Suggested 4L60E upgrades ?

[damannhw]

I've spent a good amount of time doing searches and reading, but I still have some hesitation as to what upgrades to perfrom on my 4L60E. Background - Car is a '64 Tempest, and I purchased a complete 2002 Trans Am donor car. The 4L60E tranny has less than 40K miles on it, and the LS1 engine will be getting mild mods (228R cam, exhaust, valvetrain, & tune, etc). There is the possibility of supercharging later down the road, but it may be awhile. I'm running a 9" Ford rear w/ 3.50 gears, and I plan for the car to be mainly street driven, do 4 or 5 autocross events per year, and an occassional track day.

That being said, after doing ALOT of reading, I purchased a YANK Stealth 2800 stall, a Transgo HD2 shift kit, and a B&M 24000GVW tranny cooler. My thoughts were a smaller stall to maintain driveability but improve launches a bit, and the shift kit installed with shift firmness improved a bit over stock, but not so firm it makes driving unpleasant.

My concerns are increased heat from the stall and higher line pressures. Am I going to far with these mods, or will I be OK for what I want ?

Can any of you guys make any suggestions on my set-up and direction, or what you did ?

Thanks !

[69cutlassrkt]

That all sounds good to me. I had mine rebuilt with new clutches, beast shell and vacuum modulator. Mine went out due to a few 7000rpm shifts and some aggressive downshifts like at 50mph to first gear believe. The shift kit is a good idea cause with a higher stall converter you don't feel the shift much. I think the higher line pressure is suppose to help save the clutches though I think that's why a lot of builders go with the vacuum modulator instead of leaving it computer controlled. EDIT: also my car weighs around 3800lbs so its gonna be a little harder on the trans

[Steve Chryssos]

You're likely to get different answers elsewhere, but I would recommend that you stick to street and autocross use. One of the things we do to run automatics on road courses (20-30 minute track day sessions) is to keep the converter locked up as much as possible. This keeps slippage to a minimum, which in turn, resists fluid shear and keeps down the temps.

To make that happen, we utilize billet converters with heavy duty lock up clutches. That billet steel front cover works like the flywheel in a 3 pedal car giving the oversized lock up clutch a flat, sturdy surface to apply against. In addition to the front cover and clutch, there's a 3rd piece in the puzzle: Software gives us the ability to tune lock up across a wider range of gears, speeds, and TPS angles. For track days and autocross with our in-house car, we go into the software and lock up in 2nd, 3rd, and 4th and lock up at 45mph and up to 50% TPS. When we snap off the throttle, the converter stays locked up down to 0% TPS. Billet converters are expensive, but look at all that capability. Just picture how much more your gas pedal moves at a track day than at the drags. You get to appreciate why a different converter scheme is required.

As I understand it, Yank Stealth Series has a stamped front cover and a stock style lock up clutch. It should probably only be locked-up under light loads and steady state use. One example of light load/steady state is highway cruising. For autocross, it will be absolutely fine, but you might want to skip track days. Or test and stay on top of trans temps. We fragged a lot of stamped cover/OE clutches and then just moved on to billet/oversized clutches. We haven't looked back.

Beyond the billet converter, our transmission has a ton of mods designed to help it rev to 6500 rpm lap after lap for 30 minute intervals. There's not enough talk about rev capability with transmissions. In stock form, the 4L60E was never really designed to rev. The list of mods in my transmission can be found here:
http://www.twistmachine.com/index.php?main_page=product_info&cPath=6&products_id=12

With out the hi-rev mods, keep the redline at 5500 rpm for track days. And if you don't have enhanced lock up capability, stick to autocross and street use.

Hope that helps
Steve

[damannhw]

^ Guys, sorry I haven't chimed in, but I appreciate your responses and input.

Steve, I've gotta admit, you have me thinking more about a 6 speed now ! I really wanted to keep this can an auto though. I'll stew over it awhile and decide. It may be best to just upgrade the converter and clutches now while it's out as you mentioned.

Thanks !