Not true... if the compressor wheel is spinning in a vacuum it cannot make boost.

 

ha i forgot about this thread!!! Don't worry, i got the turbo fixed up and it works great! but its good to see no one lost the thought about somethin like this.

JustRamIt, your right, The smoke we put out is cleaner than a car, Diesel fuel is 25% efficient, and gas is only like 12%, I did learn somethin in school! But diesels are much cleaner burning than gas cars, you can just actually see the pollutants a lot easier...

 

Thanks, been awhile since someone said im right!!

 

I feel your pain Nick

 

This is true if the compressor was in a vacuum. But for all practical purposes this would never happen, then engine would stall long before most of the air escaped the intercooler/intake manifold.

To see this displayed start your truck and take a piece of plywood and hold it over the turbo, sealing off the air supply, you can even use your hand, just don't get it caught in the turbine blades. Your engine will quickly stall.

 

Turbo Overspeeding is a real problem and issue if you have a leak in the intercooler/charge air tubes. This won't allow any boost to build up nor provide load to the compressor wheel and it will spin to oblivion/scatter

Edit: what I am describing above is EXACTLY what Crossy son drew up on paint. making a turbo 'cutout' in the boost air tubes will in fact grenade your turbo... Think about this as well and get back to me.

OH and BTW I am an aircraft mech/A&P mechanic like that friend of yours.

 

one thing my instructor taught me... "if you want to kill yourself, don't use a diesel. it'll take too long"

i seem to remember reading in my books that diesels are 42% efficient and gassers somewhere in the low 20s. that could be thermal efficiency however, but i would think that'd be the same thing.

 

i smoke people out every day it is one of the reasons i bought the truck just to smoke out tail gaters and reak havic in my town also do donuts lots of donuts

 

For one there are too many sides and situations being discussed at once. Its really all about perspective.
I'm sure there are many ways to grenade a turbo.

Andy-With the vacuum situation, i'm sure the engine would stall before the turbo climbed to its limits, this is why its a good way to end a runaway situation.

PipeCAT-As far as the cut out idea and problem, as long as the EGtemperature didn't get too hot, the exhaust wheel won't spin to that extent because of the lack of air moving through the engine, regardless of the load or no load on the compressor wheel. This is why disconnecting a boot in a runaway situation calms the engine down and all is well.
So what about being an air craft/air plane mechanic? Does this make me wrong?Did i say anything about a wastegate? Am i misinformed by my friend? I don't see the relevance... What is a good way to blow up a turbo/turbine?

 

Same thing, and I was going to mention that as well. Thermal efficiency's range on engine brand, model, and how they are used (ie what RPM, etc). On AVERAGE assume a gasser to be 20%+ and high speed diesels around 30%+. Some medium and slow speed diesels we use on ships are closer to 40 to even 50% efficient, but that is utilizing Exhaust Gas Boilers that we make steam from. We would need this auxilliary steam to heat the accomidation, fuel, etc anyway, so by getting it from the exhuast, we increase "plant" efficiency which is slightly different from the engine's pure thermal efficiency.

And ya, putting that boost cut out would grenade that turbo for sure. It won't have a head (pressure) to push against, and it will overspeed QUICKLY since it's free flowing to atmosphere. Take a look at he compressor map and look up max flow with 0 pressure. That thing will be screaming.

 

Another thought: Ever been to a truck pull and hear a loud BOOM? That's a charge-air boot coming undone. I've actually had it happen to me watching my boost gauge climb up over 34psi and then boom! The only reason I didn't overspool my turbo is because I got out of the throttle, and immediately pulled over. lol

 

Y'all must not have as many log-trucks, coal-trucks, and milk-trucks as we have around here; nobody in his right mind gets out on the road around here on a bicycle.

 

You haven't lived until you have been cut off by some clown on a bicycle that gives you the finger. I left him in a cloud of smoke and then I had to pull over because I was laughing so hard.