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

[ywgbandit]

I have been very worried about head gasket issues and have talked to every 6.7 owner I come across to see if there is a fix. I have discovered a few things:

1- Head studs alone do not guarantee your head gasket won't fail.

2- Stock or Deleted the issue exists, deleting the engine of the CAT & EGR doesn't mean you won't have a problem.

3- From the mechanics I've talked to, no one knows for sure what causes the head gasket failure, but they all have a theory.

4- The one recurring theory is that the drive pressure on this engine is very high. A few of the mechanics I've talked to had recorded drive a pressure double that of the boost pressure and most feel that could be the issue because they all have said drive pressure and boost pressure should be on a 1 to 1 ratio.

5- It seems the culprit is the fact that the outlet on the stock turbo is far too small and extremely restrictive.

6- Changing out the stock turbo for a larger turbo with a larger outlet and matching exhaust manifold is a solution....a very expensive one that also removes the engine brake feature. (That a lot of us want)

I have been told by 3 different mechanics that installing an exhaust waste gate on a fully deleted engine solves the head gasket failure issue and still leaves you with a 95% effective exhaust brake. The waste gate is relatively inexpensive compared to a head gasket replacement, specially if you need to deck the engine and head or O ring the head.

I would love to hear comments and observations on this, as it seems to be a very controversial issue!

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[Polaraco]

I was one of the pioneers of the deletes. The deletes alone will not cause the gaskets to fail. From experience, it seems to be the tuners and people pushing the engine beyond it's design limitations. I never had a drive pressure issue, I was pushing 600 HP on my 08. I never studded my head and never lost a gasket. Believe me, I left some SRT 10's in clouds of dust too.

The loss of head gaskets is a small percentage of the modified engines. I have heard of people losing gaskets with studs, but the question is, were the studs done right? I understand o-rings don't help either.

The two guys that can really qualify this question is @Canadiandiesel and @Terror Custom Tuning

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[Rockwerx]

I went with a larger turbo and higher flowing manifold on our 6.7. I used conservative tuning on my combination. My goal was better fuel economy.

Once I removed the stock manifold I realized how restrictive it was. It is designed to choke the exhaust so it will flow into the EGR system...drive pressure was double the boost. My drive pressure dropped in half at full boost with the new turbo and manifold. No need for studs as it runs with a lot less stress even at full boost IMO. My goals for fuel economy and extra torque were met.

My combo runs around 200 hp over stock. When towing around 12500lbs my new combo could get 15 mpg (US gal) on summer fuel. Empty it would deliver 20 mpg easily. The truck was a lot more fun to drive with the extra torque on tap!

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[ywgbandit]

I'm curious what turbo and manifold you went with? How much bigger is the exhaust outlet on the new turbo than the original? When you saw the high drive pressure was it stock or were you using a tuner?

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[ywgbandit]

I was one of the pioneers of the deletes. The deletes alone will not cause the gaskets to fail. From experience, it seems to be the tuners and people pushing the engine beyond it's design limitations. I never had a drive pressure issue, I was pushing 600 HP on my 08. I never studded my head and never lost a gasket. Believe me, I left some SRT 10's in clouds of dust too.

The loss of head gaskets is a small percentage of the modified engines. I have heard of people losing gaskets with studs, but the question is, were the studs done right? I understand o-rings don't help either.

The two guys that can really qualify this question is @Canadiandiesel and @Terror Custom Tuning

I have talked to 4 people who have blow gaskets on completely stock engines here in British Columbia, pulling trailers in the mountains. They were all covered under warranty, but one guy told me he has had 2 gaskets done on warranty and he's had it with the truck. This is most definitely not just an issue for guys with modded high hp engines. The common issue seems to relate to drive pressure being excessively high. Having said that there are guys who haven't had any head gasket issues. The problem here, for me anyway, is I don't want to be on a trip with my RV and blow a gasket and be at the mercy of some shop and end up paying three times what I can fix it for myself. I'm trying to do something to prevent this from happening in the first place.

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[turboguy327]

How can you see drive pressure? Can like an edge display it? Does it need stuff added to it or is it a factory option to display it on the edge?

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[Polaraco]

I believe an Edge CSX can see it. My H $ S could. . . But I was doing beta for them. I don't remember if it was part of the standard package on a Black Max.

Were those trucks deleted? I wouldn't think so. I can see drive pressure being up with all those restrictions in the exhaust. That and a varying status of a DPF. I have to say they were probably beating the trucks with the emissions on. Frankly, this is the first I have heard of a stock truck ever losing a HG.

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[Polaraco]

I went with a larger turbo and higher flowing manifold on our 6.7. I used conservative tuning on my combination. My goal was better fuel economy.

Once I removed the stock manifold I realized how restrictive it was. It is designed to choke the exhaust so it will flow into the EGR system...drive pressure was double the boost. My drive pressure dropped in half at full boost with the new turbo and manifold. No need for studs as it runs with a lot less stress even at full boost IMO. My goals for fuel economy and extra torque were met.

My combo runs around 200 hp over stock. When towing around 12500lbs my new combo could get 15 mpg (US gal) on summer fuel. Empty it would deliver 20 mpg easily. The truck was a lot more fun to drive with the extra torque on tap!

You and I ran about the same Stu. I never changed the exhaust manifold on mine. If I ever become rich and famous, I'll do it on this truck. LOL

Now yours is a chrispy critter and mine is probably a chevy now

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[Wildkarrd RRD]

I believe an Edge CSX can see it. My H $ S could. . . But I was doing beta for them. I don't remember if it was part of the standard package on a Black Max.

Were those trucks deleted? I wouldn't think so. I can see drive pressure being up with all those restrictions in the exhaust. That and a varying status of a DPF. I have to say they were probably beating the trucks with the emissions on. Frankly, this is the first I have heard of a stock truck ever losing a HG.

The 4th gens seemed to be more prone to popping the HG stock than 3rd gens. I've talked to quite a few guys that were bone stock when theirs went. H&S still allows for monitoring exhaust back pressure

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[Rockwerx]

I'm curious what turbo and manifold you went with? How much bigger is the exhaust outlet on the new turbo than the original? When you saw the high drive pressure was it stock or were you using a tuner?

I installed an AFE 3rd gen manifold with a Silver Bullet 66 turbo. When I started it up the first thing I noticed was how much louder it was just at idle. Way less restriction from idle on up. I ran SW5 on my Smarty device...aprox 100 hp tune with a stock engine combo...with my other mods and the new turbo combo it made around 200 hp more than stock on SW5.

I do not recall how much larger the turbo outlet was compared to the stock VGT, but it is larger and breaths a lot better till around 65 psi...after that the drive pressure goes up drastically. SW5 would never get the boost up that high so I did not worry about the headgasket. EGTs were substatially lower than with the stock VGT.

I measured drive pressure on my engine when it was almost stock. I had changed out the exhaust, the EGR, added a CAI and installed an MP8 and an Edge device. I could turn the devices off or on which was nice. At the time I had to clear codes on startup with the Edge, but it also provided alerts, gauges and the ability to run a few different power settings. Anycase, drive pressures were higher than I liked even on stock settings. After I flashed the ECM with a Smarty delete tune I left my Edge on setting Zero. I removed my rail pressure device as the Smarty performed well. The shimmed rail pressure relief valve stayed on the engine.

Looking back my first mod should have been swapping out the VGT and manifold for something that flowed better. The turbo made the truck perform so much better I did not miss the e-brake function of the VGT. Unfortunately one has to rework so many things on a 6.7 to make them perform well it is hard to decide which route to go with first. One's pocket book usually decides what to do first though. One needs to address tuning, EGR, exhaust, manifolds, turbo/turbos, gauges, ect so it ends up costing quite a bit to delete these trucks properly. Most guys start out wrong IMO and go for fueling mods too soon...this leads to blown head gaskets running the stock VGT and manifold. Higher tuning yeilds higher combustion pressures that can lift the head.

One last thing I recall. After my turbo swap I noticed the truck ran around 2 psi on the highway where the stock VGT would be running around 12 psi. Boost pressure is basically telling one how much restriction there is...so less boost for a given situation tells you there is a lot less restriction after the proper swap. There are lots of ways to modify these engines now which is nice as one can pick and choose parts and tuning to make their combination truely unique.

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