Well I am currently running my automatic 4t45-e/LE5 with 234whp/244wtq on a mustang dyno for those that might think those numbers are low it's because the mustang dyno's add load to the dyno to simulate real world driving which dyno jets do not.

Well, as soon as I figure out exactly what my combo can handle safely on the street with some drag strip use I would like to see a 300whp goal which I'm fully confident the LE5 engine can handle. Where I am worried is with the 4t45-e automatic transmission.

On GM's paperwork the 4t45-e can handle in stock form 221 maximum engine torque and 325 maximum gearbox torque.

I have added a tubular perma-cool transmission cooler and tranny programming which makes shifts faster and harder and to my understanding creates less heat since the clutchpacks are slipping less so I think that should up the power handling capability as well as the tranny cooler.

I think I will need 12 psi to realize 300whp and right now I'm running at 9 psi.

I might need a fuel pump upgrade but I'm not sure of what the stocker can do for me coupled with the return fuel system and fpr i'm running.

My question is do you all think the tranny will work ok with the 300whp and will my 42# injectors take me that high?

http://media.gm.com/division/2005_pr...ain/index.html

http://media.gm.com/us/powertrain/en...4LI4VVTENGINES

info on engine and tranny

 

bump

 

It's obvious you're in a situation few have ventured into yet -- thus the inability to answer your question.....

 

whats the difference between maximum engine torque and maximum gearbox torque?

 

personally, i would say your on the borderline....the equivalent to running 275hp on stock rods in a 2.2, knowing nitrous blew them at 283....sure your not at the break point yet, and your situation is different, but riding so close to the limits will probably kill the tranny over time. I'd go 250hp with a stock tranny (tranny cooler/mounts as well), and for 300whp, i'd get the tranny built

 

What could you do to the auto tranny to make it handle more power?

 

i was confused on that as well.

 

well considering what the ss/sc tranny is rated at.. and how thats completely and utterly false proven buy the turbo builds on this site ... i'd say you should be fine... there are more then eonugh cavi guys that are running with 300 whp and not having an issue.. talk to bill hahn would be my best guess

 

you can't get 300whp out of 42's.

 

ask GM themselves, im pretty sure they have found out the hard way

 

these guys might be able to help:
http://www.importperformancetrans.com/gmautofwd.shtml

 

tried that but having trouble getting a hold of them.

 

hmmm this is very interesting. But they don't tell you the max ratings for the tranny

 

call em

 

4T40-E / 4T45-E GENERAL MOTORS FRONT WHEEL DRIVE
Cavalier, Malibu, Cutlass, Alero, Grand Am, Sunfire

Valve bodies are custom calibrated to provide firm, efficient shifts.
Modified pressure regulation system to furnish precise line pressure increase as needed with open throttle conditions.
Redesigned converter clutch apply circuit to yield greater holding capacity under high horsepower use.
New Solenoids installed
Modified pressure control solenoid installed (4T65E)
Additional Clutches Installed
Hi-Energy Friction Material Installed
Modified pump to increase volume and enhance fluid flow throughout the unit.
Heat treated pump driveshaft to prevent spline stripping
Heat treated apply sleeve to prevent breakage
Modified aftermarket front sun gear to prevent the pitting and galling often associated with the OEM part.
Heat treated final drive sun gear to prevent the metal fatigue associated with the OEM part.
New Torrington Bearing set installed to reduce frictional losses and prevent component failure
High strength drive chains utilized to prevent stretch and skipping teeth.
Limited Slip Differential available (optional)
4T40-E and 4T45-E: $2975


Very interesting, I might utilize this after I get some more money.

 

GREAT Find! Im ordering one now.

 

let us know how it works out. it costs roughly 3500 to do the swap to a 4t65...so 2900 aint bad for a perfo rebuild.

 

i'll be sure to let you guys know.

 

That be great.

 

i ordered a full replacement.

That'll make this my 3rd tranny for the car.

I have the stocker in.

I have one being built (cryogenned gearing and such)

then i'll have this one.

The thing im more excited about is the additional clutch packs, and im trying to see if they can make a 4500 stall.

Im looking to hit mid to low 11's, high 10's on this car with drag slicks.

Kinda making it a "first" for the cobalt sedans.

I was the 1st production hahn kit for the sedan (bought it 1 week after it came out)

But in all reality..who knows.

This tranny might be a huge pile of ****.

I hope to god it isnt. lol.

 

yeah you will be a pioneer for the tranny stuff for us.

 

they got all my info, they are going to call me back to tell me if a 4500 stall is doable.

plus they are doing some research to make sure it'll work fine in a cobalt with the stock tcm.


once they call me back (said it'll be a few days), they said to give them 2-3 weeks to make it then ship it.

 

Celica, your going to need more then 12psi on that turbo to make 300whp. More like 15-20, and thats if the turbo can flow 35 lb/min of airflow(roughly 300hp worth of air). It also depends on your displacement and elevation.

I have no doubt your tranny can hold the power, just make sure you tune it right and the engine will hold up. Your going to need 60lb injectors as well. Good luck =P

 

well, lets see. From my calculations on 9 psi on a mustang dyno I am getting 13.1 wtq per pound of boost. 10 whp per pound of boost as well. Original pre turbo numbers were 144whp and 126 wtq on a mustang dyno.

With my curernt numbers to achieve 300 whp or wtq whichever can come first probably need to focus more on the tq since thats what the tranny looks at.

I would need 4 more psi to acheieve 296.4 wtq and 274 whp. Correct?

That would total me to 13 psi for those numbers.

As far as the 42# injectors, with the return fuel system and fmu the way it works it lets the 42#ers do the work of 60#ers. Might be hard to understand but maybe someone on here could explain it better.

 

hey celica, does your rpm's kinda flutter at lower rpms when driving?