DaewooOfDeath
DaewooOfDeath SuperDork
6/11/21 12:57 a.m.

I've seen a lot of builds where people adapt random transmissions to weird engines. A T5 adapted to a Ford Flathead bellhousing to a Jag I6, Nissan 350Z transmissions to K Series, BMW I4's to Miata boxes etc. Is there a general principle to this? I ask because the transmissions in Genesis Coupes aren't very good, aren't very tough and don't play very nicely with stronger engines. 

buzzboy
buzzboy Dork
6/11/21 6:13 a.m.

I'm not completely sure your question but here's the 3 general choices for engine/transmission adapting:

 

Look for combinations that somebody else has already engineered. Plenty of transmission adapters between all sorts of engines/transmissions out there. EG BMW ZF320 with KMiata adapter to install a K24 in your NA Miata.

Find a transmission/bellhousing that are built by the same company that somehow let you put a transmission you want behind the engine you want. EG Jeep AX15 with AX5 bellhousing attached to install an LS4 in your Jeep.

Buy whatever transmission you want and build your own adapter over to whatever engine you want. EG cutting up your Volvo AW30 and a T5 and welding the mating surface of the AW30 to the T5 so you can have a T5 behind a B5234T.

 

 

iansane
iansane HalfDork
6/11/21 9:37 a.m.

Man, I really love adapting engines to transmission that weren't meant to be together. 

buzzboy said:

Buy whatever transmission you want and build your own adapter over to whatever engine you want. EG cutting up your Volvo AW30 and a T5 and welding the mating surface of the AW30 to the T5 so you can have a T5 behind a B5234T.

This one you can get an off the shelf adapter already made for!

DaewooOfDeath
DaewooOfDeath SuperDork
6/11/21 9:40 a.m.
buzzboy said:

I'm not completely sure your question but here's the 3 general choices for engine/transmission adapting:

 

Look for combinations that somebody else has already engineered. Plenty of transmission adapters between all sorts of engines/transmissions out there. EG BMW ZF320 with KMiata adapter to install a K24 in your NA Miata.

Find a transmission/bellhousing that are built by the same company that somehow let you put a transmission you want behind the engine you want. EG Jeep AX15 with AX5 bellhousing attached to install an LS4 in your Jeep.

Buy whatever transmission you want and build your own adapter over to whatever engine you want. EG cutting up your Volvo AW30 and a T5 and welding the mating surface of the AW30 to the T5 so you can have a T5 behind a B5234T.

 

 

Thanks, it seems like I'm looking at number 3. The stock manual transmissions for my car (Genesis Coupe) are pretty weak and I'm not seeing any pre-engineered swaps. Is it really as simple as chopping the bellhousing off of my factory trans and welding it onto a transmission that's tough enough, followed by spacing everything correctly?

I want to put a TKO or even a Muncie behind a Hyundai Theta turbo because the car has a broad power band and the strong 6 speeds are too heavy. I also don't drive on the highway very much so overdrive(s) aren't really necessary. 

bearmtnmartin (Forum Supporter)
bearmtnmartin (Forum Supporter) GRM+ Memberand UltraDork
6/11/21 11:21 a.m.

There are some good ideas here.

https://grassrootsmotorsports.com/forum/grm/anyone-built-an-adaptor-plate/109829/page1/

I ended up buying a homemade one off a guy when it popped up on marketplace. I am not sure yet whether it will work OK but according to my dial indicator he did a pretty good job. 

frenchyd
frenchyd UltimaDork
6/11/21 1:02 p.m.
DaewooOfDeath said:
buzzboy said:

I'm not completely sure your question but here's the 3 general choices for engine/transmission adapting:

 

Look for combinations that somebody else has already engineered. Plenty of transmission adapters between all sorts of engines/transmissions out there. EG BMW ZF320 with KMiata adapter to install a K24 in your NA Miata.

Find a transmission/bellhousing that are built by the same company that somehow let you put a transmission you want behind the engine you want. EG Jeep AX15 with AX5 bellhousing attached to install an LS4 in your Jeep.

Buy whatever transmission you want and build your own adapter over to whatever engine you want. EG cutting up your Volvo AW30 and a T5 and welding the mating surface of the AW30 to the T5 so you can have a T5 behind a B5234T.

 

 

Thanks, it seems like I'm looking at number 3. The stock manual transmissions for my car (Genesis Coupe) are pretty weak and I'm not seeing any pre-engineered swaps. Is it really as simple as chopping the bellhousing off of my factory trans and welding it onto a transmission that's tough enough, followed by spacing everything correctly?

I want to put a TKO or even a Muncie behind a Hyundai Theta turbo because the car has a broad power band and the strong 6 speeds are too heavy. I also don't drive on the highway very much so overdrive(s) aren't really necessary. 

No! Absolutely not!!   The locating dowels make sure the transmission is aligned properly.  
those dowels are in different places with the engine and or whatever transmission is used.   Plus the depth of the input shaft varies.  As does the size of the input shaft.  
     If any of those three things are different or misaligned the engine and or the transmission get ruined quickly.  
     Not to mention shifting is not going to be smooth.  
      The way to do that properly is use a bare block and an empty transmission case. Using a straight( really important that it's straight )  bar machine the  bar to the size of the main journals.  And then to the size of the bearings in the transmission.   Now figure  out depth's required. 
       Welding induces all sorts of movement. So if you weld up an adaptor check that it aligns before going ahead and using it. 

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