NVH - curing the boom
 

If there has been a comment I have heard a few times from owners or passengers in a 260, it's the boom the car creates at around 50 - 60. The last time I was in one it had the XPower pipes on and it did give quite a medium level noise that was a bit intrusive really. I seem to remember that Project Drive removed quite a bit of sound deadening although I'm not sure if that applied to the ZT in some respects.

Anyway, has anyone tried to tackle this and had any success in reducing it without harming the soundtrack from the engine?

And at a slight tangent, now that many owners have models with a few miles on the clock, have there been any other NVH issues that have surfaced?

Apart from more noise Pete I would like to know what X-Powers intentions were in designing those back boxes as when we had gerrants 260 on rollers last week it only made 240BHP with the pipes fitted!

Is that at the fly or at the road wheels?

That was a corrected figure so is supposed to represent engine power mine came out at 171BHP with Torque tailing off at 4500RPM

possibly a bit over corrected

TI-Riches Diesel made good numbers though

I've read something about axle tramp??? Whatever that is on another website about the V8 ZT/75 I don't know if it's relavent to this thread or even useful but nonetheless quite interesting, I'll copy it and paste it if I don't get hit, moderators?:confused:

THe booming noise was designed out with the standard quads, the X-power put it back big time. I had the use of a car with them on for about two weeks and it became too much. Loved narrow lanes with the windows down though :)

I have Zero Quads on now and they are about half way between the two and produce a lovely rumble sound.

http://www.two-sixties.com/media/newpipes.mp3

http://www.two-sixties.com/media/new_zero_revving.mp3



http://gallery.xpowerforums.com/data...ero2600029.JPG

http://gallery.xpowerforums.com/data...ero2600033.JPG

I think there was more of a boom problem with the 75 V8 during development and that's why the production cars have a centre silencer fitted, unlike the ZT/ZT-T 260.
Tom

Tim your car is unbelievably clean underneath how on earth do you manage that or has it never been out in the wet

Do you have a pit or a ramp to work from?

If I remember correctly, someone was toying with the idea of changing their ZT 260 suspension to 75 V8 suspension to make it softer. It would mean, among other changes, taking out the diff dampers which (in Nic's opinion and I'm sure he's right) would result in axle tramp.
Tom

Been out in the wet. Womble made me go out the other week in it.:) I was the same with my motorbikes had to be clean. No ramp or pit just lay flat and suck the belly in.:D