I actually meant to post it as a response to Tom's original question which gives a tie to the strength of ball bearing turbos. Damn threaded setup.

BillyElliot Wrote:
-------------------------------------------------------
> I actually meant to post it as a response to Tom's
> original question which gives a tie to the
> strength of ball bearing turbos. Damn threaded
> setup.
Go to the bottom V and select "select view"

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.



Edited 1 time(s). Last edit at 02/24/2010 06:21PM by john vanlandingham.

Not knocking threaded setup. I like it so you can see responses and follow the chain of conversation better. But that's two pokes at me in one day JVL?

/insertinternetsmiley

BillyElliot Wrote:
-------------------------------------------------------
> Not knocking threaded setup. I like it so you can
> see responses and follow the chain of conversation
> better. But that's two pokes at me in one day
> JVL?
>
> /insertinternetsmiley
That's a poke?
man where do you spend time/

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Jay Wrote:
-------------------------------------------------------
> I know Senior Lane doesn't run one, but Senior
> Jardeval does.

> So do you run a BOV to maintain
> reliability and avoid spikes that might damage
> your throttle plate or bust a hose or break a
> turbo, along with maintaining spool between
> shifts, or go without and lose one subsystem to
> break, and don't worry cuz it won't hurt your
> turbo, and either get worse performance or better
> between shifts depending on which story you buy?
> I'm thinking once my car's back on the road, I'll
> try running it with the bov line plugged and see
> how it goes. I don't know that I wanna do that to
> my street car, but maybe.
> One other thing, it looks like vent to atmosphere
> BOV's should oughtta run an airfilter one 'em in
> rally
>
> Jay Woodward
> Snohomish, WA
> '90 Mazdog Frankenprotege
> Chronologically, 40...
>
>
>


Seems like there is some hocus pocus BS going on here...Here's my complete novice idea behind the post, I think BOV's were primarily designed for use with journal bearing turbos. Journal bearing turbos are weaker than newer ball bearing turbos (which have better side load capabilities from what I have read). When people sarted using BB turbos more often, the BOV guys hyperventilated a bit cause they realized that BB turbos are stronger and could probably deal with a bit of surge better than the journal bearing stuff did. So Blow Off guys said hey, you can still blow up turbos because of that nasty Compressor Surge!!! plus you get the cool twelve tone wooshing noise that our whisle...I mean BOV makes!

---Totally my opinion at this point, from the fan boy ranting I have been reading

Has anyone ever heard of compressor surge off throttle killing even a Journal bearing turbo that wasn't completely hammered to begin with?

---

-Tom
DemonRallyTeam | Fine Tuning | CTS Turbo & RP Turbos | RalleyTuned | JRM | Meister Autowerks
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Tom everythings possible but within reason like what you're planning with a very modest unit it may make zero difference at all.
And if one reads any ball bearing catalog---and i have a pile of 'em, ball bearings don't like thrust load.
They say only "fair' for thrust applications...

but what do bearing makers know compared to the powerxz of the Intra-webz!!!!

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

I'll be the first one to say it, I am no engineer, I just read and regurgitate more internet drivel until I am proven otherwise. Although on occasion I have real world experience too...

---

-Tom
DemonRallyTeam | Fine Tuning | CTS Turbo & RP Turbos | RalleyTuned | JRM | Meister Autowerks
Spitfire EFI | Product Apparel | JVAB Imports | NLS | AP Tuning | USRT

Add us on Facebook | Next Event: 2013 Olympus Rally June 22-23 Olympia, WA

I say just get a second turbo, run your car without a bov, so if the turbo blows before you wreck the car beyond repair you have a spare. With all the time saved we can look at boob pictures on the net, what it was designed for anyways!

Tom B Wrote:
-
> Has anyone ever heard of compressor surge off
> throttle killing even a Journal bearing turbo that
> wasn't completely hammered to begin with?

Yes, and quick closed throttle (after high boost pressure) engine stalling too!


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---

As always IMHO

SEAN TENNIS KF7JJR
SEATTLE, WASHINGTON
SAAB 99, SAAB 850
SAAB V4, SAAB 99T

i don't buy the arguement that a BOV blows off ALL your boost, and hurts "spool" when you shift.

instead i really think it's the other way around, i really do think that a BOV set-up will help out spool.



While thrust loading is probably the most destructive, i really do believe that you are also slowing down that impellor. If instead the thing can keep "free wheeling" it will be quicker to build the boost again.


I can be pulling 20 PSI, yank the next gear, and be instantly back to 20 PSI again.


The cost of a good quality valve is like $150 bucks...

---

Chris

NoCoast Wrote:
-------------------------------------------------------
> What's it have for a turbo?
>

TO4, I don't remember anything more specific than that.

Mike Whitman did not use a BOV in his Escort Cosworth, as that was how it was ran in the WRC. Made beautiful chirping sounds. Apparently he didn't like having to buy $1500 turbos with the frequency he was blowing them up and put in a atmospheric bypass valve (ABV) and didn't seem to be having as many issues.
They are cheap, they may add to reliability and turbo life, they will not be the difference between you placing in 13th overall instead of 14th overall, but not having one could contribute to not placing at all. That's my thoughts on them.

---

Grant Hughes

I personally don't buy the facts that the 18psi of boost pressure can act on the face of the impeller. The inlet of the turbo is larger than the outlet, and the impeller face is directly at the inlet. I would bet that 20 PSI in the system can escape without exerting much force on the face, the rapid decel of the impeller may be more to blame.

Here is my experience: On a car that measures air flow, not dumping the boost at closed throttle can and will cause driveability issues, like when you go closed throttle then back open, all that stored air is now un-metered, and the car goes lean, or you get a "trailer hitching" effect. If the car has a Vane Air meter before the turbo, Like a Merkur, the reversal of air flow can slam the VAM door closed rapidly, maybe hurting the VAM. With speed density, or a nice MAF, than is fixed. With a speed density system, you can do what you like with the pressure, shouldn't really hurt anything.

I have a BOV on the street Merkur, and it performs well. I have a Bosch bypass valve on the Volvo, routed back into the inlet of the turbo, and it performs well. I have no BOV or venting on the Rally car, and it performs OK, some slight stumble on certain throttle movements, but it works and sounds cool. My 9 year old swears it sounds just like the rally cars on his video games.

A properly set up BOV should open quickly at throttle snap closing, and close well before the pressure gets to 0. Than does help keep the turbo spinning, and the throttle response is good. I would say most people don't take the time to get them adjusted properly, which ends up hurting more that helping.

NoCoast Wrote:
-------------------------------------------------------
> Mike Whitman did not use a BOV in his Escort
> Cosworth, as that was how it was ran in the WRC.
> Made beautiful chirping sounds. Apparently he
> didn't like having to buy $1500 turbos with the
> frequency he was blowing them up and put in a
> atmospheric bypass valve (ABV) and didn't seem to
> be having as many issues.
> They are cheap, they may add to reliability and
> turbo life, they will not be the difference
> between you placing in 13th overall instead of
> 14th overall, but not having one could contribute
> to not placing at all. That's my thoughts on
> them.
>
> Grant Hughes
> www.nocoastmotorsports.net
> Denver, CO


Maybe he was having bad information from the same folks that charged him 20g for a simple rebuild on his motor.
And $1500 for a turbo.
Maybe he likes spending money....

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Turbos were from TEC here in Denver before the owner committed suicide.

---

Grant Hughes