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The mkiv Supra Owners Club

Maximum RPM calculator


TLicense
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I've created a spreadsheet that you can use to help calculate what the maximum RPM you should run to.

 

It basically calculates for a given rev limit and piston mass what the load on the gudgeon pin is. If you assume that the stock set-up is safe and is 100% load, then you can increase the rev limit and see what comparative increase that would produce. You can then see what effect reducing the mass of the piston would give.

USE THIS AT YOUR OWN RISK!!!

This should be used as a guide. If you are serious about setting an increased rev limit, then you should prove the physics to yourself rather than relying on someone elses.

 

Have fun! :)

Piston speed calcs.xls

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Wow, looks great, but has gone well over my head!

 

So with 350g pistons you can rev to 7700rpm? surely its not as simply as this?

 

It depends on what you're talking about....

What it says, is that without putting any extra load onto the gudgeon pin, you can rev up to 7700rpm.

However, it doesn't say whether everything else in the engine could take that kind of loading.

 

I'm already working out in my head how I can incorporate con-rod loading so that I can calculate the loads in the con-rod bolts, which would be better as this is more likely to be the weakest link.

 

Anyway, what are saying "simple as this". Have you not seen that last equation?! 2nd order differentiations of sine laws are definitely not simple! :p

 

I put 7200rpm as the stock rev limit as I thought this was the rev limit for the VVTI, which I believe has the exact same bottom end? If that's not right, then I can modify it to suit.

 

Hope that helps!

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