MBC - Bleed valve - Opinions?

Malt_Vinegar

Malt_Vinegar

Malt_Vinegar

Don
Joined
20 Oct 2002
Posts
17,050
Location
In a house
Whats the best?

Bleed valves are cheaper, but my mate with a tuned 220 turbo is telling me that they are better than an MBC?

He also said, dont touch the actuator, as it was a bad idea.

I have a decent boost gauge on the way, and this should let me see exactly what my car is making. Once i have this in i want to up the boost a bit and see how well things go :p Oh, and why does the price of bleed valves seem to vary so much, all they do it leak to atmosphere through a valve right?

Im more interested in useable power and boost, not a massive kick up the bum as the turbo goes nuts!

So, whats the best option?
 
Would that be a Rover 220 turbo?
Can't imagine what the argument would be for having a bleed valve over a manual boost controller; they're simply not as accurate and more prone to spiking.
 
Dont bother with a bleed valve as said, they can cause serious spiking. Get a grainger valve they are cheap and dont bleed off any boost and hold solid boost.
 
I agree with Bear.

I've had both a bleed valve and a grainger valve on my previous cars and the GV is far better at holding boost steady.
 
Malt_Vinegar said:
Whats the best?

Bleed valves are cheaper, but my mate with a tuned 220 turbo is telling me that they are better than an MBC?

He also said, dont touch the actuator, as it was a bad idea.
Click to expand...

Your mate is talking out of his fudge pipe, and obviously has no clue.

Grainger-Valves/MBCs are MUCH better than a bleed valve. A bleed valve is always bleeding air from the actuator, and can cause spiking etc.

An MBC only opens at target boost, ie. the actuator stays shut untill target boost is reached. Not only does this give you better boost control, it also makes the car feel faster because all the boost is delievered in one 'hit' due to the actuator being closed untill target boost is reached.
 
MBC is much better, be warned though they bring the boost is very quick. On a front wheel drive full throttle usually lights the tyres up :p

I'm using a MBC with a ceramic ball bearing (better response), the boost comes in too hard for the wet, nothing that can be solved by a bit of throttle control though :)

You can modify the actuator(change preload, add springs etc but this can cause boost spikes or boost creep. So he is right in saying to avoid that.
 
Ahh, i seee...

So, the bleed valve is just an adjustable perm bleed from the pressure line to the atmosphere.

The MBC actually holds the actuator untill full pressure is reached, then lets fly, so you get no boost - then full boost?
 
Malt_Vinegar said:
So, the bleed valve is just an adjustable perm bleed from the pressure line to the atmosphere.

The MBC actually holds the actuator untill full pressure is reached, then lets fly, so you get no boost - then full boost?
Click to expand...

Yep, that's it in a nutshell :)
 
Aye it aids spool up as the wastegate doesnt start to creep open until the boost is enough to act on the ball bearing against the spring. It gives the effect of BAMMM loads of boost, great for overtaking :D
 
You must log in or register to reply here.
Back
Top Bottom