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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: dillenger1 on December 07, 2007, 06:43:39 am
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Why does vw use wg's if they arent needed?I read a post in the tech section,about a wg setup,and it seemed he got shot down for the idea,but to my knowledge volkswagon uses wg's on older td's
thanks ben
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Because they are needed unless you like replacing turbos on a regular basis.
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Simple, the VNT turbos didn't exist (well or weren't cheap enough/proven) when VW made the older engines. Therefore not used on the old TD's.
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Im sorry guys,your probably gonna hate me ,but I meant blow off valve not waisted gate.I just got a little excited.
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Um, if you are getting excited about your blow off valve, I don't want to know about it. :P :lol:
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i thought they put BOV's as back ups for the waste gate in case you make too much boost
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Too much boost, what's that? :lol: :twisted:
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i dont know i love the sound of a bov ,but i dont want to run one unless its got function.Please someone tell me theres a function/intended use
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Absolutely no use on 99.99% of all diesels since there is usually no throttle plate. I did read on here someone used it with a VERY large turbo so that it wouldn't make the compressor surge (something along those lines) upon sudden deceleration.
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that wasnt enough
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What wasn't enough? Need more opinions, hit google :)
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vw added the BOV to the 1.6's only. even 1.9's have wastegated turbo's but no BOV.
it is just some type of 'safety' device in case the wastegate fails. and funny enough, i actually think that extra boost might be a good idea if the wastegate fails to help cool down those EGT's... but then again it would help lower the chance of runaway and reduce fueling since the LDA wouldn't be getting shoved down its little hole. :lol:
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It is not a blow off valve. It is a pop off relief valve to prevent engine damage from too much boost pressure in the event that the wastegate fails.
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In my manual its listed as a bov.
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Well that manual is 20 years old :) The terminology has changed a bit.
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I am considering the options of adding a BOV based on the issues of compressor surge because I have a Hybird turbo that I have built and am worried about surging the compressor vanes.....
I have been doing some reading and yes gas turbo cars need BOV because of throttle plate ( or massive loss in airflow).... Air has no were to go and needs to be vented, isn't this the same case if your running up the gears and hit 22 PSI and then say you need to let off or need to engine break ( were does the excess boost go)......
I am setting my wastegate to open around 22-25 psi, but I am worried that if the exhast impellar is unloaded(wastegate open) and the compressor still having the left over boost is still loaded may surge.
So if I tap into the wastegate line which senses compressor pressure and run a line to the wastgate, they should open simultaneously, allowing the turbo to have a balanced amount of pressure between the compressor and impellar.....
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but... thats how wastegated turbos regulate pressure already...
they surge because of the inertia of the spinning parts, ant the time it takes the wastegate to actually move and let the exhaust gasses out.
they only surge for that brief period of time, but bad things happen quickly :(
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if your running up the gears and hit 22 PSI and then say you need to let off or need to engine break ( were does the excess boost go)......
Through the engine, there is no throttle to block airflow.
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i would imagine that boost would also leak past the compressor wheel as it spools down... a BOV couldn't hurt anything though... except your wallet :lol:
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I have a k26 from i believe an audi 5000 .it doesnt have a wastegate.At least on the exhaust housing.Would there be problems with running a bov in replace of a waistgate to regulate boost?
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Would there be problems with running a bov in replace of a waistgate to regulate boost?
Yes, the compressor wheel would explode when it overspeeds.
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Not to thread jack,but does anyone know why these(k26)didnt have a waistegate?Could it have been on the manifold some how.I dont see a pressure line anywhere on the compressor?
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5cyl gasser Audis have external wastegate.
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Well....
i plugged mine with a cork and she FLIES now. especially with more fuel and massive downpipe and no cat or muffler just 3 inch pipe. watch that egt though
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It seems the factory setup would sacrafice the turbo to save the engine. ie. headgasket, maybe rods. In the event of a wastgate failure.
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It looks that way.