About turbo waste gates

[fitterski]

Both of my 12-valve Cummins had around 130 kilokilometers on them, close to what 1500 hours would mean. The 175hp one I'm building right now had a rust-perforated waste-gate actuating diaphragm chamber making it useless. Kind of surprising and also a lesson because this thing will never complain until it's needed and by then it'll be too late if it don't work!

So I looked at my requirements and just removed it, locking the waste gate closed, I might replace the actuator with a new one later. This engine will never be run at 2000 rpm and I think that even at that speed the trigger boost of around 15 psi would not be reached. I do plan to replace it later because otherwise in the event of a runaway a destructive over boost would be guaranteed.

I also wonder WHY this complex mechanism would be needed instead of a simple sprung blow-out valve on the intake manifold?

 

[fitterski]

Re: About turbo waste gates ...turbos & inter-coolers

A secondary addendum which I might as well just append:

The truck originally sporting this engine used an inter-cooler, which I have no intention of using UNLESS I HAVE TO given that I will operate at temperatures below 0c and at first at or below optimal torque or +/- 1600 rpm. It may not be possible to do this because of temperatures but ideally I would just route the turbo output over the valve covers directly into a custom-made intake adapter over the toaster.

Any comments from 'diesel persons'?

 

[3Lfarms]

Wastegates and blow off valves serve two different purposes.
Diesels can usually handle high boost pressures, so a blow off valve isn’t necessary in a stock application. Since there is no throttle plate, the air is just forced into the cylinders and fuel is reduced which lowers drive pressure and thing slow down naturally.
The wastegate controls the drive pressure and nowadays are computer controlled to manage optimum boost levels.

 

[fitterski]

Wastegates and blow off valves serve two different purposes.
Diesels can usually handle high boost pressures, so a blow off valve isn稚 necessary in a stock application. Since there is no throttle plate, the air is just forced into the cylinders and fuel is reduced which lowers drive pressure and thing slow down naturally.
The wastegate controls the drive pressure and nowadays are computer controlled to manage optimum boost levels.

Thanks for the info, this engine is going into a snow blower with no computer and very limited electrics. The waste-gate in this case is actuated by directly piped intake pressure, no digital service involved. It's calibrated according to a very poorly written procedure in the Cummins manual and from what I can make out a lever travel of 0.015-0.050 inches is sought at either 7 or 12 psi of pressure, but this distinction is also poorly written and my 175hp engine isn't covered at all. 7 psi seems very low, like one might get that as soon as the engine is started, I have no idea. If the engine can otherwise take the boost without dumping then no waste-gating should not be a major problem. If fuel is reduced (by a computer) in the event of some over boost that's feature I cannot duplicate at all.

 

[firemanmike69]

Don't even bother with the waste-gate, you don't need it. Boost is a function of heat and engine load, too much boost and you will exceed what the turbo can produce in terms of useful air charge.

 

[thepumpguysc]

I wouldn't give it a second thought, given the application of the engine..
That's gonna be 1 helluva snow blower..!!!
What fuel system are you running on it? Bosch inline P pump or rotary VE or a Cummins PT system??

 

[dieselcrawler]

I have the wastegate disconnected on my daily driver and never worry about it. Based on your comments, I'm hoping you will have a pre-turbo EGT gauge, as the missing intercooler will bring up EGT temps. Not likely to be an issue under light load, but even at low RPM, in a high load demand situation, when full fuel is applied, you might get the temp up... just advising you to keep an eye on it.

 

[3Lfarms]

Since this is a snowblower, and I doubt it will ever need to make its full rated power for any length of time, I think it will be fine without the intercooler. If this thing turns into a monster and needs 500 ftlbs of torque, it would be easy to add a used intercooler horizontally so some snow falls onto it and keeps the temps down.
Dieselcrawler is very right in that monitoring the pre-turbo exhaust temps will tell you everything you need to know about what the engine wants and can handle.
You can just fix the wastegate closed and forget about it as long as you monitor the exhaust temp. FYI, keep the exhaust under 1000 degrees. Those older Cummins may not have the oil squirters for the bottom of the pistons.
Common rail Cummins are easily good to 1300 degrees EGT.

 

[fitterski]

I wouldn't give it a second thought, given the application of the engine..
That's gonna be 1 helluva snow blower..!!!
What fuel system are you running on it? Bosch inline P pump or rotary VE or a Cummins PT system??

This engine is a 175hp Ram survivor and has a P-pump, kinda weird actually. I also have a more powerful 215hp engine waiting for my attention and that one has a CAV rotary pump. I would have been happier with a VE on this and the big P on the 215hp.

 

[fitterski]

Since this is a snowblower, and I doubt it will ever need to make its full rated power for any length of time, I think it will be fine without the intercooler. If this thing turns into a monster and needs 500 ftlbs of torque, it would be easy to add a used intercooler horizontally so some snow falls onto it and keeps the temps down.
Dieselcrawler is very right in that monitoring the pre-turbo exhaust temps will tell you everything you need to know about what the engine wants and can handle.
You can just fix the wastegate closed and forget about it as long as you monitor the exhaust temp. FYI, keep the exhaust under 1000 degrees. Those older Cummins may not have the oil squirters for the bottom of the pistons.
Common rail Cummins are easily good to 1300 degrees EGT.

I like the falling-snow intercooleer idea that certainly would be original:laughing::laughing::laughing::laughing: