Manual Boost Controller and wastegate adjustment

[306Puggy]

Right, first let me say, wow! An MBC really IS a great improvement. There is next to no turbo lag now and the boost flies all the way up without slowing down when the wastegate starts creeping! I think that the manual boost controller overrides the wastegate as on the lowest setting of the MBC I am getting a peak boost of 17 psi when before I was getting 14.5 psi which is standard. So as I understand it I do not have to touch the wastegate anymore, correct?

[Tom]

Correct i think.

[con67]

Yes wg standard and mbc does the work, it is a great improvement over shortening the bar!

[306Puggy]

Heh, KKK K14 turbo on mine anyway so it's even more of a faf to adjust than a T2 which has a bar to shorten! Loving it so far!

[Mattcheese31]

Heh, KKK K14 turbo on mine anyway so it's even more of a faf to adjust than a T2 which has a bar to shorten! Loving it so far!

i would say K14 is easier to adjust than a T2 . . . .go figure . .

[Piggy]

k14 is so easy to adjust!

takes me about 4/5min max and thats with jacking the car up for better access!!

[306Puggy]

But it doesn't work for over 19psi it is dangerous and will blow your turbo. You can adjust an MBC from inside the engine bay and it is the proper way to set it up. Also with the other benefits it absolutely flies and I'm only running 17 psi!

[cwspellowe]

Right, but if you dont add preload you'll only get so far with an MBC until exhaust mani pressure starts to force the wastegate open

[306Puggy]

Damn, I didn't think of that! So I have to add preload to the spring in the wastegate still? I was under the impression that the MBC completely overrides the wastegate, but now I think about it like you said there is nothing to stop the exhaust gases in the mani. What is the best setting to have it on? Just screwed all the way in?

[con67]

Right, but if you dont add preload you'll only get so far with an MBC until exhaust mani pressure starts to force the wastegate open

I didnt get this on my k14 even when I put the 30psi gauge right round to vacuum.

---

Damn, I didn't think of that! So I have to add preload to the spring in the wastegate still? I was under the impression that the MBC completely overrides the wastegate, but now I think about it like you said there is nothing to stop the exhaust gases in the mani. What is the best setting to have it on? Just screwed all the way in?

Just stay below 40psi and you'll be fine!

[306Puggy]

Cool, thanks con.

[CJ_Derv]

Welded WG FTW lol

[306Puggy]

That means that you can't adjust the boost though :\

[Tom]

You can only give the car enough fuel to make so 24psi. Thats how welded gate people do it, through fuelling.

[CJ_Derv]

That means that you can't adjust the boost though :\

I can by adding or lowering fuelling im happy with 28psi atm and when resealed manifold upping to 35

Then will be looking at 40psi with 11mm and devilsown kit

[306Puggy]

Heh, nice if you've got a spare engine handy I suppose! Thing must fly. So there is no benefit to an MBC for the people going for a high power tune then? I always thought an MBC was the "proper" way of adjusting the boost, seems like I needn't have bothered But then I don't know anywhere that does welding or how I would get the turbo there without my car working so...

[Mattcheese31]

MBC is the proper way of adjusting boost but not always the easiest, it's hard to fit the wastegate in near the bulkhead with a TD04 for instance . .

[con67]

I would go the effort of having a working wg, you aren't controlling boost with fuel your limiting fuel with boost imo. eg 2 identical cars, or the same car different time one wg one without, the turbo/engine/ic etc is capable of say 24psi, thats the limit, anymore the turbo breaks or doesnt add air, the wg'd car will be able to run more fuel and be faster......no?

[cwspellowe]

De-wastegate: Car can produce as much boost as it wants as it's deregulated. It also means every last drop of exhaust gas spins the turbine, which produces silly heat and can drastically shorten turbo life. All the while the turbo is spinning up at silly high speeds, the compressor isn't efficient enough to flow more than a maximum rate of air, so while the turbo is running itself into an early grave, there's no real benefit past a point. Welding wastegates just means faster spool and crazy bad heat/stress

Wastegate and MBC: wastegate stays shut until the desired boost pressure is reached, pretty much no wastegate creep, turbine spins up to peak RPM's for your desired boost pressure, excess EM pressure is diverted out the wastegate and down the exhaust, turbo is happy for a long time. It also controls boost very well, as opposed to a de-wastegated blower that does whatever the f*ck it wants until it decides to overspeed the turbine, bits break and everyone gets sad.

Ruan will back me up on this. If you want big boost pressure, fit a stronger actuator spring and an MBC. Don't just de-wastegate it, i'm the king of all rednecks and even I wouldn't do that after learning the hard way.

/rant