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Transmission strength for SR20DET OR 300+ hp motors - options..?

Posted: 07 Nov 2019 14:47
by cartel
searched around and the majority of the posts are S14 related-- i know for a fact that the SR transmissions do in fact break- i am not sure at what HP they have issues and there is more problems as the s14 crowd is into drifting and that kills them for sure. now a 510 is almost 800lb less than a 240sx but i dont know how much that will help it live., from what ive read the 280zx 5 speed is even weaker than the SR/KA one? bellhousings between all 3 are pretty easy to swap.

i have the motor with xmember mocked up and ive made the SR (KA it seems is identical save bell pattern) 5 speed fit- the shifter is pretty far back as i have the valve cover bolts at the rear about 1/2" from the cowl lip. to get the driveshaft angle nice i have the mounts holding the oilpan about 3/8" above the rack mount. now my dilemma--

my friend who will drive this beast is lets say "hard" on things- he will beat the ever living crap out of it .. so my worry is i will be looking for KA trans to buy every season- i have "tentatively" got 275-35-15 Hoosier A4 to fit under Andys rear flares- on a 15 x 9 .. now im worried it may be too much stick for the SR trans.. originally we had nankang AR1 245-50-15s to go on it..

the Z32 Trans is a fat -tall height and short in length pig-- :lol: i have one here as well with a mazworks adapter - i think i can make it work - and keep the heater- with relocation of the shifter possible its further forward than the SR one.. other than the fab work on the tunnel its fitting quite well .

now most posts ive seen say its too heavy and not needed in a dime-- now most dont have the HP this does-- it may not get used much but this motor has already dyno'd 400+ on e85.. can run a very mild tune on 91 and make 300 easy..

the SR/KA trans seem to be the same as rx8- and a bunch of other cars so parts are plentiful--

are there any other options? this IS a street car- not putting a Saenz/jerico in it ..

Re: Transmission strength for SR20DET OR 300+ hp motors - options..?

Posted: 07 Nov 2019 17:31
by icehouse
The SR trans will last, my buddy runs one in his drag 510 which makes almost 500whp on E85 and hasn't broken it yet. He says the axles are the problem. He runs 11.7's on slicks in the quarter, with fuel cut at the top end. If you have the Z32 trans and adapter I don't see any reason to not go that route though. Those are strong!! I'm planning on putting the Z32 trans behind the VET I'm going to put together soon. Don't have to worry then.

Re: Transmission strength for SR20DET OR 300+ hp motors - options..?

Posted: 07 Nov 2019 18:25
by cartel
ok so since "I'm" a bit gentler than him then the SR should be ok for me-
i will never go to the drag strip-- he probably will just to see what it can do-
building almost 2 identical cars- but one has vintage BRE flares and the other has Specialty larger bubble "race" flares..

is he having problems with driveshaft shop CVs? thats what i have here for his car - 4.44 r180 clutch type diff

Re: Transmission strength for SR20DET OR 300+ hp motors - options..?

Posted: 07 Nov 2019 19:49
by datzenmike
icehouse wrote:
07 Nov 2019 17:31
The SR trans will last, my buddy runs one in his drag 510 which makes almost 500whp on E85 and hasn't broken it yet. He says the axles are the problem. He runs 11.7's on slicks in the quarter, with fuel cut at the top end. If you have the Z32 trans and adapter I don't see any reason to not go that route though. Those are strong!! I'm planning on putting the Z32 trans behind the VET I'm going to put together soon. Don't have to worry then.
Agree with Jeff on the FS5W71C and they are plentiful. If scared, and have an adapter, the RS5R30A is unbreakable.

Re: Transmission strength for SR20DET OR 300+ hp motors - options..?

Posted: 09 Nov 2019 12:36
by icehouse
datzenmike wrote:
07 Nov 2019 19:49
icehouse wrote:
07 Nov 2019 17:31
The SR trans will last, my buddy runs one in his drag 510 which makes almost 500whp on E85 and hasn't broken it yet. He says the axles are the problem. He runs 11.7's on slicks in the quarter, with fuel cut at the top end. If you have the Z32 trans and adapter I don't see any reason to not go that route though. Those are strong!! I'm planning on putting the Z32 trans behind the VET I'm going to put together soon. Don't have to worry then.
Agree with Jeff on the FS5W71C and they are plentiful. If scared, and have an adapter, the RS5R30A is unbreakable.
Mike I picked up a "broken" 71C form so drift kids. I opened it, it was jammed with a super small chunk of reverse gear tooth in the main gear set. Took it out and the trans was free! Needs bearings though.... They let some water get in it. It's amazing what simple things will make guy think certain transmissions are junk. That could happen to any of them.