torque converter stall v cruise rim question

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maca
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torque converter stall v cruise rim question

Post by maca » Wed Jan 13, 2016 3:42 am

Hey guys
I'm wondering how it will affect my transmission As I have a 2800 stall converter but my car cruises on 2200 rpm because it is cruising below the stall amount does this mean my transmission is slipping and creating extra heat or am I worried about nothing.

F-BIRD'88
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Re: torque converter stall v cruise rim question

Post by F-BIRD'88 » Thu Jan 14, 2016 12:29 pm

Ya but how much is the converter slipping when at that cruise speed?
If the slip% is low the heat will be low too.

The slip % is dependant on load (weight, drag, gearing, level-uphill-downhill, etc.)

Slip% ratio is actual rpm/ theoretical rpm thru drivetrain and tires at any tested road speed.
You have to accuratly measure the loaded tire radius.

Tire-wheel center to ground length x 2. (Loaded radius)
Accurate road speed (radar gun) accurate tach too.
Rpm\gear ratio x tire dia /336 = mph

At cruise speed a factor of 340 instead of 336 is good.
Indicates 2% slip at cruise.

At wot at the end of the 1/4 mile a factor around 355-360 is ok.

6-7% slip.

Where you run into converter heat issues is when climbing long hills and or towing heavy stuff, with a high stall, as when load and throttle is high(er) , slip rato % is higher.

At steady speed on level ground with proper gears the converter slip ratio % is usually ok

F-BIRD'88
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Re: torque converter stall v cruise rim question

Post by F-BIRD'88 » Thu Jan 14, 2016 12:47 pm

A good trans fluid cooler thats mounted to get good airflow thru it at road speed
Keeps the trans fluid temp in control.
Needs air flow to cool.

maca
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Re: torque converter stall v cruise rim question

Post by maca » Thu Jan 14, 2016 10:28 pm

Thanks I was just worried that my cruise speed was lower than my stall speed.
my transmission is a lock up transmission and the torque converter I purchased for it is a dacco 2800 stall.
I have hooked up the overdrive on the transmission and it works great but I have never tried to lock it up I just assumed that's because the dacco converter was an aftermarket stall converter that it wouldn't have the clutches to lock up. I do have a vibration shudder which I have not been able to find. I was thinking that if the gearbox Is setup to be a lock up box but the converter was not a lock up converter that perhaps the mismatch may cause a vibration the reason I was thinking this was I was reading up about bodies and read the lockup boxes and non lock up boxes at different valve bodies even though they are the same trans

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