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The mkiv Supra Owners Club

Any fluid dynamacists on here?


Chris Wilson

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Ok, thanks ;) I posted the below on a Skyline forum. What I also need to know is the effect of moving the restrictor "pill" away from the turbo (they are normally put inside a female thread in the banjo bolt that screws directly into the centre bearing section of the turbo itself). I am thinking about 6 to 10 inches away, in another banjo bolt, where access to change pill sizes is unrestricted. What changes to flow rate et cetera may occur? I can maybe create an image showing the two locations if need be. The photo below shows where I'd like to put a pill, the arrow shows where, hidden from view, the steel oil feed pipes wraps around the turbos, and where, also hidden from view, a second banjo bolt secures the banjo to the turbo centre section itself. This latter banjo is whre people normally fit the restrictor pill. Thanks.

 

http://www.gatesgarth.com/pill.jpg

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Hi Tony. I have another question, one just made for you i would think, regarding my inability to decide how best to place an intercooler in the Toyota engined Zeus race car I am turbo charging. Would you be kind enough to take a look at some photos if I make up a bit of a scrap book on my site, and say where you think a good location for air in, and out might be created please? I am so indecisive over this I was actually contemplating building the engine to run on methanol and not have an I/C at all ;)

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Hi Tony. I have another question, one just made for you i would think, regarding my inability to decide how best to place an intercooler in the Toyota engined Zeus race car I am turbo charging. Would you be kind enough to take a look at some photos if I make up a bit of a scrap book on my site, and say where you think a good location for air in, and out might be created please? I am so indecisive over this I was actually contemplating building the engine to run on methanol and not have an I/C at all ;)

 

Sure no probs, would need to see pics of potential placement sites with / without bodywork.

 

I'll take a look at the restrictor in a bit more detail when I get home.

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Right, I'm not sure if I follow what you want to do. If I'm reading this right, in the circled banjo, there is a restrictor. You want to move it about 6 inches down the line? Is that right?

If you could do a paint sketch of the lay-out, that might help. It's probably really simple, but I'm shattered and can't quite get my head around what you're trying to do!

 

My gut feeling is that if you're talking about just moving the restriction further down the tube, it would have a tiny effect yes, but I imagine at the pressure and mass flow that would be going through the pipe it would make little difference.

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And youre moving it closer to or further from the turbo? Only difference will be the time the pressure takes to build on the downstream side of the restrictor, which will be fractions of seconds.

 

Wouldn't have thought the issue is pressure, could be wrong, but in the CFD stuff I've done in the past it usually down to the flow patterns and cavitation. (Admittedly, my usage of CFD and such is from a data centre cooling aspect and not on a smaller level like this)

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Its a small bore pipe running low pressure oil Gav, the flow rate or cavitation wont be affected because the restrictor is the same size. Admittedly Im lifting this info from aircraft hydraulic and engine oil systems but the principal is the same.

 

Fair enough :), I see what you are saying (My CFD modelling is restricted as previously mentioned, hehehehe)

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I've had a bit more of a think with an early morning instead of a late evening head on.

It won't make any difference. The oil can be considered as non-compressable, so it follows a simple density(1) x CSA(1) x velocity(1) = density(2) x CSA(2) x velocity(2) formula.

If you're looking microscopically at it then yes you could see a marginal increase in pressure drop due to friction, but it would be tiny and massively overwhelmed by the pump. Certainly nothing to worry about.

 

Hope that helps.

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I've had a bit more of a think with an early morning instead of a late evening head on.

It won't make any difference. The oil can be considered as non-compressable, so it follows a simple density(1) x CSA(1) x velocity(1) = density(2) x CSA(2) x velocity(2) formula.

If you're looking microscopically at it then yes you could see a marginal increase in pressure drop due to friction, but it would be tiny and massively overwhelmed by the pump. Certainly nothing to worry about.

 

Hope that helps.

 

In engrisch :D

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Doh. Been stuck in a boring meeting all day…

 

 

Based on what has been said already I'd say that it won't make any difference. However I'm intrigued why most other people go for putting the pill in such an inaccessable location.

 

 

The simplest way to solve it would be for you to do a simple sketch of that part of the lube circuit (could just be a "London tube map" with all the pipes laid out straight to make it easy to interpret). Start at the feed from the block or head and finish at the turbo, showing all the branches and couplings, changes in pipe diameter or anything else obvious - plus the two proposed locations for the pill.

 

 

A decisive answer should follow shortly thereafter :)

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In engrisch :D

 

Only difference will be the time the pressure takes to build on the downstream side of the restrictor, which will be fractions of seconds.

 

If you're looking microscopically at it then yes you could see a marginal increase in pressure drop due to friction, but it would be tiny and massively overwhelmed by the pump. Certainly nothing to worry about

 

:D

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