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  #1  
Old 02-09-2012, 04:28 PM
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OM617.952 Max Exhaust Pressure

Does anyone know the maximum safe exhaust pressure you can run with a OM617?

(Unrelated) I've read that the intake side is really only good for ~2bar.

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Last edited by whunter; 02-09-2012 at 07:35 PM. Reason: correction
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Old 02-09-2012, 07:30 PM
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Quote:
Originally Posted by Simpler=Better View Post
Does anyone know the maximum safe exhaust pressure you can run with a 67?

(Unrelated) I've read that the intake side is really only good for ~2bar.
OM617.952 Max Exhaust Pressure?
I thought the Intake Manifold Pressure from the Turbo could go as high as 12psi.

I am not sure what the Exhaust Pressure would be between the Turbo and the Exhaust Manifold or what the Back Pressure if any would be in the Exhaust Pipes/Muffler.

This sounds like info that might be on the superturbodiesel site.
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Old 02-09-2012, 07:45 PM
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FYI

Quote:
Originally Posted by Simpler=Better View Post
Does anyone know the maximum safe exhaust pressure you can run with a OM617?

(Unrelated) I've read that the intake side is really only good for ~2bar.
The maximum safe stock intake pressure is 12psi.

.
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Old 02-09-2012, 08:24 PM
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To clarify: I'm installing a Holset HE351V, and plan on experimenting with modified injectors / methanol injection / more fuel one way or another

A refreshed head will be used, my bores are at ~ 0.0015" wear.

This engine will be run outside of the recommended operating parameters
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Old 02-09-2012, 08:42 PM
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I think we are wondering what you mean about exhaust pressure? I assume you are referring to boost pressure, that would be intake pressure after the turbo.

as far as maximum boost, as said factory is 12 psi. No idea of what the limit will be. I would say a few more should be no problem. Hopefully some others will say how much boost they have gone up to. I am at 12 psi on a 616, and may end up around 15psi once I up the fuel some more.

At some point lifting the head will become a problem, and you will need to o-ring the block and use studs to hold the head down.
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Old 02-09-2012, 08:53 PM
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I'm speaking to the exhaust pressure, between the exhaust vales and the turbo. I don't want to float a valve if I run too high on the exhaust side.

From what I have read, it's "safe" to run up to 28psi of boost with adequate fueling before I start to bend rods
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Old 02-09-2012, 10:11 PM
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OM616 might have an answer to this, I know he does have a pressure gauge for emp. Exhaust manifold pressure.

Just offhand I would think you could take the area of the valve, and spring pressure to calculate what it would take to lift it. However not so sure this would be reliable to compare to what is happening when the engine is running. How much boost are thinking of running? as this must corilate to emp. It is a bit out of my area of expertise, so really just thinking out loud.

I know the cummins crowd are pushing 50 -60 psi boost for pulling trucks, might be worth seeing if they have valve float issues.
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Old 02-10-2012, 10:00 AM
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I won't be going over 28psi on the intake, but since I'm running a VGT the exhaust can become very restricted. While the head is off I think I'll pressurize the exhaust manifold until the valves start to open, that will give me a rough idea of my "absolute limit"
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Old 02-10-2012, 01:19 PM
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Turbine inlet pressure is what it's called.

I'm not sure how TIP is going to bend your rods. The compressive load on the rod during the combustion stroke will dwarf the same load on the exhaust stroke. And since there are a lot of variables that can affect TIP beyond just engine power output, I don't think it's a good thing to monitor if you're concerned about your rods. I've measured TIP to gauge the effectiveness of hot side turbo mods and to gauge the efficiency of the turbo at varying boost levels.
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Old 02-10-2012, 02:51 PM
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I'm worried about floating a valve with high exhaust pressures, the bending rods comment was kinda unrelated.
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Old 02-10-2012, 03:07 PM
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You test of static float seems like a good idea. This seems unrelated to the kinetic float you usually hear about. It will be hard to measure turbo inlet pressure directly, but maybe the manufacturer has mapped that to boost side pressure and flow.

Because you're dealing with an exhaust system and pulsating flow within each runner, I expect you may deal with resonant effects as you go through the RPM range. Your max pressure would be when you have nodes at the exhaust valve and the exhaust manifold plenum. I think.
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Old 02-11-2012, 11:31 AM
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I will definitely be monitoring the exhaust manifold pressure once it's all together, I did with my 2056V setup, I want to say 40-ish-psi was the most I ever saw

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