Let's take the example of 2003 MY trucks. They need a boost elbow to restrict the vacuum pressure used to actuate their wastegates, but they also need a boost fooler to tell the ECU the turbo is making stock boost levels.

The key there is that they need the boost elbow to restrict the vacuum pressure, not hold the wastegate shut. This modifies the wastegate operation, not eliminates it. If it were a matter of disabling the wastegate, they could just disconnect the vacuum lines and run a boost fooler for ECu reporting.

 

yes a mechanical boost controller is an other route one can take, can be made from some parts from home depot for a few bucks, this i think would be a good way to limit max boost with budget in mind, as long as you have a boost guage.

I might have to check boost controllers out on my rig. i have a friend with a EBC and i can make a MBC for a few bucks. maybe ill give them both a try to see what benifits there might be if any.

 

Jrussell is exactly right. Boost foolers just alter the signal to the ECM so it does not set codes or derate for overboost. With my current set-up, I can read the boost signal through the data link with my Modis and it never exceeds 26 PSI but on my manual gauge it is 42 PSI.

 

Gassers use a boost controller to help eliminate boost creap. That is when you hit the higher gears and boost more than what is intended.... Boost creaps up to higher pressure getting spark knock. More controllable on a diesel.

 

I was the one saying the BF just modifies the signal to keep the wastegate closed longer, but still operational. jrussell is saying it keeps the wastegate shut at all times.

I get 42 PSI also with my boost-fooled truck, but I know my wastegate is still operational because the boost goes back down to 0 immediately upon release of the throttle. If the wastegate didn't work at all, it would take a few moments for the pressure to become volume again and work its way through the cylinders.

 

It does modify the signal to the ECM...in such a way that the ECM never sees enough boost to open the WG or trigger an overboost code.

The boost going back down after letting off the throttle has nothing to do with the WG. With diesels the pressurized air simply reverses direction and travels back out of the air filter when you let off the throttle quickly. This is what causes turbo bark.

The fact that two similar trucks running the same brand boost fooler will have different max boost levels proves the foolers themselves aren't controlling max boost at all. Think about it.

 

I agree turbo bark would happen without wastegate operation (by virtue of having a lot of presurized air in the intake tract, and only a few small valve openings compared to a large set of tubes from the turbo and intercooler). But since I've ben running a boost-fooled truck for a while and never had turbo bark, I'd have to say that's further evidence in favor of my wastegate still operating.

Can you explain the 03 MY point I brought up above? If the wastegate were simply disabled, those guys would not need a boost elbow - they'd just need to disconnect the vacuum lines to their wastegate, then use a resistor from the MAP sensor to fool the ECU into thinking normal boost was being made. The boost elbow modifies wastegate operation so that the vacuum-operated wastegates open later instead of sooner. But the key there is that they still open.

You're right, the boost fooler doesn't limit max boost at all; the ECU does by controlling when the wastegate opens. I think we both agree on that one.

Different max boost levels is a function of fueling, and when the ECU says to open the wastegate (or when enough vacuum builds up in older trucks to actuate the wastegate arm).

 

Other things such as intake type also play a role in turbo bark. I couldn't bark mine with a stock intake and stock fueling, but it would bark big time with an AFE Stage 2 and Quad XZT module. Your lack of turbo bark has nothing to do with the WG. The WG does not open when you let off the throttle, whether you're using a boost fooler/elbow or not. Don't confuse WG's with BOV's.

I think the problem here is that we're talking about two completely different WG designs. The WG on your '03 is mechanically controlled. My '06 (when stock) was electronically controlled. You're correct that the mechanical WG will still function when using a BF on the '03. When we first started this discussion you mentioned "electronic WG" so I assumed we were talking about the later trucks. On those trucks the electronic WG will be disabled when running a BF.

This is where I'm confused. Now you're talking about the later electronic WG's again. Yes the ECM ultimately controls max boost, but if it's fooled into never seeing enough boost it won't ever trigger the WG to open.

AFAIK it's pressure not vacuum that actuates the older style mechanical WG's. That's what would make it impossible for your WG to open when letting off the throttle. There is no mechanical way for that to happen.

 

I am using a Blitz SBC i-D electronic boost controller right now that I had laying around from other boosted projects. It actually does help spool up, and black smoke output at lower rpms has definitely decreased to almost nothing. Messing with the gain, you can actually change the point where the wastegate starts to open. It made quite a bit of difference. The only drawback of the Blitz is the 35.5psi limit, but I'm fine with that for the stock turbo.

 

I own an '06. I was just using the example of an '03-04 to illustrate my point.

Maybe... I'm not too familiar with those systems. I know my old Subaru did have a vacuum-actuated WG. If you pulled apart a vacuum T-fitting, wastegate no worky.

So... if you do agree that the 03-04 trucks had modified WG operation vice WG disable, why would the 06-07 trucks have the wastegate disabled?

I'm just not comfortable with the idea of no wastegate!! I know Dodgezilla disabled his (not voluntarily!) and he does okay, but the idea of the turbine spinning at insane velocity, then stopping and spinning the other way to let out some pressurized air just doesn't seem like it's a good way of doing business. Then it has to stop and go back the other way if you hit the throttle again...

I will ask Quad about it.

 

If you are using only a programmer (like a smarty) then the boost pressure from the sensor is the actual pressure up to the limits of the sensor. The ECM actually reads the real pressure. Again to the limits of the sensor. On the 05 trucks, the stock ECM program appears to open the WG at about 32 psi and holds the boost at about 30 psi. With a module, the data from the sensor is modified to trick out the ECM in thinking the boost is below 32 psi. Now, the question is, a programmer type unit like a smarty, it should be able to program the point where the WG is opened. It would nice to have this point be adjustable or have a program sw settings with a preprogram boost limit. The thing that most people forget is the drive pressure needed to generate the boost pressure. The stock turbo is not efficient at boost pressure over 40 psi. That means it takes more and more drive pressure to make one more psi boost pressure. The crazy thing is the fueling tables in the ECM are looking for boost pressure before the program will add more fuel and make boost, and the WG control program is opening the gate when you make the boost pressure.

 

I thought it might help, i just hadnt seen or heard of anyone using one, Do you know of a EBC that goes to 60 or 70 psi?

 

When running an electronic boost fooling device, the '03 will still have a functioning mechanical WG because it's controlled/driven by boost pressure. The same boost fooling device on an '06 will essentially disable the WG because the ECM no longer sends a signal to open it.

Many people clamp off their WG's with 1st, 2nd, and earlier, 3rd gens. Clamping off the line to a mechanical boost controller will also disable the WG. As long as you only have the fuel to spin it up to 42psi or so the '06 stock turbo will be fine.

When you let off the throttle the turbine/compressor wheels don't reverse rotation. Turbo bark is the result of pressurized air violently rushing backwards through the wheel...while it's still spinning in the normal direction.

Maybe if we're lucky Quad will see this thread and chime in.

 

the wastegate is not the issue I'm trying to find out about, or foolers which are completly different than boost controllers. I was questioning whether or not a boost controller helps at all. As far as I can see they would help the turbo build boost faster and make the truck faster. Boost controllers keep the wastegate from bleeding by just keeping it shut until full or a preset boost limit it reached, I imagine it would help with keeping smoke down a little too

 

Turbosmart makes a 60psi one.
http://www.turbosmart.com.au/index.php?id=42