Boost Controller Question

[Jay2525]

Hey,

Been reading through all the threads regarding MBC and have found it all very helpful, but just a few things im not 100% clear on.
When setting up where do you start tuning from, completly wound down or middle? How much do you open it, is it possible to open it up to much, or is it a case of if its open to much fuel cut will kick in?
When fuel cut hits in 3rd and near red line does that mean you have reached max boost?
Garry if you read this I know I could just ask your dad but didnt want to bother with with something so trivia and simple.
Thanks

[Davezj]

you will probably hit fuel cut at about 4-5k revs not red line.
it should feel like you have lost all power and if you keep your foot down it will come back in a second or so, it will seem much longer, but doing this is not advisable.

[Jay2525]

That is if the valve is open all the way?

[elnevio]

Depends on the type of MBC, as to whether it needs winding in or out to increase boost. However, if it is new, it *should* be shipped to you in the safest position, i.e. no boost increase. Ideally, you want to measure things like the air fuel ratio while messing with the boost. Realistically, you should at least be using a boost gauge to see what boost you are hitting as you adjust it.

When I fitted my MBC nearly four years ago, I opted for the approach of turning it one turn between each test, until the boost started showing signs of increasing, then by doing it half a turn each time, until the desired boost was achieved. Good thing that I have a 5 mile private test track near me with a lay-by almost every 3/4 of a mile!

And I also agree with Dave, fuel cut will be around 4-5k rpm.

[Jay2525]

Yes i have boost gauge, so how do i know when desired boost is achieved?

[elnevio]

Well, what boost do you desire?!

You are likely to achieve peak boost around 4-5k rpm (hence why this is usually where you hit fuel cut). The sort of boost where you start hitting fuel cut varies, but anecdotal evidence suggests this in the region of around 13-15 psi (or about 0.9-1.0 bar).

[Jay2525]

Ok to put it a different way, it seems average to then by these comments to hit fuel cut at 4-5 rpm, is this the norm then? so basically i crank it until this happens?

[elnevio]

Yes, it is the norm, for the reasons given above. And yes, cranking it up until fuel cut is hit will work. You'll need to dial it back a bit so that you don't hit it.

Just remember that when it comes to the winter months, you may find you'll need to dial it back a bit more, as the colder denser air means you are more likely to hit fuel cut at slightly lower boost. This is because the ECU does not look at boost when determining to protect the engine with fuel cut, rather a function of the air volume/flow (or something like that - but not boost directly).

I would still want to be getting it onto a rolling road as soon as possible once it's set up, just to be sure that everything is running as it should.

[Ryan]

Ok to put it a different way, it seems average to then by these comments to hit fuel cut at 4-5 rpm, is this the norm then? so basically i crank it until this happens?

Pretty much. You'll know when you hit it!

(A RR as Nev suggested is a good idea, the procedure results in some useful information).

[Confused]

Yeah the usual technique is to crank it up until you hit fuel cut, then drop it a bit until you don't, just as Nev said!

[Jay2525]

Ok, this is what ive got for now until i get some dollar
Now im confused as theres 3 points on the t piece and 2 on the controller and of course one pipe to fit to?? Does one get blanked off? Sorry another noob question
Ive nicked someones pics of here, if some anyone could give us a bit of guidence would be appreciated,!BdsDERg!2k~$(KGrHqUH-DsErgrIt5JNBK6CZM48sg~~_12.jpgDSC00111.JPGE_2.jpg

[fassi1]

Dont want to start new thread so will ask here.
Is that gonna be the right EBC for VR4
http://cgi.ebay.co.uk/ws/eBayISAPI.d...tchlink:top:en

[elnevio]

Just about any EBC should be okay for the VR-4, as they do the same function. That one is clearly a good brand - don't if anyone has on here has used that exact model though. Looks all right to me though! And you seem to have enough wiring and boost piping, depending on where you mount the various bits.

[Davezj]

Ok, this is what ive got for now until i get some dollar
Now im confused as theres 3 points on the t piece and 2 on the controller and of course one pipe to fit to?? Does one get blanked off? Sorry another noob question
Ive nicked someones pics of here, if some anyone could give us a bit of guidence would be appreciated,!BdsDERg!2k~$(KGrHqUH-DsErgrIt5JNBK6CZM48sg~~_12.jpgDSC00111.JPGE_2.jpg

if you are only just buying a MBC now and have been only been running stock boost until now, you should not have been hitting fuel cut with a factory stock boost level, if you are then there is something wrong with your car. You should fix this before fitting and MBC.

on the question of MBC though.
Is that the exact one you have?
chack the arrow direction on yours.
if that is the exact one you have bought (£13-£15 for ebay) then it is very cheap and can be quite nasty. the build quality is not very good on these type and it can be a bit hit or miss if they work correctly.
Read the instruction very carefully as some have arrow on T pice pointing to the waste gate and some say the arrow point away from the wastgate, this was due to a manufacturing cock up i believe. so rather than building then correctly they changed the instruction.

Basically the ball and spring part of the valve is in the T piece and the air bleed control part is in the other bit, so you have to use both parts. Don't do do what some have done a use a different T piece thining the suppied T is just a straight throught T piece.

i think this is correct way to connect it up,
normally the T piece sits inline with thee factory boost pipe, arrow towards the wastegate using the silver ports, the blue port from the T piece normally goes to the air bleed adjuster to the port that is arrowed.aand the other is left open to air.
take this as just a guide, read and follow the instructions you get with the MBC.

If you have issues with the MBC or connect it up wrong then it might just open the wastegate pipe to atmosphere and allow the turbos to boost to the max they can which is bad. you should set the MBC to give min boost as a start point, then turn up the boost in small increments to the point of fuel cut then back it off a bit until fuel cut disappears. this is the max boost youcan run with this setup with out hitting fuel cut.
i am not saying you should run this level of boost it is up to you want you set it to.

before planting your foot after install, just build the boost very gently as a test in 3rd gear with little squirts of accelerator until you know the boost is being limited to a safe point by the MBC then and only then can you start to turn the boost up to get to fuel cut point.

[Nick Mann]

Dont want to start new thread so will ask here.
Is that gonna be the right EBC for VR4
http://cgi.ebay.co.uk/ws/eBayISAPI.d...tchlink:top:en

I used to have that exact model. One tuner told me never to get rid of it as it works so well! It is a PITA to set up properly, but once it is set up it is very easy to use and does exactly what it needs to.

[fassi1]

Thats exactly what i want, good and wirking properly. Pipes and wiring is no problem.