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Opeler
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99 Posts
Discussion Starter · #1 ·
Hey guys,
After looking at the other posts on a rotary transplant, I saw that most people had some type of problem with the length of the stock rx-7 5 speed tranny being to large. I was wondering if anyone had thought about using a miata 5speed with the rotary. It should be shorter-as the miata is a small car.

Thanks,
Rob
 

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Detritus Maximus
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2,993 Posts
It might depend on the transmission they used. The RX7 TurboII (86-92) transmission is larger than a non turbo trans. Or is it the shifter location and trans length that is the problem?
 

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648 Posts
Now I'm no RX7 expert, but I do have friends that have played with them for years. Different year trannies had different length tail shafts and shifter placement. I also remember there was a lot of good info in the Grassroots Motorsports build up articles of their Roto-Spit. Seems like I remember them using a 1st gen tranny but putting a truck tailshaft and shifter to shorten things up. It would be worth looking up their past articles.
My 2C,

Jc
 

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Currently in Opel Detox.
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78 Posts
the 79-80 rx7 tranny has the shortest length to the shifter.

The Miata transmission is just as long ( I know, but it is, I've measured both and I have the rx parts here to compare.

THe later model rx7 (second gen 86-91) has the shifter exeternally mounted back kinda like the Getrag situation. I've looked at mine, and with minimal work, (no more than the getrag), the shifter can be relocated 6 inches further forward.

Now, Martin Reimer's rotary GT just has the engine almost as far forward as the front crossmember, and his 12a first gen setup with the 81-85 tranny fits the stock location just fine.
Someone correct me if I'm wrong, i've only seen the photos and talked to Marty for a very short period of time.

Also, the 12a's are much easier to mount given thier stock setup of mounts, but we all want power from the slightly larger 13b's

I know that the early covers will fit late model 13b's, I just have to see about the crank angle sensor for the ecu, or you can just use an early style dist. with one of the aftermarket carb adapters that are out there to throw away the FI.

In most cases I would never tell anyone to go carb over FI, but the RX7 FI was not every sorted out until 1990 which is known as the s5 version. It still was not as maintence free as non rotary cars, but it was as good as it got until they went 13btre (twin turbo).

So, I have the stuff here and all the measurements have been made for test fits, and I believe I will be droping in a 1990 13b non turbo with an 85 tranny into my opel sometime before October. I just have the sell of my house and the purchase of another taking precendence. Oh, and the arrival of a 74 manta that might get bumped ahead.
 

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Detritus Maximus
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2,993 Posts
For the crank angle sensor, look for the 84-85 four port 13b EGI (f.i.) engine. It should have the crank angle sensor and the 1st gen front mounts.
 
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