Lexus 1/4 mile times...

[UZZ30-Québec]

Update on tranny hp capacity, I have read one person blew the stock tranny at 320whp in second gear...So becareful, I am sure anywhere from 300-350whp you are pushing it.....I am waiting for my stock tranny to give way any day now...

how frequent was this guy's oil changes? was he running an external big oil cooler and an external High performance A/T oil filter?

If not, that already exlpain part of the blow-up.

 

[stevechumo]

Kool, that's a good number for me read in a previous post that the stock injectors will go lean at about 370RWHP. One more question what are you using for fuel for you NOS system. I just bought a 150HP kit, but I don't have an FPR or fuel pump. I was going to get an SAFC to tune but I heard that the car already runs rich. What should I do for fuel?

I've used the SAFC-II before on different cars with no problems. You can increase or decrease the fuel easily. Your car will eventually detonate if you don't increase the fuel when you're running NOS or any forced induction systems. This is a common sense, most stock engines are designed with that particular fuel/air condition so when you change/alter it, you'll need something to support it.

 

[jibbby]

Quebec - He had 150,000 miles on the stock SC4 tranny according to his post..he is a hotrodder so I would assume the tranny was maintained...I have seen stock trannies reach 300,000 with no problems so they are somewhat durable......I am almost positive I pushed my stock tranny to around that 320whp number with no problems. My tranny was dealer maintained and driven by an old doctor up until 90,000 miles in which at that time I bought my SC4 and then changed to synthetic tranny fluid and proceeded to beat on it daily with 100hp shots, exhaust change, ECU piggy, DTC, etc.. for what is going on over two years. No problems to report other then some untimely shifts at higher nos shots...but all else seems to be ok...Even with the S&S Header addition which is all topend, I have ran good nos runs already with no problems...The car pulls hard and is shifting fine...... Others with true wet 150hp nos shots are close to those numbers and having no trouble either...Just maybe some trannies are in better shape and stronger then others...I always thought Metal is Metal and they should all be close to the same breaking point. Unless there is noticeable teeth wear or something going on..

Can anyone else jump in with proven stock tranny HP numbers?

I am thinking with my SC400 running at atleast 200-230 or so whp and the 100-150hp nos shot I would have matched and or would have exceeded those hp numbers for a while.now....I have not dyno'd but based on my mods I have in my car now those numbers should be realalistic and that is what I come up with....So I think 320whp is very conservative if you ask me..I think 350whp can be managed.....Traction and car weight is a factor too that must be considered when rating the trannies holding capacity...Also, I am running nos where the power and torque is generated more at lowend , where as the other member like RDM... and one or two others have smoked their trannies with turbo setups where the horse power is generated more so at topend...Maybe that too has something to do with tranny breaks....Who friggin knows????????????? I am definetely dyno testing and tuning early this week....so I will post the numbers that my car is generating on the stock tranny, maybe that will help with this discussion...Stay tuned..and I will report back to this thread with more numbers this week.......

 

[UZZ30-Québec]

the main problem of Automatic trannies is slipping.

If it slips, it burns.

Since you have a higher T/C stall rate, and an improved pressure line in your transmission, the clutches will grip more then, reducing slip.

What kills a transmission is kicking it when it is shifting, or stalling the trans on dragstrip (holding brake and gas).

and the main reason why A/T transmissions dies, is heat. Hot hydrolic oil = no oiling properties. Your synthetic oil will also help the transmission to keep up the good work even under very hot and hard conditions.

I have no doubt the A-340E can handle a lot of power. But the clutches and pressure might be the problem. High pressure, hard clutches = harder shifts, good for drag strip but not comfortable for the everyday driver. I really don,t think someone will strip a gear below 500WHP.

And you're right, the heavier the car, the more the trans work to move the car.

Also, i'm not an exepert in transsmissions, but it might not be very good for the Torque converter to lock-up when you're applying 500 horsepowers on the transmission? It might be the reason why it breaks? Who knows. I'm just like you and want to know the most possible about those cars.

But i know that Dragme on cressida forums run in the 10 seconds with a built A-340E without any problems. (trans built by MV )

 

[jibbby]

Your points are valid, but I seriously dought any Lexus stock auto tranny can handle 500RWHP without failure....Expecially the Stock SC400/SOARER earlier models lexo's...Heat is the problem with trannies and clutch slippage, you are 100% correct... Increased line pressure, synthetic, and DTC, all contribute to helping with tranny durablilty...I had a long discussion with the tranny pro that was going to build up my tranny...He said the exact same things...

I am not a tranny expert either...

 

[UZZ30-Québec]

you,ve read too fast. I said I'm sure the A340E won't STRIP A GEAR beyond 500WHP not Handle 500HP on it,s stock form.