Outer Limits 4x4 Board

does any one now how to make a blow off valve work on a 12ht its all hooked up but not sure were to connect the vacuum to tried a couple spots but didnt work :( some one please help

Why are you putting a blow off valve on your 12HT?

ahhh, yeah. No need for a blow off valve unless you have really long intake runners and intercooler........

62series wrote:does any one now how to make a blow off valve work on a 12ht its all hooked up but not sure were to connect the vacuum to tried a couple spots but didnt work :( some one please help

What makes you think it's vacuum actuated....

Shaun05 wrote:Why are you putting a blow off valve on your 12HT?

This is the question we need answered.

You sure its not either a waste gate?
Fuel compensator?

Most likely a boost controller? (i.e. lets off pressure at preset maximum?)

62series wrote:does any one now how to make a blow off valve work on a 12ht its all hooked up but not sure were to connect the vacuum to tried a couple spots but didnt work :( some one please help

to run a bov on a diesel you need to use system vacuum and use throttle/clutch switches to activate a vac solenoid which then feeds vacuum to the bov. usually need to play with the BOV springs to match the vac thats supplied.

The big question has been asked before: WHY?

the only reason you need to run a BOV on a diesel is if you are getting boost spike, usually happens on gear changes if you have a very looong... intake runner/intake system (usually combined with an intercooler)

If you are not getting boost spike, putting a BOV on will probably decrease performance as the turbo will have to build up pressure again....

turbo loses all boost pressure anyway due to lack of drive. it builds back up after every gear change with or without bov.
only difference bov should make is turbo won't slow down so quick as it doesn't have boost trying to go back through the wrong way.

if it will make any difference to driving the vehicle ???
that will depend a lot on how poor the turbo is, how much boost, size/weight of vehicle and driving style.
theres a few vehicles that do gain a bit but IMHO not worth the $$$.

only difference bov should make is turbo won't slow down so quick as it doesn't have boost trying to go back through the wrong way

This effect is most pronounced on a petrol engine. When the driver lifts off the accelerator pedal, the throttle plate being suddenly closed creates a spike in boost pressure, as the compressor charge is left with nowhere to go.

A diesel (the vast majority anyway) does not have a throttle plate. During normal operation, there is a clear path between the compressor and the cylinders. There is really no need for a blow off valve in this situation.

I had to put one on my 75ser 2H turbo as it made some awful noises when changing gears. Apparently the pressure that pulses back through the turbo can spin the compressor wheel backwards, unwinding the nut that holds it on and turbo gets breaky breaky, goes bang bang bang and bye bye engine.

You can only (and only need to) run a blow off valve on an engine with a throttle body. I didn't think the 12ht runs a throttle body, so it would not need one, could be wrong tho.

Rowen

No throttle valve on the 12HT. There is a throttle plate that is used only to shut off air to turn the engine off, not used for any other reason.

craz3d wrote:

Shaun05 wrote:Why are you putting a blow off valve on your 12HT?

This is the question we need answered.

100 free ricer horsepower points with every BOV!!!

Clanky wrote: 100 free ricer horsepower points with every BOV!!!

With all due respect, they do serve a purpose as they are factory fitment on most turbo applications although plumbed back into the intake. I'm not really a fan of a car with a cold either... Achoo

BadMav wrote:

Clanky wrote: 100 free ricer horsepower points with every BOV!!!

With all due respect, they do serve a purpose as they are factory fitment on most turbo applications although plumbed back into the intake. I'm not really a fan of a car with a cold either... Achoo

Turbo petrol - yeah
turbo diesel - ummm no. On a 12HT it will serve no useful purpose other
than eye candy

Sell your Cruiser, buy a suzuki swift with a turbo and a blow off valve and drive round maccas carpark carrying on like a tool box, and leave 12HT engines for real blokes

P.S. You idiot

Clanky wrote:

BadMav wrote:

Clanky wrote: 100 free ricer horsepower points with every BOV!!!

With all due respect, they do serve a purpose as they are factory fitment on most turbo applications although plumbed back into the intake. I'm not really a fan of a car with a cold either... Achoo

Turbo petrol - yeah
turbo diesel - ummm no. On a 12HT it will serve no useful purpose other than eye candy

BadMav wrote:You can only (and only need to) run a blow off valve on an engine with a throttle body

Any engine that runs a throttle body whether it be petrol or diesel and producing any decent amount of boost will suffer the same when the throttle slams shut. Most diesel engines are not set up this way and therefore don't need them and can't actuate them anyway, they require a vacuum signal combined with the boost to open it.
I said it before:

BadMav wrote:I had to put one on my 75ser 2H turbo as it made some awful noises when changing gears. Apparently the pressure that pulses back through the turbo can spin the compressor wheel backwards, unwinding the nut that holds it on...

So...
Turbo petrol, yeah
Turbo Diesel, where applicable.

my old hj45 with the H diesel-(vac gov,t/body)(custom exhaust manifold with 180sx turbo) used to get boost spike when changing gears as you would see the boost reading rise when you took your foot off the accelerator to change gears but was only 2 psi spike and it was only on low boost like 6 psi. Some big trucks get them put on, owners choice really

fumduk3 wrote:my old hj45 with the H diesel-(vac gov,t/body)(custom exhaust manifold with 180sx turbo) used to get boost spike when changing gears as you would see the boost reading rise when you took your foot off the accelerator to change gears but was only 2 psi spike and it was only on low boost like 6 psi. Some big trucks get them put on, owners choice really

You turboed a H motor? I want to throw mine away.

i was a diesel fitter apprentice on $6 per hour and was bored. there are no manifolds for them obviously so i made my own custom steam pipe one actually looked like a bought 1 turbo bolted on from side(dunno how 2 post pics here) and it went better/faster than a 2H not that they go fast but you no what i mean and used no more fuel

He probably likes the sound....

My 12ht with a straight through 3 inch and 13 pound boost sneezes every gearchange no bov.

Sounds like a bloody truck.

Its kinda grown on me now though.

Now i can mix it with the ricers

not sure about a bov i know that i would get sick of hearing ffss very time i change gear. hahah just my opinion.

on a deisel it is called a over boost valve and it is used to release excess boost and can be adjusted to suit the boost that the turbo is set to .it is not vacume operated it is opened by boost presure that forces the dieaphram to open and they are factory fitted to a lot of late model deisel like gu 3ltr etc

crazy eyes wrote:on a deisel it is called a over boost valve and it is used to release excess boost and can be adjusted to suit the boost that the turbo is set to .it is not vacume operated it is opened by boost presure that forces the dieaphram to open and they are factory fitted to a lot of late model deisel like gu 3ltr etc

no overboost valve on the gu 3ltrs. it generally the older motors such as thee SD33 and they are set a lot higher than factory boost. its only there in case wastegate jams.