1992gen1_fan

Hello, today I installed a 60psi pressure gauge to measure exhaust/drive pressure Installed to monitor the exhaust pressure that the VGT creates so I dont run into problems on the road.

How much pressure should I see under normal driving conditions?

What is the maximum safe exhaust pressure on a stock engine???

Thanks for any usefull input

jimbo486

Typically, you'll see anywhere from 1:1.5-2.0 (boost pressure:drive pressure) or 1.5 to 2 times the amount of boost pressure. An optimum ratio would be 1:1, of course.

1992gen1_fan

Ok, at 8psi of boost I was around 15psi of drive.

Is there a max safe drive psi?

Marty Z

That is a little high,on mine I have about 8# of boost at 65 mph and about 12# of drive.

Love that VGT

dieselJon

There are some nice setups getting 10# boost, 8# drive...

1992gen1_fan

I can probly do some adjustments on the vgt and IP and help get the ratio a little closer. Still fine tuning.

I really like the vgt also.

Douglas2

hey-Hey!!!,
Now y'all have got me wondering what is going on with my heap. I would also like a minimum ov drive pressure...which leads me to this, one can measure it to atmosphere, or differential( subtracting the pressure due to the rest ov the exhaust ). The former is ov course a lot easier...
cheers,
Douglas

bmoeller

What is the safe limit with back pressure without 60# valve springs? Want to use the "exhaust brake" function of the VGT once it is on. Will get heavier springs when I get a chance.

1992gen1_fan

Thanks for the input fella's.

Thats another question im asking also, what is safe exhaust pressure limit with stock valve springs???

Marty Z

60# of Bach pressure is what most recommend max.With the 60# springs

1992gen1_fan

So, no more than the spring pressure. How many lb springs are in these stock? 40lb?

bmoeller

I was asking about the safe back pressure WITHOUT the 60# spring, re stock springs.

1992gen1_fan

I was watching my gauges today. During acceleration the back pressure will go up to about 17-18psi then the boost starts rising. Once the boost gets to 6psi the back pressure steadily drops down to 12-13psi and stays as boost keeps rising. Had 13psi drive and 20psi boost for a bit.

Cruising at 65mph the back pressure sits around 12-15 and boost at 4-9psi, and 6-750*f for the egt's.

Is 20psi of back pressure bad with stock springs??????

Marty Z

I think 40# is a safe number.

1992gen1_fan

Alrite, thanks.