Max turbo pressure

SpitfireMK461

SpitfireMK461

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This should be a quick one.

Disregarding anything a turbocharger is connected to, is there any information on the physical limit of its boost and rpm, ie, at what point the turbocharger breaks itself (by both boost and rpm)?

As I understand, turbos will operate anywhere around 100k-200k rpm, but since they are usually limited by what the engine can withstand, I assume these aren't limitations of the turbo itself. I've tried finding information like this, but I've no luck as of yet.
 
The most I ever heard was a modified diesel tractor (used in tractor racing) at 300PSI. I know that Evo guys routinely run 50+psi.
 
prizrak said:
The most I ever heard was a modified diesel tractor (used in tractor racing) at 300PSI. I know that Evo guys routinely run 50+psi.
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So I'm beginning to believe the capabilities of turbos far far exceed what they get used for in even highly tuned vehicles.
 
Well after realizing I'm an idiot, I used my education and answered my RPM question. The max RPM should correspond to the compressor blade Mach number (should not exceed 1). Even if the physical characteristics of the fans can withstand higher RPM, that is the highest it should spin for max efficiency.

My pressure question remains, though I imagine most compressors are not designed for boosts much higher than street cars see.
 
Every turbo has a compressor map. That will tell you where peak efficiency and it's limits are.

THis is a demo of one.

Fig4.gif
 
I'm sure you can continually compound the turbochargers in order to achieve higher and higher boost pressure.
 
If you are going to compound boosters, use a turbo/s feeding into a supercharger. Although a turbo'd turbo might sound cool as hell.
 
GRtak said:
If you are going to compound boosters, use a turbo/s feeding into a supercharger. Although a turbo'd turbo might sound cool as hell.
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Yo, dawg...
 
GRtak said:
If you are going to compound boosters, use a turbo/s feeding into a supercharger. Although a turbo'd turbo might sound cool as hell.
Click to expand...

like a sequential turbo setup?

Sequential twin turbo can also refer to a system where the output pressure must be much greater than atmospheric. In this case, two similarly sized turbochargers are used in sequence but with both operating all of the time. In this case the first turbo boosts pressure as much as it can (for example to three times the intake pressure) then the second turbo takes this charge and increases it further (for example to an additional three times intake pressure, for a total boost of nine times atmospheric pressure) to a pressure not possible by a single turbo. This is commonly found on piston engine aircraft which usually do not need to rapidly raise and lower engine speed (therefore turbo lag, while still present, is not a problem) and where the intake pressure is quite low due to low atmospheric pressure at altitude, requiring a very high pressure ratio. High-performance diesel engines also sometimes use this configuration, since diesel engines do not suffer from pre-ignition issues and can use significantly higher boost pressure than Otto cycle engines.
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While its a good idea, putting stock turbos into series isn't very easy (at least for my purposes), but also gets back to my question of how much pressure a turbo can withstand before it fails.
 
SpitfireMK461 said:
While its a good idea, putting stock turbos into series isn't very easy (at least for my purposes), but also gets back to my question of how much pressure a turbo can withstand before it fails.
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See that mainly depends on a turbo, as you have seen there are 300psi turbos around. Also technically speaking jet engines are at their core turbos (you can make a jet engine out of a turbo quite easily, I seen a few of those). As you can imagine those put out a lot more pressure than 300psi. There are also gigantic turbos that are used on ships/airplanes, I'm not sure what the boost they make but I suspect its a lot. For all intents and purposes turbo provides unlimited boost as you will be hitting the limitations of your motor.
gargantuan20turbo.jpg
 
I'm trying to get an idea of what average turbos you'd see in average cars would be able to handle. Jet engines are purpose built to create and withstand huge pressure ratios (20-30 or more), but turbochargers on cars normally don't see much more than 2 stock and 3-5 tuned. What I want to know is what pressure ratios these turbos could withstand if they weren't limited by whatever engine they are hooked up to. If I stripped a turbo out of an Impreza and built the pressure higher and higher, where can I expect to see failure. That is my interest.
 
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but turbochargers on cars normally don't see much more than 2 stock and 3-5 tuned.
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That's not quite right.

My car is 10 stock 15-21 tuned (tho it doesn't stay at 21 for too long, it drops off after about 4500rpm to 15)

For the SR20DET stock boost is 8-12 (depending on who you ask) and you can run 15-20 on them as well.

Stock Evo X is 26psi. Not sure about the Saabs and the BMWs.

Normal turbos you would see on regular cars? 20-40psi depending on the turbo. HKS and Precision ones tend to be quite big and capable of 50+, something like a GT35-40 is around 40psi, most stock turbos are 15-20 (tho they will burn out quickly if they sit at 20 all day)
 
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GRtak said:
If you are going to compound boosters, use a turbo/s feeding into a supercharger. Although a turbo'd turbo might sound cool as hell.
Click to expand...

There was once a prototype Audi TT that had 2 superchargers and 2 turbochargers. The noise was strange to say the least.

In terms of "how much boost can you get?" the real question is "how much are you willing to pay?".
 
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