SL55/63/65/R230 AMG: Mating a 7G-TRONIC to an SL55 engine
10-17-2017, 01:25 AM
#1
Mating a 7G-TRONIC to an SL55 engine
Need help!
My car is actually an SLK55 but I thought you guys may be in a better position to help since it has an SL55 engine, supercharger and all! It's mated to the original SLK55 7G-TRONIC box and all works well except for one problem that my tuner cannot remedy. Light acceleration, perfect. Tromp on it, also perfect (but not for the tires
Problem is normal acceleration, when the supercharger clutch engages power is robbed momentarily, sometimes in a minor way but at others, quite aggressively.
I don't know whether this is a clue but my tuner says that changing the valve body (not sure to what) fixes this issue but creates a fault condition causing the engine to go to limp mode within a couple of minutes.
Anyone mated this box with a supercharged 55 engine before?
My car is actually an SLK55 but I thought you guys may be in a better position to help since it has an SL55 engine, supercharger and all! It's mated to the original SLK55 7G-TRONIC box and all works well except for one problem that my tuner cannot remedy. Light acceleration, perfect. Tromp on it, also perfect (but not for the tires
Problem is normal acceleration, when the supercharger clutch engages power is robbed momentarily, sometimes in a minor way but at others, quite aggressively.I don't know whether this is a clue but my tuner says that changing the valve body (not sure to what) fixes this issue but creates a fault condition causing the engine to go to limp mode within a couple of minutes.
Anyone mated this box with a supercharged 55 engine before?
10-17-2017, 08:55 AM
#2
MBWorld Fanatic!
I dont know the answer. But is your trans ecu tuned for the old slk engine, or tuned for a 55. Or maybe ecu for a 55 is a different ecu unit
10-17-2017, 09:21 AM
#3
That's a good question. My understanding is that we are using the SL55 ECU and SLK55 TCU, with some software mods. The problem I see here is that the 7 speed box has never been mated to the supercharged version of the 55 in any Mercedes model so no proper code exists.
The thing I find amazing is that apart from this one glitch everything else is perfect, shifts, shift points, everything. That's why it's so hard to accept that my only option appears to be swapping out the 7 speed for a 5 speed, which will also mean changing diff ratios.
As far as the glitch goes I am certain it occurs only when the supercharger clutch switches in, which seems totally unrelated to the gearbox or TCU. I thought that perhaps the torque change was triggering the ESP but I think I've discounted that as turning ESP off makes no difference.
The only clue we have is that swapping out the valve body fixes the glitch, even though it creates a new problem. I also remember reading here somewhere about a similar reported glitch with a standard E55 (engine gearbox combo) so I had hoped that may lead somewhere. I'm not sure what fixed the issue.
The thing I find amazing is that apart from this one glitch everything else is perfect, shifts, shift points, everything. That's why it's so hard to accept that my only option appears to be swapping out the 7 speed for a 5 speed, which will also mean changing diff ratios.
As far as the glitch goes I am certain it occurs only when the supercharger clutch switches in, which seems totally unrelated to the gearbox or TCU. I thought that perhaps the torque change was triggering the ESP but I think I've discounted that as turning ESP off makes no difference.
The only clue we have is that swapping out the valve body fixes the glitch, even though it creates a new problem. I also remember reading here somewhere about a similar reported glitch with a standard E55 (engine gearbox combo) so I had hoped that may lead somewhere. I'm not sure what fixed the issue.
