Cylinder Pressure Monitoring

[TooMuch03]

With all the build threads that are going on around here and all the people talking about live tuning their truck in the future, I got to thinking. There are several people pushing the limits of stock connecting rods, and I plan to be at that point in the near future. If a person could monitor the cylinder pressure as the truck is being live tunes to make sure there aren't any spikes or excessively high pressures, they would theoretically be able to get more power out of the engine without damaging the rods, right?

Do any of the common tuners have the capability to monitor cylinder pressures, or does anyone know of someone who does? I understand the equipment is quite expensive...

[g2shuck]

where would you even drill and tap for 8 pressure sensors lol

[rentstdi]

It's already drilled and tapped! Glow plugs! I guess that's what the lol is for...

[snafu!]

I know some old hot rodders that know how to calculate cylinder pressures but I haven't ever been able to wrap my head around everything involved to do the calculations.

[smokersteve]

Originally Posted by rentstdi

It's already drilled and tapped! Glow plugs! I guess that's what the lol is for...

GLOW PLUGS!!! great idea

[kdogg85]

The glow plug holes will work, but what amount of pressure does a stock file make? That would be where I'd start and work my way up. Or just go until something gets thrown out the side.

There are also so many material differences to account or as well, like density of rods, pistons, pins, caps, etc.. You are putting in parts that are more than capable of killing the rotating assembly. But, doing this test will give you a better shot at keeping it together.

[TooMuch03]

Right. I know there is equipment that uses the glow plug holes and will monitor cylinder pressure. A nearby shop has some but only for Duramax trucks. It won't work with the powerstroke. The only place I know of that has this capability is Swamps and they won't offer that service unless I am running their products, since they don't have crap for 6.0 parts that is not happening either.

I know it will not guarantee that I don't throw a rod, but if we are able to monitor the cylinder pressure during the tuning process you can minimize spikes in pressure which should help relieve some stress on the rotating assembly.

[PGreenSVT]

The stock rods in the 6.0 have proven to be quite robust. Especially compared to the 6.4 or 6.7. What kind of power are you planning to put down that you are worried about your rods? 800 whp is nothing for the stock bottom end.

[TooMuch03]

Mitch, I really wish i had your confidence in the stock bottom end. I really do. maybe it is just because it is a pretty expensive problem when it fails, but I want to be on the safe side. kdogg busted a rod when his truck hung a gear and over-revved and my build is going bigger on turbo and injectors than his set up. So some truck have windowed blocks at under 700 hp, but on the other hand, like the truck that just made 863 with 205s and spray, some trucks are making well over 800 on stock rods. A few guys have pushed the stock rods to 1000 hp before they started bending so I don't know.

I guess I am just a little worried because I don't want to be putting new rods in for a little bit.

[kdogg85]

Adam, mine broke a wrist pin and grabbed the piston, pulled it down where it went below the cylinder and pushed its way out the bottom. The crank end of it was fine. The rod end was boogered up but all still there, it just pushed through the wrist pin.

But, he is right some will live and some won't. I assume your truck is your dd so you are probably not going to hammer on it at every red light. But, who can resist with that much on tap.

I would say go for it checking the pressures if you can find someway to do it. what range of sensor would you use(100k psi?) This stuff is what this site needs besides the threads on high idles and zoodads. You may want to give Mike at MPD a call, they seems to be into all this more advanced stuff alot and may give you some advice.