Dump Valves - I know nothing!
Discussion
What do they actually do? My understanding is that they're not normally an OEM standard fitment. Are they really necessary? Is it possible to get quiet ones?
I'm looking at a P1 which has been modifed slightly more than I would ideally have wanted - Andy Forrest map and hybrid turbo, full 3" system (manifold-back) and a really loud dump valve. I don't midn the fairly loud exhaust note but the noise of the dump valve really bothers me. The car seems to have been well looked after, has a huge pile of history, full MOT with no advisories and the owner doesn't seem like a barry-boy!
I'm looking at a P1 which has been modifed slightly more than I would ideally have wanted - Andy Forrest map and hybrid turbo, full 3" system (manifold-back) and a really loud dump valve. I don't midn the fairly loud exhaust note but the noise of the dump valve really bothers me. The car seems to have been well looked after, has a huge pile of history, full MOT with no advisories and the owner doesn't seem like a barry-boy!
Lefty said:
What do they actually do? My understanding is that they're not normally an OEM standard fitment. Are they really necessary? Is it possible to get quiet ones?
I'm looking at a P1 which has been modifed slightly more than I would ideally have wanted - Andy Forrest map and hybrid turbo, full 3" system (manifold-back) and a really loud dump valve. I don't midn the fairly loud exhaust note but the noise of the dump valve really bothers me. The car seems to have been well looked after, has a huge pile of history, full MOT with no advisories and the owner doesn't seem like a barry-boy!
Quiet ones are called recirculating dump valves IIRC.I'm looking at a P1 which has been modifed slightly more than I would ideally have wanted - Andy Forrest map and hybrid turbo, full 3" system (manifold-back) and a really loud dump valve. I don't midn the fairly loud exhaust note but the noise of the dump valve really bothers me. The car seems to have been well looked after, has a huge pile of history, full MOT with no advisories and the owner doesn't seem like a barry-boy!
Lefty said:
What do they actually do? My understanding is that they're not normally an OEM standard fitment. Are they really necessary? Is it possible to get quiet ones?
Just use the OEM recirculating dump valve - most turbo cars come with one that has to be disconnected to fit a loud chav one. What they do is equalise the pressures either side of the turbo compressor when you lift off the throttle. It reduces turbo decelleration, and can reduce lag between gear changes.I find them annoying too. I don't know if they are any better than the standard waste gate tbh.
Barries like to hold their s
tboxes in gear until they arrive by you and then change gear, trying to get your attention, as if they genuinely believe that you will be impressed. 
For that reason alone, I really don't like them.
Barries like to hold their s
tboxes in gear until they arrive by you and then change gear, trying to get your attention, as if they genuinely believe that you will be impressed. For that reason alone, I really don't like them.
You could hear the one on my celica at very low revs, but the turbo used to spo very quickly. I'm running high boost on the ax so thought it best to get one, can't recirculate as the inlet is too small so dumping to atmosphere.
look for a recirculating one if you don't like the noise. Don't scoobys run a maf though on some models? Best make sure yours is setup right.
look for a recirculating one if you don't like the noise. Don't scoobys run a maf though on some models? Best make sure yours is setup right.
Baz Tench said:
Barries like to hold their stboxes in gear until they arrive by you and then change gear, trying to get your attention, as if they genuinely believe that you will be impressed.
For that reason alone, I really don't like them.
Sometimes a gear change is just a gear change. tboxes in gear until they arrive by you and then change gear, trying to get your attention, as if they genuinely believe that you will be impressed. For that reason alone, I really don't like them.
What makes you think that you are special enough for barries to impress? Are you a 15 year old girl?
They dump the boost pressure on gear change (or throttle shuting) to stop then engine being on boost when you're trying to let it slow down. Loud ones vent to atmosphere, quiet ones vent back into the inlet side of the intake system.
Just swap it for a recirculating type if it bothers you ,and I think you might need to re map it too once you've done that to make sure the car behaves itself.
Just swap it for a recirculating type if it bothers you ,and I think you might need to re map it too once you've done that to make sure the car behaves itself.
WeirdNeville said:
They dump the boost pressure on gear change (or throttle shuting) to stop then engine being on boost when you're trying to let it slow down. Loud ones vent to atmosphere, quiet ones vent back into the inlet side of the intake system.
Just swap it for a recirculating type if it bothers you ,and I think you might need to re map it too once you've done that to make sure the car behaves itself.
Or it'll fix the car Just swap it for a recirculating type if it bothers you ,and I think you might need to re map it too once you've done that to make sure the car behaves itself.
Captain Muppet said:
Baz Tench said:
Barries like to hold their stboxes in gear until they arrive by you and then change gear, trying to get your attention, as if they genuinely believe that you will be impressed.
For that reason alone, I really don't like them.
Sometimes a gear change is just a gear change. tboxes in gear until they arrive by you and then change gear, trying to get your attention, as if they genuinely believe that you will be impressed. For that reason alone, I really don't like them.
What makes you think that you are special enough for barries to impress? Are you a 15 year old girl?
It's obvious when they do it though. Knobs. (yes, I really hate the sound of a chavvy i.e. Loud dump valve).
WeirdNeville said:
They dump the boost pressure on gear change (or throttle shuting) to stop then engine being on boost when you're trying to let it slow down.
Are you sure? My fiesta Turbo back in the day never had a dump valve fitted as standard and still slowed down.I thought the aim of the dump valve was to reduce / stop back pressure in the intake flowing back to the turbo charger when the throttle is closed. Without one, the pressure would stall the turbo between gear changes taking it more off boost as well as extra negative pressure on the turbo causing premature wear?
How about removing it all together and get some lovely turbo chatter?
http://www.youtube.com/watch?v=8iiKMCeYYBo&fea...
http://www.youtube.com/watch?v=8iiKMCeYYBo&fea...
Wow, lots of answer quickly, thanks fellas.
Erm, like i said, i know foxtrot-alpha about them BUT I think it might be a recirculating one - there is a hose running back to the inlert manifold.
It's been dynoed at 352bhp so is probably running a fair bit of boost!
I really don't like the sound of the damn thing though.
Erm, like i said, i know foxtrot-alpha about them BUT I think it might be a recirculating one - there is a hose running back to the inlert manifold.
It's been dynoed at 352bhp so is probably running a fair bit of boost!
I really don't like the sound of the damn thing though.
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