Manual Boost Controllers

November 6, 2006

Why are these so bad, i presum its because the more you wind the more you bleed valve the more the boost goes up untill pop time. ie no rear control

If you have a bit of self control are these valves so bad, eg find the mark where your required boost level is and then dont turn it anymore

November 6, 2006

As long as you dont go silly they are alright from my experience.

I had a grainer valve on my MR2 for over a year set at 15.5Psi and it was fine and the RR showed a good healthy power curve.

Now with my ST205 i have the same type of grainer in and this time set at 16psi which is perfectly happy at the moment but i wouldnt go above that figure.

The main problem is boost creep and spikes when coming on boost in dense cold air. You find that it blips above by a few psi sometimes which is not good as you have no control over it.

I will be lowering my boost a little during the winter months due to this.

Also before upping the boost i would seriously reccomend getting the breathing sorted out with regards to Zorst and filter.

A panel filter would be better than a cone or mushroom filter unless you spend some extra monies and get it shielded from the engine heat.

So yeah.. if your a bit conservative then i believe that there is minimal risk in getting a MBC fitted.

One thing to note though.. Dont get a bleed valve... its a lot worse than a grainer valve which only costs circa £20.

November 6, 2006

I have been given a manual boost valve which hasnt been used. It has a a knob on top to turn, on the bottom are 2 inlet and in the middle is a outlet, if unscrew the knob a bit and the blow some aire though the inlets , air comes out of the middle on >> is this a bleed valve?.. i think it is

Where can a buy a grainer valve from , i have a moongoose exhaust and downpipe and a K&N filter so breathing should be ok ...

November 6, 2006

I have been given a manual boost valve which hasnt been used. It has a a knob on top to turn, on the bottom are 2 inlet and in the middle is a outlet, if unscrew the knob a bit and the blow some aire though the inlets , air comes out of the middle on >> is this a bleed valve?.. i think it is
Where can a buy a grainer valve from , i have a moongoose exhaust and downpipe and a K&N filter so breathing should be ok ...

The one you have is a bleed valve you need a relief or grainer valve.

It's not that Manual Boost controllers in general are bad but certain types i.e. bleed valves that are bad.

Bleed valves are bad because they don't really control anything they just introduce a variable hole in the actuator pipe so basically it's the same as cutting a hole in one of the boost pipes and having a great boost leak all the time.

A Relief or grainer valve works as a switch. It's basically a ball and spring inserted into the actuator pipe depending on how tight the spring is set it take more boost to "crack" the valve open and until it's open the actuator see no boost at all. This is better because it introduces actual control ie the spring adjustment and it's not just a !Removed! great boost leak.

Electronic boost controllers work on the same principle but use a Solenoid instead of a relief valve and have a closed loop control system operating the valve.

November 6, 2006

I have been given a manual boost valve which hasnt been used. It has a a knob on top to turn, on the bottom are 2 inlet and in the middle is a outlet, if unscrew the knob a bit and the blow some aire though the inlets , air comes out of the middle on >> is this a bleed valve?.. i think it is
Where can a buy a grainer valve from , i have a moongoose exhaust and downpipe and a K&N filter so breathing should be ok ...

Get your profile changed btw... :rolleyes:

I thought you had a NA for a moment.. :lol:

December 4, 2006

Hi,

Yep....DO NOT use a bleed valve!

I used to make boost controllers for sale and they can be almost as good as an EBC. The ones I used to make had two controls.....a max boost setting and a boost rate setting. I also attached a re-circulating valve that would relieve all the pressure from the line under gear shifts to ensure there was no residual pressure in the line holding the wastegate open which can happen, even with expensive MBC's, as most use a small hole to bleed this pressure and bleeding is uncontrolled.

I may still have a couple knocking about in the workshop but can certainly give advice no probs.

John

December 6, 2006

I have been given a manual boost valve which hasnt been used. It has a a knob on top to turn, on the bottom are 2 inlet and in the middle is a outlet, if unscrew the knob a bit and the blow some aire though the inlets , air comes out of the middle on >> is this a bleed valve?.. i think it is
Where can a buy a grainer valve from , i have a moongoose exhaust and downpipe and a K&N filter so breathing should be ok ...

I`ve got a Grainger valve sat in the workshop looking lonely. Supplied by K1ANO off gt4oc. If you want it it`s 15 squid posted. PM me if interested. :thumbsup: