Turbo rpm query

[brock 108]

Hi Guys,

Formula one cars of the 70's/80's used turbos. Does anyone know what rpm these turbochargers spun at?

Thanks.

[manchild]

Hi Guys,

Formula one cars of the 70's/80's used turbos. Does anyone know what rpm these turbochargers spun at?

Thanks.

Welcome to forum. Around 150.000 rpm if I'm not mistaken.

[Belatti]

well, any Diesel street car turbo can spin at 150.000rpm

I dont know how fast a 70/80s F1 turbo spun but surelly it depeded on the boost pressure allowed that changed from year to year (5,5 - 2,5 bar) and from qualy to race (fuel restriction)

A little F1 Turbo history…….

In 1986,when the rules allowed turbocharged engines, the money teams were building special “Kamikaze” engines just for qualifying. they could spin their wheel on a dry track in any gear ,including 6 gear.BMW calculated that there were moments when they were getting 1300 HP from there 1.5-litre engine. When Gerhard Berger saw a 5.5 bar boost on his turbo pressure gauge at Monza during qualifying in 1986,it meant he was getting five and a half times atmospheric pressure of fuel and air into his combustion chamber. So theoretically his little 1.5-litre engine was pumping out power like an 8.25-litre monster.1300 horse power from 1.5 litres made those engine’s go boom in the afternoon session’s of qualifying. They only lasted 20 laps……..

Crazy stuff....dont you think....

[Belatti]

http://forums.autosport.com/showthread. ... id=2022544

Both turbine and compressor speed (blade tip speed) is important if you want to reach high boost pressures. Based upon the Euler turbomachine equation and some assumptions about the turbine and compressor one can calculate the blade tip speed required for a certain compressor pressure ratio. To reach pressure ratios around 6 (needed for a boost of around 5.5 bar absolute) you typically need a turbine blade tip speed of around 500 m/s. With a 63 mm turbine that equals to around 150,000 rpm.

The compressor blade tip speed used was slightly higher (the compressor wheel is also larger), around 640 m/s. For an 82 mm compressor that equals to around 150,000 rpm (the IHI RX6D turbocharger used on the Hondas had a 62.9 mm turbine and a 82 mm compressor and used speeds up to 160,000 rpm). Since the centrifugal stress is proportional to the square of the blade tip speed, this should indicate that the stress was around 60% higher in F1 than in normal turbocharger applications and the compressor wheels where therefore billet machined from a forged piece of high strength aluminium (7075 was used, at least initially).
Since the inducer tip speed is supersonic at some conditions the F1 turbochargers where equipped with a trans-sonic inducer design.

[manchild]

Well, now you know. It's not about rpm as much as it is about pressure.

This Renault 5 super production from 1987 had same turbo as Renault F1 turbo engines.

Tuned works 1400 cc engine single turbo 400 HP (it had around 700 kg so it would make most of modern high performance cars look funny performance wise).


F1 1500 cc V6 twin turbo 1350 HP


Loads of great pics here http://www.forum-auto.com/sport-auto/th ... 261910.htm

[Matra]

Welcome back ManChild. You were one of the reasons I kept reading this forum, and knew you'd be back.

Cheers, and don't F-Off again,

alpiner

[zac510]

Well, now you know. It's not about rpm as much as it is about pressure.

I wouldn't say that. They're practically exclusive to each other but it's much easier to measure boost, so everyone does that.

See compressor map:
http://www.boostplanet.com/images/td05map.gif

If you go for boost you'll just push it out of its efficiency range.

[manchild]

The initial question sounded like some enormous difference between rpm of F1 turbo and passenger car turbo was expected. That's why I said that it's all about the pressure one engine can withstand because turbo chargers run at quite similar rpm.

Rpm of the turbo charger doesn't define the "brutality" of an engine but settings of BOV relative to capability of engine. It can run on 150k on your Volvo and BOV opens up at zero point something bar while on an old F1 car it would also run on 150k but BOV wouldn't open until 5 bar.

[Belatti]

well, rpm does define the brutality in the locomotive engine I once saw... if you take into account the diameter and mass of that turbo spinning at 90K you would be afraid to be standing next to it if it blows up!!! but thats another story...

When a turbine is designed the basic starting parameters are flow and pressure bands it will work with, with that you choose blades inclination (this is very important) number of blades, diameter and speed range necesary to maximize efficiency (that would be making the turbo work in the center of Zack´s Mitsubishi curve) then its important to trace the optimal outward spiral (the place where air speed decreases and pressure increases).

PS: Manchild, thanks for the link, very cool pics, the R5 is awesome!

[brock 108]

Hi guys,

Thanks for all the advice. Really appreciate it.

I was just curious. I expected it to be around the 400,000rpm region. Now i know its not.

Later

[Belatti]

no way 400.000 rpm can happen!!!

remember Ec (energy) = 1/2 I (inertia) * w^2 (angular speed^2)

400K rpm means 7 times the energy of 150K rpm

maybe with a tiny winy rotor with very low inertia moment

[Ciro Pabón]

Precisely as you say: you can get a powercraft tool, with a light bit, that turns at 400.000 rpm, exactly. I still have a Dremel MotoTool (not that fast) and I love it.

http://www.sculptingstudio.com/index.ph ... duct_id=34

Some dental equipment works in that range: 350.000 to 430.000 rpm:

http://www.dentalcompare.com/matrix/60/ ... rbine.html

So, next time you visit your dentist, you can start to think how you could use that drill in your car injection... You could use one for each injector (hey, good idea!).

I've read of gas bearings that allow you to reach over 800.000 rpm: http://www.iop.org/EJ/abstract/0960-1317/15/9/S08 That's not an article but an abstract. However, I swear I read about them a few years ago, now I cannot find the article.

[donskar]

Just as a point of reference/interest, turbocharged Supra and Skyline inline 6s have reached 1,000+ hp on gasoline. That's from engines displacing 2.5 - 3.0 liters.

A local (Houston) shop hit 1,500 hp with a turbo Supra.

Not unheard of for 2 liter Nissan and Hondas turbos achieving 500+ hp in (barely) streetable form.

[manchild]

I've read of gas bearings that allow you to reach over 800.000 rpm: http://www.iop.org/EJ/abstract/0960-1317/15/9/S08 That's not an article but an abstract. However, I swear I read about them a few years ago, now I cannot find the article.

and there's this... electromagnetic bearing with no friction at all - axle levitates within magnetic field.

[alleyoop]

Mohawk Innovative made the prototype of turbocompressor with the air foil bearings you are talking about Ciro. It's an interesting oil free technology already used in airplane on board air units. The turbo is not revving very high but other machines reach 700.000 rpm with this kind of bearings!

http://www.mohawkinnovative.com/newslet ... ewsletter6

pdf here
http://www.mohawkinnovative.com/newslet ... ations.pdf

The smallest car turbocompressor I know is Borg Warner K31 (fit the microcar Smart diesel)
with a speed up to 290000 rpm