Goodbye Dumpvalve
31 August 2001, 12:02 AM
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Best option I'm told is to blank off the BOV and put a decent induction system in.
The BOV is there to remove stress from the Turbo on road cars... Ordinarilly you dont want one as it releases pressure on overun, theoretically letting the turbo run free... but then you have less pressure on re-application of the throttle.
Some people have mentioned risk of the turbo stalling, but I have seen no evidence, and it does seem to improve pickup (and I still have standard induction)
Lots of people have much better knowledge of this in real applications though.
The guys who make them always say they improve performance (for life of me I can't work out how... you are letting compressed air *out* of the system.) But the tuners I know all say blank it off as long as you have a turbo with a 360 deg bearing (IHI turbos do as it is a bearing race, the TD4 I believe has not, it has a bronze type bearing with oil guide)
The trick is to try it and see (after checking your turbo of course)
For noise remove the airbox/use induction cone and get a bigger exhaust!!
...©
The BOV is there to remove stress from the Turbo on road cars... Ordinarilly you dont want one as it releases pressure on overun, theoretically letting the turbo run free... but then you have less pressure on re-application of the throttle.
Some people have mentioned risk of the turbo stalling, but I have seen no evidence, and it does seem to improve pickup (and I still have standard induction)
Lots of people have much better knowledge of this in real applications though.
The guys who make them always say they improve performance (for life of me I can't work out how... you are letting compressed air *out* of the system.) But the tuners I know all say blank it off as long as you have a turbo with a 360 deg bearing (IHI turbos do as it is a bearing race, the TD4 I believe has not, it has a bronze type bearing with oil guide)
The trick is to try it and see (after checking your turbo of course)
For noise remove the airbox/use induction cone and get a bigger exhaust!!
...©
31 August 2001, 08:39 AM
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After many months of enjoying the old 'whooooosh tsssssshhhhhhh' sounds of a piston dumpvalve I am toying with the idea of removing it. Many threads on this BBS indicate little need for one on an Impreza. Whats more I am becoming worried that it may be causing a few probs myself. Things like being slow to spool up on occasions, and that it may be tricking the MAF and thus giving me duff mixtures etc,etc.
If I change it I was wondering what the consensus opinion was as to what valve is best??? I still have the standard recirc at home somewhere, but is there an uprated aftermarket part or what about a BOV etc? At the moment I am not running above standard boost, but with turbo and link mods to come it is likely that I will in the future.
On the basis that I know very little about anything other than dump valves I would appreciate any thoughts.
Cheers
Disco
If I change it I was wondering what the consensus opinion was as to what valve is best??? I still have the standard recirc at home somewhere, but is there an uprated aftermarket part or what about a BOV etc? At the moment I am not running above standard boost, but with turbo and link mods to come it is likely that I will in the future.
On the basis that I know very little about anything other than dump valves I would appreciate any thoughts.
Cheers
Disco
31 August 2001, 10:09 AM
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If you still want the whoosh sound, remove your resonator box. Helps turbo spool up slightly quicker as well.
Have to check for water getting into air box as there is a slight risk, but mate has been running it like this for over a year and I did mine the other day.
Sounds (from inside anyway) like you have a dump valve fitted
Have to check for water getting into air box as there is a slight risk, but mate has been running it like this for over a year and I did mine the other day.
Sounds (from inside anyway) like you have a dump valve fitted
31 August 2001, 11:50 AM
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Forge recirc.
Dont run without unless you can afford to replace turbo cores.
More likely to get away with it on a td05, which I think you might have but cant remember.
If an early car, then more likely, but do so at your own risk.
Dont run without unless you can afford to replace turbo cores.
More likely to get away with it on a td05, which I think you might have but cant remember.
If an early car, then more likely, but do so at your own risk.
31 August 2001, 11:54 AM
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Disco,
Im in the same boat as you, I have a forge atmos. DV. I quite like the noise and enjoy scaring smal children with it.
However, my fuel consuption is now shocking, and it occasionally threatens to cut out at idle.
But, the worst thing is (for us youngsters) is taking out a young lady and having to subject her to pops / bangs / whooshes. All the descent ones are not overly impressed!
Worse is having to explain why you put it on!
Let me know what you decide...
MB
Im in the same boat as you, I have a forge atmos. DV. I quite like the noise and enjoy scaring smal children with it.
However, my fuel consuption is now shocking, and it occasionally threatens to cut out at idle.
But, the worst thing is (for us youngsters) is taking out a young lady and having to subject her to pops / bangs / whooshes. All the descent ones are not overly impressed!
Worse is having to explain why you put it on!
Let me know what you decide...
MB
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31 August 2001, 03:32 PM
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I have the answer, up to the other week I used a Forge dump to air (as you know Mark) I had may problems with sticking pistons from dirt getting in etc, spring being the wrong one, spring breaking! more fuel being used as it does fool the maf, lot's of flames which I did like, but no good for the life of my back box.
Until the other week when I fitted my APS FMIC, I also acquired a APS BOV, what a great design!
It is adjustable and dumps to air and re-cir's also dependent on weather you are boosting or not. It gave a much smoother ride, no flames, and a very different sound almost like the blitz when dumping at 3-3.5rpm. I do miss the flames though but get them sometimes at higher rev's.
The piston is a brass one, you have 3 ports, 1 for the vac pipe, 1 for the intercooler, 1 for the inlet man.
I strongly recommend it, I got this from Rich R who now has an Evo 7 with a Forge and misses the APS one big time.
take a look at it on the NAM site.
Moe
Until the other week when I fitted my APS FMIC, I also acquired a APS BOV, what a great design!
It is adjustable and dumps to air and re-cir's also dependent on weather you are boosting or not. It gave a much smoother ride, no flames, and a very different sound almost like the blitz when dumping at 3-3.5rpm. I do miss the flames though but get them sometimes at higher rev's.
The piston is a brass one, you have 3 ports, 1 for the vac pipe, 1 for the intercooler, 1 for the inlet man.
I strongly recommend it, I got this from Rich R who now has an Evo 7 with a Forge and misses the APS one big time.
take a look at it on the NAM site.
Moe
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