Project C5X back at Next Level...
Project C5X back at Next Level Performance for another round of testing with a new VMax Motorsports throttle body.
Technical Assistance: Geoff Skorupa
Last month we talked about the how we were going to make some power with our almost-stock LS1 engine. Early in the project we decided the prudent use of our time and energy would be to build the stock engine we had in Project C5X instead of swapping in a brand new LS stroker. With that in mind, we decided to install a LS1X World Warhawk heads and a custom grind C4orce Comp Cams hydraulic roller camshaft and valvetrain. As most of you already know, a head and cam upgrade is one of the simplest and most productive upgrades for any car but especially so for the free-breathing LS1.
This month, we want to install a new throttle body to Project C5X and see what kind of horsepower it can mean to a near-stock Corvette. Pete Incaudo, owner of VMax Motorsports has been working with World Products for quite some time and knows their product line well. As we mentioned last month, Pete worked on the development side for the LS1X World Warhawk heads. While Pete is one of the best cylinder head guys in the country, he also knows engine air flow like nobody's business.
The ported inside of the VMAX...
The ported inside of the VMAX modified LS1 throttle body. Notice the shaved down throttle shaft.
With over 40 years of airflow experience, Pete has also developed his own VMax Motorsports ported throttle bodies. VMax throttle bodies are available for all LS-applications on an exchange basis. All of his throttle bodies are CNC-machined to smooth the flow characteristics of the throttle body past the throttle plate while avoiding the tip-in stumbles that can plague other porting jobs. When you first see one of these throttle bodies, it looks more like a work of art than a part to make horsepower. We know we will have to modify the LS1X World Warhawk heads when we do the cam and head install so we decided we would do this TB install now to keep the results as simple as possible before the big wrenches have to turn. Let's jump right into the TB install.
| Difficulty Index - 3 Wrenches |
| Anyone's Project: no tools required | 1 Wrench |
| Beginner: basic tools | 2 Wrenches |
| Experienced: special tools | 3 Wrenches |
| Accomplished: special tools and outside help | 4 Wrenches |
| Professionals Only: send this work out | 5 Wrenches |
To begin the install, remove...
To begin the install, remove the screws for the air intake and remove the intake system.
Next remove the three screws...
Next remove the three screws for the throttle body and electrical connectors for the TPS (throttle position sensor) and the TAC (throttle actuated control) and remove the stock throttle body.
Transfer over the TPS andthe...
Transfer over the TPS andthe TAC assembly from the original throttle body to the new VMax throttle body.
The TPS...
...and the TAC assembly use...
...and the TAC assembly use Torx screws for attachment to the throttle body.
When removing the TaC assembly...
When removing the TaC assembly be careful not to tear the gasket when pulling it away from the body.
Notice how the gear on the...
Notice how the gear on the shaft is removable to install onthe new throttle body, make sure you put it in the new TB the same way it was on the old TB.
Reassemble the TPS and the...
Reassemble the TPS and the TAC assembly...
...with Torx screws to the...
...with Torx screws to the new throttle body.
After installing the TPS,...
After installing the TPS, and TAC assembly, push the blade open and watch it close to make sure nothing binds during the operation of the blade.
Wallah, the assembled VMAX...
Wallah, the assembled VMAX ported LS1 Throttle body.
Before installing the throttle...
Before installing the throttle body, check the o-ring gasket on the intake manifold to make sure there are no cuts or problems with it sealing to the TB.
Reinstall the throttle body...
Reinstall the throttle body and install the three bolts...
...TPS and TAC electrical...
...TPS and TAC electrical connectors.
Reinstall the fresh air hose...
Reinstall the fresh air hose from the valve cover.
Reinstall the intake system...
Reinstall the intake system to the throttle body.
Back to the rollers for testing...
Back to the rollers for testing on Next Level Performance's Dynojet 224 XLC chassis dynamometer.
Geoff Skorupa of Next Level...
Geoff Skorupa of Next Level Performance unlocking the mysteries of the laptop computer while tuning Project C5X with HP Tuner software.
We decided to run a check run to make sure we were in the same ballpark since it had been a while since we had Project C5X on the dyno. The first run produced 327.90 horsepower at 337.37 lb-ft of rear-wheel torque which was pretty close to where we needed to be. After the VMax TB install, the next dyno run produced 335.49 horsepower at 343.21 lb-ft of rear-wheel torque, picking up another 7 peak horsepower and almost 6 lb-ft of rear-wheel torque.