NewHilux.net

Hi, does anyone know how to fit a Blow Off Valve on the D4D engine? and where would it go.
Cheers Metin.

what is the purpose of a blow off valve

It relieves the pressure from the turbo system at high RPM when the throttle valve is closed suddenly. It helps prevent wear and tear to the turbo and allows better gear shifts.

contact this guy, he must know how to install one

http://www.newhilux.net/rides.php?id=594

Ooh gross. Don't blow it off... Plumb it back.

I am so heavily against BOV's. Why decrease your performance just to sound cool

Ok, Where would i put it. I cant see enough space between the throttle body and the intercooler. any suggestions?

Just bringing to the top

Not sure on our engines, but I used to have a few petrol turbo cars, and the blowoff is designed to allow the release of air between the compressor housing of the turbo, and the throttle body.
This is useful (and increases performance) when the throttle is closed or reduced suddenly when changing gears at full boost - the turbo rpm does not drop as much, and the turbo is closer to boost rpm in the next gear, I found it to make a big difference.

NOW,

This won't work on normal diesels, as there is no "throttle flap", the rpm is controlled by injection of diesel, which draws more air as a secondary effect.
A petrol increases rpm by allowing the engine more air, which is then matched by the computer adding more fuel to obtain the correct mixture.
So with no throttle flap you have no real obstruction requiring venting of intake piping air,
AND
with no throttle flap you have no vacumn created in the plenum chamber / intake manifold to enable the actuation of the valve..
(the blowoff valve plunger is sucked open by the vacumn in the intake when the throttle flap is closed at high rpm..ie. engine trying to draw in air, but throttle butterfly is closed, so none can get in, creating a strong vacumn..)

Also the reason diesels need a vacumn pump to operate brake boosters and other vacumn actuated equipment. A diesel has no natural vacumn, unlike a petrol engine.

That probably makes no sense, but is the explanation as to why you can't have a blowoff valve on a diesel.

Sam.

makes allot of sense, but i thought that our engine has a flap! because it has a sensor for the position. or am i wrong.

Metin

I'm pretty sure most (if not all) diesels lack the severe back pressure that you need a BOV to protect against. Mostly due to a lack of a throttle plate.Even if you could somehow get one to work. It would be mostly pointless.

Alternative: [url]http://www.sunamiturbo.com/sunamiturbo.html[/url]

Shrek.
Bloody funny mate.
I also though the lack of a diesel to backfire unlike a petrol because the mixture is injected directly into the combustion chamber at maximum compression in the with the valves closed is the other reason why a blow off valve is unnesisary. I am assuming a blow off valve is the same as a waste gate. I have noticed though that under heavy acceleration the diesel tends to hang on to its rpm for a split second before running down to the next gear.
When I line a WRX up at the lights in the d4d i always scream PITSHHHH!!!!!!, when I back off the throttle to change gear. My fiance always looks at me like chopped liver when ever I do this.
Skog

HH, you are definately correct .. However, the D4D Common Rail engine has a Thottle Flap... You will notice there is no vasumm pump on your alternator... The new EFI Common rail diesels are basicly set up the same way as an EFI petrol engine except the the "SPARK" is created through higher pressure rather than a spark plug.

This subject has been discussed before... look here
http://www.newhilux.net/phpbb/viewtopic.php?t=688

Cheers TOMUCH

Here is a pic...



Cheers TOMUCH

Could you probably use the vacuum line for the EGR valve with a T piece?

The throttle plate is a shudder vavle and does not work like a petrol car it is only there on a d4d to stop vibration when turn the car off and on decel.

i also tried the blow valve and it will not work cause you will not able to control the vacum so the blow valve will open when under booast that not good.

What type of bov did you use? is it possible that the boost capacity of the bov was lower than what the turbo put out? e.g spring strength..

Yeah tried that we cut the spring and the valve would open before it would hit 15 psi. check this with a booast/vac gauge there is no vacum in the intake at all only when can is shut off the blow off vavle will not work unless you hook up a stiwch on your throttle pedel which would go to a vacum solnoid, swiching vacum from the vacum pipe.

I think if a blow off valve (wastegate) was worth doing someone would be exploiting all those boy racers who want to race their d4d. Get a wrx if you want to go woooooosh
Has anyone mentioned that diesel engines don't like to rev hard? That's why they have low down torque.