Regarding raising the line pressure on the transmission, does this cause the transmission to shift now instead of the loooong drawn out 5-700rpm shift?

I'm not too concerned with the firmness as much as I am with the quickness of shift.


As it stands now, I have my shift points set to 5700 so that the shift can complete by 6100 or so. This sucks and is costing me some time I believe.

I know the concensus is that raising the line pressure is dangerous but i'm trying to find some problems with the car and this is the only choice I have right now. A trans-Go will be installed soon - within a couple weeks.

I don't plan on keeping the line pressure raised but for testing puposes I have to try it tonight.

I'm thinking around the 115 area - does this sound right? What table in Tunercat?

Thanks

 

I don't have my TunerCAT in front of me but there are some tables that allow you to change the shift speed. You'll notice that most of them are set to something like 6.35 (or something like that). I've changed mine to .3 all across the board and noticed a considerable difference in the speed of the shifts. I was cautioned to not go any lower than about .25 though.

As far as line pressures, I'd love to hear what others have done with these also. I considered changing mine too but don't want to blow anything.

You don't use a ratchet shifter do you?

 

Thanks for the reply.


No, I don't use a ratchet shifter. If your referring to the sig, I quoted some numbskull that posted that here regarding his 4L60E

 

I need to call B&M and find out why the ratchet shifters for the 700R4 don't work for ours. Ticks me off....

 

when you increse the line pressure... you start to crosss the line of:

the transmission opens and closes a vlave to compensate for the pressure of a higher (faster) spining assembly. if you increase the line pressure... you can wreck your tranny..... this is something that the shift kit will not help!!!!

my transmission no longer controls the lne pressure beceause i have a vaccum modulated transmisson from LT1 dave... FLP has this also and its highly reccamended!!!!

what problems are you having that you belive will be corrected by increasing line pressure.... ?

 

My understanding is that the valvebody or something inside the transmission actually determines the hard limit on line pressure. Stock is a max of 90 psi I believe.

While in LT1 Edit (and I presume TunerCAT as well) allow you to up the max line pressure above 90, I think the stock transmission is hardware limited to 90 so that would have no effect.

However, I understand that adjusting the line pressures up slightly in places where it is currently below 90 (below 93% TPS basically) it will have an effect on the performance of the transmission. Will it harm it? I can't say. But I've seen several tunes from several people and many of them are adjusted slightly up from stock.

I've heard that running them at max pressure for extended periods can cause damage, but again I do NOT speak from experience here.

 

Well, my mph seems to be unbelievably low compared to others running either similar setups or actually less (bolt-ons)


Problem with going by people on message boards, no offense, is that there's so much bull****ting going on you don't know who to believe.

"I had headers and drag radials ...went 105mph"
"Full bolt-ons - 110mph"

etc.......

I'm currently running 103.95 (fastest) and average in the 101-102 range normally. I've logged every single run since installing the cam and I can't figure out where the mph is. Bryan Herter looked at my tune and my datamaster logs and thinks i'm down approx 50-80hp and that i'm not getting enough air in grams per second. "Could be the rockers are too tight" well, that wasn't it although after I readjusted them I ran a 13.12 - could have been better weather though. Got down to a 1.86 60' and still running 13.20's.

I still have 1.5 stock rockers, shorties, no e water pump, no pulley but according to most people I should have better mph.

I was thinking maybe the lack of shift kit and the fact that the tranny takes 5-700rpms to complete a shift that this was the problem. I'm not putting any more money into the car until I feel that it's running the way it is supposed to. I'm changing the fuel filter tonight possibly and hitting the track.

There seems to be some weird ignition miss according to my datamaster logs. Can't figure that one out.

 

Well, my best is 13.780 at 100.2 with the mods in sig plus 200 lbs stereo equipment in the trunk.

I've had an odd miss and stuble along with some hesitation since installing my headers in January, so I just replaced my Opti this weekend. Car pulls MUCH better so I'm hoping for better times.

I have not touched the line pressures or shifting times in my tune, only the MPHs where the shift occurs.

Best of luck getting your problem sorted out.