dump valve on B4????

B

blackB4

Sunday Drivers
just wonderin what the lads with b4's think about dump valves?? any info appreciated like price,make where to get ? are they worth it??
also have my b4 6 months and ince I joined this site im wonderin should i have it remapped any info on that much appreciated too cheers........................
 
i have a hks dump valve on my leggy and it sound sweet, think its a hks ssqv model or something like that, they sound great..!! not too noisy but a lovely little whistle off them..!

i never got my leggy remapped coz i dont think it ever needed it, i dont drive the arse out of it, i think it depends on what kinda performance/how your gonna drive it as to get it done or not..?? :ponder:

slan

smurf

:subaru:
 
markobucko said:
dont recommend on a twin turbo model mate!!!!!!
:thumbsup: :thumbsup:
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????? :ponder:

They're deadly, really nice on them, i have a hks ssqv on mine and it's loud enough have to say, but i'd miss it now if i dint have one.
 
Think its cause they dump boost off the first turbo which is used for the second turbo. something like that cant remember
 
have i seen your legacy around maynooth nick nack ??? if its the one ive seen its a beauty!!! how much you pay for your dump valve??
im wondering if it would get annoying driving it every day.............

Cheers Dave
 
Yeah thats me alright, live here, where you from yourself?

Its not annoying, it just sounds lovely each time you hear it set off. If you want i'll meet ye somewhere soon and i can show you how it sounds.
 
ye sound, im just up road in Leixlip, mines been in garage last 2 weeks after it overheated have to ring tomorrow see how it is,cant wait to get it back!!!!
 
oh lovely! ah yeah, mines in the garage getting the front wing sorted so aint got mine either!

But definately get one, they sound the bogs dollox
 
they sound great have on on my new shape Legacy, got mine for 200 delivered fron nengun.com . I heard the make the VOD situation worse on the twin turbo setup. Not recommended according to davelegacy. Is it just me being parnaoid or does an after market BOV increase your fuel consumption or maybe my foot got heavier!
 
I had a HKS on mine and as above you could really notice the VOD. Changed it back and its not as noticeable now and a fair bit smoother through the revs! :thumbsup:
 
The pressure from the first turbo is recirculated and used to spool the second turbo...dumping it to atmosphere causes more lag on the second turbo, increasing the VOD....the VOD is about the biggest draw back of the TT system making it worse and decreasing your performance for a sound doesn't make any sense to me but each too their own...
 
blackB4 said:
just wonderin what the lads with b4's think about dump valves?? any info appreciated like price,make where to get ? are they worth it??
also have my b4 6 months and ince I joined this site im wonderin should i have it remapped any info on that much appreciated too cheers........................
Click to expand...

I have a hks one on mine I'll swap you the standard setup on yours and my hks one for a ton???pm me yeah
 
i have a hks ssqv on mine for a year now .. it made no difference to the vod ,.. whenever you bring the car into the secondary turbo your normally gunning it through the primary turbo anyway so i cant see any difference ! each to his own .
 
i have a turbosmart on mine but the cars bein in my garage since i put it on so i havent had a chance to test it properly yet
 
A lad called matt from the club bought one off richie in proparts the other day and I help him fit it while I was there doing nothing, sounded great. Direct replacement for the one that was on the car. If you want one give Richie a shout.
 
The standard valve dumps the air into the inlet of the primary turbo, you can see that by following the pipe. I've never heard of any turbo that uses compressed air to spool a turbo. I've only ever heard of a turbo spooled by the exhaust gases. When you change gear, it dumps the boost completely, according to my boost gauge anyway, either into the inlet or into the atmosphere if you have a bov.

I personally wouldnt get one because as dave says you are dumping already compressed air into the atmosphere rather than back into the system. I am open to correction on this but i dont think that it spools the second turbo, i personally have never heard any mechanic say that either. If anybody can show me how this is done the i stand corrected but i just cant see it
 
yeah your right its probably wron to say it spools the turbo ..the exhaust gases do that ovbiously but it does recircualte already compressed air which your losing if you dump to atmosphere....probably makes feck all difference but thats what i was told and it makes sense..why would subaru recircualte the air when its much easier just to dump it...BUT does the BOV just replace the secondary wastegate? in which case it wouldn't matter??
.......hmmm confused now....because there is an exhaust flap that controls the spooling of the second turbo SO even if you dont have a dump valve and you drop off you must be dumping the air from the first turbo to atmosphere anyway...only recirulating it as you pass a certain rev point and it opens one valve and closes another....seemed to have talked my self out of it there....
makes more sense..it couldnt be recirculating the air if your just boosting to 4k and changing gear....
so the BOV only replaces the secondary wastegate i PRESUME.. so i cant see a problem now...friday afternoon logic could be way off...anyone any thoughts or even understand my ramblings?
 
Dagnut said:
yeah your right its probably wron to say it spools the turbo ..the exhaust gases do that ovbiously but it does recircualte already compressed air which your losing if you dump to atmosphere....probably makes feck all difference but thats what i was told and it makes sense..why would subaru recircualte the air when its much easier just to dump it...BUT does the BOV just replace the secondary wastegate? in which case it wouldn't matter??
Click to expand...

To the best of my knowledge, there is only one wastegate. If you look at your intercooler, the wastegate is just to the right of the intercooler with a pipe that leads to the inlet of the primary turbo. To install a bov, you need to take the wastegate off, block the pipe leading to the primary turbo, then attach the bov. If you take the B4 up to 5 or 6,000 revs and change gear you can hear the wastegate dump the boost into the inlet. The sound comes from the pressure equalising on both sides of the wastgate, so in essence the air being dumped is the same pressure as the inlet is already before you changed gear... if that makes sense... so maybe there is no problem with having a bov??? The only thing i can think of is that subaru thought there was no point in wasting the air that has already been filtered?? but maybe someone that actually knows would clarify....

I would like to know if any1 here knows for sure, what way does it bring in the second turbo?? When using the primary turbo, all exhaust gas goes through the primary but when switching and using the second turbo, does all the exhaust gas travel through the second turbo only or do the turbos work together and the exhaust gases split? I know when i'm going through the vod, my boost goes from 0.6 on the primary down to about 0.3 as the second turbo comes in and then shoots back up to 0.8 as the exhaust gases are traveling fast enough at those revs to spool the secondary turbo very quickly
 
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