a heavy little motor. Does anybody know the rough wieght if an installed, running two rotor? Sounds like it would be a killer package if the wieght is reasonable. icon_confused.gif

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3rotor motors get imported here but they're not stock in anything on this shore. They come out of the Japanese Cosmo.

 

Turbo manifolds DO crack, it's not a big deal. Usually the crack is short and doesn't require replacement. New manifolds can be gotten and I happen to have one as well as a good used one with only a slight crack. Side note - this material has been tested by a metallurgist in one of the car groups since Mazda wouldn't tell anyone what it's made of. Seems it's stainless and the same sort of metal used in blast furnaces - still cracks icon_eek.gif Rotaries have VERY hot exhaust, normal catalytics melt right down...

 

Detonation, yup go lean and you toast apex seals. So long as you don't go lean it's not a big deal. Rev limiters fix the other problem too - I bumped mine the other day 8K+ (doh!) First time too. They used ot have buzzers in them to warn you before hitting it because the motors were supposed to be so smooth you couldn't hear the Rs. I dunno' aboout that - mine sounds like a baby crying VERY loud at WOT and with the removal of the stock cats (hi-flow installed) it's noticably LOUDER. Smooth as glass straight to redline though! When it hits boost it flat out flies...

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the 13 bt is pretty heavy. it has 3 slabs that are pretty much solid cast iron with ports in them and a big hole in the center for the shaft. the rotor housings are aluminum. all together a big guy could pick up the block by himself. but bolt on all the stuff and you need 2-3 guys to move it around. the advantage to a rotary is its size. in a z you could set that baby so far back its not even funny. you could prabably sit in the engine compartment with the engine installed ;> i want to say the entire block is maybe 18-20 inches long 24 inches max. that would actually put it completly behind the stock engine member ;> You could fit the radiator, intercooler and alot of other stuff inside the engine compartment.

would be too cool ;Z>

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