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FA20dit Transmission options?


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17 replies to this topic

#1 Veganpotter

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Posted 20 April 2018 - 02:49 PM

I've got a wonky swap I'm doing into a 95 300zx. I just received my JDM drivetrain out of a Legacy GT. It has a CVT though. That doesn't bother me other than the RWD conversion. But I'm wondering what other transmissions I can potentially use...assume this were a RWD conversion in a Subaru😉 I've read that a BRZ transmission isn't actually a direct fit. Can it fit with a custom bell housing or is the bolt circle too big on that transmission?
Anyone swap in a RWD transmission from any other car?

#2 Veganpotter

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Posted 20 April 2018 - 02:58 PM

Also, potential standalone ECUs? The guy doing all the wiring thinks he can make the stock ECU work. I have my doubts even though he's a total wizard. ECU options as a plan B? This isn't going to be a super high performance build at all.

#3 Subaru Scott

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Posted 23 April 2018 - 09:25 PM

Also, potential standalone ECUs? The guy doing all the wiring thinks he can make the stock ECU work. I have my doubts even though he's a total wizard. ECU options as a plan B? This isn't going to be a super high performance build at all.

 

Head on over to Speeduino. DIY, open-source standalone developed by the Aussies.

 

It is tunable and can be configured to work with whatever sensors and injectors you like.

 

You can get into a basic setup for a couple hundred bucks.

 

This is being used on everything from lawn mowers to V-12 tank engines.

 

The future is now!!



#4 1 Lucky Texan

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Posted 24 April 2018 - 07:01 PM

i'm just guessing but, don't Subaru and Nissan both use JATCO trans? seems like there is a good chance something would bolt-up. But, I realize also, the trans could easily be built to incompatible specs....

 

nasioc.com could be a good source for you to check out. Search and read before posting as there's always a coupla folks there ready to attack a noobie it seems.


Edited by 1 Lucky Texan, 24 April 2018 - 07:01 PM.


#5 86BRATMAN

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Posted 24 April 2018 - 09:20 PM

The brz/frs transmission doesn't quite line up with ej/ez engines because the starter is on the opposite side of the transmission. It will bolt up and work just fine with the fa20dit because it was designed with starter clearance on both sides. Both the turbo and na fa20 variants use the same engine case.

#6 Subaru Scott

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Posted 24 April 2018 - 10:58 PM

Bratman, do you know where the clearance issue is in that scenario?

 

I've never seen a BRZ transmission up close, so I'm trying to imagine what would get in the way.

 

Can you not use an EJ nose-coneless starter on that side? And the BRZ starters are the direct-drive with a nosecone that hits the engine flange?



#7 Veganpotter

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Posted 24 April 2018 - 11:03 PM

Thanks guys, I'm totally clueless here and have no idea what's gonna work because nobody has done this in my car and nobody runs the CVTs RWD. If it can handle all the power going to the back, I'd like to make this work due to how efficient the thing is. And high MPG is my real goal with this car. I would have bought a FA16dit but they're even harder to find in the US and I have doubts that transmission can handle moving my bigger car dependably as a RWD car

#8 Subaru Scott

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Posted 24 April 2018 - 11:13 PM

I don't see why you couldn't take the center diff out and weld it, or fix it in some other manner. 

 

Old hot rodders used to fill them with molten lead.

 

Best thing would be to find someone on here who has a bad diff, and would gladly pay shipping both ways to swap with you.

 

Then, weld away with no regrets!



#9 Veganpotter

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Posted 24 April 2018 - 11:22 PM

Ah, thanks!!! Great idea!!! I've just never seen anyone do this with a CVT IN even a Subaru so I'm concerned with durability. Especially since its rare to see this with even a regular automatic. Also, potential drivetrain losses vs normal drivetrain losses in a RWD car

#10 Subaru Scott

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Posted 25 April 2018 - 12:49 AM

The way I see it, you've got nothing to lose. Unless you were planning to get rich selling the CVT.



#11 Veganpotter

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Posted 25 April 2018 - 08:44 AM

Will you buy my very rare CVT for $10,000?😂 Its a tough build. The engine really doesn't fit. I'm going to need to cut out a huge portion of the frame, re-box and add in strength. The engine is +31" wide. The opening is 32" wide for only the upper 10" or so, then it's 29" between the frame rails. The intake manifold is way higher than the BRZ. But if this happens, it'll be the only 300zx on the planet with a boxer!!!

#12 Veganpotter

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Posted 25 April 2018 - 10:58 AM

I dug into the Speeduino stuff. Their website doesn't have much detail so I'm gonna shoot them a message

#13 Subaru Scott

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Posted 25 April 2018 - 11:10 AM

Yeah, I think I asked you about it being to wide on another thread.

 

Go to the Speeduino forum. You can get pretty much all the details there, reading about other builds.



#14 Veganpotter

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Posted 25 April 2018 - 02:55 PM

Will do!!! Any clue about drivetrain losses with a converted RWD transmission vs the typical rwd 15-20% with a normal manual and modern automatic?

#15 GeneralDisorder

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Posted 25 April 2018 - 03:04 PM

It is unlikely the transmission will work for this purpose. It is too highly integrated with traction control systems, and other module that you couldn't possibly make work. It is designed to be AWD and the control computer will certainly not appreciate you attempting to turn it into a RWD. It will not operate at all without it's computer, and there is no way to reprogram it as they have not been hacked by the open source community. 

 

What you are attempting is going to be quite difficult, if not impossible. At the very least it will be much harder than other options that would be a LOT easier and arguably much more fun. An LS swap for instance. 

 

GD



#16 Veganpotter

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Posted 25 April 2018 - 03:09 PM

Yeah, I'm totally expecting a headache. I do wonder how different it is than a RWD conversion with a regular automatic though. That has definitely been done with modern Subarus. I'd love it if there really was a CVT available for a BRZ that I could swap over.
Any clue what the engine differences are between a FA20 and a FA20dit? Obviously compeession is lower for the turbocharged motor

#17 Veganpotter

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Posted 25 April 2018 - 03:35 PM

I'm totally aware of a lack of fun factor with the CVT. If this were 10 years ago, I'd surely go manual but this is an oddball project. Peak mpg is my goal while having decent horsepower and now, manuals don't beat autos and surely not CVTs. I'd go with the 60hp less FA16dit if they were more available and it wouldn't offset my weight balance as poorly. I think the FA20 will actually improve my car's handling but losing any more weight would hurt it.

#18 Subaru Scott

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Posted 26 April 2018 - 05:30 PM

I think if the center diff were mechanically locked, the TCU would have no way of knowing... till you did a burnout.

 

Of course it would take a lot of work to fool it. You'd need ABS sensors as well.

 

I've always thought it would be cool to just hook up manual switches to the CVT. Maybe like a lever or paddle switch on the column to change ratio. And a microswitch on the gas pedal to control the converter, just like the Justy ECVT.






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