Drivetrain shunt

[markrichards]

Not having driven many other Nobles, I just wanted to get people's experience of drive train shunt.

The M400 has the gearboxman upgraded 6-speed and uprated clutch. There is a noticeable jolt when coming on/off the power in any gear, which may just be symptoms of large / high compression engine with light car. Does anyone else with a similar setup have any noticeable shunt? No noises at all, simply a mechanical jolt.

Cheers

[XLRONYX]

markrichards said:

Not having driven many other Nobles, I just wanted to get people's experience of drive train shunt.

The M400 has the gearboxman upgraded 6-speed and uprated clutch. There is a noticeable jolt when coming on/off the power in any gear, which may just be symptoms of large / high compression engine with light car. Does anyone else with a similar setup have any noticeable shunt? No noises at all, simply a mechanical jolt.

Cheers

Sounds to me as though your ECU needs some mapping adjustment. My M400 has never done that, not with the factory MBE map, not with MBE remapping by a US shop, and not in its current state with a different ECU tuned by me.

Jeff

[TuxMan]

Same setup as you Mark and mine is very smooth on and off the power , only problem I have is the noisy clutch on the downshifts .

[GTO600]

Check your engine mounts & driveshaft cv joints.

[markrichards]

Thanks gents. Feared as much. Mounts look sound, so will drop it to Dave/Matt for a poke around.

[5paulmv]

might be a bit off diff lash used to get it on my tvr griff has it always done it or is it getting worse ?

[markrichards]

Has done it since I put in a new box and clutch. Used the same diff I had in it before the re-build. It used not to shunt.

At, say, 40mph in 4th, there is a slight floaty sensation when trying to hold the same speed on the throttle. Happens in any gear. Almost as if there is a bit of play in the drivetrain and the car is moving within this play while the engine is trying to hold a constant speed.

It's less noticeable when driving hard / fast.

Hoping it's not clutch / box related?

[Hollowpockets]

Not normal, it probably is a mount or play in something that shouldn't have, as tux's mine is also smooth.

[jdearden]

Mine did this and we played about with the map and it stopped. It is now doing it again since my boost regulator decided to die.
Having it replaced on Tuesday.
From my experience I would say it needs mapping tweaked

[TuxMan]

Hi Mark , I've upgraded the front and rear ones to stiffer units on Jetstreams advice , the rear one looked fine but when I got it off the heat from the exhaust had killed it !!!'
Might be worth changing them just to be sure , also jack it up and check for play on the rear wheels .

Tux

[node]

Mine is very smooth and does not do what you're describing. Yep, take it up to Jetstream and let them have a poke around.