Reasons for varying performance at high altitude

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
roon
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Re: Reasons for varying performance at high altitude

Post by roon » Thu Nov 02, 2017 9:35 pm

MrPotatoHead wrote:
Thu Nov 02, 2017 1:23 am
roon wrote:
Wed Nov 01, 2017 9:19 pm
Do the engine test stands adjust their plenum pressure, or drop the pressure in the entire room? To simulate elevation.
Adjusting the plenum pressure would not simulate the different air density.
The only way to do it would be to lower the air pressure being fed to the turbo inlet. But that is troublesome because you have to lower the pressure but still maintain enough volume of air for the engine.
Does seem troublesome. I wonder if OEMs do anything like this. A large enough room and large enough vacuum pumps might suffice to balance what the engine is ingesting.

NL_Fer
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Re: Reasons for varying performance at high altitude

Post by NL_Fer » Thu Nov 02, 2017 9:37 pm

Wouldn’t a intake restrictor cause the same lower pressure in the intake tube?

roon
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Re: Reasons for varying performance at high altitude

Post by roon » Thu Nov 02, 2017 9:51 pm

Wouldn't that be forcing the engine to cause the drop in local pressure?

rscsr
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Re: Reasons for varying performance at high altitude

Post by rscsr » Fri Nov 03, 2017 8:19 am

NL_Fer wrote:
Thu Nov 02, 2017 9:37 pm
Wouldn’t a intake restrictor cause the same lower pressure in the intake tube?
You also have to keep the exhaust at that lower pressure. And a pump to regulate the pressures is just way easier to control than restrictors.

MrPotatoHead
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Re: Reasons for varying performance at high altitude

Post by MrPotatoHead » Fri Nov 03, 2017 2:21 pm

OEM's will test for temperature variations and startup in their test labs but I do not believe they test for air pressure changes.
They typically test that during the road test / test mule phase as far as I know.

But yes as mentioned it's not only the intake side that has a lower pressure but the pressure differential on the exhaust side will be larger relative to atmosphere.

johnny comelately
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Re: Reasons for varying performance at high altitude

Post by johnny comelately » Fri Apr 13, 2018 12:42 am

old thread i know, but wouldnt you use a ,say, 5mm bigger compressor wheel

Mudflap
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Re: Reasons for varying performance at high altitude

Post by Mudflap » Fri Apr 13, 2018 6:47 pm

For just the one race?
How much TQ does it make though?

MrPotatoHead
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Re: Reasons for varying performance at high altitude

Post by MrPotatoHead » Fri Apr 20, 2018 3:02 pm

You would have to sacrifice one of your turbo unit stash to do it.
So yes yo could do it in theory - but it would compromise the rest of the season.