Waste Gate....good, bad, waste of money?

[ywgbandit]

You didn't mention what the turbo and manifold set you back?

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[ywgbandit]

So I was talking to a buddy about the head gasket issues and he said he had read on another forum that their survey showed deleted engines were having more head gasket issues than non-deleted. This kinda makes sense because the 6.7 was designed to have higher drive pressure so that the exhaust would be able to flow thru the EGR valve. If the drive pressure isn't higher than the boost it couldn't flow into the boosted intake pressure thru the EGR. The EGR acts as a dump valve or a pressure relief valve for the drive pressure. When we remove the EGR valve we are removing the ability of the engine to bleed off drive pressure. The solution is either a better exhaust manifold and turbo or a waste gate to keep the drive pressure in check.

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[Wildkarrd RRD]

So I was talking to a buddy about the head gasket issues and he said he had read on another forum that their survey showed deleted engines were having more head gasket issues than non-deleted. This kinda makes sense because the 6.7 was designed to have higher drive pressure so that the exhaust would be able to flow thru the EGR valve. If the drive pressure isn't higher than the boost it couldn't flow into the boosted intake pressure thru the EGR. The EGR acts as a dump valve or a pressure relief valve for the drive pressure. When we remove the EGR valve we are removing the ability of the engine to bleed off drive pressure. The solution is either a better exhaust manifold and turbo or a waste gate to keep the drive pressure in check.

That's part of it. There very well may be more cases with deleted trucks than stock, I can guarantee that there are enough cases stock to ensure there is more going on causing the issue than the simple answer. Yes, the egr cooler and valve acted kinda like a waste gate, but there comes a point where restriction still is an issue. If the egr flap isn't open, and your wound up, pressure has to go somewhere. Yes, adding a waste gate to a deleted engine will help, but like mentioned, it's a band-aid. Your treating the symptom not the problem. I can vouch that walking that path is cheaper now, but twice as expensive down the road. Now what you can do to attack the problem (still not a cure but it helps) is re map the VGT so it's not as aggressive and doesn't cause near as much back pressure. The other big factor that will determine how much that helps is you the driver. Gotta watch the gauges, don't let the foot get too heavy when it's cold, pay attention to fueling, it can cause just as many issues. your smoke output is often first indication of troubles, excessive black, grey haze, etc. best, cheapest first step is to get a good safe tune put in the ecm, from there bad air out, clean air in. Fix the problem, not the symptom, let the engine breathe.

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[ywgbandit]

No argument here, this most definitely is a bandaid, but my problem is I can't afford the proper fix, retired on a fixed income! I'd like to drive my truck with some peace of mind. If I was using it as a daily driver or work truck, I'd go the turbo & manifold route, but it's mostly used to tow our RV trailer (under 10,000#). I have replaced the Head studs with A1 Technologies, H-11 head studs, done a full delete, and I will get the waste gate. (I discovered a good feature of the A1, H-11's that's in the "Heat Stud" thread.)
How and where can I get the VGT remapped, because that also sounds like a very good idea, that shouldn't be too expensive. My hottest tune on the RaceMe is only 100 hp, and I run the timing only on notch over stock. Please tell me more about the VGT remapping, I wasn't aware this was a possibility.

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[Polaraco]

That's part of it. There very well may be more cases with deleted trucks than stock, I can guarantee that there are enough cases stock to ensure there is more going on causing the issue than the simple answer. Yes, the egr cooler and valve acted kinda like a waste gate, but there comes a point where restriction still is an issue. If the egr flap isn't open, and your wound up, pressure has to go somewhere. Yes, adding a waste gate to a deleted engine will help, but like mentioned, it's a band-aid. Your treating the symptom not the problem. I can vouch that walking that path is cheaper now, but twice as expensive down the road. Now what you can do to attack the problem (still not a cure but it helps) is re map the VGT so it's not as aggressive and doesn't cause near as much back pressure. The other big factor that will determine how much that helps is you the driver. Gotta watch the gauges, don't let the foot get too heavy when it's cold, pay attention to fueling, it can cause just as many issues. your smoke output is often first indication of troubles, excessive black, grey haze, etc. best, cheapest first step is to get a good safe tune put in the ecm, from there bad air out, clean air in. Fix the problem, not the symptom, let the engine breathe.

Have to remember the exhaust pressure has to be greater than the boost pressure for the EGR to work. That explains the restriction in the manifold

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[DRD]

Guess I'm a little late here with my opinion. I've been out of the loop as my son has been sick and in/out of the hospital but he is well now, praise God!

With a 6.7 Cummins and the factory HE351VE VGT , you don't need a waste gate with the right tuning selection. The turbo itself is a waste gate. With the variable geometry function it has, the turbo mapping can dump quite a bit of drive and boost pressure when you want it too...especially with custom tuning. I can make the factory VGT run at a 1-1.2:1 drive/boost pressure ratio all the way to around 25 psi of boost. Even up to 30 psi, it's not a bad ratio at all. It's when you try to push 30+psi on a 6.7 with the factory turbo that the ratio gets up there. I run mine all the way to 40 psi on occasions but it comes at a price of 65-70 psi of drive pressure...but I've got ARP 625s holding my head down too. Keep the boost around 35 psi or less and you'll be good with the factory turbo.

The factory VGT is actually a fine piece of equipment. It works very well within its limits. They can malfunction but if you take care of them, they'll last a long time. Now they are not what you need for 500 plus HP on a 6.7 Cummins...but for most guys they are just fine.

Cylinder pressure with the lack of plenty of gasket surface between cylinders is the culprit for blown 6.7 Cummins gaskets. Elevated drive pressure, boost pressure, high injection timing are the main components of excessive cylinder pressure on a 6.7 Cummins. One of the quickest ways to blow a head gasket is to run some tuning/and or a compound turbo setup that dumps boost pressure very quick/at a low engine rpm. This condition causes the engine to make tremendous low end torque which feels good but is at the expense of very high cylinder pressure at a low engine speed. Mechanical forces in this situation will either try to lift the head or push connecting rods out the block.

My advice for long gasket life...drive sensibly and don't expect stock parts to last forever with hotter tunes, especially with the factory turbo. Also if you do plan on bumping up the power by a good bit or tow heavy alot, get some head studs. They're not hard to install and can save you a costly repair. Waste gates are not needed on a stock 6.7 Cummins.

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[fourteen]

Guess I'm a little late here with my opinion. I've been out of the loop as my son has been sick and in/out of the hospital but he is well now, praise God!

With a 6.7 Cummins and the factory HE351VE VGT , you don't need a waste gate with the right tuning selection. The turbo itself is a waste gate. With the variable geometry function it has, the turbo mapping can dump quite a bit of drive and boost pressure when you want it too...especially with custom tuning. I can make the factory VGT run at a 1-1.2:1 drive/boost pressure ratio all the way to around 25 psi of boost. Even up to 30 psi, it's not a bad ratio at all. It's when you try to push 30+psi on a 6.7 with the factory turbo that the ratio gets up there. I run mine all the way to 40 psi on occasions but it comes at a price of 65-70 psi of drive pressure...but I've got ARP 625s holding my head down too. Keep the boost around 35 psi or less and you'll be good with the factory turbo.

The factory VGT is actually a fine piece of equipment. It works very well within its limits. They can malfunction but if you take care of them, they'll last a long time. Now they are not what you need for 500 plus HP on a 6.7 Cummins...but for most guys they are just fine.

Cylinder pressure with the lack of plenty of gasket surface between cylinders is the culprit for blown 6.7 Cummins gaskets. Elevated drive pressure, boost pressure, high injection timing are the main components of excessive cylinder pressure on a 6.7 Cummins. One of the quickest ways to blow a head gasket is to run some tuning/and or a compound turbo setup that dumps boost pressure very quick/at a low engine rpm. This condition causes the engine to make tremendous low end torque which feels good but is at the expense of very high cylinder pressure at a low engine speed. Mechanical forces in this situation will either try to lift the head or push connecting rods out the block.

My advice for long gasket life...drive sensibly and don't expect stock parts to last forever with hotter tunes, especially with the factory turbo. Also if you do plan on bumping up the power by a good bit or tow heavy alot, get some head studs. They're not hard to install and can save you a costly repair. Waste gates are not needed on a stock 6.7 Cummins.

And he has spoken!

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[chrisd91]

I was reading through, hoping for someone to actually say the cause and not the symptom. As said a couple posts up, cylinder pressure is what blows headgaskets. Everything else is negligible to cylinder pressure. Now, if you have excessive cylinder pressure, you will likely also have high drive pressure etc. The factory VGT is great at producing low rpm power, which directly correlates with cylinder pressure. Timing also plays a very large role. By lessening exhaust manifold restriction and putting a larger turbo on, you are moving the power band up the rpm range. You sacrifice some low end torque for power in higher rpms and a happier headgasket.

So to repeat what was already said quite well, it mostly all comes down to the tuning and if you are trying to use factory hardware outside of its limits

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[ywgbandit]

So can someone answer the questions,.... How and where can you get a stock VGT remapped? Is it readily available or proprietary mapping. How is it installed?

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[turboguy327]

So can someone answer the questions,.... How and where can you get a stock VGT remapped? Is it readily available or proprietary mapping. How is it installed?

You talk to Ray @Double R Diesel LLC.

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