Too low drive pressure in turbo?

Headcase98002 said:
What is your driving style?
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Fairly hard street driving/racing. tow 5-10,000 pounds once a month. and i had the truck stuck in the snow the day before i noticed the last thrust going out and was working it pretty hard to get out.

Blownoiler said:
I'll go with Turbo2332's suggestion, surge seems to be the most obvious killer.
Going by your pressure ratio figures I would also check the pressure lines to your gauges as it sounds like they could have been switched over inadvertently. Are you running name brand turbo's or using an aftermarket brand?
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Gauges are right and not plugged. the truck is an 08 ford with edge CTS and im using the factory digital sensors.
They are all original Borg units bought from reputable sources.

turbo2332 said:
i would still strongly advise running some kind of waste-gate in your system.
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What would wastegating do when the drive is ALWAYS lower than boost?

jasonc said:
What timing are you running, advancing timing will lower boost pressure. Your boost to drive pressure seems odd from what I've experienced running similar turbos.
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Pump is "supposed" to be pinned at 30 and i have an adjustable pump gear retarded all the way, so it should be 20. I will try to bump it up 10 degrees just to see what it does to DP and boost...probably something worth trying.

Backhoe man said:
I don't see that either my s400's have always needed the drive to be a little over boost typically 5 to 10 psi. My guess is the drive pressure is not reading accurately for some reason.

Is your compressor surging when you shift gears?
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Like i said before i really dont think its the gauges, the old truck had mechanical gauges and the new one has the factory digital ones, both with similar readings.

I wouldnt really say it surges, but it does "bark" when it shifts.
 
That bark is what's killing it. The gate will limit overall boost to a set level possibly preventing that bark, which is killing your thrust bearing.
 
What size air filter are you running on this turbo-eating Ford/Cummins conversion?
 
if it were a restrictive air filter he would see a spike in pressure than a drop as it couldnt maintain and tried to make a vacuum, assuming it can breathe good enough to still make drive pressure. and even so the turbine would be pushing on the thrust not the compressor
 
Watching I want to put a upgraded thrust in the charger I am about to get
 
Surge control

Quote:
Originally Posted by Blownoiler View Post
I'll go with Turbo2332's suggestion, surge seems to be the most obvious killer.
Going by your pressure ratio figures I would also check the pressure lines to your gauges as it sounds like they could have been switched over inadvertently. Are you running name brand turbo's or using an aftermarket brand?

Gauges are right and not plugged. the truck is an 08 ford with edge CTS and im using the factory digital sensors.
They are all original Borg units bought from reputable sources
Click to expand...

I had a similar "barking" noise on one of my previous turbo diesel engines, every time I wound the boost up to 12 psi or more the compressor would bark at 3200 revs. After some experimenting I found a relatively easy fix, I replaced the sharp 90* bend at the compressor inlet with a 10 inch straight length of pipe, and added an aftermarket filter to keep the dust out- no more surge/barking was the result.
Another thing to consider is the location of the pressure sensor in the exhaust manifold, as different locations can give different readings, especially when the sensor (or pick up point) is angled incorrectly, possibly creating a venturi effect at the sensor. Maybe other contributors can chime in with the location and angle of the back pressure sensor on their engines!
 
24vriviera said:
That bark is what's killing it. The gate will limit overall boost to a set level possibly preventing that bark, which is killing your thrust bearing.
Click to expand...

Boost was already fuel limited to about 42lbs in the last charger. Are you suggesting that if boost was 40 and drive is 30 that it should be waste gated at 25? Would a blow off valve in the :intake be better than a waste gate?

And the air filter is the biggest 5 1/2" inlet filter S&B makes.

Unfortunately I'm out of town till Sunday and won't be able to mess with the timing of anhthing else till then.
 
Blownoiler said:
I had a similar "barking" noise on one of my previous turbo diesel engines, every time I wound the boost up to 12 psi or more the compressor would bark at 3200 revs. After some experimenting I found a relatively easy fix, I replaced the sharp 90* bend at the compressor inlet with a 10 inch straight length of pipe, and added an aftermarket filter to keep the dust out- no more surge/barking was the result.
Another thing to consider is the location of the pressure sensor in the exhaust manifold, as different locations can give different readings, especially when the sensor (or pick up point) is angled incorrectly, possibly creating a venturi effect at the sensor. Maybe other contributors can chime in with the location and angle of the back pressure sensor on their engines!
Click to expand...

The angle is just 90 degrees. Tapped the manifold same as for pyro.
 
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