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Posted: Tue Jun 09, 2009 4:45 pm
by colezy91
well the funny thing is i took it to an exhaust shop and they said that they wouldnt do it because its kind of pointless unless you have a intercooler setup.... but what difference would it make if you had a front mount???? or is that cause its probs alot easier to install...
Posted: Tue Jun 09, 2009 5:05 pm
by Adriano
Its because they are idiots. Redzone, what happened to the turbo? Plenty of factory vehicles dont have them without tuebo issue, running more than 20 psi
Posted: Tue Jun 09, 2009 5:06 pm
by OLD FART
iXNAY wrote:id assume 80% of people would also want it for the sound factor alone!
cant you just plumb it back to your turbo inlet to not be wasting compressed air?
Ryan to comply with the ADR'S it has to be plumb back system
To the doubters if they were of no benefit why does Subaru install them at the factory as the bean counters are always looking for ways to maximise the bottom line (profit ) ??????????
Has anyone seen any turbo competition cars without and if there were I think they would be a minority if any
I believe that the main role is to prevent a sudden reverse shockwave when the throttle is snapped shut and slowing the turbo rpms whereas with a BOV the rpms ars much higher so it will spool up faster
Docile where can we see the data to back up your opinion ??????
I AM NOT looking for a verbal stoush only something to back up your opinion and for my enlightenment :)
Posted: Tue Jun 09, 2009 6:28 pm
by RiceThief
Rally cars run anti lag rather than a bov to keep the turbos spinning . Also larger turbos have bigger problems with reversion than smaller turbos both in terms of stalling the turbo and damaging from the reversion.
Posted: Tue Jun 09, 2009 7:07 pm
by Adriano
BOV's prevent reversion as said, however they are fitted, as the reversion causes havok with afm's, and basically makes it impossible to pass modern emmissions. FYI many toyota's dont run bov's from the factory, on the models that run map sensor based systems(supras and soarers)
Posted: Tue Jun 09, 2009 7:11 pm
by Adriano
The only way(s) i can see reversion killing turbos is either destroying the comp wheel due to the forces(but ive never seen it), or more likely the pressure surges would cause premature wear to the thrust bearings due to the pouding on the end float.(which may explain the excessive end float on my turbo)
Posted: Tue Jun 09, 2009 7:20 pm
by TomVR4
are adriano and docile the same person? no offense if your not, it just always seems you are saying very similar things?
Posted: Tue Jun 09, 2009 7:42 pm
by Adriano
No, not the same. Actually i think we are making fairly different points.
In terms of BOV effectiveness in reducing transient response there are arguements both ways. I may be about to try a gtr bov on my starion and datalog the difference in boost rebuild after momentry overrun, however consistency will be difficult.
Posted: Tue Jun 09, 2009 7:55 pm
by JD_Stazza_Brendan
Posted: Tue Jun 09, 2009 7:58 pm
by RiceThief
The problem with afm and bov are only there if the bov is vented, if it is recirculated after the afm then the air wont be metered, the gtr bov is an example of this. No bov from the factory is vented into the atmosphere whether its a map sensored car or one with an afm obviously for emissions.
As you stated the damage will be in the thrust bearing causing premature play.
Posted: Wed Jun 10, 2009 4:16 am
by OLD FART
RiceThief wrote:Rally cars run anti lag rather than a bov to keep the turbos spinning . Also larger turbos have bigger problems with reversion than smaller turbos both in terms of stalling the turbo and damaging from the reversion.
Correct anti lag is better for no lag but it's hard on turbos as they have to be changed reguarly =$$$$$$$$$ but how long do you think you would get away with it on the street ???
Posted: Wed Jun 10, 2009 6:21 am
by Station
I think it's just further recycled internet forum bollocks. I've never seen a turbo destroyed by one personally. I put the BOV in to see if my turbo was boosting, it was literally in there a day. I think the noise is a bit 'common' now.
Posted: Wed Jun 10, 2009 6:46 am
by redzone
Adriano wrote:Its because they are idiots. Redzone, what happened to the turbo? Plenty of factory vehicles dont have them without tuebo issue, running more than 20 psi
it was a TC06 high flowed with a T03 wheel that it happened to, was on the orange car, and yes it got about 3mm of end float until the exh wheel contacted the housing. turbo was fine before i boosted it up. used to make an awesome WRC style flutter noise, unfortunately loving that noise cost me a turbo... that turbo was fine running on 14 psi, before i boosted it up when i fitted the 2.4 head. turbo only lasted about 3 months at 20.
compressor surge hammers the shit out of thrust bearings.
also FYI the reason WRC cars can get away with running anti lag and without running BOV's is because they change the frickin turbo's at nearly every service park....
Posted: Wed Jun 10, 2009 11:05 am
by thrash
grrrrrrrrrrrrrrrrrrr pshhh
Posted: Wed Jun 10, 2009 2:07 pm
by docile
From the autospeed article with Nizpro, which JD_Staz linked,
"The fact that people think that they keep the turbo spinning is a problem. The people that suggest this have never had an engine on the dyno and never had a turbo tacho in their hands. What people don't realise is, when you shut off the throttle, you shut off the air supply to the engine - this shuts off the exhaust gasses coming out of the engine. When there is no exhaust flow, there is no energy to keep the turbine spinning - the turbo slows down at an alarming rate.
"If you change gears at quite a good speed, you can actually get a boost spike on changes; if you're trying to hold a constant 30 pounds, when you do a racing change you'll get 32-33 pounds when you crack the throttle open again. If everything's working well, you've got a full head of stream waiting to go into the throttle as soon as it's opened.
"I've done this on a rally car and it was quicker through every timed section without a dump valve.
Firstly, I agree, on some of the really old compressor wheel designs, like the a,b,c and g (circa 1990's) along with the garret t wheels and some gt, wheels then surge will wear our the trust bearings sooner.
Mitsubishi 't' wheels (circa 2002), ie, 12,14,15,16,19 and 22T wheels are exceptional and shouldn't need a BOV. Same with the new BorgWarner series Turbos, surge lines are so far to the left it puts the Garret wheel designs and maps to shame.
:beer