Q: If you have de-cat downpipe please...
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Had a scoobysport downpipe fitted 2 weeks ago and still loving it to bits. I posted about the wonderful increase in Turbo whistle, as soon as the throttle is pressed, reallt addictive.
My question is, under full boost, particularly in higher gears, 3rd, 4th, 5th i.e. long sustained acceleration the turbo makes quite a loud "chattering" sound - it is not a constant whistle in this case, I would describe it as more of a flicking sound. In these gears it comes in from around 2500 - 3000 rpm and is there until you change gear, sometimes throughout the range of acceleration, sometimes for a band of revs, then a bit quieter, then a band of revs.
Before the DP I used to get a whistle, noticeable really in 4th & 5th only.
I was wondering if others with a de-cat DP also get this "flicking" sound. You really can hear everything (including air flow)
Cheers
Paul
My question is, under full boost, particularly in higher gears, 3rd, 4th, 5th i.e. long sustained acceleration the turbo makes quite a loud "chattering" sound - it is not a constant whistle in this case, I would describe it as more of a flicking sound. In these gears it comes in from around 2500 - 3000 rpm and is there until you change gear, sometimes throughout the range of acceleration, sometimes for a band of revs, then a bit quieter, then a band of revs.
Before the DP I used to get a whistle, noticeable really in 4th & 5th only.
I was wondering if others with a de-cat DP also get this "flicking" sound. You really can hear everything (including air flow)
Cheers
Paul
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From: Scoobysport, Basildon, UK
Kempo
Its the wastegate valve chattering against the turbo casing, just as it starts to open.
Its always done it, but with the lagging around the original DP you couldn't hear it.
Its the wastegate valve chattering against the turbo casing, just as it starts to open.
Its always done it, but with the lagging around the original DP you couldn't hear it.
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Great, thanks for the replies all, cheers Pete.
It made me wonder when I read a post recently about having the turbo balanced, I was a bit worried that the sound was actually the turbo as it was spinning as if this was the case it would be "wobbling", i.e. not spinning smoothly.
DP is just awesome!
It made me wonder when I read a post recently about having the turbo balanced, I was a bit worried that the sound was actually the turbo as it was spinning as if this was the case it would be "wobbling", i.e. not spinning smoothly.
DP is just awesome!
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Second question then: 
If there is now a considerable increase in the noise of the Wastegate, is there any chance that by increasing the breathing with the DP is actually having an adverse effect on power?
I wonder if the wastegate is now working overtime to relase the pressure through the turbo whereas before the restriction of the cat kept things sensible.
Without a doubt the car pulls harder through the gears, although cruising down the motorway last weekend opening the throttle in 5th was accompanied by the sound of the wastegate and I could not honestly say whether it picked up faster / slower than it had before the DP was changed.
Paul
If there is now a considerable increase in the noise of the Wastegate, is there any chance that by increasing the breathing with the DP is actually having an adverse effect on power?
I wonder if the wastegate is now working overtime to relase the pressure through the turbo whereas before the restriction of the cat kept things sensible.
Without a doubt the car pulls harder through the gears, although cruising down the motorway last weekend opening the throttle in 5th was accompanied by the sound of the wastegate and I could not honestly say whether it picked up faster / slower than it had before the DP was changed.
Paul
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