yeah....i was looking to upgrade to about a stage 2 type clutch...but i'm not sure yet...i can probably go with the stock clutch seeing that it's not that much of an upgrade (but in effect it is) but most of my driving is highway to and from work...so...after about 2k on the clutch after turbo setup...yeah it will be time for the clutch swap

i know that what gm rates the F23 is 171ft torque but like you said....the j-bodies and even some of the cobalts are running up to 3X that rating....thanks though

 

ok so here's my question:
the f40 will bolt up to the lsj block, but will the axles work with the final drive hub? if i get the answer i'm looking for i will take this on and be the guinny pig on this one.

bump-i need answers on this guys, i have been trying to do some research, but not getting very far.

 

What about for those of us who are going to upgrade our ss/sc's with the tvs supercharger upgrade? What are we going to have to do with our tranny's to make sure they don't self destruct while trying to put the power to the ground?

 

anyone happen to know what jason whitfields cobalt has for a transmission????

 

lolz. Mine is no more.

 

i believe the 4t65 hd

 

A couple of thoughts:

The only 4t65 transmission that is rated at 400 pound/feet is the hd, not the other models.

The 4T45 transmission is used in the HHR SS, in which, horsepower and torque are LIMITED compared to the F35 model due to transmission concerns. Thus, it makes absolutely no sense that the 4t45 would have a higher rating than the F35.

The F40 transmission can be used with the ecotec engine. It is being used with one in the current 9-3. The question still remains as too which clutch housing, clutch, and flywheel are used in this combination, however. Furthermore, the gearing of the F40 is in question (see first gear).

 

i believe they limit HP and TQ due more to heat build up. the tranny can take the tq, but not the heat that comes with it under multiple hard runs. GM wouldnt warranty a part like that. Even the 4t45 on the cobalts needs a transmission cooler to reliably run 250hp...

 

from what i learned there are 3 diff bell housing gm uses on the f40, one for the saab mu9 version, one for the g6 mwl version, one for the opel vauxhall version. the only one that fits from what i gathered is the saab version. and they are the hardest ones to find.

 

Actually, I'm pretty sure the vauxhall one is used in the 2.8L Saab as well. But regardless, upgrading our transmissions without knowing what clutch we can use with it is a waste. I'm working on sorting out more myself. I work right next door to a Saab dealer, and Tom a CED is helping figure out part #'s as well.

 

the 4t65e-hd will NOT handle 400 ft lbs.

 

But it will come closer to doing so than any other 4t65 and is still vastly stronger than any 4t45.

 

mine **** it self in the gxp i owned. under 400, and over 400 {the second time}

 

Normal driving?

 

depends if you call a 60 shot on the first tranny normal, or 120 shot on the second normal

 

sweet, i was gonna try to get it done, but i'm gonna wait till i get to germany this summer to try the swap, the transmissions should be easier to get over there in sweden

 

wanna pick it up in sweden if it works out? always wanted to go there
it's only 1000 km one-way

 

The 5.3L LS4 is rated at 303/326 right? So, with a 60 shot, you were probably around the 380/415 range for horsepower/torque or so, wouldn't you think? And if you were sprying from a dead stop (at launch), I'd be surprised if the trans didn't fail after little while.

 

thats a day drip at 280kph

 

yeah, doesnt n2o have a violent tq curve compared to turbo or supercharger?

 

The shock to the engine and drivetrain generally goes from least to most:

na <turbo < supercharger < n2o

Of course, the initial displacement itself is going to have a big effect as well. Once the components are already moving, shock is much reduced.

 

i thought a supercharger would have less shock as compaired to a turbo when drivin all out. I understand that with a turbo your not always in boost as opposed to a supercharger. however, being that a supercharger is always engaged, wouldnt the torque curve be flatter than that of a turbo?

 

The torque curve on a dyno would most likely be flatter, yes, but the fact that inbetween shifts the torque remains high, whereas with a turbo it drops down a little is what is causing MORE shock, not less. The turbos ability to increase torque gradually instead of all at once is what makes it easier on other components.

 

323ft lbs.

never sprayed from a dig because all the car did was blow the tires off till 100 mph.

421ft lbs to the tires = me about hitting a bpu supra from a 75 punch due to torque steer

 

FOUND THIS, ON THE SAAB FORUMS THEY SAY THE MU9 IS A DIRRECT FIT WITH THE COBALT 'S F35

2008 F40 (MU9)
General Motors Powertrain-Europe F40 six-speed manual car transaxle
2008 Model Year Summary

Carryover Features and Benefits from 2007 model year

DETENT SYSTEM FOR QUICKER AND EASIER SHIFTING
The addition of a ball-and-spring-type detent on the shift sleeve and detents on the shift rail assists the driver in shifting quicker. The detent raises the force required to move the shift lever which prevents excess movement of the shifter by the driver, and reduces the chance of double bump. Tension between the shift sleeve and the shift rail also prevents the sleeve from vibrating while in gear.

GEAR RATIO CHANGES FOR QUICKER ACCELERATION
To adapt the F40 to North American applications and maximize performance, 3rd through 6th gears have been changed to higher-ratio gears starting in 2007 model year. The ratio for 3rd gear is now 1.37:1, and the ratio for 4th gear is no longer an overdrive, with a new ratio of 1.05:1. The 5th gear ratio is 0.85:1 and the 6th gear ratio is 0.71:1.

LOW MAINTENANCE

The MT2/MU9 uses a Castrol Burmah (BOT 0063) manual transmission fluid, and is validated as "fill-for-life". No maintenance is required for normal operation.

OVERVIEW

Originally a design developed for Fiat, Opel and Saab applications, the F40 (MT2) is a GM Powertrain - Europe six-speed manual transaxle built in Russelsheim, Germany. Its first use in a North American application was the Pontiac G6 for the 2006 model year. It is also used in some Saab 9-3 and 9-5 models.

It is a three-axis design, with first, second, fifth, and sixth gears on an output shaft behind and below the input shaft, and third and fourth gears are on an output shaft in front of and above the input shaft. Both output shaft pinions drive a helical gear with a conventional differential. The clutch is mounted on a dual-mass flywheel to dampen vibrations on whichever output shaft is idle depending upon which gear is selected.

The F40 is cast in aluminum, and weighs 124 pounds (see specs). It has been certified for up to 400 Nm of engine torque.

Triple-cone synchronizers are used on 1st and 2nd gears. These synchronizers have three friction surfaces, which increase their ability to transfer the flow of torque more smoothly from one gear to another. Synchronizers act as clutches to speed up or slow down the gearsets that are being shifted to, and greater friction area results in easier shifting for the driver. The 3rd, 4th, and reverse synchronizers are double-cone, while the 5th and 6th gear synchronizers are single-cone. All of the friction surfaces on the synchronizer rings are sintered bronze. The ratios in the 6-speed are widely spaced for versatile performance and efficiency.