Are Xforce Varex exhausts bad for the engine?

[3rspecb]

Nice efforts on the custom fab . I was playing with a porche gt2 on Monday and it had actuators on each muffler to open butterfly valves. I was quite surprised and confused as to how that is legal?

Completely legal as 1) the system is factory fitted hence ADR'd and 2) The ADR for External Noise is measured at a certain RPM and not WOT.

Thier is also a drive by test that is performed and from memory its like at cruising speed.

The lastest HSV's have it too.

The DB level is dropping each year so I reckon we will see more cars from the factory come out with bi-modal exhaust systems.

[senator]

Nice efforts on the custom fab . I was playing with a porche gt2 on Monday and it had actuators on each muffler to open butterfly valves. I was quite surprised and confused as to how that is legal?

Completely legal as 1) the system is factory fitted hence ADR'd and 2) The ADR for External Noise is measured at a certain RPM and not WOT.

Thier is also a drive by test that is performed and from memory its like at cruising speed.

The lastest HSV's have it too.

The DB level is dropping each year so I reckon we will see more cars from the factory come out with bi-modal exhaust systems.

Note the location of the butterfly…… its usually after the muffler and only on one side of the outlet.

[SH30RB]

just going off topic briefly...

i dont understand why they hammer the whole "legal DB noise level" issue into cars, what about motorbikes?

dont get me wrong, i love the sound of a very aggressive harley, but those things surely dont fit under the DB level.

[3rspecb]

Nice efforts on the custom fab . I was playing with a porche gt2 on Monday and it had actuators on each muffler to open butterfly valves. I was quite surprised and confused as to how that is legal?

Completely legal as 1) the system is factory fitted hence ADR'd and 2) The ADR for External Noise is measured at a certain RPM and not WOT.
Thier is also a drive by test that is performed and from memory its like at cruising speed.
The lastest HSV's have it too.
The DB level is dropping each year so I reckon we will see more cars from the factory come out with bi-modal exhaust systems.

Note the location of the butterfly…… its usually after the muffler and only on one side of the outlet.

Good point Tony, here is a pic of the HSV E2 bimodal muffler.


Uploaded with ImageShack.us

[bigBADbenny]

I modified my 3.5 inch Varex so it opens under boost.

That's a wastegate actuator in place of the Varex servo? Awesome

[hamish_023]

just going off topic briefly...

i dont understand why they hammer the whole "legal DB noise level" issue into cars, what about motorbikes?

dont get me wrong, i love the sound of a very aggressive harley, but those things surely dont fit under the DB level.

+1 why are bikes excused from the same noise levels

[Scotty's Customs]

just going off topic briefly...

i dont understand why they hammer the whole "legal DB noise level" issue into cars, what about motorbikes?

dont get me wrong, i love the sound of a very aggressive harley, but those things surely dont fit under the DB level.

+1 why are bikes excused from the same noise levels

They have to adhere to the same laws we do.

I like the HSV actuator, that one would work on manifold pressure so it would be open a lot earlier than my modified 2psi actuator. Any idea how much one would be worth? I might do some ringing around...

[senator]

just going off topic briefly...

i dont understand why they hammer the whole "legal DB noise level" issue into cars, what about motorbikes?

dont get me wrong, i love the sound of a very aggressive harley, but those things surely dont fit under the DB level.

I know Bikes have their own standard and Harley as a manufacture has even its own specific standard of 108db

[senator]

Good point Tony, here is a pic of the HSV E2 bimodal muffler.


Uploaded with ImageShack.us

I’ve seen an interesting modification of the HSV bi-modal system where the actuator is removed from the muffler tip and moved further up the system to just after the cross over (under the rears seats).

Throttle response is greatly increased along with the sound of course….

[t.renshaw34]

just going off topic briefly...

i dont understand why they hammer the whole "legal DB noise level" issue into cars, what about motorbikes?

dont get me wrong, i love the sound of a very aggressive harley, but those things surely dont fit under the DB level.

+1 why are bikes excused from the same noise levels

They have to adhere to the same laws we do.

I like the HSV actuator, that one would work on manifold pressure so it would be open a lot earlier than my modified 2psi actuator. Any idea how much one would be worth? I might do some ringing around...

You could have asked for one when buying your varex? they come optional with them but run a little different. The varex ones run off the ECU and open when the turbo reaches a preset PSI. I was going to run one but went with the remote on my keys as it give you play time with it lol.

[Scotty's Customs]

The only one they had was a motor controller that worked on a rev window, set it to 4k and it will open then. This unit was discontinued a while ago, they wouldn't sell me one. This actuator ended up costing me nothing to try.

You cant have it open at higher boost as it slows the turbo spool badly, making it feel even laggier than it is. Mine is set to open very low, 1-2psi which seems to work well so far and it doesn't close fully either which helps. If it plays up again I will be going back to the motor and remote.

I have been looking into Helmholtz chambers to try and tame the volume, the 3.5 inch Varex aren't very good as a muffler when open so I might try the noise cancelling instead.