Need Help With Shift Points

[abeane4]

I have a 94 camaro A4 with LT, off road Y, CAI, 2025 stall, and a mild shift kit. I also have 3.42 gears in place of the 2.73s. I had a local guy tune the car to correct the speedo and to get the car to shift correctly at WOT. He has tried to fix this twice and I still hit the rev limiter before it will shift. I was wondering what the rev limiter should be set at and what the shift points should be. In other words what works for you guys with a close set up. The car has 99,xxx miles so I dont want to go to high. Thanks for your input.:hmm:

[robmnrd]

It's always been my opinion that you gain enough top-end with a CAI and full exhaust (LT's, like you have) that shift points can be bumped up to 6000 rpms.

[Fire67]

I'd have to check, but I believe there is both an RPM and MPH target that has to be met for the ECU to command a shift. It is like this with the 98+ cars for sure, but I havent looked at the Lt1 pcm stuff in a long time.

If its hitting the rev limiter, there is something off with the settings. Also be aware that there is a small delay from when the PCM commands a shift to when the trans can actually do so. Datalogging is your friend here, you need to note the difference between shift command rpm/mph and actual shift rpm/mph to dial this in.

[abeane4]

If I set the shift points at 6000 what should the rev limiter be. Would 6400 be enough?

[Fire67]

It 'should' be plenty. But if your not meeting the correct criteria to shift (mph and rpm) it will still hit the limiter.

Do you have any way to log data? How about a screen capture of the available transmission controls (assuming your trying to tune this)?

Get me some data showing mph, rpm, tps, and the screen capture. I'll be able to help then.

[abeane4]

I have a friend with a scanner. I think it will record data I'm going to try it tomorrow I'll post it when I get it.

[jakesz28]

I'd have to check, but I believe there is both an RPM and MPH target that has to be met for the ECU to command a shift. It is like this with the 98+ cars for sure, but I havent looked at the Lt1 pcm stuff in a long time.

If its hitting the rev limiter, there is something off with the settings. Also be aware that there is a small delay from when the PCM commands a shift to when the trans can actually do so. Datalogging is your friend here, you need to note the difference between shift command rpm/mph and actual shift rpm/mph to dial this in.


^^^^^^^ I'm with him.

You have to have the mph points set so that you reach them and the shift rpm to command a shift.

I usually try to set the mph points on the low side then I control the shift with the rpm table. The thing to remember is if you set the shift rpm at 6000 rpm you will usually be above that rpm when it actually shifts. I had to set a number of cars at 5700-5800 to get them to shift at 6000.

[ThreeHonks]

Exactly^^

you need to figure out what speed you go in each gear and go from there.

For example: Let's say that from the 1st to 2nd gear shift at 6000 rpm, you are at 40MPH. Set the shift RPM at 6000RPM and set the shift MPH at about 35MPH

[MoeHorsePower]

Sometimes no matter what you do it gets into the "Stall Wall" side of the house, and yes most of the time both mph and rpm need to be within each others parameters to command a shift. But what I have found (At times) that work in the stall wall issue is to set the 1-2 shift mph to 5 and the 2-3 to around 80, If all fails try this and see if it helps you..

[96formulabird]

well my car was tuned by a guy named jeremy formato he is from florida and comes up my way every couple of months. only thing you have that i dont is a stall. he set my rev limiter at 6100 and my shift points at 5950. works very well. maybe this helps. good luck

[Fire67]

Ah, I wasnt even thinking of the stall wall issue Moe! I guess I didnt even see were he said he has a converter :doh:

OP, there is a wealth of info in here. Now you just need a way to get some data...

[abeane4]

thanks for all the info guys i think we got it figured out now. if not i will be back with some numbers for you.

[romanianfury]

i was having the same issue as this guy almost, i also have the 3.42 gears and same basic mods. i still have factory stall and the only problem i have with the shifting is from 2-3 it hits the rev limiter. whats up with this? and would a mail order tune be able to fix this?

[HITN94]

This thread is exactly where i need to be. I have a 383 LTX. It has a 3000 rpm convertor and a 3.42 gear. I recently had a 26" tall tire on the car and it shifted fine. I now have a 28" tire on it and it acts stupid, does not want to shift just hits rev limiter. The speedo HAS been corrected and still the same. I also have the tunercat software, but i am still not very farmiliar with it. Whats parameters do i need to edit to change the shift points. I have tried changing only the shift point mph, but no change. Do the shift mph and rpm have to be sycronized or what is going on here? Oh and the only time it wont shift is at the racetrack when i leave on the convertor.

[MoeHorsePower]

With the taller tire you will be increasing your MPH at a lower RPM so try lowering your rpm shift points by 100 at a time, then try raising you mph by 2. Its a trial and error, Like I stated in the post, If all else fails ( and this too doesn't work all of the time) I set my shift point to around 53-5400, set the 1-2 mph at 5mph and the 2-3 mph at 8. this has worked for me (at times) for the "stall wall" issue....At this setting the car will shift at around the 6000-6200 where I want them..Hope this helps..

[HITN94]

right now i have the 1-2 shift rpm set at 5700 and the 1-2 shift mph set at 35mph. but it doesnt shift set where it is. when i make a pass and leave on the convertor it spins 7,000 according to the factory tach (which is probably not very accurate). where should i go from here maybe lower the shift rpm to 5000?

[MoeHorsePower]

right now i have the 1-2 shift rpm set at 5700 and the 1-2 shift mph set at 35mph. but it doesnt shift set where it is. when i make a pass and leave on the convertor it spins 7,000 according to the factory tach (which is probably not very accurate). where should i go from here maybe lower the shift rpm to 5000?

Yea the factory tachs are off by usually around 200 rpm or so at wot. Dont make that drastic of a change, try the 53-5400 rpm range, again if all fails, try the stall wall procedure that I mentioned...

[HITN94]

ok thanks. i talking to a tuner today and he said it was obd1 stop shift or something like that. he told me to send him my tune and he would fix it. after i get it back im going to figure out what all was changed.

[HITN94]

i got the tune back and looked over it. he basically changed it like moehorsepower said. he didnt change the shift rpm it is still set at 5700 on the 1-2. main thing he changed was the normal shift mph in both tables, he set the 1-2 upshift to 2mph and the 2-1 downshift to 0mph. he also turned off all the trans diag and vss diagnostics in the switch tables. i dont know yet if it works but he said it will.