spooled142

What is a safe amount of boost for an HY-9. I've heard of people hiting 35 lbs. Is that the max to push?

spooled142

Never mind found what i was looking for 32-35 psi max

Big Smoky

Don't forget to watch drive pressure. It'll kill ya

spooled142

what do you mean by drive pressure???

Erska

He means the pressure in your exhaust side, the pressure between the exhaust valves and the turbos exhaust housing, but it seems that nobody really monitors drive pressures in these motors...

Big Smoky

Big mistake when running stock or small turbo and a lot of fuel.

Erska

I know that it is. But at least in here I haven't read that anybody has monitored their drive pressures. What kind of gauges do you have for that?

RowJ

Proper engineering term for drive pressure is Turbine Inlet Pressure .... or TIP.
Any air pressure gauge can be used... simply disconnect your EGT gauge, at the manifold, and plug it in there.
I use a cheap 0 - 100 psi gauge with 6' of copper tubing and run it over the engine ..... under the hood..... and inside through the passenger window.
Rest the gauge on the opened glove box door and test at WOT.

Spooled142 -I found any boost over 32 psi on an HY-9 is producing expansion pressure from heat ... as opposed to compressed boost pressure.
Over 32 psi releases no additional HP.
The earlier automatics with HX-35 turbos could handle 35 - 38 psi but I wouldn't go that high on yours. Cooler is better.

RJ

spooled142

Thanks for the info. That really helps me out.