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Showing posts with the label Tuning

Starter battery relocation to trunk

The GM engineers allocated space for a starter battery in the trunk, but it remained in the engine bay until the release of the C6 Z06. I decided to replicate the setup as it improves the corner weight balance by shifting weight to the rear right wheel, which is the lightest corner of a stock C5. For the power cable, I used a heavy gauge 50 mm2/1 AWG multi stranded copper cable cable and press fit terminals. The heavy gauge is necessary to reduce the voltage drop caused by the long stretch and the high current required by the starter motor.  The ground cable is connected to the chassis, which is available in short distance from the battery inside the right wheel well. I installed a 350A automatic fuse next to the battery. The power cable is then routed forward above the right wheel well and then follows the existing wiring in the door sill to the front. With a battery in the passenger cabin it important to use a battery which does not emit harmful gases, so I used a sealed SMF battery.

Clutch pedal stop

Clutch pedal throw on the C5/Z06 is far too long. On track days, I can literally watch other cars gaining distance during a gear change. Trying to speed up the pedal movement only results in bad timing and loss of traction. Inspired by the thread at Team ZR1, I made a clutch pedal stop to reduce the throw length.  In most cars, the last part of the pedal travel is a waste, as the clutch is fully released with less movement of the slave cylinder.

Electric power steering conversion

Almost the first thing I did after buying the Corvette was to participate on a track day. When returning to the pit after the first session, there was power steering oil everywhere! The reservoir was filled to the correct level, but the heat caused the oil to expand and overflow. Home in the in garage, I found not only the power steering pump to be leaking oil, but all the lines and the steering rack. I cleaned everything, replaced the old brittle return hoses to the oil cooler and refilled with Redline power steering oil - this time only up to the bottom of the dipstick, to allow capacity for the fluid to expand. Next track day, the power steering was still leaking. The power steering pump is simply overwhelmed by the high RPMs, it builds too much heat and pressure and cavitates the oil. As I enjoy the thought of interfacing new electronics to the car, I decided to add an electric power steering pump to resolve the issue. After some research, I found that the TRW/Vauxhall Astra H pow

HPtuners - ECU remap

While changing the spark plugs, I was bothered by the secondary air injection pipes blocking access. Suddenly, the whole system was on the garage floor! -This triggered multiple fault codes, giving me the perfect excuse to purchase HP Tuners. Using HP Tuners, the air pump activation was disabled and the associated fault codes disabled. Obviously, I couldn't stop there and I've now spent quite a few hours researching what other settings I could tweak without affecting the fuel and ignition base maps. Disable all engine torque management/reduction and reduce traction control sensitivity Reduce sensitivity to IAT and ECT below 100 °C (don't retard timing) Disable CAGS/skip shift function Disable column lock failure speed limit Reduce the transmission temperature warning to 120 °C (the trans temp will then be shown in the DIC). Reduce cooling fan activation temperature, and also activate fans after ignition off Turn off AC compressor above 65% throttle Disable cat over temp pro

Water separator as oil catch can

While changing valve springs, I noticed that the intake manifold was soaked in oil. This is due to the crankcase ventilation returning to the air intake.  Burning oil is bad for the engine, as it causes carbon buildup. Combined it can lead to pre-detonation (engine knock) on high load. I decided to add an oil catch tank to remedy the issue. Internet vendors charge stupid money for "tin cans" produced in China, so I usually design my own solution using the stock PCV and an aluminum bottle with steel wool to suspend and separate the oil vapor from the air. This time, I came up with the idea of using a water separator for compressed air, $25 in a hardware store.  The water separator contains a 5 micron filter to suspend the particles, and is rated for 1500 liters/minute (although at a much higher pressure). They are also designed to be easily drained. Perfect fit as an oil catch can. The only modification required is to remove and seal off the bottom spring loaded drain valve (I

Throttle body porting

I used a Dremel tool to port the throttle body. I removed most material from the outer edge to flare out the air entry. To avoid issues with idle control, I made sure not to remove material too close to the butterfly valve. The air passage for the crankcase ventilation is a massive air block, so I shaped it more aerodynamic using chemical metal. I intentionally left a rough surface, as the physics says so After taking the picture, I also decided to bypass the coolant loop, so I cut off the coolant hose connectors. The coolant loop is there to prevent the butterfly valve from freezing in cold weather, but that can only happen in extreme conditions (I drove my Subaru WRX in -35°C (-31°F) with the same bypass, and had no issues). Stock throttle body for reference Update: After 4 years, I've had no issues with the ported throttle body. Pickup on acceleration is sharper, which was the goal.

Rear steam vent crossover pipe

The rear crossover pipe/steam vent reduces local hot spots in the rear cylinders by allowing air and steam to escape. The LS1 came with the crossover pipe, but was removed for the LS6 as it came in conflict with the larger intake manifold. The ports are still in the LS6 engine block but they are blocked off.  . When I had the manifold off to change the valve springs, I decided to add the crossover pipe. I simply used the pipe from a truck, GM part 12605716. I only had to slightly bend the pipe to refit the LS6 manifold. I put on a T-junction and routed the hose back to the coolant expansion tank.

Intake manifold heat shield

With the intake manifold off, why not? I very much doubt the results of this dyno test (ref link below), but I've noticed that the engine is struggling high air intake temperatures on track days, so a thermal barrier between the hot engine and the intake manifold can't hurt. Link: Heatshield Products I-M Shield Install and Dyno Test: More Horsepower for Less