Quick question about turbo's...

[MCummings]

I was thinking about this for a few days, but not putting much thought into it I just settled ith my answer.



Here's my question...



Would a turbo making 15 PSI of boost at 1,500RPM be spinning faster making 15 PSI at 3,500 RPM?



I assume yes. It would be spinning much faster. So this would translate into more extremem cases...



What about a single turbo making 40 PSI Boost at 2,500RPM on a 24V, but take that same turbo and put it on a 12V spinning 4,000RPM making 40 PSI Boost?



Wouldn't a turbo be more likely to blow up on the 12V @ 4,000RPM than the 24V?



Ideas? Comments?

 

[formula]

Wow, lots of views, but no replies... ...



"Would a turbo making 15 PSI of boost at 1,500RPM be spinning faster making 15 PSI at 3,500 RPM?"



Assuming this is the same engine/turbo combination, then yes... ... . as the engine spins faster, it moves more air, and the turbo has to spin faster to supply the increased volume.



"What about a single turbo making 40 PSI Boost at 2,500RPM on a 24V, but take that same turbo and put it on a 12V spinning 4,000RPM making 40 PSI Boost?



Wouldn't a turbo be more likely to blow up on the 12V @ 4,000RPM than the 24V?"



I don't think that the airflow or volumetric efficiencies of these engines are different enough to have a substantial effect on the perameters in your question... . so... . based soley on the displacement and rpm, then, again, as the engine turns faster, so does the turbo. Assuming it's making the same boost pressure.



Sean

 

[fest3er]

Originally posted by MCummings
... Would a turbo making 15 PSI of boost at 1,500RPM be spinning faster making 15 PSI at 3,500 RPM?...

Ah, yes. Just like the radiator fan on your truck, it needs to spin faster to move more air. The engine moves about 2. 3 times more air at 3500 than it does at 1500.

Also remember that 100 cubic of 15 PSI air has the same volume at 100 cubic feet of 100 PSI air.

Fest3er

 

[Strick-9]

Merrick,

Your answer is in the compressor map.



I'll try to post one here

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It might seem confusing at first, but it is actually quite simple.



For a brief rundown, more airflow (more rpm) moves to the right.

Boost is up and down.



So for your question, you pick a point on the map and move directly to the right. This simulates holding a constant boost level and increasing RPM.



Now, look at the numbers to the far right. Take 55,300 for example. That number is compressor RPM.



You can see the kind of airflow that this compressor will put out at a constant turbo shaft RPM by following that line.



Notice that as you follow the 55,300 speed line to the right, it actually goes slightly up first then down. What this means is that if you hold a constant boost level and increase RPMs, the shaft speed will actually slow down slightly while still maintaining your boost level. Then as you continue to increase RPM, the shaft speed will have to increase to maintain boost.



At high boost levels it requires huge increases in RPM levels to maintain boost as RPM climbs.



Not sure if this answers your question, but basically, it depends on the compressor you're using.



More rpm does not ALWAYS mean more shaft speed.



-Chris

 

[Huff N Puff]

The answer to your question is No

A 24v engine will spin the turbo up quicker than a 12v engine and therefore will develope more boost at a lower engine RPM. The 24v engine took more air in and exhausted it faster spinning the turbo at a lower engine RPM and therefore developing more boost earlier. So the answer to your queastion is the turbos are spinning about the same RPM for the boost but the 24v can get it there quicker . If I understood your question properly. Merv