developer215

Hello guys - I've just had a remap on my M157, now giving 700hp and 800ft/lbs torque.

Problem is, under full load (giving it the beans) I get a significant "shunt" at the point of gear change - you can really feel the car thud, seemingly from the rear.

It didn't do it previously - it's as if the box or LSD isn't happy with the power.

Any ideas please?

PeterUbers

reset the tcu, Google "mbworld reset tcu" and if doesn't help call your tuner

gaspam

its normal if you are saying you get a really hard shift, almost like a crack/clunk sound.... when i first got mine tuned i thought i broke the tranny input shaft on the first WOT 1-2 shift.... over a year later tranny is still fine

Tonypw

iTrader: (1)

My car does this and drives me nuts. Sounds like it is normal with the added power.

PeterUbers

does it do it under moderate or light load?? This would drive me nuts

Tonypw

iTrader: (1)

It does it under full load from 2nd to 3rd.

developer215

Light load changes are fine - mine was also 2nd to 3rd, but I haven't been able to find a piece of road yet to see if it's in other gears.


I generally drive in S+ but again haven't assessed the change in C,S or M.


It's been suggested the box will adapt to the new power so I'll see what the weekend brings and report back.


Thanks

gaspam

1 yr later on my renntech tune and shift under WOT are still super hard and snappy

developer215

Had a decent road test now.

Definitely only S+ and 2nd to 3rd WOT change - though it's a significant shunt, I'm in discussion with the tuner and will report back.

kponti

Its the happy kick found in tunes. Enjoy it

dav461

its normal for S+ even in stock car.

PeterUbers

i don't have this on my stock e63s

wot in S+ I have no harsh shifting or thuds or "shunts"

developer215

Nor mine when it was stock.

kponti

I remember reading somewhere where it was stated by a tuner than MB briefly, cuts boost right before a shift to make the shift appear (feel) faster and more aggressive in some years (newer models of the E63). I noticed a more pronounced "shunt" after the latest software update (which I didn't ask for, but that's another debate).

PeterUbers

hopefully then it can be dialed out

kponti

It was dialed out by AMS for that particular customer. He did not get the advertised power from the mail tune. Took his car to the shop and it was dyno tuned to get the advertised power level. Also had the shunt tuned out which resulted in smoother shifting under WOT

PeterUbers

nice

Brucealeg

My car under WOT will do this bone stock going from 2-3, not all the time - but most of the time. Usually get's not that harsh, but I notice it.