Anti-Boost: Keeping others under control

[Adrenaline406]

Im looking to be stage 4 by summer. Whats left on the list: DP, Turbo (15t), and the chip itself. The thing is, i would like to be able to let other people drive my car without them finding out what 300 fwhp feels like (mainly dont trust my dad haha). I've heard you can do this with a MBC, but as I sit here thinking about it, im not sure thats the case.

Any ideas short of making a turbo bypass?

[JK]

first off, stage 4 isn't going to be 300whp, it will be around 255-270 whp.

To limit boost you could just unplug the BPC and run base boost, or if your car is Trionic 5 you can stick a manual boost controller in there and turn the boost down (just be sure to also unplug the BPC or you can fry it - I've done this twice now )

[slspf2]

Originally Posted by Adrenaline406

Im looking to be stage 4 by summer. Whats left on the list: DP, Turbo (15t), and the chip itself. The thing is, i would like to be able to let other people drive my car without them finding out what 300 fwhp feels like (mainly dont trust my dad haha). I've heard you can do this with a MBC, but as I sit here thinking about it, im not sure thats the case.

Any ideas short of making a turbo bypass?

You could get another ECU and swap it in for the tuned one (takes only a few minutes)... but then you run the risk of being dangerously rich or lean.

[Castor Troy]

install a switch that opens the BPC circuit, limiting the car to base boost

[mcrowley]

Originally Posted by JK

To limit boost you could just unplug the BPC and run base boost

Thats what I would do. Quick and easy.

[JK]

Originally Posted by slspf2

You could get another ECU and swap it in for the tuned one (takes only a few minutes)... but then you run the risk of being dangerously rich or lean.

No you don't.

You can run a stock ECU in a car with stage 4 hardware with no problems at all. Bad/misleading info with that statement

[Adrenaline406]

So okay, i have a dual stage/switched mbc right now, are we talking about just opening that thing up all the way, that shouldn't work, as then it would be just turning it back into an open pipe, therefore running off of the ecu again. Might as well have no mbc at all.

And unplug the BPC? how so? do you mean one/several tubes or the electrical connector? JK, what were you doing that killed a couple of these things?

So there are three tubes, one to the wastgate, one to the turbo housing and... im not sure. But it seems like in all of these cases using an mbc will cause the bpc to think boost is lower than it really is. Not higher.

Thanks

[codesplice]

Originally Posted by Adrenaline406

So okay, i have a dual stage/switched mbc right now, are we talking about just opening that thing up all the way, that shouldn't work, as then it would be just turning it back into an open pipe, therefore running off of the ecu again. Might as well have no mbc at all.

And unplug the BPC? how so? do you mean one/several tubes or the electrical connector? JK, what were you doing that killed a couple of these things?

So there are three tubes, one to the wastgate, one to the turbo housing and... im not sure. But it seems like in all of these cases using an mbc will cause the bpc to think boost is lower than it really is. Not higher.

Thanks

Unplug bpc == electrical connection.

With no power, it can't control t3h boost.

[Palmer]

If you wanna get fancy, you could hook a switched evap purge valve into the wastegate line.


I think Eric did something like that on his red viggen.

[Castor Troy]

palmer, wouldnt that do the same thing as putting in an MBC, cause cause the bpc to go on the fritz?

i still think a switch to open/close the BPC electrical connection is the easiest/cleanest way to do it

[Palmer]

I swear someone has done it.


I rigged up a BPC switch on my C900. It worked very well.

[StX221]

It was eric on his red ng with the vig bumpers.
Cant find his site now...

Edit: here you go http://www.ericsaabsite.com/Upgrades...stControl.html

[JK]

What eric did (from what I remember) is use the valve to switch between manual boost control and BPC boost control without having to physically remove the MBC.

The way I fried my BPCs was by plugging in a MBC without unplugging the electrical connection to my BPC.

I had a working BPC, installed my MBC. I drove it for about 20 miles before I remembered that I had not unplugged the BPC. I took the MBC out and hooked the vac tubes up to the BPC and it was already too late, it was stuck wide open. For some people this does not seem to happen, but it happened twice for me.

[NahumCC]

Just unplugging the electrical connector to the BPC is the quickest route and will do the job.

[JK]

Originally Posted by NahumCC

Just unplugging the electrical connector to the BPC is the quickest route and will do the job.

Yes, easiest, most simple, and very effective. K.I.S.S. is the best method in my opinion. No sense in making things complicated just for the sake of making them complicated

[Castor Troy]

yes, unplugging the bpc is the simplest route, but having to pop the hood every time would be a pita, plus the wear on the connector.

[JK]

A person with a tune or custom go-fasties should be checking fluids and the general state of things under the hood once a week anyway. I don't think wear will be a factor on the connector. Keep a bit of dielectric grease on it and I bet it wouldn't wear at all.

[slspf2]

Originally Posted by JK

No you don't.

You can run a stock ECU in a car with stage 4 hardware with no problems at all. Bad/misleading info with that statement

Are you trying to tell me that with a bigger turbo, bigger injectors, new fuel pressure regulators and a stock tune you would be perfectly fine? I'm currently running full exhaust, intake, and intercooler and am leaned out like you wouldn't believe. "Bad/misleading" info for telling him that that would be a safe route...

[b dash rian]

ya, stage 4 hardware on a stock ECU makes for an unhappy car. Fuel cut happens faster than you'd think, and suddenly you're biting the steering wheel. I know from experience

[JK]

Originally Posted by slspf2

Are you trying to tell me that with a bigger turbo, bigger injectors, new fuel pressure regulators and a stock tune you would be perfectly fine? I'm currently running full exhaust, intake, and intercooler and am leaned out like you wouldn't believe. "Bad/misleading" info for telling him that that would be a safe route...

You've dyno'd it?

I ran a TD04 15T and FMIC w/ 3" exhaust on a trionic 5 car with a boost controller set at 17psi. Ran rich, dyno proven, in fact it ran more rich than my car does with the stage 4 ecu.

That's my experience, and there are others out there who can echo that. We have to be comparing apples to apples though, and trionic 7 might differ because of having different sensors and uses a different method to make power.

Originally Posted by b dash rian

ya, stage 4 hardware on a stock ECU makes for an unhappy car. Fuel cut happens faster than you'd think, and suddenly you're biting the steering wheel. I know from experience

How did you hit fuel cut? I don't understand how 3" exhaust and a aftermarket intercooler would cause a person to hit fuel cut. Even adding a TD04 15t to a car with a tune for a t25 or gt17 should not cause this, as fuel cut is related to manifold pressure (at least on T5 it is).

The TD04-15t is still a very small turbo, they might be a bit larger than a t25, but its really pretty minimal. My AFR hardly changed at all when I made the switch to a TD04.

I was at 10.5:1 with the t25 @WOT and around 11.0:1 with the TD04 @WOT.