Well, if its a 1997 SSEi, is *most likely* has the 4T65E-HD Tranny, but 97 was an iffy year. 350-400 is kinda high. The 4T65E-HD which now comes in all Grand Prix GTP'*, SSEi'*, etc behind the L67 supercharged motor is rated to handle a "recommended" maximum of 280 ft/lbs of torque, which is exactly what the Supercharged L67 puts out.

This has been a huge complaint from GTP owners for years now, but GM has done nothing to boost the torque ratings on the 4T65E-HD :( They are hoping the G-Force might also bring a new model tranny.

So if the tranny is the problem.. and the 4t65HD tranny can take approximate 350-400 hp.. adding about 100 - 150 horsepower ( 100 - 150 shots ) would mean the total power output would be 340 - 390 hp. The tranny might take it then.. I know I would be getting a shift kit in and hopefully a tranny cooler too.. what else is there to help bulletproof the tranny ??

Well.. after talking and a little researching.. I think I will go with 75 to start.. and then go to 100 max shots .. however.. when I was talking to one of the guys at the performance shop ( who use to be right into drag racing w/ funny cars ). He told me that if I went with NOS.. there is no point in doing the */C pulley because that means I would have to decrease the NOS shots even more. I was planning on changing it down to 3.25 from stock (3.6 ??). Is this true ?? I know a few of you gurus' have experience with this, so I wanted to know if that'* true or not. I know I would get gain through the */c pulley when the NOS isn't running.. but what about when it is ?? I thought I could still run with NOS ( same shot as planned ) and change the */C pulley.. and be better off...

Stock is 3.8 inches on the 96+ L67 found in SSEi'* and GTP'*. A 3.4 is the most common mod, and most common pulley size used for alot of GTP'ers I know. Some go less, but they also have pretty extensive engine mods too. 2.8 / 3.0 is possible with an intercooler and other ways to keep the Knock retard down.

How do I check the knock retard degree ?? I know 0 is the ultimate.. but what would they be on a stock engine...

Do you have a laptop? You could even use a PC if you temporarily moved it to your garage with this software Http://www.autotap.com

It hooks up to your serial port, and plugs into your OBD II connector to give you all kinds of readings. It will give you your KR, and is what most GTP'ers use. With a laptop it will also record real-time data while your driving.

For example, if you took it to the track with you, it records everything from every sensor and saves it while your making your run, etc. You could go back and look and find out exactly how fast you were going when you shifted from 1-2, 2-3, etc.. what the oil temp was, tranny temp, water temp and a TON more. I think there is an example on thier site too.

I would personaly start out with a 50-75 hit and see how everything goes from there. Something to remember is that when Nitous is injected into the engine it goes from a liquid state to a gas state. This phase change absorbs a lot of heat from the air charge which will help produce more power. The nitrous phase shift will have a similar effect as an intercooler but it will only happen when you hit the nitrous.


Every 10 degrees decrease in intake air charge is 1 percent more hp. I would love to see some data on intake temp, measured after the supercharger, and exhaust temp, measured at the collector, comparing a non-nitrous 1/4 mile run to a run using nitrous.

One other thing you might want to use if you do go to the higher 100 plus hp hit is to use an incremental nitrous system. These systems are much more expensive but you can program the system to slowly increase the nitrous level over the course of a run. The system could be programed to start the nitrous feed at 25% of max once you hit WOT and increase the feed steadily to 100% over the next two seconds.

That is just on example of what a system like this could do. If you want to get a similar effect for much less money then just wire a seperate nitrous switch so that you can manualy activate the system in say second gear. This will give time for the all the driveline parts to build up speed and reduce shock.

If you want a progressive system, ZEX makes them. But yeah, start smaller, I suggest using the 3.4" pulley and running a 50 shot or maybe a 75 maximum. Don't push it too far unless you upgrade the tranny even though you want to put a shift kit and tranny cooler, that still wont save the internals from doing a nice grinding, slipping, or exploding.

Go find a shop that offers synthethic transmission flushes. My shop has them and we have had many customers report much smoother shifting and highly improved gas mileage afterwards.

We have done one RV that had a trans temp guage installed and he reported a maximum temp drop of 50 degrees.

Temperature is the enemy of an automatic transmission and the synthetic fluid combined with a good cooler will extend the life of the fluid and the tranny for a very very long time.

We normaly consider the synthetic transmission flush a lifetime fill. As long as the transmission does not leak you should never have to mess with it again. Of course this is considering normal driving and really extreme driving like racing, lots of towing, and heavy 4WD use are all going to decrease the life of the fluid.