Drive pressure question

D

docta

New member
Joined
Sep 8, 2009
Messages
47
For those monitoring drive pressure and running twins, anybody running two drive pressure gauges to monitor the drive pressure of both the primary and secondary chargers? Trying to get my gauges in order before upgrading the twins.
 
We use a billet boost gauge manifold made for tuning twins & wastegates - that way, a pair of boost gauges is all the instrumentation required.

For twins, we run TIP kits on the exhaust manifold & hot pipe, and read boost off the cold pipe & intake airhorn/manifold... another pair of pressure taps if running both an IC & CAC.

Basically, you monitor drive pressure to each turbine, and charge-air pressure on both side of each heat exchanger - takes less than a minute to swap the gauge lines between any pair of the 6 pressure taps.
 
XLR8R said:
For twins, we run TIP kits on the exhaust manifold & hot pipe, and read boost off the cold pipe & intake airhorn/manifold... another pair of pressure taps if running both an IC & CAC.
Click to expand...

Thanks for the info, can you indulge a rookie question...What's a TIP kit?
 
TIP = Turbine Inlet Pressure IIRC


XLR8R, what kind of drive pressure differentials do you typically see across the turbos in twins?
 
docta said:
Thanks for the info, can you indulge a rookie question...What's a TIP kit?
Click to expand...

White Knight said:
TIP = Turbine Inlet Pressure IIRC.

XLR8R, what kind of drive pressure differentials do you typically see across the turbos in twins?
Click to expand...

Exactly.

PRs vary with turbo selection & tuning, but a general rule of thumb is 2:1 from the primary (atmosphere charger) & 3:1 through the secondary (top) turbo.
 
I guess I need to work on my search skills. Found the website (Lazarsmith.com). Nice looking stuff! appreciate the info.
Scott
 
XLR8R said:
Exactly.

PRs vary with turbo selection & tuning, but a general rule of thumb is 2:1 from the primary (atmosphere charger) & 3:1 through the secondary (top) turbo.
Click to expand...

I've seen numbers for single systems suggesting optimal drive pressure to boost ratios approaching 1:1, although most suggest 1.1-1.2:1. Do you still look for an overall Drive pressure/boost ratio of 1.1:1 or 1.2:1 across the whole system (exhaust manifold to intake plenum)? The only graphs I've seen posted on this site showed what appeared to be about 2:1 across the whole system.
Thanks
 
Oh OK - I was addressing load-sharing between the compressors.

Theoretically, PRs at or below 1:1 are best, but often optimal ratios for actual performance & street manners are a bit higher, even extending closer to 1.5:1

PRs across the whole system are useful for quantifying things like pumping losses, but PRs across each turbo help to keep the compressors on their maps' better efficiency islands.
 
XLR8R said:
Oh OK - I was addressing load-sharing between the compressors.

Theoretically, PRs at or below 1:1 are best, but often optimal ratios for actual performance & street manners are a bit higher, even extending closer to 1.5:1

PRs across the whole system are useful for quantifying things like pumping losses, but PRs across each turbo help to keep the compressors on their maps' better efficiency islands.
Click to expand...

Thanks again, I understand what your saying and appreciate your input on this
 
Can someone get this down to laymans terms and pictures of the manifold what type tubing and so forth,I have an S400 /he 351 installed and need to check the pressures but it's an all new game for me. Thanks
 
You'll have to forgive mike. He sometimes forgets that we aren't all of the engineer mind set. LOL
 
You must log in or register to reply here.
Back
Top