Thread: Lt4 blower swap
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Old 01-20-2020, 04:00 PM   #38

Drives: SS 6 speed of course
Join Date: Jan 2016
Location: austin
Posts: 3,442
Originally Posted by Eldi Z View Post
Thanks for the insight oldman.
Yes, best thing is to ask around people running this setup for a while. Assuming GM is comfortable with ~ 10 PSI on an engine with 1 point lower C/R and with forged material, then my guess for a "safe" boost on a 1 point higher C/R with non-forged material should be ~ 7-8 (Max.) PSI - and yes, no less than 100K reasonable use (not "beating on her") miles longevity is the target.
IMO that is conservative, I like that. I'd do GM's high 9s (on 93) and work on the exhaust with either CA cat deletes move the 02 behind the second cats, or for an auto LT with cats. I know I'm "avant garde now" Also RotoFab, both mods reduce pumping losses so it is stress-free HP, which is longevity HP, ported tb and snout too. I figure the blower is probably optimized for high 9s and a 6.2 liter engine (never saw an efficiency map on it), I figure the aftermarket is doing plus 70 to plus 100 on a LT4 so dunno 12 to 14 PSI which has to be WAY off the efficiency map. We are dealing with a temp rise in either case, either before the intake valve or mechanical compression.

I hope others with the actual build will chime in. I would expect the build to be very responsive and fun.
2016 to 2017 Stage 1, FBO, ported MSD, 103 TB, E85

2018 Stage 2, P1C, 4.0 pulley, Pray ported heads, Pray stage 1 blower cam, TxSpeed valvetrain, Katech ported 87mm TB, ported MSD, 1 and 7/8 headers

2019 stage 3: Forged short block 11.5 CR, huge duration sub .600 lift Cam Motion cam, Pray Ported Heads, 3.85 pulley D1X, stage II intercooler, 2 BOVs, DSX secondary low side, DSX E85 sensor, Lingenfelter big bore 2.0, CA-offroad pipe, 60609 Borla, Lingenfelter injectors, ZL1 driveshaft and half shafts, Katech ported TB,MSD intake, BTR valvetrain.
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