Supra Forums banner
1 - 20 of 32 Posts

· Registered
Joined
·
26 Posts
Discussion Starter · #1 · (Edited)
Built Auto Trans owners.... 1st to 2nd shift

Guys, wanted to throw a question out to anyone with a BL built trans or possibly any built trans.
I went to the track last week for the first time after installing my new BL trans and a 2800rpm stall. Made three passes and noticed that my car was shifting from first gear to second gear around 5600-5700 rpm... does this seem a little early for the first to second shift? It held every other gear just fine. I feel like that the car is loosing mph/et by this early shift.

btw
94 tt, full bpu, pulled trac fuse, factory ecu, car ran 12.5 @114 on street tires.

Thanks for any feedback.
 

· Registered
Joined
·
26 Posts
Discussion Starter · #6 ·
Fluid levels are right on the money. The new transmission and converter were installed less than 500 miles ago with all fresh Toyota fluids... I also installed a B&M trans cooler with a 7.5in pull fan behind it. .... any other thougths :(

Could it have to do with the 2800 stall?
 

· Boost Junkie
Joined
·
15,155 Posts
No, what should happen when you get up on the stall during hard acceleration is the rpms will jump up and then seem to float from 5000-7000rpms. Then the trans shifts and the rpms will stay higher. This is what a high stall converter does. It keeps the car in the meat of the power band. Do you have an SAFC?

Steve
 

· Registered
Joined
·
26 Posts
Discussion Starter · #8 ·
few more specs of the car:
greddy front mount, downpipe and exhaust
SAFC
AVC-R
VFC
car made 394 rwhp on the dyno before installing the new trans.

Should I just be happy with a 12.5 @ 114 or should I be getting more? Btw the car cut a 2.03 & 2.09 60ft.(believe it or not the car hooked great on my 285's, no spinning at all, the track was prepped well)
 

· Boost Junkie
Joined
·
15,155 Posts
No, you shouldn't be happy with the 2.03 and 2.09 60ft times. Those should be in the 1.6x range, or you may need to up your stall speed on your converter to 3500 or so.

If you have an SAFC you use the peak hold function to see what the max rpm that was achieved during your pass. I have an SAFC 2 and I simply push the center button up to use this function when you are monitoring RPM. That will truly tell you how high the car revved. I would say if you trapped 115mph with such poor 60ft times, then more than likely your tach is off or you are going past 5600-5700 rpms because with 394whp you are trapping about right. Get your 60ft down to where it should be and your trap speed will increase by 3-4mph.

Are your street tires drag radials? If not, you may want to pick up a cheap set on stock TT wheels just for the track.

Steve
 

· Registered
Joined
·
26 Posts
Discussion Starter · #10 ·
Thanks for some great feedack.

I am really good with adjusting/monitor boost with the avcr.... will have to work on the safc. Will this record each gear? I am only having this problem with the first to second shift. All other are holding all the way. BTW love this boost logic trans.

Yes the car is currently on street tires on some fairly heavy 19x10' rims....
 

· Boost Junkie
Joined
·
15,155 Posts
IF that is the case then I would say your tachometer can't keep up. Just take it out on the street and floor it in 1st. Once it shifts into 2nd let off, and pull the peak setting from your SAFC. I bet it will say 6800 or so RPM.

If you are serious about getting your 60ft times down then get some drag radials and go back to the track with them. If you can get your 60fts in the 1.6x range, which you should be able to, you'll hit mid/high 11s. Probably an 11.6-11.7 or so. The 60ft is the most important part of the 1/4 mile.

You need to work on your launch technique too. Utilize the foot brake as well as the e-brake so you can launch the car under boost. It won't do you any good until you get drag radials though because you'll just spin on your 19s.

Steve
 

· Registered
Joined
·
1,735 Posts
IF that is the case then I would say your tachometer can't keep up. Just take it out on the street and floor it in 1st. Once it shifts into 2nd let off, and pull the peak setting from your SAFC. I bet it will say 6800 or so RPM.

If you are serious about getting your 60ft times down then get some drag radials and go back to the track with them. If you can get your 60fts in the 1.6x range, which you should be able to, you'll hit mid/high 11s. Probably an 11.6-11.7 or so. The 60ft is the most important part of the 1/4 mile.

You need to work on your launch technique too. Utilize the foot brake as well as the e-brake so you can launch the car under boost. It won't do you any good until you get drag radials though because you'll just spin on your 19s.

Steve
+1

I was running 2.04 60'on a similar setup only using the foot brake, add the ebrake in with that and even the stock stall should be able to pull better 60' times.

I put in a 3200 stall and was confused at first becasue my tires would still spin at 2400 rpms or so, had to lean on the ebrake to get up to the full 3200 and it made a real difference. about .3 s on the '60
 

· Registered
Joined
·
26 Posts
Discussion Starter · #13 ·
I'll check on the rpm with the safc but I still think it shifting early. I even had specators asking why I was shifting so early and it sure felt that way.
I'll use some different technique as both of you recommended. I was stalling it up to about 2600 with the foot brake, didn't think to use the ebrake.
 

· Mods before Broads ;)
Joined
·
845 Posts
It does sound like your car is shifting early (my car shifted at redline when on stock twins and gas with a looser stall) but if you are on 19's that might account for the tach and speedo being off. When I upped my tire to a 28 the instrument cluster was off considerably.
 

· Night in the Ruts
Joined
·
979 Posts
My first MKIII had a built auto tranny, when they modified the valve body they had the shift points set too low, like your explaining. I brought it back and they fixed it to where it shifted like it should. Totally different car when they fixed it.
I would still talk to the folks that did the tranny.
 

· Registered
Joined
·
26 Posts
Discussion Starter · #16 ·
Hmmm I thought the ecu controlled the shifting? If the pressures in the valve body are to low/high could it have this affect?

I called Boost Logic last week and then couldn't really seem to understand it either.

Love the feedback and responses.
 

· Night in the Ruts
Joined
·
979 Posts
Hmmm I thought the ecu controlled the shifting? If the pressures in the valve body are to low/high could it have this affect?

I called Boost Logic last week and then couldn't really seem to understand it either.

Love the feedback and responses.
They worked the valve body, when I first got the car back it shifted at 5500rpm which sucked, but the shifts were tight and hard, then they re-worked the valve body and were able to change the shift point up to 6500rpm. The car would chirp 3rd gear. When the boost came on the car would spin the tires, hit 2nd and keep spinning with out missing a beat, until I let off the gas.
 

· Registered
Joined
·
26 Posts
Discussion Starter · #20 ·
Just wanted to thank everyone for their input/suggestions.

I think I just figured it out. I just removed the trac ecu (previously had only pulled the trac fuse) went out for a quick spin and hit 6300 in first gear based on my safc. Looks like that did it. The stall even feels different.

Thanks again maybe this will help someone else.
 
1 - 20 of 32 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top