XLR8R

Twins only - what are you getting out of your bottom compressor? Please post turbo size, max primary boost and/or advertised P/R... wastegate info if the big turbine needs help. TIA

XLR8R

Bump......

soulezoo

I'm right on the edge of the poll question. I see 36-40 from primary and from 70-80 total.

This is with a Hybrid GT4218r as the primary.

jaredb900rr

My top turbo makes 28-32psi and my overall boost at the manifold is 54-58. It's a 62/71/13SS over an S474. I don't have the advertised ratio on it.

Jared

XLR8R

Thanks Terry - I was hoping you'd post up.
Isn't that about 100lbs/min through the primary?

Only working the top ~ 2:1 P/R? Remind me which secondary you have...







Jared, did you mean 28-32psi out of the S474?
Ever check your drive pressure up top?

banshee

S475 makes 32-34psi depending on the temperature. Feeds an HX-40 which puts right at 60 to the intake manifold. I run a 38mm external and the internal gate on the 40's 16cm2 housing.

soulezoo

The primary is a hybrid and not mapped but supposed to be capable of up to 138-139 lbs/min but is probably closer to 130. I don't think I am pushing it anywhere close to that right now. Your 100 guess is probably close... maybe 110... who knows.

The secondary is a hybrid gt4088r and is wastegated at 40psi.

The ratios vary throughout the range and depending on how I mash the pedal.

They will be heavy on the secondary side up to about 20 psi then they are both pushing the same air until about 55-60psi total then the primary starts pushing just a little more of the air load... but for the most part, it is 2:1 p/r and drive pressures stay at 1:1 (on both the secondary and primary) up to about 70-75 psi. At 80psi boost, overall drive pressure is about 90-95psi. I could run a larger EH on the primary and alleviate that, but it spools so darn fast I don't want to touch it.

rmalone

With flux 1's, TST at 3/1 and Va3.1 (at low power) I see about 28psi on the primary at WOT. No studs so I haven't fueled any higher. That 28psi is about 50% of total boost, which seems to be the case from about 45psi on up. My primary is a GT4202 (non BB).