Tiptronic & TC upgrade for those planning more power
Discussion
Guys,
As you may have read on
http://www.pistonheads.com/gassing/topic.asp?h=0&a... 996 tt car soon to be in the UK - cannot wait
I have been deliberating over what to do about the gearbox. I had decided that it was better to find the limits of the upgrades on an old box, rather than take preventive measures e.g. new the clutch packs etc.
I also looked at upgrading the torque converter, since this is something that is done by a company in the US.
In the end after much research, I have decided to upgrade the torque converter and leave the box as it is for the moment. I have found a specialist company locally to whom I am spoken and what they will do is: -
- split the TC
- replace the internals and upgrade specific parts within the internals
- increase the stall limit to 2500rpm
- brazen (not sure that is the correct word) the TC to allow high levels of power.
The guy I spoke to really seems to know his stuff ( I did my research before so I knew terminology and what each bit does) and I will be dropping the TC to him on Tuesday. Turnaround is 2 days + another 2 days for the brazen work. Cost is max of £600, with around half that on the brazen and upgrades. The company has done this for many cars and has a strong history with customers for extreme hp projects re TCs.
I won't comment on here about what was said re the US upgrade to the TC, but you can PM me.
This should allow the car to run up to the levels that we plan without issues.
I will report back on the end result, but this might turn out to be a good source for those doing more power on a tiptronic. It is the TC rather than the transmission that requires the upgrade.
One final thing, is that of course to get the TC out, you have to have the engine out. For me that was happenning anyway, so timing was good.
As you may have read on
http://www.pistonheads.com/gassing/topic.asp?h=0&a... 996 tt car soon to be in the UK - cannot wait
I have been deliberating over what to do about the gearbox. I had decided that it was better to find the limits of the upgrades on an old box, rather than take preventive measures e.g. new the clutch packs etc.
I also looked at upgrading the torque converter, since this is something that is done by a company in the US.
In the end after much research, I have decided to upgrade the torque converter and leave the box as it is for the moment. I have found a specialist company locally to whom I am spoken and what they will do is: -
- split the TC
- replace the internals and upgrade specific parts within the internals
- increase the stall limit to 2500rpm
- brazen (not sure that is the correct word) the TC to allow high levels of power.
The guy I spoke to really seems to know his stuff ( I did my research before so I knew terminology and what each bit does) and I will be dropping the TC to him on Tuesday. Turnaround is 2 days + another 2 days for the brazen work. Cost is max of £600, with around half that on the brazen and upgrades. The company has done this for many cars and has a strong history with customers for extreme hp projects re TCs.
I won't comment on here about what was said re the US upgrade to the TC, but you can PM me.
This should allow the car to run up to the levels that we plan without issues.
I will report back on the end result, but this might turn out to be a good source for those doing more power on a tiptronic. It is the TC rather than the transmission that requires the upgrade.
One final thing, is that of course to get the TC out, you have to have the engine out. For me that was happenning anyway, so timing was good.
Edited by 996ttalot on Wednesday 28th April 00:21
J__D said:
I'm am not planning on increasing the power at all, but would this give other benefits other than just being able to handle the power? What's the benefit of raising the stall level?
Couple of points to answer your question.1) Instead of buying a new TC, these guys will cut it in half, replace the internals like new, and weld it back for approx £300. That is a big saving on new TC. They quoted £130 to cut in half and inspect and then discuss what needs to be done. As I said I am going for some upgraded parts and brazen to handle the extra power but that is a maximum of £600, still cheaper.
2) A TC is basically like a clutch. When a clutch is fully released and you get all the power from the engine, that is the stall speed i.e. the RPM required at which power is transfered to the transmission.
A 2,000 stall speed doesn't mean you need to rev the motor to 2,000 rpm for the vehicle to move. What it does mean in this case is 2,000 rpm is the limit at which the TC will hold back the engine speed if transmission output is prohibited (e.g. by keeping your foot on the break). By disallowing further gain, the increase in engine rpm "stalls." The speed at which stall occurs with a given TC is a function of engine-peak torque.
So to give you an example - you are doing a standing start in a 996tt. You put your foot on the brake and raise the revs. At 2,000 the car will try to move (okay it might wheelspin etc). Now if you raise the stall speed to say 3,000rpm, what you will get is more boost/tq at that point in the curve, so as soon as you shift your foot from brake to accelator, you will be on better boost/tq curve. And therefore quicker launch.
Just to update on this topic for those of you thinking of upgrading to much high power levels
- tiptronic limit (gearbox itself) is 520-550 AWHP (that's 660-700 at the crank) - there are not enough clutch packs to stop the gears slipping - I know - been there!
- TC upgrade worked fine
- You need to fit an oil cooler to keep the ATF fluid at the correct level - very important
So if you go down this route you will need to spend
- £4,500 on upgraded gearbox (all clutch packs replaced with kelvar versions and additional plates in all banks e.g. increasing from 6-8 plates, 10-12 in higher gears. In addition the control unit including the solenoids needs to be updated because this controls the shift pressure etc). If you want to know who does this then send me a PM
- cost of install - if the engine is out then not much extra, but otherwise you are looking at 12 hours (take out and reinstall)
- TC upgrade costs around £600
- TCU upgrade to set limit of tq to 1300nm is part of the upgraded gearbox cost
- oil cooler is around £200 plus fitting.
The only people who can do this are Merc specialists, since that is the gearbox.
I had mine shipped to Germany.
So if you want high end power in a tip, you need to budget an extra 6k or so.
- tiptronic limit (gearbox itself) is 520-550 AWHP (that's 660-700 at the crank) - there are not enough clutch packs to stop the gears slipping - I know - been there!
- TC upgrade worked fine
- You need to fit an oil cooler to keep the ATF fluid at the correct level - very important
So if you go down this route you will need to spend
- £4,500 on upgraded gearbox (all clutch packs replaced with kelvar versions and additional plates in all banks e.g. increasing from 6-8 plates, 10-12 in higher gears. In addition the control unit including the solenoids needs to be updated because this controls the shift pressure etc). If you want to know who does this then send me a PM
- cost of install - if the engine is out then not much extra, but otherwise you are looking at 12 hours (take out and reinstall)
- TC upgrade costs around £600
- TCU upgrade to set limit of tq to 1300nm is part of the upgraded gearbox cost
- oil cooler is around £200 plus fitting.
The only people who can do this are Merc specialists, since that is the gearbox.
I had mine shipped to Germany.
So if you want high end power in a tip, you need to budget an extra 6k or so.
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