Dump Valves/BOV
22 June 2004, 05:32 AM
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Hello Paul
dump valves and whooshing sounds hmmmm
...be prepared to take some stick (calling greasemonkey)
...and be prepared for people telling you what else you should consider spending money on first
What makes the "nicest WOOOOSH" is subjective, what is nice to one person is asthmatic wheezing to another. The loudest dump valves are are the vent to atmosphere (VTA) type. But be aware that VTA dump valves can diminish your engines performance (hesitation after gear changes is the usual symptom) and lead to a rich air/fuel mixture during/after venting which will lead to extra engine wear through bore wash. It is difficult to quantify how much extra wear will take place and nobody seems to have any data to say if it's a real problem. But bore wash is not good for an engine, so extra bore wash can only be worse.
A HKS SSQV makes a lovely pppsssssooooooo sound and I happen to be selling mine, so if you want to save some money over a new one, send me a PM
Also do a search for recent threads on dump valves, I've seen it written several times recently that the best performance mod many have made was to refit the OEM recirc dump valve after previously running a VTA!
dump valves and whooshing sounds hmmmm
...be prepared to take some stick (calling greasemonkey)
...and be prepared for people telling you what else you should consider spending money on first
What makes the "nicest WOOOOSH" is subjective, what is nice to one person is asthmatic wheezing to another. The loudest dump valves are are the vent to atmosphere (VTA) type. But be aware that VTA dump valves can diminish your engines performance (hesitation after gear changes is the usual symptom) and lead to a rich air/fuel mixture during/after venting which will lead to extra engine wear through bore wash. It is difficult to quantify how much extra wear will take place and nobody seems to have any data to say if it's a real problem. But bore wash is not good for an engine, so extra bore wash can only be worse.
A HKS SSQV makes a lovely pppsssssooooooo sound and I happen to be selling mine, so if you want to save some money over a new one, send me a PM
Also do a search for recent threads on dump valves, I've seen it written several times recently that the best performance mod many have made was to refit the OEM recirc dump valve after previously running a VTA!
22 June 2004, 06:08 AM
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Thanx for the advice, i was'nt sure if you lost any performance by fitting VTA dump valve, and worse cause any extra ware. It was a difficult choice Quad H/light Conversion or Dump Valve but i think your putting me off the dump valve.
Cheers Paul
Cheers Paul
22 June 2004, 06:38 AM
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Assuming you have a classic then the quad headlamp is a very practical mod as the OEM headlights are a bit lame.
Fitting an induction kit is another way to make great noises, but again comes with health warnings..particularly with regards to the later cars fitted with the 'film' maf as opposed to hot wire. What year is your car?
C
Fitting an induction kit is another way to make great noises, but again comes with health warnings..particularly with regards to the later cars fitted with the 'film' maf as opposed to hot wire. What year is your car?
C
22 June 2004, 04:11 PM
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i've got a forge vta dump valve and it's quite loud and makes the exhaust pop little flames when lifting off the throttle(which is nice),don't know about engine wear but its been on the car over a year and i had one fitted to my old mx5 turbo and that never had any problems.
After reading a few threads like this i'm sure greasemonkey will pop up soon and warn you off them.
He sounds like he knows his stuff tho to be fair
After reading a few threads like this i'm sure greasemonkey will pop up soon and warn you off them.
He sounds like he knows his stuff tho to be fair
22 June 2004, 04:25 PM
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On the contrary Paul, I've never "warned anybody off" doing whatever they like to their own car, or indeed meted out any stick (please find examples of otherwise!). What I have done is presented the technical whys and wherefores as completely and as dispassionately as I can.
If someone chooses to do what they were gonna do anyway, it's not something I'm going to take personally. However, it's interesting reading of the number of people who've put standard dump valves back on after running aftermarket ones, and commented on how much better their car goes.
Personally, given the choice between spending money on a mod that makes your car work worse, and spending the same money on something that makes the car work better, I know where my dosh would be spent. What Sheffield Paul does though is entirely up to him. If he does as Brit in Japan suggests though, and reads the other threads on this subject, at least he'll do it with his eyes open.
If someone chooses to do what they were gonna do anyway, it's not something I'm going to take personally. However, it's interesting reading of the number of people who've put standard dump valves back on after running aftermarket ones, and commented on how much better their car goes.
Personally, given the choice between spending money on a mod that makes your car work worse, and spending the same money on something that makes the car work better, I know where my dosh would be spent. What Sheffield Paul does though is entirely up to him. If he does as Brit in Japan suggests though, and reads the other threads on this subject, at least he'll do it with his eyes open.
22 June 2004, 04:33 PM
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Seeing as i have just seen this, a question for Greasemonkey:
I picked up a MY95 Wrx Wagon just over 2 weeks ago, it was already fitted with a Blitz SUS Induction Kit and Blitz SS Dump Valve, is this a good dump valve or should i be better off with something else?
Apologies for hijacking the thread!!
I picked up a MY95 Wrx Wagon just over 2 weeks ago, it was already fitted with a Blitz SUS Induction Kit and Blitz SS Dump Valve, is this a good dump valve or should i be better off with something else?
Apologies for hijacking the thread!!
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22 June 2004, 04:38 PM
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Personally, if the standard dump valve was supplied with the car I'd be tempted to refit it. However, in your particular case the first thing I'd pay attention to would be the fuelling. Combination of JDM ECU plus induction kit could lead to quick blowup, especially if you don't have the right fuel in it.
If I were you I'd buy a KnockLink pretty quick, and make sure you run it on Optimax plus plenty of good octane booster until you do. Ignore the above if you're already on the case in this regard, but wouldn't like to see you sobbing over a broken engine only a few weeks into your ownership.
If I were you I'd buy a KnockLink pretty quick, and make sure you run it on Optimax plus plenty of good octane booster until you do. Ignore the above if you're already on the case in this regard, but wouldn't like to see you sobbing over a broken engine only a few weeks into your ownership.
22 June 2004, 04:42 PM
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Was looking into getting a Knocklink, not sure how much or from where though.....
As for original dump valve....didnt come with it
As for fuelling....running on Optimax and Millers Octane Boost from the moment i picked it up!
As for original dump valve....didnt come with it
As for fuelling....running on Optimax and Millers Octane Boost from the moment i picked it up!
23 June 2004, 02:34 AM
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The short answer Paul is not really. The standard valve is a pretty good component, and the only time you can really benefit from changing it is if you're running elevated boost, sufficient to cause the standard one to leak.
Unlike some turbo car manufacturers, Subaru did a really good job designing their dumpvalves. They do exactly what they say on the tin, and in many cases the supposedly "better" recirculating aftermarket ones can be tricky to get adjusted just right, to the extent where if you don't spend ages fiddling with them the standard part will still perform better.
If I were you I'd spend the money on something that'll actually make your car work better/safer, whether that's a decent set of headlights, a KnockLink, a set of anti-roll bar links or whatever.
Unlike some turbo car manufacturers, Subaru did a really good job designing their dumpvalves. They do exactly what they say on the tin, and in many cases the supposedly "better" recirculating aftermarket ones can be tricky to get adjusted just right, to the extent where if you don't spend ages fiddling with them the standard part will still perform better.
If I were you I'd spend the money on something that'll actually make your car work better/safer, whether that's a decent set of headlights, a KnockLink, a set of anti-roll bar links or whatever.
23 June 2004, 04:10 PM
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Originally Posted by greasemonkey
The short answer Paul is not really. The standard valve is a pretty good component, and the only time you can really benefit from changing it is if you're running elevated boost, sufficient to cause the standard one to leak.
Unlike some turbo car manufacturers, Subaru did a really good job designing their dumpvalves. They do exactly what they say on the tin, and in many cases the supposedly "better" recirculating aftermarket ones can be tricky to get adjusted just right, to the extent where if you don't spend ages fiddling with them the standard part will still perform better.
If I were you I'd spend the money on something that'll actually make your car work better/safer, whether that's a decent set of headlights, a KnockLink, a set of anti-roll bar links or whatever.
Unlike some turbo car manufacturers, Subaru did a really good job designing their dumpvalves. They do exactly what they say on the tin, and in many cases the supposedly "better" recirculating aftermarket ones can be tricky to get adjusted just right, to the extent where if you don't spend ages fiddling with them the standard part will still perform better.
If I were you I'd spend the money on something that'll actually make your car work better/safer, whether that's a decent set of headlights, a KnockLink, a set of anti-roll bar links or whatever.
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