PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

torque converter sluggish?

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Old Nov 4, 2007 | 07:58 PM
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Default torque converter sluggish?

Hi guys,

I need your help determining if I should ditch my torque converter with a different vendor's one.

Before I start flaming it, I'd like to know if what I am experiencing is 'normal' for a 3400 rpm brand new torque converter. A friend of mine rode in my car (please see the signature) and felt that my shift points weren't fast enough to take advantage of my engine potential. They were sluggish with no 'seat in the pants' feeling. It is hard to describe it, but my torque converter under WOT doesn't produce pronounced locked shifts. I hit the rev limiter as well, which I will fix by lowering my shift points under WOT by another 100-150 rpms.

Could someone please have a look at my tune and let me know if there is anything that I am missing? I installed a TCI shift kit before putting the tq in.

I am ready to ditch my tranny/tq and replace it with a LVL2 with a 3200 yank or vig unit. Please advise before I make another expensive mistake.

I appreciate your help. Thanks!
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Old Nov 4, 2007 | 08:02 PM
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when i first put my 3400 fuddle in, i couldn't even feel the shifts. once i had it tuned and bumped up the shift pressures it was 100 times better and actually hits pretty hard for not having a shift kit.
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Old Nov 4, 2007 | 08:28 PM
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what's your pressure set at? mine is at 96, from 90 stock. Thx!
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Old Nov 4, 2007 | 09:02 PM
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Zero out your desired shift time vs torque table.
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Old Nov 4, 2007 | 09:25 PM
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Gotta ya, thanks, 2xls1! I will give it a try.
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Old Nov 4, 2007 | 09:48 PM
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Here, compare this to the file you posted and see what all is changed. Give it a try and see how it does ya.
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Old Nov 5, 2007 | 01:31 AM
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When you get a higher stall converter it is going to do that due to the looseness. If you adjust the firmness you are over doing it on the trans side because you don't feel it as much. You are putting personal comfort over the needs of the trans.
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Old Nov 5, 2007 | 09:14 AM
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Thanks, Frost! I will go over your file when I get home from work.

2002_Z28 - since I never owned a car with a high stall (my 67 has a 2100 t.q. which almost feels like stock), I couldn't tell if my 3400 was performing properly. I did hear about 'driving through the mud' feeling, but I didn't realize I couldn't make shifts more pronounced without breaking the tranny :-)
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Old Nov 5, 2007 | 12:00 PM
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Originally Posted by darom
Thanks, Frost! I will go over your file when I get home from work.

2002_Z28 - since I never owned a car with a high stall (my 67 has a 2100 t.q. which almost feels like stock), I couldn't tell if my 3400 was performing properly. I did hear about 'driving through the mud' feeling, but I didn't realize I couldn't make shifts more pronounced without breaking the tranny :-)
you can; it's the normal thing to do
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Old Nov 5, 2007 | 03:24 PM
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You can make the shifts firmer. The trans won't blow up. It just might not be needed.

The only thing the trans won't like is an autotrans interceptor and no one uses those anymore.
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Old Nov 5, 2007 | 07:26 PM
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Frost, I applied your changes and the car feels more responsive. I also lowered my shift points a little not to hit the rev limiter on 3-4. Is it pretty much normal to apply the same RPMs to normal, performance and hot tables (shift points)?

Any pointers on a slight bucking condition while coasting with no foot to the pedal? My original tuner told me that it was pretty much granted with bigger cams in our cars.

Guys, thanks again, this is a great board.
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Old Nov 5, 2007 | 09:19 PM
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Your idle airflow table is crazy high... I would expect your cam would need 8-9.x g/sec and the table is set at 15 g/sec hot! your target RPM for idle is 750.... I bet it never gets there until the car has been stopped still for 4-5 seconds. I bet it hangs at 1000+ RPMs whenever the car is moving. That airflow is the primary cause of your grief like surging after throttle. I bet it's bad on the highway with the stall locked up in the 1500-2000RPM area, prolly bucks pretty good.

Post your current tune (since you change some shift stuff) again.
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Old Nov 5, 2007 | 10:10 PM
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Here it is. The car idles at around 850-900 rpms. You are right, it won't settle to 850-900rpms unless it is still for a few seconds. The tuner also had to bump my Idle Airflow vs. Coolant Temp - when it was cold outside, I had to keep my foot on the pedal for 30 seconds.

Bucking is not loud/violent, it is always when in coasting, coming to a stop. I also noticed I have to use my brakes more, before the tranny would downshift and the engine would help breaking. Now it is not noticeable.

I appreciate your input. I just bought HP Tuners and I'd rather fix little problems myself, instead of bugging my tuner guy who lives in another part of town.

Btw, if you happen to be in town, PM me - I will take you out for lunch :-).
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