soarer1988

how much hp can a stock r154 hold

scENFORCER

Depends. How much searching can you do?

Toyboxx

iTrader: (1)

^^^^LAWL.


700-800ish. But it's not really HP that kills trannys, axles, or drive shafts. It's TQ.

INTIMAZY

iTrader: (5)

More than you can afford, pal.




No but seriously. It will handle just about anything. You'll end up ditching it because of rear seal issues and tractor shifts before it ever blows up.

KahnBB6

iTrader: (5)

^^ lol

750whp is supposed to be the reliable ceiling assuming the internals are in good shape and it isn't power shifted or drop-clutch launched but the 1st gear thrust washer and front bearing retainer plate will need to be replaced (which means you might as well rebuild it and throw in MC parts) well before hitting that level of horsepower. It's funny that the maximum whp number is thrown around so much and not the torque number JZ's usually put out at that level.

I don't think it shifts like a tractor. It's definitely a chunky transmission but it's pretty smooth after initially warming up. Reverse takes some getting used to though.

Edit: The OP did say "stock R154". I think the number for a stock R154 I recall is somewhere around 500whp assuming the thrust washer and bearing retainer plate aren't too worn such that a rebuild would be needed.

lexforlife

iTrader: (7)

^^^^^ this ... im at 600 rwhp and on my second genuine soarer box .. it really comes down to how you drive it and what type of clutch and fluid you are using ..

red line mt 90 works wonders in this box .. if you are deep into the 550rwhp+ world and do not have mc internals and a solid twin or triple disk clutch , i would refrain from hard launches and definitely no power shifing /banging 2 to 3 rd gear as thats when you actually smash the thrust washer from the sudden load then break the 2-3 gear shifter fork .. then your box sounds like a box of marbles

KahnBB6

iTrader: (5)

^^^ Yep :/

I also use Redline MT-90 transmission oil (you must use the non-LSD type MT-90 oil). I have all the MC parts available except for the new 5th/Reverse fork from Driftmotion which wasn't available when I rebuilt mine. Replacing all the forks with the billet pieces from MC and DM is recommended. Someone commented on another CL thread that the majority of the R154 is built like a tank but the factory 1st gear thrust washer, front bearing retainer and all shift forks are the under built pieces that can be overstressed. But all of those can be replaced now with better parts. And still... this is a much, much stronger transmission than a W58.

Twin and triple disc clutches are supposed to help with transmission wear and avoid crank walk from a heavy single disc pressure plate. I have no experience with them to comment on. I'm still using am OEM 7MGTE clutch and pressure plate on my car while I'm NA (very cheap interim clutch for NA use). My understanding is that upgrading the clutch disc to an ACT or Southbend while still using the factory 7MGTE pressure plate keeps the stresses out of dangerous territory. Of course, that's only good for maybe 400-450whp. Someone correct me if I'm wrong.

The other thing with R154's and V160's is that on original manual cars the neutral safety switch on the clutch pedal must be disconnected and jumpered. Always start with the transmission in neutral. Reason being that this helps to prevent crank walk due to oil starvation on the rear crank bearing upon startup. W58's and automatics don't cause this problem, and 7M engines with R154's don't have the issue, just 1JZ/2JZ's with R154/V160's. Supra MKIV guys will also disable their NSS with either manual transmission.

99SC42

iTrader: (44)

700tq all day on mine, depends on a lot of things.. But a low mile un molested on will do take just about 700wtq.