stall converter affecting highway acceleration?
Thread Starter
Instructor
Joined: Nov 2005
Posts: 184
Likes: 0
From: San Antonio TX
stall converter affecting highway acceleration?
Does this make sense?
I can swear my car doesnt pick up as fast on the highway anymore.
Sometimes I have even noticed that it would shift too early, by like 500-750 rpms, into third gear.
maybe with a tune this can be fixed im guessing right? is this normal?
I can swear my car doesnt pick up as fast on the highway anymore.
Sometimes I have even noticed that it would shift too early, by like 500-750 rpms, into third gear.
maybe with a tune this can be fixed im guessing right? is this normal?
Team Owner
Joined: May 2003
Posts: 23,480
Likes: 9
From: East Meadow NY
St. Jude Donor '12
It doesn't sound right. Acceleration on the highway is normally improved when you add a converter. The engine spins more freely and gets you into the upper RPM band faster.
The shifts are controlled by computer. Did anything else change in the car besides the converter.
The shifts are controlled by computer. Did anything else change in the car besides the converter.
Safety Car
Joined: Oct 2000
Posts: 4,949
Likes: 10
From: Monticello MN
1) What make and stall speed converter did you put in?
2) Did you change differential gears, or anything else, at the same time the converter was installed?
3) Are you sure the converter is locking and unlocking? It should unlock when you go WOT or touch the brake pedal.
4) Have you looked at your transmission temps after a run on the freeway?
Other than the obvious change in stall speed, most aftermarket converters are smaller diameter and lighter weight than the factory unit, and, therefore, should spin up a little easier. Kind of like a lighter flywheel on an M6. I would suggest you get a tune to ensure the converter is both locking and unlocking properly and performing correctly. The tune will also ensure your shift points are set correctly for your engine, transmission, differential, stall combination.
Ed
Last edited by C5XTASY; Jan 16, 2009 at 09:38 AM.
Thread Starter
Instructor
Joined: Nov 2005
Posts: 184
Likes: 0
From: San Antonio TX
yea I completely left out the fact that I swapped the tranny at the same time. But it only had like 30k miles on the tranny and it was in great shape.
I tried it again and temp is fine after hard runs, but I do also notice after hard runs sometimes it seems to "slip" if thats the correct term. If I hit a bump or something it feels like the car goes into neutral for like a split second and then goes back into gear. You can hear it more than you feel it. Like the RPMs go up a bit for a split second yet the car feels like its cruising in neutral. SO i guess something more might be the problem. Any ideas?
Its a 2500 stall and I got 2.73 gears.
I tried it again and temp is fine after hard runs, but I do also notice after hard runs sometimes it seems to "slip" if thats the correct term. If I hit a bump or something it feels like the car goes into neutral for like a split second and then goes back into gear. You can hear it more than you feel it. Like the RPMs go up a bit for a split second yet the car feels like its cruising in neutral. SO i guess something more might be the problem. Any ideas?
Its a 2500 stall and I got 2.73 gears.
