500 SEC Gearbox Issues URGENT

[kai performance]

Hi All and sorry for the brief introduction.

Basically we have a customers car in which is a 500sec that has been highly modified. Forged Pistons, supercharger etc

But its automatic gearbox sucks. In drive it is very very dissapointing on pull away.
If you drop it to 1st then pull away its a bit more impressive.

Apparently it is a modified gearbox but not the standard box apparently it is a "ZF" box from a mercedes van ? which is heavier duty than the standard box.

Not sure it is the right box to be honest and was wondering if anyone can give me a model number of what box it should be and what box you think it is in it.

Also who can build competition automatic boxes any recommendations please.
money is not an issue.
Thanks ever so much
Kai Performance

 

[kai performance]

Oh also any indications on some serious power from these engines.
As mentioned there is a newly fitted supercharger, and nitrous.

Are there any upgrades required on the :-
Injectors?
Fuel Pumps?
Timing ?
Diff (quaiffe)
Any help would be greatfully received.

Customer has been told engine can take 700bhp to 800bhp and he would like to acheive that and we are here to make it happen.
Thanks once again !!!

 

[television]

Hello and welcome, you do not say if the car is a 126 or a 140

the 140 uses a 722370 or 722620

I have no info on the 126 as that possibly does not use a MB gearbox

Best I can do

 

[MotardMan]

More info required, is it a manual or auto box? YM of the car would help a lot.

 

[jibcl500]

722311

jib

 

[jibcl500]

whats the chassis number WDB126044 ?

jib

 

[television]

When I looked up that car no gearbox was listed, why I asked if it was a 140 or 126

 

[kai performance]

:Oops::Oops: apologies for being vague, I should know better

It is a Y reg 1983/4 I believe and it is a 126

the chassis number is wdb126044

also the box is Auto

But as mentioned I have been told it has a ZF gearbox from a police van apparently.

Hope this helps you all.
Thanks for the prompt responses.
Much appreciated

 

[jibcl500]

so the auto box should be a 722 311 then.

jib

 

[kai performance]

Is that what it would be "standard" or is that the ZF bullet proof police use one ? or is that a load of tosh and they have just had my customer over becuase he has had this box rebuilt TWICE ! already.

 

[jibcl500]

that number is for the gearbox that should be fitted to the car, I wouldnt think there is a police spec gearbox that could or would fit on the back of that V8.
ZF would build a box to take a certain amount of torque, that engine was never designed to push 700-800BHP and the box would have never been specced to take that either.
I dont think a box exists personally, even the police wouldnt trash a ZF that quickly, Police spec range rovers only have the same ZF as any other range rover but the point is if they trash it they replace it.

The diff should be the weakest link on this setup blow that and its cheaper and easier to replace.

Is it a race car or street rod, might be worth speaking to AMG to see what they have kicking about, so what actually breaks on the box anyway?
jib

 

[television]

The only interesting thing here is that many commercials were fitted with a ZF box, saying this they only use the same engines as in the cars, so the BHP or torque was not that high

 

[kai performance]

So what is the answer ? is the ZF box the better choice or the standard box that is supposed to be in the car ?

 

[brandwooddixon]

I know that Brabus have sold vehicles producing upto 700BHP, but I think that they have been the V12 rather than V8. Even they only give just over 500BHP for their V8 tuning.

As far as I am aware they don't mod the transmission, but it still may be worth a check. http://www.brabus.com

I know that it's a daft question, and I don't mean any insult, but is it really the box? Could there be another problem that's engine related, like the good old MAF issue?

 

[television]

I know that Brabus have sold vehicles producing upto 700BHP, but I think that they have been the V12 rather than V8. Even they only give just over 500BHP for their V8 tuning.

As far as I am aware they don't mod the transmission, but it still may be worth a check. http://www.brabus.com

I know that it's a daft question, and I don't mean any insult, but is it really the box? Could there be another problem that's engine related, like the good old MAF issue?

Reading the post again I think that you could be right

 

[brandwooddixon]

Another point occurs to me, from my time as a programmer for engine management systems.

It may be worth checking that the timing for the engine isn't retarded in anyway. I only mention this as if the original gearbox was electronically controlled, as opposed to hydraulically controlled, then typically the engine and gearbox ECUs communicate to each other and retard the ignition during gear changes. This provides for smoother gearchanges.

It is also possible if the ECU has been remapped to miss out these values.

 

[falconho]

Hi this really wont work , 7/800 bhp through one of these ZF auto boxes will never happen in a million years, I also think it is highly unlikely you will achieve this power from the 126 Merc V8, if you do it won't be for very long. They did use one of these boxes behind the Rover V8, on Sherpa ambulances, I am about to fit one of these four speed ZF's on my Rover P6 V8 to make it a four speed auto, but it is certainly not putting out that sort of power and should be OK.Probably the easiest and cheapest route even though a big task to achieve these kind of figures would be to fabricate some engine mounts and fit one of the early pushrod American V8s. Lots and lots of different power options anything from 250 bhp to well over 1000 bhp. The good thing about this is it leaves you the option also, of using one of their auto boxes, all of which can be modified to take this kind of power. All of these parts are readily available from no end of American speed shops here and ofcourse in the States, due to their long history of drag racing. There are so many options it is mind boggling. This has all been tried and tested for many years and would be a hell of a lot cheaper it is surprising just how little some of these parts cost, I have been involved with them for a long time now, and it does not take loads of money to build a fast car.