NVH - curing the boom

Pete · 26th October 2006, 19:54

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?

Keith · 29th October 2006, 15:22

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!

GreyGhost · 29th October 2006, 15:46

Quote:

Originally Posted by Keith

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?

Keith · 29th October 2006, 16:41

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

Phil · 5th November 2006, 15:18

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?

Tim · 5th November 2006, 17:22

Quote:

Originally Posted by Pete

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?

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

anglaslt · 5th November 2006, 19:36

Quote:

Originally Posted by Pete

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?

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

Keith · 5th November 2006, 19:37

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?

anglaslt · 5th November 2006, 19:40

Quote:

Originally Posted by Phil

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?

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

Tim · 5th November 2006, 20:20

Quote:

Originally Posted by Keith

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?

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.

26th October 2006, 19:54	#1
Pete Owners Club Director Rover 75 Join Date: Oct 2006 Location: Sherfield-on-Loddon Posts: 4,872 Thanks: 137 Thanked 996 Times in 444 Posts	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?

5th November 2006, 15:18	#5
Phil This is my second home Rover 75 CDT Connoisseur SE Join Date: Nov 2006 Location: Wales Posts: 12,227 Thanks: 469 Thanked 523 Times in 241 Posts	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? __________________

29th October 2006, 15:22	#2
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	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!

29th October 2006, 16:41	#4
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	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

5th November 2006, 19:37	#8
Keith This is my second home ZT400 Join Date: Oct 2006 Location: Ellesmere Posts: 5,948 Thanks: 0 Thanked 43 Times in 29 Posts	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?