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-   -   13b into Porsche.... (https://www.rx7club.com/1st-generation-specific-1979-1985-18/13b-into-porsche-1078738/)

Arcolithe 02-14-15 10:35 PM

13b into Porsche....
 
So my friend has a blown porsche, too poor to fix it... he loves my car...

Can I put a carburated 13b to the transmission, get a custom driveshaft to the differential and it's good to go?

Or would the differential also need to be customized?

Jeff20B 02-14-15 11:06 PM

I think the point of that car was to be like an RX-7 with a front/mid engine and the trans in the back. They were able to put a big engine in the front because there wasn't a tranny in the way. It was kinda slanted, to fit better under a low hood line.

hmm, a rotary would be like totally tiny in there. Yeah, get a carbed 13B. Ask Kennedy Engineered Products about an aluminum engine adaptor plate. See what will work.

Jhereg 02-14-15 11:09 PM

I'd shoot a message to Stilettoman
(RX7Club.com - View Profile: stilettoman)

He's done it, not sure of the year Porsche, but it looked great.

Arcolithe 02-14-15 11:38 PM

woah wait, what do you mean trans in the back?
his trans is in the front... I know having an ecu/FI will bring the cost of the drivetrain a lot higher, so I think I'll stick to a carb and a 12a or 13b (whichever I find first in better condition for cheaper). He doesn't rag on his car so he's not a power seeker.

By engine adaptor plate are you talking about engine/tranny mounts?

j_tso 02-14-15 11:50 PM

If we're talking about a Porsche 924/944/928, then yes, the transmission is in the back. Like Jeff20B said, it was for weight distribution.

Adapter plate is for the torque tube, which is what the driveshaft spins inside and connects to the rear.

I know online I've seen someone put a Chevy V8 in one, so swaps are possible.

j9fd3s 02-15-15 10:35 AM

i remember seeing a magazine that had a 13B 944 in it, its been done. good swap too, get rid of the stupid boinger

Natey 02-15-15 11:19 AM

Not a 13b, but rotary into a Porsche, yes. There's a guy on this club with a (pretty damn sick) 3 rotor 911.

https://www.rx7club.com/20b-forum-95...roject-815969/



DreamInRotary 02-15-15 11:33 AM


Originally Posted by Natey (Post 11871034)
Not a 13b, but rotary into a Porsche, yes. There's a guy on this club with a (pretty damn sick) 3 rotor 911.

That car is amazing to say the least

Arcolithe 02-15-15 01:25 PM

That is sexy but I think his budget is wayyy too low for it haha. Especially a 20B (that I doubt you'd want to carburate)

so what I'm curious is why it needs a driveshaft housing when the rx7 doesn't?

Is there a lot of play and risk of the driveshaft slapping/grinding against the underbody at high rpms (due to the transmission being in the back?)

Also, with the transmission being in the back, does that mean the stock transmission needs to be re-used and adjusted for the rotaries high rev? ( I assume even if it's porsche, that it can't handle the heat from the 9~12k range spins.

midnight mechanic 02-15-15 01:59 PM

I was at mazdatrix. I saw 3 911's. "What are those 911's doing here?", I asked. Either he was pulling my leg, or they had rotaries in them!!

Also consider stuffing a chevy v-8 into the porsche. I've seen them in cali. Also seen some real hack jobs when positioning the radiator in front.

Which porsche are you talking about?? My old 914 could run circles around my rx-7 in 1st gear.

Jeff20B 02-15-15 02:02 PM

Sounds like you need to confirm where the trans is before making anymore plans.

DreamInRotary 02-15-15 02:24 PM


Originally Posted by midnight mechanic (Post 11871108)
I was at mazdatrix. I saw 3 911's. "What are those 911's doing here?", I asked. Either he was pulling my leg, or they had rotaries in them!!

Awesome! Man I wish you could have gotten pictures of those.

I've always wondered what a cool car to rotary swap would be...still haven't come up with anything besides maybe a dune buggy or the Samurai we have in the back yard.

j9fd3s 02-15-15 04:10 PM


Originally Posted by Arcolithe (Post 11871091)
so what I'm curious is why it needs a driveshaft housing when the rx7 doesn't?

because its a reject volkswagon. the clutch is in the normal place, and they extended the input shaft. the tube is probably there to keep everything lined up, or complicated and expensive, hard to tell what the design goals were, as its a VW, and they had only done the one car before....

http://www.porsche924-944.nl/manual/.../image002e.gif

peejay 02-15-15 04:47 PM


Originally Posted by Arcolithe (Post 11870860)
So my friend has a blown porsche, too poor to fix it... he loves my car...

Can I put a carburated 13b to the transmission, get a custom driveshaft to the differential and it's good to go?

Or would the differential also need to be customized?

No Porsche has a separate differential unless your friend has a Cayenne.

peejay 02-15-15 04:52 PM


Originally Posted by Jeff20B (Post 11871111)
Sounds like you need to confirm where the trans is before making anymore plans.

If it's a 924/944 then it's really not all that expensive to fix, just a pain in the arse to work on, and you'd be doing a lot more work with an engine swap than you'd be doing fixing the engine.

I really like the 924s. 944s not so much because they were trying too hard to be 928s. Not that there's anything wrong with the 928 but it's not my bag.

Also the 924s had Porsche transmissions, 944s have Audi transmissions. Again NTTAWWT, heck I have two cars with 016 transmissions in them. But the Porsche trans has the proper 5-speed gear pattern for a sporting vehicle :)

j9fd3s 02-15-15 04:54 PM


Originally Posted by peejay (Post 11871196)
If it's a 924/944 then it's really not all that expensive to fix, just a pain in the arse to work on, and you'd be doing a lot more work with an engine swap than you'd be doing fixing the engine.

I really like the 924s. 944s not so much because they were trying too hard to be 928s. Not that there's anything wrong with the 928 but it's not my bag.

Also the 924s had Porsche transmissions, 944s have Audi transmissions. Again NTTAWWT, heck I have two cars with 016 transmissions in them. But the Porsche trans has the proper 5-speed gear pattern for a sporting vehicle :)

i actually like the 924 also, the 944 has all these tacked on boy racer wings and stuff.

ray green 02-15-15 05:05 PM

There's not a lot of space in there.

http://bringatrailer.com/wp-content/...gine_Bay_1.jpg

wankel=awesome 02-15-15 06:33 PM

Lol at the 914 running circles around the 7. Even my 12a had no problems beating 914 lap records at mid ohio...

midnight mechanic 02-15-15 11:25 PM

Lol at the 914 running circles around the 7. Even my 12a had no problems beating 914 lap records at "mid ohio... "

then you were not in 1st gear

Arcolithe 02-16-15 07:34 AM

don't you mean the 944 tried to be like the 924? I see no similarities between the 944 and 928.
Never been a fan of porsches like I did for mazdas, so never really was able to distinguish which was built for what purpose.

Either way, anyone know if the porsche transmission can withstand an N/A non-ported 13b?

j9fd3s 02-16-15 09:42 AM


Originally Posted by Arcolithe (Post 11871410)
don't you mean the 944 tried to be like the 924? I see no similarities between the 944 and 928.
Never been a fan of porsches like I did for mazdas, so never really was able to distinguish which was built for what purpose.

Either way, anyone know if the porsche transmission can withstand an N/A non-ported 13b?

the 944 and 924 are the same car, Porsche introduced the 924 with an Audi engine, and the Porsche faithful didn't like it, so they put a porsche engine in it, and changed its name, fooling everyone.

if you're in the porsche world, which is like the scientology of cars, the 924/944/928 all have front engines, and are all water cooled, and thereby banned from meets in perpetuity.

and you see what they did with the "transaxle" right? they just took an Audi FWD trans, put it in the back, and with a bunch of adaptors, its a transaxle!

Natey 02-16-15 12:06 PM


Originally Posted by wankel=awesome (Post 11871238)
Lol at the 914 running circles around the 7. Even my 12a had no problems beating 914 lap records at mid ohio...

Everytime I go to my local track, which happens to be Laguna Seca, I see crazy fast 914s. 1st gen RX-7s, not so much.

Don't get me wrong, I own, drive and love RX-7s, but a well-sorted 914/6 on a racetrack is nothing to scoff at. They're gaining value fast, too. A beater 914/4 is worth about 10k these days.

One like this will cost you around 60k IF you can find it.
http://www.mazdas247.com/members/Nat...want%20One.JPG

One more pic, because a 914 and the rotary is not a new or bad idea. ;)
http://www.mazdas247.com/members/Natey/wankel_914.jpg

wankel=awesome 02-16-15 05:46 PM


Originally Posted by Natey (Post 11871569)
Everytime I go to my local track, which happens to be Laguna Seca, I see crazy fast 914s. 1st gen RX-7s, not so much.

Don't get me wrong, I own, drive and love RX-7s, but a well-sorted 914/6 on a racetrack is nothing to scoff at. They're gaining value fast, too. A beater 914/4 is worth about 10k these days.

One like this will cost you around 60k IF you can find it.
http://www.mazdas247.com/members/Nat...want%20One.JPG

One more pic, because a 914 and the rotary is not a new or bad idea. ;)
http://www.mazdas247.com/members/Natey/wankel_914.jpg

I know that, but those arent stock... And I was comparing to "stock" class records from the scca. My 85 (former track rat) was in the same "class" if you will. Stock, only modifications really allowed were paint and tires, lol.

Natey 02-17-15 12:36 PM

I don't mean to be argumentative, but that's a pic of a bone stock 914/6 GT. Porsche killed the 914/6 because it was quicker than the 911 and that's a no-no...for the same reason we'll never see a turbocharged Cayman.

I hear ya, though. A 1.7l 914 isn't anything to go drag racing in. I think they had like 80hp.
Unless it was autocrossing or a really tight track, I can definitely see how an SA would turn a quicker lap time.

j9fd3s 02-17-15 01:37 PM


Originally Posted by Natey (Post 11871569)
Everytime I go to my local track, which happens to be Laguna Seca, I see crazy fast 914s. 1st gen RX-7s, not so much.

that is more because of the noise limit than anything else, a nearly stock FD will run in the mid 1:40's with a good driver.


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