JSCumms2000

Im curious to see what everyone is running on their twin setups.. what kinds of drive boost, what kinds of primary boost, and what kind of secondary boosts... also, what works for you and what doesn't.. and advantages of both... just searching for some opinions and anything interesting... thanks

dodgezilla04

my bottom turbo is at 29-31 and top gets to 62... but i have small turbos, no DP gauge.

soulezoo

LOL DZ04... gt45=small turbo...

As I mentioned in another thread recently I will see 70-75psi boost and 1:1 drive pressures to 70. Bottom turbo provides roughly 1/2 of total boost.

Most well matched coumpound turbo sets will mirror roughly what I just posted above where each turbo is splitting the boost duties roughly equally and ideally maintaining a 1:1 drive pressure ratio, top and bottom, all the way to max usable boost. The differences end up being spool time and adjusting wastegates for optimum tuning and some other minor issues.

RJOS

Hey do you guys with twins have boost gauges for each one? Flame suit on.

soulezoo

I do... 100psi and a 60 psi.

The 100psi is plumbed in the intake manifold with a boost bolt, the 60 psi is plumbed to the primary turbo compressor housing.

Dieselhed

I do. Primary on the intake manifold. Secondary on the back of the cold pipe.

RJOS

Sweet...............

RowJ

This is fairly common. Guys with facctory turbos over S400 will see slightly less than1/2 from the bottom.
My BD's read 35 psi primary and 65 psi total (top turbo). BD's get a bit more than 1/2 from bottom turbo..... roughly a 66/74/24!

RJ

dodgezilla04

yep, 0-100 on the air horn, and 0-60 on the cold pipe as well...

omaharam

I just hooked up a temporary gauge to get the little one dialed in and then just run one gauge to monitor overall boost.

RyeThomas

I dont see 50/50 till I get over 30+lbs total, takes a little longer for the 480 to roll but she catches up quick . But more or less top end they are 50/50.

rmalone

I think you got those reversed, the cold pipe reads the primary.

On mine I see 1:1 from about 40psi on up, though it's close to 1:1 from 30psi. I haven't checked DP, but I don't push 'em past 55psi anyway, no studs.

WICKEDDIESELS

A properly set up twin kit will run in the 2.0-2.2:1 ratio. Drive pressure should be in the 1:1 ratio, once the compressor gets into its map range. When the secondary turbo reaches pressure to open the wastegate, it can drop 50,000 rpm. This is how a compound set can see high boost levels, in comparison to a single. The air being delivered to the secondary reduces thrust loading, yet will allow high volume low pressure air to further increase the compounding.

Dieselhed

Get off my ***, I work nights......