Possible to meaqsure EBR?

[Stereophile33]

How do you measure EBR?

Jonathan

[stylngle2003]

i've seen magazines and such measure backpressure, but i think you might have a hard time measuring pressure inside the exhaust manifold collector.

but, to calculate EBR, i think it's just exhuast pressure/intake pressure

[coldfusion21]

The solution for measuring exhuast backpressure that i have heard is to tap a hole in the manifold or whatever and then run a section of metal tubing (10-12 inches i believe). Then run some rubber tubing to a low pressure gauge, i would guess that 5-10 psi would be enough, but i havnt really a clue.

This is something i want to do eventually as well, i think it would be very interesting.

[stylngle2003]

i would conjecture that especially right before the turbine, that exhaust backpressure is much higher than that

[The Aspirator]

I was reading alot about this on some turbo mustang forum a few months ago. They say it works like a charm, just like Jared described it above. Tap a hole, screw in a fitting, some metal tube then 3' of rubber hose to either an actual boost gauge or an electrical pressure gauge so you can datalog it with your computer. I was worried about the heat from the exhaust gas melting the boost gauge, but either Athal or Matt reminded me that this air is not flowing through the hose, so with a tube that long it might actually be plenty cool enough. I think 2:1 EBR is what to shoot for, meaning 20psi exhaust pressure PRE-turbo : 10psi intake pressure. Getting it even lower is good, I think. If you have more than like 5-8psi after the turbo then you have a really restrictive exhaust.

I've never tried this, it's only what I've read from turbomustangs, but I DEFINITELY want to measure this with my new engine. Definitely. Thanks for reminding me about it!

John

[Stereophile33]

ok well that sounds like a possibility then....just gotta figure out a way to tap a 90+ then....

[`pr0digy]

Would be an interesting number to have, eh ?

[The Aspirator]

Remove the mani, drill, tap. The hardware store taps should be plenty good enough, and they say right on the package what size drill bit to use. Get something common so you can use it elsewhere, like M8x1.25 or 1/8" NPT.