The Ultimate Sleeper exhaust

[ckyfreak2010]

basically a wastegate for your whole exhaust, pretty bad ass

[fahr_side]

It's very common. Big problem is if you tune boost for a closed valve you have massive overboost when the valve is open. If you tune boost for an open valve, good chance you won't hit targets with it closed. You end up having to push the actuator with a boost signal, or conversely use a Hobbs switch to let vacuum keep it closed when off boost and have it open in boost, which means every time you get on it the car is screaming.

IOW, people that like dump to atmosphere EWG setups would love it, and those who don't will hate it.

 

Oh, and the cheap Chinese valves you see on eBay last about 7 minutes 32 seconds before going tits-up.

[fahr_side]

I prefer one of two approaches.

 

1. Get a normally-closed valve that uses positive pressure to operate, like a normal internal WG actuator. Use one that operates at about 5~8psi. Tap the up-pipe for a pressure source, as EGBP rises much faster than manifold pressure in spool. Use a cooling coil of narrow hard pipe to protect the soft hose you'll use to connect to the actuator from exhaust heat.

 

Advantages: Simple install, no electrical parts. System defaults closed. Disadvantage: Have to wait for EGBP to rise before the valve reacts, closes very quickly, like on gear changes.

 

2. Get a normally-open valve operated by vacuum. Use the brake booster as the vacuum source, i.e. from the other side of the check valve from the manifold. Install a Hobbs switch set at 5~8psi and tap that to the intake manifold. Use the switch output to operate a simple solenoid valve that controls vacuum to the valve's actuator.

 

Advantages: Normally-open valves seem to open faster and close slower.

Disadvantage: On cold start up there may be no vacuum left in the tank and the valve will be open a split second until the booster 'recharges'.

 

If the valve closes on gear changes use a timer relay to operate the solenoid so it still gets signal for a preset time after MRP drops and the Hobbs switch opens.