High HP and AUTO trans

**92pearltt** · 06-13-2011, 04:40 AM

Has anyone ran a high horsepower car coupled with an auto trans. I am really thinking about swapping an auto into my fwd drag car in the making. I would just like to know if anyone knows how much power the FWD trans can handle. Also is the AWD auto trans stronger and can I swap it to FWD like the getrags? Does an AEM standalone have the ability to control the auto or do I still need a tcu. I am kind of an automatic trans noob so help me out if you can.

Imperfect drop me some knowledge lol.

**MR2** · 06-13-2011, 05:27 AM

Nelson would be a place to start.

**IPD** · 06-13-2011, 07:32 AM

neither nelson nor chris have experience with high HP FWD ATX, afaik. in fact, i'd say 11secFWD is probably the most knowledgeable member we've got. http://www.3sgto.org/garage_vehicle...._vehicle&id=39

you can check my blog on here for some of my thoughts on the matter. succintly, the ATX in the 3/s is a mechanical duplicate of that in the 1/2g DSM's. there are guys who have gotten 8's out of them with welded VCU's. the only real achilles-heel is OD--and anyone who has raced them will tell to use it as minimally as possible, if at all. it appears to be sufficient for normal driving, but it really isn't designed to handle power shifting in a high HP application.

FWD and AWD ATX's are the same; you're not going to get more or less durability from switching--and you can't convert (even if you could, since they're identical, it's a rather pointless idea...especially given the difficulty in finding a 3/s compatible one).

i don't know AEM well enough to know if you can run extras like the trans off it. my guess is you'll simply have to use the TCU & tell the AEM or ECU to send the readouts that the TCU needs (there's about three of them). both nelson and chris ran AWD ATX's in manual-shift mode--so they won't really be able to help you out much with the wiring aspect.

p.s.
fwiw, if you want to primarily run drags with the car, get a custom-stall torque-converter with a stall of 3500-4500 rpms. it will make the car shitty for casual driving, but the effect at the dragstrip is definite. my guess is that it's probably good to set the stall at a MINIMUM as high as the rpm band where your turbos spool. add a translab shift kit, end clutch kit, and a nice-sized trans-cooler (i'm going with c3's 2" + fan cooler). here's one of the shops you can start asking around at:

Transmissions

IPT is a good place to buy--if you're having the work done by yourself. i've heard mixed-signals about level 10. dsmtuners is a great place to ask around.

**Ninja Performance** · 06-13-2011, 09:40 AM

No, the 3S AEM does not do ATX control.
IPT sucks (IMO)
Get the TC restalled and brazed at Hughes in AZ. They are the shit.
Run full ine pressure and use 2 toggles to shift thru the 4 gears.
The input shaft will snap at high HP hard shifts. 500HP and under shouldn't be an issue

-Chris

**n2nsanity** · 06-13-2011, 04:42 PM

you're welcome to buy mine if you want
was in a 94sl i got from another member
said he had like $5k invested into it
i think 10k on a rebuild, shift kit, high stall tq converter and lsd
i did a 5spd conversion, so it's just sitting in my garage
also have the fwd atx axles. i have a 92 5spd mtx, so i couldn't use them
and the atx engine harness and tcu
i'd let it all go for stupid cheap if you're interested

i had trouble getting everything to work, so i'm unsure of the condition
i really wanted to see what it could do, but i got impatient and did the mtx conversion instead

pm me for more info if you're interested

**IPD** · 06-13-2011, 08:27 PM

Originally Posted by Ninja Performance

No, the 3S AEM does not do ATX control.
IPT sucks (IMO)
Get the TC restalled and brazed at Hughes in AZ. They are the shit.
Run full ine pressure and use 2 toggles to shift thru the 4 gears.
The input shaft will snap at high HP hard shifts. 500HP and under shouldn't be an issue

-Chris

i think IPT is ok if you're just buying the translab shift kit & clutch packs from them--but that's about it. for a torque converter, i'd buy one NEW--not a rebuild. i forget the name of the place i was looking at, but DSM tuners can probably point you in the right direction.

p.s.
due to incessant nay-saying...i've pretty much decided i'm going to run stock internals on my trans until it shits the bed. if it can hold up to 500+ awhp of dd & a few 1/4 passes--that'll pretty much be the end of discussion, as far as i'm concerned.

**Ninja Performance** · 06-14-2011, 07:02 AM

Stock internals will be fine for 500HP. Use full line pressure. Use Hughes to restall and braze. You will be fine. IPT did our first "high performance build" and when it blew we rebuilt it ourselves. Turned out the special clutch packs were off the shelf aftermarket units, like NAPA. Nothing special. And the stall was never right. So we started rebuilding ourselves and sent the TQ to hughes and things improved big time.

-Chris

**IPD** · 06-14-2011, 07:23 AM

Originally Posted by Ninja Performance

Stock internals will be fine for 500HP. Use full line pressure. Use Hughes to restall and braze. You will be fine. IPT did our first "high performance build" and when it blew we rebuilt it ourselves. Turned out the special clutch packs were off the shelf aftermarket units, like NAPA. Nothing special. And the stall was never right. So we started rebuilding ourselves and sent the TQ to hughes and things improved big time.

-Chris

yes. i would rather pay brett to build it than IPT. that said, IPT sourcing just the clutch packs/translab stuff is probably just as good as anywhere. i've never ran across anything definitively proving that "clutch pack A" is superior to "clutch pack B". if you know of something, i'd like to hear it. the biggest "difference" i've heard between any of the stuff on the market is a kit having 4 vs 5 clutch packs included.

p.s.

here's where i would shop for a torque converter. DSM tuners seem to think rather highly of this place:

http://www.converter.com/

**Ninja Performance** · 06-14-2011, 07:47 AM

Originally Posted by inperfectdarkness

yes. i would rather pay brett to build it than IPT. that said, IPT sourcing just the clutch packs/translab stuff is probably just as good as anywhere. i've never ran across anything definitively proving that "clutch pack A" is superior to "clutch pack B". if you know of something, i'd like to hear it. the biggest "difference" i've heard between any of the stuff on the market is a kit having 4 vs 5 clutch packs included.

p.s.

here's where i would shop for a torque converter. DSM tuners seem to think rather highly of this place:

Precision Industries

Bret graduated, mech engineering, and has a real job now.

-Chris