EJ1 wilcox

I have been having some problems getting my MBC to work and I'm thinking maybe I need to try hooking it up differently.

A little info on my setup... basic d series turbo setup, T3 turbo, Drag mani, Tial wastegate with a .5bar (~7 psi) spring. I originally ran my wastegate signal from the compressor housing which would yield about 6psi total, due to pressure loss through the charge pipes and intercooler.

My goal with an MBC is to raise the boost to 10psi. <---shouldn't be that hard right?

Here are the configurations I've tried (none of which worked, every time I have tested them the boost has gone up to 13+ psi when I let off the gas)

1. compressor --> TurboXS MBC --> wastegate
2. intake manifold --> TurboXS MBC --> wastegate
3. compressor --> TurboSmart MBC --> wastegate
4. intake manifold --> TurboSmart MBC --> wastegate
5. intake manifold --> wastegate (this is how I have it now, nets about 7-8 psi but I want more!)

All of these configurations were done with the signal hooked up to the side port of the Tial and the top port open.

I sold my TurboXS because I couldn't get that to hold 10 psi and bought the TurboSmart, which I also can't get to hold only 10 psi, so I took that off too...

**My question is this! How do you have your MBC hooked up with your external wastegate? Like I did with the top port open? Or, like the Tial instructions below?**

Both the TurboSmart and TurboXS instructions show a simple installation of the MBC between the vacuum source and wastegate (like I had it).



I would have already tried the Tial way but I don't have the fitting for the top port on my wastegate, plus it would hit my hood if I installed it.

How do you have yours?

093turbo16

iTrader: (2)

you can just put the boost controller in line with the bottom port. Get the source from the manifold or the turbo, doesn't matter too much. Then just put the MBC in line with the bottom port.

Boltz

Yea you dont need to run the top port on the Tial. Is it a basic MBC of are they the HPMBCs with two ways to adjust?(ball and spring, and bleeder)

Sounds funky, sure its hooked up right ?

Either get it tuned at 13psi or do what some guy was posting a few weeks ago. Use a 12psi radiator cap to bleed off excess pressure past 12psi. What manifold are you running?

EDIT: I would say take the MBC apart and make sure nothing is sticking but you have already had the same problem with 2 boost controllers

Check silly **** like vacuum lines to and from the BC to make sure there isnt somehow something inside the lines, open up the WG and make sure everything is ok. It sounds like an install error because at the lowest BC setting you should be running right off the wastegate.

EARLdaSQUIRREL

you sure you have the boost controller facing the right way, id either loosen up the controller all the way so it stays at stock boost then slowly turn it to increase the boost

i love my tial 44mm hold boost rock solid

EJ1 wilcox

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boltz &raquo;</TD></TR><TR><TD CLASS="quote">Yea you dont need to run the top port on the Tial. Is it a basic MBC of are they the HPMBCs with two ways to adjust?(ball and spring, and bleeder)

Sounds funky, sure its hooked up right ? </TD></TR></TABLE>

I'm positive that I hooked them up correctly as far as the inlet/outlet goes.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boltz &raquo;</TD></TR><TR><TD CLASS="quote">Either get it tuned at 13psi or do what some guy was posting a few weeks ago. Use a 12psi radiator cap to bleed off excess pressure past 12psi. What manifold are you running?</TD></TR></TABLE>

I'm not even sure it would hold 12psi... when I let off the gas I couldn't hear the wastegate opening at all, so I don't know how far it would have gone up. It's a stock engine so I don't really feel comfortable tuning it much past 12, especially with the stock MAP sensor. I am working on a built engine but it won't be done for a few months, I need this one to last until then.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boltz &raquo;</TD></TR><TR><TD CLASS="quote">EDIT: I would say take the MBC apart and make sure nothing is sticking but you have already had the same problem with 2 boost controllers</TD></TR></TABLE>

I took them both apart and they are fine.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boltz &raquo;</TD></TR><TR><TD CLASS="quote">Check silly **** like vacuum lines to and from the BC to make sure there isnt somehow something inside the lines, open up the WG and make sure everything is ok. It sounds like an install error because at the lowest BC setting you should be running right off the wastegate.

</TD></TR></TABLE>

I have tried a few different sizes of vacuum line. Orignally I had some line that I think was too big, so I replaced it with smaller tubing without any sucess.

I think I am going to pick up some more tubing today, this time I will get the absolute smallest ID tube that I can fit over the barbs. The tial instructions say that the line has to be a minimum of 6mm ID, which is pretty large.

Boltz

Thats pretty weird man. Unless I was there I dont know what else I could help with.

If i think of anything ill post back up

EJ1 wilcox

Would the size of the vacuum line make that much of a difference?

And if so, what would be better to use? Smaller tubing or larger tubing?

BlackCRX

bump, i would like to know this as well
currently running 7psi and plan to hit 10psi next season

i thought the picture you posted was the correct way ?? i know a few ppl running it this way with no spikes or creeps

igo4bmx

have u tried another mbc to eliminate the possiblity it is the mbc itself?
maybe u can fab up a homedepot special and try that too

EJ1 wilcox

Okay,

Yesterday I bought some really small tubing, the smallest that would fit over the barbs on the MBC.

This morning I hooked the MBC up with the super small tubing, which was very hard to fit over the wastegate barb by the way because it is so small.

On the way to work I tested it out a few times with some weird results. The first time I tried it out was in 3rd gear. The boost spiked to 12 and then held at 10. Yay! I'm thinking I have the problem solved.

So I shift into 4th and stay on the gas while watching the boost gauge... again, it spikes to 12 and settles at 10... then at about 6000 RPMs it shoots up to 15 psi and I let off the gas.

I tried it a few more times on the way to work and each time it did the same thing... spiked to 12 initially, then held 10 for a few thousand RPM, and towards the top of the RPM range it spiked up to 15...

I'm wondering if the problem with spiking and overboosting might be due to the poor design of my Drag manifold. I don't know what else it would be...

Anyways, I think I am going to get rid of this boost controller and just buy wastegate springs from now on.

fjt

I have a turbosmart MBC..
I have a line from the Intake Mani to the MBC and a line from the MBC to the WG port... thats it.

Dr. D-Series

Mine is the same way as fjt's.
Im using an ebay ball spring mbc.
I basically cut my spring in half though, because my boost would fly to 15+.
Now im at 11 psi, and I cant lower it any more than that without cutting my spring more.

I am using a ebay fake tial WG with 7 psi spring.