hi guys,

i've been reading thing on here for a while, i've resently just got a 535 auto, once i've tidyed it up i want to add a turbo, i was just wanting to know if the boxes are strong enough to hold it and if there is anything that needs to be changed( other than a manual box)

cheers chris

You could do it and the tranny would last, depending on how hard you drove the car. What hp numbers are you going for?

You could do it and the tranny would last, depending on how hard you drove the car. What hp numbers are you going for?

With all due respect, the trans would not last. BMW autos can barely take more than 10% more power/tq than stock.

If you are going to use the auto, you need to have it built to do so. Better torque converter, better clutches, better valve body setup, the works. Probably run you in the range of 2k quid, based on the prices I have seen for such things around here.

Re-building is a good solution. But Id run what you got until it breaks. If that happens, I guess the upgrade would be the 4hp24 from the 750i of the same vintage. Its a more robust tranny and can probably handle the increased torque better.

RussC

My auto slush box held fine to 15 psi. After that if the damn thing downshifted at full boost it would slip and post trans error. If you only boosted to 6-8 psi and didn't let it kickdown all the time you will be fine. Autos suck. Do the 5 sp swap. I am.

Auto and turbo go very well together.......if done right! i don't care who you are, there is no way you shift faster than an auto. plus a turbo'd car with auto will keep spooling more linear through the gears.

upgraded the VB and TC and other internals+turbo =wide grin from ear to ear

Don't bother with a 4hp24 swap, you're not going to get anything out of it. I've spoken at length with a ZF rebuilder in CT (I live in CT) called Eriksson Industries. I had a 5hp19 I was rebuilding for a car we were sending to the auction (we took it in on trade) and Nat (Eriksson owner) was very informative and patient with me through the whole rebuild. Afterwards I picked his brain about the 4hp 22 and 24s, and asked what I could do to make it hold more power.

The long and short of it is: Nothing. The upgrades the 24 has over the 22 are basically bigger clutches and a bigger stator. The weak link has nothing to do with any of this, the problem is that they both use a floating planetary gearset, and there's no upgrade path for it. I also found out that a 4hp22 is a 4hp22, doesn't matter the year or what it came out of, they're all case compatible. Find one in one car, swap bellhousings and valve bodies and you're good to go with it in your car. The 24s are also case compatible, but have a longer tailshaft to allow for the longer stator, something like 1/2".

I told him money was no object, make it stronger. He told me there's no point as even with updated clutches and whatnot there's no point where the weak link isn't going to be what fails first. He also told me not to bother as both trannies are plentiful and easily rebuilt, and stock trannies would be able to hold about as much power as you can throw into them.

The real killer (according to him) is neutral drops, or swapping quickly from forward to reverse or vice versa, as this will (according to him) "Cause the planetary to wrap around itself"

hi guys,

i've been reading thing on here for a while, i've resently just got a 535 auto, once i've tidyed it up i want to add a turbo, i was just wanting to know if the boxes are strong enough to hold it and if there is anything that needs to be changed( other than a manual box)

cheers chris

Save yourself time and trouble.......the auto slush box will fizzle out on you....

Hey Pat, how did you get the tranny to work with standalone?

Kind of on topic

thats what i had thought! shame i like the lazyness of autos, i'm only looking for300-400 at the most.loks like i'll need to search for a auto-manual swap.

cheers chris

Hey Pat, how did you get the tranny to work with standalone?

Kind of on topic

it worked fine we just let the main ecu control that ....but after a few weeks she went limp.....so i just got rid of it for a custom built 5 spd tranny.

There was another E34 with an auto down here also and his trans went out at about 450rwhp.

It could have been that in these instances the trans was on its way out...
even rebuilding to me was a waste, 5 speed is far better....:buttrock

With all due respect, the trans would not last. BMW autos can barely take more than 10% more power/tq than stock.

No problem with a good debate and speculation :)

I have seen a 535i that dynoed 340rwhp on an automatic transmission. I talked to the guy and he said he had about4k miles on the car since his 745i turbo steup was installed. There is no telling if that autmotic is still in commision today.

No problem with a good debate and speculation :)

I have seen a 535i that dynoed 340rwhp on an automatic transmission. I talked to the guy and he said he had about4k miles on the car since his 745i turbo steup was installed. There is no telling if that autmotic is still in commision today.

Every FI auto BMW I have every heard of without a built trans kills said trans in less than 10k miles.

10k is very optimistic