Super Chevy Magazine Homepage Super Chevy
Facebook Click here to find out more!

5.3L LS Small Block Build - Modern Mouse, Part 7

Turbocharged Boost!

By Richard Holdener, Photography by The Author
Sucp 1206 000 3L Ls Small Block Build Part 7

Additional components included a pair of 45mm Hypergates and a single RacePort blow-off valve all from Turbo Smart. The exhaust system featured shorty truck headers from JBA connected to the turbos using short tubing sections designed to adapt the stock exhaust flanges to the T4 turbos. The Turbo Smart Hypergates were positioned inline on the adapter tubing, while the single RacePort blow off valve was welded to the single 3.5-inch aluminum inlet tube.

CXRacing also supplied the necessary 3-inch aluminum tubing, couplers and clamps to connect the turbos to the intercooler as well as the 3-inch stainless tubing, v-band flanges and clamps used to complete the exhaust. In addition to offering complete kits, CXRacing was a one-stop source for our do-it-yourself turbo kit. The final upgrade was to replace the 36-psi injectors with a set flowing 75 lbs per hour.

With Modern Mouse ready to rock, we first dialed in the air/fuel mixture at just seven psi before working our way up in power. Even at just over 7 psi, Modern Mouse produced nearly 750 hp. Eventually the boost was increased to nearly 13 psi (12.8 to be exact), where Modern Mouse pumped out 963 hp at 6,500 rpm and 868 lb-ft of torque at 5,000 rpm. Torque production exceeded 800 lb-ft from 4,650 rpm to 6,300 rpm, but never dipped below 700 lb-ft.

Being so close to 1,000 hp, it took all of our will power to stop from cranking up the boost. In the end, we decided to limit the boost to a reasonable level.

  • Sucp 1206 015 3L Ls Small Block Build Part 7
    10 All testing on the NA and turbo combinations was run with the FAST XFI/XIM management system. Fast also supplied the necessary 75-pound injectors for our turbo motor.
    Sucp 1206 015 3L Ls Small Block Build Part 7
    10 All testing on the NA and turbo combinations was run with the FAST XFI/XIM management
  • Sucp 1206 013 3L Ls Small Block Build Part 7
    11 We ran Modern Mouse normally aspirated prior to the installation of the twin turbo system. Obviously the heads from Procomp Electronics worked well, as the 383 responded with peak numbers of 539 hp and 516 lb-ft of torque.
    Sucp 1206 013 3L Ls Small Block Build Part 7
    11 We ran Modern Mouse normally aspirated prior to the installation of the twin turbo sys
  • Sucp 1206 016 3L Ls Small Block Build Part 7
    12 The custom turbo system utilized JBA shorty truck headers feeding custom tubes to adapt the stock header flange to the T4 turbo.
    Sucp 1206 016 3L Ls Small Block Build Part 7
    12 The custom turbo system utilized JBA shorty truck headers feeding custom tubes to adap
  • Sucp 1206 014 3L Ls Small Block Build Part 7
    13 CX Racing supplied a pair of 76-mm turbos. In truth, these were more than we needed for Modern Mouse (they also offer smaller 67-mm and 72-mm versions), but we had them on hand. Each of the T4-based, 76-mm turbos featured a 4-inch compressor inlet, a 2.5-inch discharge and 3-inch exhaust outlet. The exhaust system consisted of a pair of 90-degree, 3.0-inch stainless steel elbows.
    Sucp 1206 014 3L Ls Small Block Build Part 7
    13 CX Racing supplied a pair of 76-mm turbos. In truth, these were more than we needed fo
  • Sucp 1206 017 3L Ls Small Block Build Part 7
    14 To ensure proper boost control, TurboSmart supplied a pair of Hypergate45 waste gates. The trick threaded collar design not only decreased overall size to improve fitment, but facilitated easy spring swaps. The waste gates were secured to the dedicated waste gate flanges using V-band clamps.
    Sucp 1206 017 3L Ls Small Block Build Part 7
    14 To ensure proper boost control, TurboSmart supplied a pair of Hypergate45 waste gates.
  • Sucp 1206 018 3L Ls Small Block Build Part 7
    15 TurboSmart also supplied one of their RacePort blow off valves. A high-flow blow off valve is a necessity on high-boost/power applications. The blow off valve opened to provide pressure relief during shifts or lift-throttle applications. Without the valve, the pressure wave that flows back after slamming into the closed throttle body would try to escape back out the turbo. Attempting to instantaneously stop or reverse the flow of an impeller spinning upwards of 100,000 rpm is not a good situation! The RacePort shared the threaded collar design with the new Hypergates.
    Sucp 1206 018 3L Ls Small Block Build Part 7
    15 TurboSmart also supplied one of their RacePort blow off valves. A high-flow blow off v
  • Sucp 1206 019 3L Ls Small Block Build Part 7
    16 Keeping things cool was a dual-inlet, single outlet, air-to-water intercooler from CXRacing. Capable of supporting over 1,500 hp, the dual-core system was supplied dyno water for this testing. CXRacing also supplied the necessary 3.0 and 3.5-inch aluminum tubing, couplers and clamps to complete our custom kit.
    Sucp 1206 019 3L Ls Small Block Build Part 7
    16 Keeping things cool was a dual-inlet, single outlet, air-to-water intercooler from CXR
  • Sucp 1206 021 3L Ls Small Block Build Part 7
    17 With everything finally assembled, we were finally ready to run Modern Mouse under boost. We started at the lowest boost setting (7-psi waste gate springs) and worked our way up to just under 13 psi. Even at 7.3 psi, Modern Mouse pumped out nearly 750 hp, but things got really interesting once we cranked it up. Running 12.8 psi, the turbocharged 383 produced 963 hp and 868 lb-ft of torque.
    Sucp 1206 021 3L Ls Small Block Build Part 7
    17 With everything finally assembled, we were finally ready to run Modern Mouse under boo
  • Sucp 1206 022 3L Ls Small Block Build Part 7
    18 Stock LM7 5.3L-NA vs HP Performance Single Turbo (8 & 11.3 psi) The stock 5.3L was run with a set of long-tube headers, 36 psi injectors, and FAST XFI/XIM management system. Run in normally aspirated trim, the 5.3L produced 361 hp and 386 lb-ft of torque. Running with the Precision turbo on the single turbo kit from HP Performance resulted in 510 hp and 521 lb-ft of torque at just under 8 psi. Adding an intercooler and increasing the boost pressure to 11.3 psi resulted in a jump to 608 hp and 641 lb-ft of torque. At this point, the stock combination would benefit greatly from a cam swap.
    Sucp 1206 022 3L Ls Small Block Build Part 7
    18 Stock LM7 5.3L-NA vs HP Performance Single Turbo (8 & 11.3 psi) The stock 5.3L was r
Sucp 1206 023 3L Ls Small Block Build Part 7
19 Modern Mouse-NA vs Twin CX Racing Turbos (12.8 psi) Though we ran Modern Mouse at lower boost levels, the final test resulted in peak power numbers of 963 hp and 868 lb-ft of torque at just under 13 (12.8) psi. That represented a gain of 448 hp and 361 lb-ft of torque over the normally aspirated combination.
SOURCES
Comp Cams/Fast
3406 Democrat Road
Memphis
TN  38118
800-999-0853
www.compcams.com 		Probe Racing
2555 West 237th Street
Torrance
CA  90505
310-784-2977
www.probeindustries.com
Holley/Hooker
1801 Russellville Road
Bowling Green
KY  42101
270-782-2900
www.holley.com 		Procomp Electronics
605 S. Milliken Avenue
Unit A
Ontario
CA  91761
909-605-1123
www.procompelectronics.com
L&R Automotive
13731 Bora Drive
Sante Fe Springs
CA  90670
562-802-0443
www.lnrengine.com 		CX Racing
626-575-3288
www.cxracing.com
By Richard Holdener
Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!

*Please enter your username

*Please enter your password

*Please enter your comments
Comments:
Not Registered?Signup Here
(1024 character limit)
Super Chevy