dump valve - hows it work??
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Soldato
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I imagine a wastegate is used on TT setups? Small turbo spools up....hits max boost and the largeer turbo spools up.....so the wastegate opens on the smaller one so it doesnt over do it?
Soldato
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- 23 Nov 2004
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TaKeN said:
No thats what a BOV/DV is for....the air forcing its way back through the turbo is bad. A wastegate is to slow the turbo down and hence limit the boost.
Jonny ///M said:
Just found this...
http://www.streetracersonline.com/articles/turbo/wastegate.php
So basically a waste gate limits the amount of exhaust gases going into the engine to stop too much pressure damaging it
Only at silly pressure.
A few people on Rovertech run T25's @ 12psi with no dump valve. Have done for months with no ill effects.
Another guy with a 200sx S14 turbo on his car (they don't have a dump valve bolted onto the turbo like the T25s) hasn't fitted an atmospheric and has had no problems either.
A few people on Rovertech run T25's @ 12psi with no dump valve. Have done for months with no ill effects.
Another guy with a 200sx S14 turbo on his car (they don't have a dump valve bolted onto the turbo like the T25s) hasn't fitted an atmospheric and has had no problems either.
People actually like to drive cars that sound like a bus? Pttisssssss.
Sure, they might be usefull for certain high performance turbo systems, but I remember cruising past a little fiesta once, and as he changed gear Ptissssshhhhh. I nearly wet myself laughing.
Sure, they might be usefull for certain high performance turbo systems, but I remember cruising past a little fiesta once, and as he changed gear Ptissssshhhhh. I nearly wet myself laughing.
agw_01 said:
The s14 has a recirc fitted as standard. The s13 doesnt.
I have been running without a recirc on my car because when I fitted the FMIC the recirc stopped working for some unknown reason. Its been running 15psi and 17psi for several years and it seems to be fine.
Couple of things that also need clearing up with this subject.
All this "dump valve stops the turbo from stalling" stuff is pretty much myth. If you run a dump valve of any sort you will experience a loss in throttle response compared to not running one at all.
When you come off the throttle with a dump valve in situe, the charge (compressed air) leaks away, usually to atmosphere. If you have a boost gauge attached you will see a smooth linear, boost drop until the level reaches zero. Depending on the boost being run, the valve in use and how fast it opens, this can take anywhere up to a second or so.
When you don't have a valve in place, the charge hasn't got anywhere to go apart from back through the turbo. But think about it - the turbo is still spinning at about 100,000rpm or so with the air coming IN to the system. The charge in the system is rushing out and the two pretty much cancel each other out, but with the charge leak will "win" since the turbo is starting to slow. If you watch this process on a boost gauge you will see a violent shuddering of the needle which very slowly reduces to zero. This takes a fair bit longer to equalise which is why you get the better response - because at any point when you nail the throttle again, there is already a bigger charge in the system, in turn giving you better response.
Now dump valve manufacturers will have you believe that this is a bad thing. They say it will destroy the turbo - this is NOT the case unless you're running silly boost. R5 GTT's will run 100,000 miles or more on the standard turbo without any difficulty, and they don't have one as standard. Audi only ever introduced them to road cars in the early 80's since customers kept returning cars saying they kept hearing a fluttering sound when changing gear! I ran a GTT at 18/19psi every day as a daily driver for 3 years without any kind of turbo problems. Hell, I've seen people run 30psi or more without a valve and not have any problems. Modern turbos with strong 360degree bearings just don't suffer from this kind of problem any more.
Saying all this though - I ran the Clio Turbo with an SSQ, but purely because I liked the noise. If I ever wanted to do anything serious I'd remove the valve and go without.
http://www.andrewlowe.plus.com/ClioPMTTurbo.mp3
Yes it's chavvy, but I loved the noise that car made when driven in anger.
All this "dump valve stops the turbo from stalling" stuff is pretty much myth. If you run a dump valve of any sort you will experience a loss in throttle response compared to not running one at all.
When you come off the throttle with a dump valve in situe, the charge (compressed air) leaks away, usually to atmosphere. If you have a boost gauge attached you will see a smooth linear, boost drop until the level reaches zero. Depending on the boost being run, the valve in use and how fast it opens, this can take anywhere up to a second or so.
When you don't have a valve in place, the charge hasn't got anywhere to go apart from back through the turbo. But think about it - the turbo is still spinning at about 100,000rpm or so with the air coming IN to the system. The charge in the system is rushing out and the two pretty much cancel each other out, but with the charge leak will "win" since the turbo is starting to slow. If you watch this process on a boost gauge you will see a violent shuddering of the needle which very slowly reduces to zero. This takes a fair bit longer to equalise which is why you get the better response - because at any point when you nail the throttle again, there is already a bigger charge in the system, in turn giving you better response.
Now dump valve manufacturers will have you believe that this is a bad thing. They say it will destroy the turbo - this is NOT the case unless you're running silly boost. R5 GTT's will run 100,000 miles or more on the standard turbo without any difficulty, and they don't have one as standard. Audi only ever introduced them to road cars in the early 80's since customers kept returning cars saying they kept hearing a fluttering sound when changing gear! I ran a GTT at 18/19psi every day as a daily driver for 3 years without any kind of turbo problems. Hell, I've seen people run 30psi or more without a valve and not have any problems. Modern turbos with strong 360degree bearings just don't suffer from this kind of problem any more.
Saying all this though - I ran the Clio Turbo with an SSQ, but purely because I liked the noise. If I ever wanted to do anything serious I'd remove the valve and go without.
http://www.andrewlowe.plus.com/ClioPMTTurbo.mp3
Yes it's chavvy, but I loved the noise that car made when driven in anger.