3AT tranny speed max out.

[SiriusBlack]

I have an 87 XT turbo coupe. As far as I know it has the 3AT, I've heard the 3AT can handle a fair amount of power increase. What I'm wondering is how much power I can add to my EA82T before it becomes too much for the tranny. I'm also curious, if I reach my goal of getting my EA82T to 150-160 HP, how much more top speed and how much shorter 0~60 time will I end up with using the stock 3AT tranny? I have dug up various articles on the XT, back in 87 it was rated for 115 top speed and a 0~60 time of about 9 seconds. I don't know if those numbers were with the auto or the manual, but i would like to know what kind of improvement I might see with the 30 extra HP.

Thanks in advance.

Edited March 12, 2021 by SiriusBlack

[silverhelme]

I'm sure GD will chime in shortly but the short answer is NO. Unless you know how to build automatics and keep them tuned don't even think about adding hp to a 3at. I know how to and have made mine live behind an ej swap for several years but it's getting tired and parts are getting hard to find so I'm finally going to swap it for a 5 speed. Either get the harness out of an '88 or newer and swap in the newer 4eat or put in a 5 speed for best performance, no harness needed.

Edited March 13, 2021 by silverhelme

[nipper]

Those stats are for a fresh tranny not one set in its ways. Also the tranny is only part of the formula. I dont know what the torque converter is rated for but that has to be part of the discussion

 

 

 

[Numbchux]

The transmission is not your weak link. The 3AT sucks, but you'll melt a dozen EA82ts long before you break a 3AT.

[SiriusBlack]

I guess I'm wondering about the final gear's ratio. At what point does adding power not contribute to the top speed. What is the realistic top speed for the final gear's ratio?

[DaveT]

There were 2 different final ratios in the 3ATs.   My 86 had slightly taller gears than all of the ones I got later, from 88 through 93.  The 88 up do about 65mph at 4000rpm on the flat.  To go faster, you need more rpm.  The 86 was something like 500 to 600 rpm lower.  Also noticably slower acceleration,  and bog down on hills more.  More HP would level that off.

[GeneralDisorder]

The 3AT is garbage and has the same availability of parts problem as the EA82. The local AAMCO needed an oil pump drive for a customer's loyale and one of my tech's had to go through the scrap metal pile at his house to find one that was sort-of acceptable in that it *only* had the teeth half worn through as opposed to almost entirely worn through or stripped in the case of the one being replaced. One of the many flaws in that trans. 

It can't support any additional HP for any significant length of time. That's why most of them are dead and crushed by now. 

GD