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Stock.

Just tighten it down 2-3 turns and your holding more than the banks or turbosmart.

Also, unpolitically and cap the red line. It’s not needed and will open any wastegate too early
 

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Wow, sooo much misinformation...

First of all, the wastegate is on a turbocharger to limit turbine speed (to prevent turbocharger over-speed), and as a result, limit maximum boost pressure.

Removing or blocking off the "red" line to the wastegate actuator is never a recommended practice. The wastegate actuator on a GT38 (stock) turbo will only hold between 6-8 psi before actuating. Even when the shaft/spring is cranked down, they are not designed to allow excessive boost. That is precisely why there is a solenoid valve in the boost control/wastegate circuit (more on that below...). In addition, since the diaphragms are relatively small (in diameter) and the springs are a bit weak, the actual wastegate itself can "blow open" under high drive-side (exhaust) pressure situations. And, believe me... the wastegate only has to "crack" open to lower the exhaust-side pressure, and drop the drive speed and boost pressure.

Even the actuators on the Ball-bearing GTP-38R turbo (rated for up to 40 psi boost) are "factory" set for, and will begin to open at only 6-8 psi. (I have tested them).

Since the actuator operates at such a low pressure, the wastegate solenoid valve was put in.

The wastegate solenoid valve is normally open, and bleeds the boost signal from the intake Y-spider (red line) back to the intake boot (through the green line). When the PCM commands less boost (via the MAP sensor signal), the wastegate solenoid is commanded shut to direct the boost signal directly to the actuator (the solenoid valve closes, reducing the bleed to the intake, and redirecting the signal to the red line/actuator), thus limiting turbo speed and boost pressure.

I personally run the Banks "Bighead" actuator (it was on the truck when I got it). This one has a larger diameter diaphragm, and much heavier (yet adjustable) spring, which prevents "blow open" of the wastegate. I also run the 38R turbo. I bench-set my BigHead (with compressed air, using an accurate gauge and pressure regulator) to begin opening right at ~39-40 psi. That way I'm assured of max boost potential without over-speeding/over boosting (beyond the recommended limit of the turbo).

I believe there are a couple of companies offering "aftermarket" wastegate actuators, similar to the Banks unit. So any that have a larger diaphragm and spring, and allow you to set the desired opening pressure should work fine. If you're running a stock GT38 turbo, I would set the gate to open at no more than 25 psi. That's the max pressure they should run at, and last.

I highly recommend testing and pre-setting the actuator cracking pressure on the bench, BEFORE the turbo is installed (or in the truck, if the turbo's still installed). This will assure proper operation. Unfortunately, it's a b!tch to do it if it's in the truck, and buried back under the firewall! LOL. But it can be done...

So I'd say Banks, but only because I have personal experience with them. I can't speak to the others... but I definitely would replace the stock one! The Banks stuff is a bit over-priced in my opinion, but it is of good quality.

~Al
 

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I respectfully disagree with the first half of your statement.

But the second half makes sense. But......there is no need to buy a 200$ wastegate when 2 turns on the stock unit holds the same boost reliably. Tons of folks have done this over the years.

The stock turbo handles 25 psi just fine. Add a billet compressor wheel and drive pressure stays the same up to 32 psi.

Excessive drive pressure is what Kills the stock turbo.

35 psi with a billet wheel or 30 with the stock compressor has a drive pressure of 50-60.

Capping the red line (which we have been doing forever) prevents the wastegate from opening down low for no reason. There is no reason to waste drive pressure at 8 psi. It opens mechanically much later when it should. Because that’s when drive pressure needs to be kept in check.

Add in the fact that now we have 360 degree thrust rebuild kits that add a lot of durability to the stock turbo. I haven’t heard of any stock turbos failing under 32 psi in years with a 360 kit.
 

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I respectfully disagree with the first half of your statement.
Well, that's what makes America great! You can disagree...

But it doesn't change the facts.

Read any manufacturer's engineering info on turbos. You will find what I have stated to be fact, not my opinion. I've spent a good deal of my nearly 45-year career (as a mechanic) in training, classes, and reading manuals and engineering bulletins, and I've worked on a $hit-load of big (and little) engines. So I'm not pulling this info out of thin air (or my a$$, LOL). It's all out there...
 

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Yessir!!

While I agree your info is correct.

Personal experience and years of data on the forums backs up what I’m saying.

The stock turbo is a stout unit. And with a few mods handles 30 psi with ease
 

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All I did was tighten up the end and I see up to 21psi and cruise at 70mph pulling 8psi. The 21psi is not even at full throttle I have never pushed her that hard.
 

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All I did was tighten up the end and I see up to 21psi and cruise at 70mph pulling 8psi. The 21psi is not even at full throttle I have never pushed her that hard.
Nice. Could be that the gate is now opening closer to, or above, 21psi.

One thing to consider is that at somewhere around 22 psig, you're at the maximum pressure that the MAP sensor can read. Literally, the sensor's maximum working pressure is ~22psi. At that pressure, the output signal [to the PCM] is at its maximum value, ~4.6v. You simply can't drive it to any higher pressure, without throwing a DTC.

My 70 mph cruise (on flat) is at about 1950 RPM, 4-5psig boost. Max boost I see (hard acceleration) is 39-40 psi (I'm looking at the road, and only a glance at the gauge, LOL). Pretty sure I could get more boost out of it, but my wastegate was set to relieve at ~40psi, so it must be working!


~Al
 

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Yea the stock readout does max out in the low 20’s the ses light is either disabled or set to come on at a higher pressure via aftermarket tuning
 
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