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The mkiv Supra Owners Club

Boost leak detector


ardasaliah

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It's sort of a leakdown test for the intake.

However, the throttle plates are not meant to be airtight, and the idle control valve could be open, couldn't it?

 

I doubt that it's worth setting up this gizmo at all.

Small leaks can be caught just by looking at the boost gauge. If you only see 10mm Hg vacuum on hot idle, you know you've got a leak, don't you?

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10mm Hg -whats that in PSI or BAR

It's about a third of a bar.

Vacuum in boost gauges is denoted in mmHg usually, not psi (so when people refer to '20psi' vacuum it is obvious that they are fresh ;) )

 

you mean BIG leaks.

I mean small leaks --- big ones you can hear or feel!

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It's about a third of a bar.

Vacuum in boost gauges is denoted in mmHg usually, not psi (so when people refer to '20psi' vacuum it is obvious that they are fresh ;) )

 

 

I mean small leaks --- big ones you can hear or feel!

 

I think the idea that the 300 owner had was to find any SMALL leaks by running this test and then sealing them up. Yes you will know that you have a large or a small leak from a boost gauge, but finding a big leak isn't normally a problem, but trying to find a litle leak with no pressure behind it is a little more tricky.

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10mm Hg = 0.0133 bar

 

1 bar = 14.5psi

 

10mm Hg = 0.193psi

Heh, I said 'mmHg' when of course it's inchesHg (easy to mistype when there are so many standards, mmHg are used extensively as well)

About 30 of them are 1 bar.

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well 1 bar vacuum means that there is not a single air molecule (feasible only in outer space)

 

over 1 bar vacuum means there's a brain leak ;)

 

Around 20inches Hg is normal vacuum for engines when at operating temp (closed throttle ofcourse), that's about 10psi vacuum.

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That's how mine is when idling cold - remember that idle control valves etc are controlled intake leaks.

A cold engine doesn't seal fully either.

 

On hot idle the vacuum is higher, and lifting the throttle with the car moving I can see 20 inHg, which is around 10psi

 

I hope others will chip in with their readings.

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