MBC Problem

[ANDYRACER]

Hi all,

Wondering if anyone can shed some light on this issue.
I have fitted a MBC to my 850R, now i can only get it to hit 0.7 bar, no matter how much i playing with the mbc.
Its defo doing something because it is so much quicker threw 1st and 2nd gear but i want 1.0 bar of goodness.
Any ideas?

[p fandango]

Wondering if anyone can shed some light on this issue.
I have fitted a MBC to my 850R, now i can only get it to hit 0.7 bar, no matter how much i playing with the mbc.
Its defo doing something because it is so much quicker threw 1st and 2nd gear but i want 1.0 bar of goodness.
Any ideas?
what make is the MBC? R-spec are a good known make & don't think i've ever heard of any problems with them

[ANDYRACER]

Its a purple version of the R-spec jobbie.

[p fandango]

does adjusting it make any difference?

if it does then i would say the internal spring can't tension up enough

if not then check & see if you've fitted it in the right way round (no offence intended, i've done it myself)

[ANDYRACER]

Ive tried another of the same mbc off my mates turbo saxo and still does the same thing, it has been fitted the same way it is fitted to my mates saxo.

And no adjusting it doesnt seem to do alot really.

[p fandango]

Ive tried another of the same mbc off my mates turbo saxo and still does the same thing, it has been fitted the same way it is fitted to my mates saxo.

And no adjusting it doesnt seem to do alot really.
if adjusting it doesn't make any difference, & you've tried another valve then i'd say its how you've fitted it tbh mate. The input for the MBC comes from the pressure side of the turbo, the output goes to the actuator. You can use both pipes straight off the BCS then block the remaining one that goes back to the air intake pipe

or could be an air leak (other problem) with the car

turbo Saxo, brave man lol

[AlanG]

I fitted mine (R-Spec) as per the instructions and found it was only useful for lowering the boost. At full adjustment it was as before I fitted it. I then spoke to Hamish at HLM and on his instruction re-fitted it keeping the factory bcs in the loop (split the yellow pipe from bcs to actuator) and now there's as much boost as you want. Mine has a re-map though.

[p fandango]

I fitted mine (R-Spec) as per the instructions and found it was only useful for lowering the boost. At full adjustment it was as before I fitted it. I then spoke to Hamish at HLM and on his instruction re-fitted it keeping the factory bcs in the loop (split the yellow pipe from bcs to actuator) and now there's as much boost as you want. Mine has a re-map though.
i appriciate keeping the BCS in the boost circuit is getting the reults you want, but with more & more people on the forum coming forward with boost issues which is more than likely to old age & the high mileage on the system i'd want it gone. For the sake of spending a bit more time trying to sort out the problem with the MBC you can then ditch the BCS & know your safe if/when the BCS does fail or start showing its age

[Dangerous Dave]

I haven't got the bcs in the line, and mine boosts more than the standard.

Could be a cbv or wastegate problem?

[callyuk]

what make is the MBC? R-spec are a good known make & don't think i've ever heard of any problems with them

thats a lie mate you no i had a problem with mine.

it got stuck open lol

[p fandango]

thats a lie mate you no i had a problem with mine.

it got stuck open lol
my bad, in my defence i have slept since then so forgot about it lol

[daveforber]

I had exactly the same problem on my V40, where the MBC wouldn't raise boost above 12psi. Turned out to be a 'loose' actuator arm on the turbo. A couple of turns on the adjuster sorted it out.

[WOODY T5]

Its a purple version of the R-spec jobbie.hi mate i ad a 850R FITTED ONE TO THAT DIDNT DO ANYTHING I THINK ITS DO TO THE ECU WITH IT BEING A 850R ITS MORE CONTROL ECU THEN MY 850 T5 I HAVE GOT ONE ON THAT ITS RUNNING JUST OVER A 16psi hope this help cheers dean

[Dangerous Dave]

If the BCS is bypassed, then the ecu has no control whatsoever over the boost. Therefore there must be a mechanical problem or air leak to cause low boost conditions, or human error.

The 850R ecu has no more control of boost than the T5 ecu, as they are the same just with different settings hence the higher bhp, they still use the same components/sensors

The actuator arm is probably the best thing to check first, as it is an easy job.

[LeeT5]

Hi all,

Wondering if anyone can shed some light on this issue.
I have fitted a MBC to my 850R, now i can only get it to hit 0.7 bar, no matter how much i playing with the mbc.
Its defo doing something because it is so much quicker threw 1st and 2nd gear but i want 1.0 bar of goodness.
Any ideas?

If your car boosts at 0.7 standard (about right as my T5 was 0.6 standard) and when the MBC is fitted your still getting 0.7 then, assuming you have fitted it correctly you have a duff MBC or it's not man enough. It won't be the BCS because if it won't boost above 0.7 then the BCS wont do anything anyway! My BCS on my T5 wouldn't let it boost above 1.1 bar.

[ANDYRACER]

Well guys checked my actuator arm and it has some play in it, are they bolted or circlipped?
And how do i go about tightening it?

[AlanG]

It's a doddle matey. Remove the heat shield above the turbo,slacken the locknut on the rod and remove the R-clip on the wastegate. Then its just a case of winding the threaded part in to shorten it. When you're happy with the adjustment,stick it back together. Job's a good 'un.

[daveforber]

...and don't forget to wind the MBC back out before trying it. You'll find it's a whole new car :D