bleed valve/adjustable boost control VS FSE Powerboost valve

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bleed valve/adjustable boost control VS FSE Powerboost valve

Bushboy

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Ok, so my new car has a bleed valve/adjustable boost control valve. Ive been told that they make the car run lean in higher revs and so could potentialy damage your engine.

Im not going to name names as i dont know whos right or wrong etc. but another guy on here thats owned the same car said to get rid of the adjustable bleed valv thing as they make the car run lean in higher revs and so could potentialy damage your engine.

He also said to replace it with an FSE powerboost valve and get it setup properly at a rolling road as then it wont run lean and should be fine etc.

is this a good idea? he also mentioned just removing it all together? :confused: im confused. im not all up on this turbo lark yet :D
 

bulldog5046

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right, i think that on your new car it does have to be tuned correctly as its old, you've kinda shot youself in the foot now aswell as people will need to know what car your talking about:eek:
 
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Bleed valves are a hangover from the 80's school of tuning turbo cars, they are mostly responsible for many turbo cars from the 80's Uno turbo's, RS turbos, R5GTT's, MG Montego Turbo(when launched fastest saloon in world no less) form getting reps as unreliable, people stuck bleed valves on and then wonder why pistons melted, head gaskets blew and turbos exploded.

Remove it immediately, and get the car set up by a "professional", if you want more power do the conventional things that you do to a n/a car as a turbo car normally responds even better to things like head work, cams etc as they are even more reliant on good breathing as you are forcing air into the car.

I have no knowledge of the FSE valve but do know that an integrale has a rising rate fuel regulator as standard so if yours doesn't then it may be worthwhile, but check as it ma do already.

Aaron.
 

Liam

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Many of my mates run tuned Jap cars and there isn't a FSE in sight with there engines.

I would say a remap or fuel controller is a better solution.

Liam
 

jamie86

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An FSE effectively gives you adjustable pressure fuel pump is my understanding.. which can stop the bleedvalve from leaning the car out...

Personally I would ditch the bleedvalve altogether though ;)

Liam- Most *fast* Jap cars have these as standard i think..
 
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Bushboy

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right its going then. but will taking it straight out make it run crap or will the car readjust itself and run like it did before it was put on?

reason being that if I take it out and seal the hose and it runs rubbish then ive still gotta drive it to work etc. before I can get a proffesional to look at it.
 

jamie86

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Just get a new bit of hose and replace the bit the bleed valve is on.. you wont have any probs (y)
 

GhostWKD

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was wondering about this today too, if i remove the bleed valve, how will the turbo be restricted in what its boosting to? ie will it just boost freely to like 1bar or something silly? (did this the time one of the bleed valve pipes came loose - so quick! but so about to blow up lol :p)
 

jamie86

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It will boost to whatever the wastegate actuater lets it from my understanding
 

GhostWKD

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i dont know much about turbos etc :( only the easy most ppl know bits :( So if i remove the bleed valve is it pot luck what car will then boost to? may boost to 0.3 bar or may boost to 1bar? :confused: :eek:
 

pinin__prestatyn

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Your mate's talking balls.

You need an uprated fuel pump, not pressure regulator. If you whack up the boost and add an FSE you are asking for trouble. A 255 walbro fuel pump is needed if you are running higher boost. (Not sure if this would be the right one for your car tho) there's a group buy on at fccuk I think and they are about £80.
I'd get your car on the rollers to see if it's running lean anywhere in the rev range.
Also if you are going the mechanical boost controller route I'd recommend a PRV or pressure relief valve as opposed to a bleed valve, the boost instantaneous as opposed to the slight lag from the bleed valve.
I'm running an ARMVAL PRV and it's good kit, just until I can get that Apexi AVC-R jobbie :cool:
 
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pinin__prestatyn

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GhostWKD said:
i dont know much about turbos etc :( only the easy most ppl know bits :( So if i remove the bleed valve is it pot luck what car will then boost to? may boost to 0.3 bar or may boost to 1bar? :confused: :eek:

Removing the bleed valve will either cause you to run base boost (whichever your actuator is set at) or what happened when one of the hoses came loose on my coop, is there was no boost limit, and I saw 2 bar of boost before I realised something was amiss.
It was fun, if totally dangerous :p
 

HP

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GhostWKD said:
i dont know much about turbos etc :( only the easy most ppl know bits :( So if i remove the bleed valve is it pot luck what car will then boost to? may boost to 0.3 bar or may boost to 1bar? :confused: :eek:

With any turbo car it depends entirely on how the bleed valve is set up and to what extent it bleeds off the signal to the actuator as to what the effect will be when you remove it. It's a 'how long is a piece of string' thing, m'afraid. You need a boost gauge before you play with one.

They work by reducing the pressure the turbo wastegate actuator sees, so the actuator doesn't open as early, so the boost pressure will run higher.
 

pinin__prestatyn

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Of course I forgot to say if you haven't got a boost gauge get one before anything else, they are vital for turbo cars. I can't beleive the coupe didn't have one as standard! The focus ST has one :cool: The uno turbo does to doesn't it?
 

GhostWKD

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Cant quite get my head around this bleed valve stuff so you'll have to bear with me :eek:

So if a bleed valve is the crude way to manage boost what would be the effective/proper way to manage the boost? as from what i can understand it will otherwise just boost to x amount (x being determined by the actuator) also, is the actuator adjustable or will it be a fixed variable?

Thanks all for your help :D hope its as useful to bushboy as it is to me :eek: :p

Edit: oh and dont worry i do have a boost gauge :p think the UT has one as std, mk2 one does anyway :D
 

pinin__prestatyn

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Ghost - have a good look at garrett's site they have a very informative guide to turbo's in three stages, beginner, average, and boffin!

http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html

I'm no expert on turbocharging, but I pick up a bit on various forums.

The coupe and most modern turbocharged engines run an EBV as standard, or Electrical bleed valve. This is monitored by the car's ecu and in the case of the coupe, it is set to minimise boost to .6 bar in first and second gears to minimise wheelspin.
Also the ecu can launch into "limp home mode" if it detects a problem, which is again to cut the boost to .6 of a bar (normal is just under 1)
you can get problems with the EBV like after a while they stick open giving too much/little boost.
Changing to a mechanical boost valve (bleed valve/pressure relief valve) takes away the engine's powers to control the boost, and removes the limp home mode. However you know get full boost in any gear as the ecu is no longer controlling the boost.

The best form of boost controller is an EBC (electronic boost controller) like the Apexi AVCR (more info here)

http://www.modyourcar.com.au/product_info.php?products_id=449

these use a solenoid to control boost and you can set when the boost comes in, how fast boost comes in, how much boost you want at which revs, have low boost for day to day driving, a scramble setting for when you want to try keep up with that supra ;) etc. As well as them having a built in boost gauge, they also look the nuts. These are the best form of boost control but they aren't cheap (£250 new)
 
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A waste gate/actuator controls how much boost the car receives by opening at a predetermined level of boost to release excess boost produced, this is it in layman's terms. On an integrale for instance it has an electronic waste gate so it can limit boost in certain gears to protect the drive train, and a MG Metro Turbo limited it dependent on revs again to protect the drive train.

A bleed valve is nasty, as it "tricks" the waste gate/actuator into not seeing how much boost in being produced and therefore stays closed meaning the car receives more boost, the problem with them is they are inaccurate in the way the "bleed" off boost and therefore with out an accurate gauge you can easily turn it up to far so cars runs lean, pistons melt, gaskets go etc etc

They have been pretty much dropped by most professional tuners now who know more about turbos and they will fit boost controllers linked into fuel regulators, ECU's, uprated waste gates/actuators etc to ensure that when the boost goes up it don't exceed predetermined levels.

HTH, Aaron.
 

HP

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GhostWKD said:
Cant quite get my head around this bleed valve stuff so you'll have to bear with me :eek:

So if a bleed valve is the crude way to manage boost what would be the effective/proper way to manage the boost? as from what i can understand it will otherwise just boost to x amount (x being determined by the actuator) also, is the actuator adjustable or will it be a fixed variable?

Thanks all for your help :D hope its as useful to bushboy as it is to me :eek: :p

Edit: oh and dont worry i do have a boost gauge :p think the UT has one as std, mk2 one does anyway :D

If the bleed valve is not already completely closed, then removing it will reduce the boost pressure.

Running with the actuator pipe disconnected or broken (one between turbo housing and wastegate) will make it run the maximum boost that the turbo / induction will produce as the wastegate will not open.

The wastegate is a bypass for the exhaust gas, so the gas goes around rather than through the turbo.

Mine has a threaded rod on the actuator, so I can adjust the boost pressure that way. Shortening the rod increases the boost, lengthening it decreases boost.
 
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Bushboy

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been reading through this and im kinda lost.

car does have a boost gauge but to be honest, i dont want to play around with it just yet.

if i remove the bleed valve and replace the hose. the car will take care of itself right? obviously if its boosting to stupid levels ill get it checked out but will it be ok for me to just take it straight off without any other tinkering?

to be honest ide rather have the turbo bit back to standard rather than little add on bits to make it quicker. ide rather go the route of tunning the engine, not the turbo becuase as I see it, the turbo is likely the most unreliable part of the engine so I would rather it not have to work as hard when the engine can do the rest of the work :)

plus its bloody quick enough as it is without silly valves :)
 

HP

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Right, I've been away for a few days so I don't know what car you've bought, what boost it's supposed to be running and what it's running now.

Bleed valve should increase boost, should not be able to reduce boost. If you remove it and join up the hoses in and out of it, the car should run at the boost it was made to run at.
 
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