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The 6.0 LQ4 has been pulled from it’s donor. First step is to clear off any unneeded stuff and get it ready to run up before it gets the intake and headers installed.
Project 6.0 LS Cherokee - 1
The intake will need to be replaced with a car intake. The truck intake is too tall for hood clearance. This is to be a sleeper, so no hood scoop! I ordered a used LS1 intake off eBay. I plan to use the truck injectors as the LS1 injectors are rated for a higher flow than the truck PCM is programmed for. I don’t plan on having it tuned yet. The truck injectors are shorter than the LS1 injectors, so I bought injector adapters that install over the top end of the truck injectors to extend to the fuel rail. Speaking of fuel rail, the truck engine and the Jeep use a fuel return setup, the LS1 is returnless. The PCM would need to reprogrammed for that also, and a return type setup is much better! A return style fuel system sends most of the fuel back to the tank, the unused fuel. A returnless fuel system only has the one supply line and the fuel sits in that line until it is consumed. The problem with that is that when as the fuel travels through the fuel rails and through the engine compartment it picks up heat. If the fuel sits in the fuel rails until it is consumed it will be very hot. In a return style system the hot fuel is sent back to the fuel tank and is cooled there. This greatly reduces the heat in the fuel rails. Restarting a hot engine can be very difficult when the fuel in the fuel rails has boiled, you get a vapour lock.
So, I bought a pair of aluminium fuel rails, off eBay, and I’ll make a return fuel rail setup.
The cheapest fuel rails were purple, so that’s what I bought.
The used LS1 intake came with the throttle body and fuel rails which I won’t be using. The LS6 intake flows much better, but then again, they cost more, and the throttle body is 4 bolt, and mine is 3 bolt. The truck intake actually makes more power than the LS1 intake Hotrod magazine did a dyno test of popular intake manifolds for LS engines -
Maybe later if/when I upgrade the engine for power.
Using an Aeromotive referenced fuel regulator. This has a vacuum hose connection to bump the fuel pressure up when the vacuum drops, just like the truck’s LQ4.
September 27 -
Injector adapters
One modification I did was to the MAP sensor of the LQ4 to fit the LS1 intake. Both sensors are just pushed into the intake through a rubber grommet and held in place with the plastic clips on the side of the sensor. The truck MAP sensor is has a clip on each side of the sensor, the LS1 only one side. I just cut off the side that was in the way of pushing the sensor in, fits like it belongs there. Saved me having to buy a sensor and possibly needing to have the PCM programmed for it.
You can click the images for a larger version.
Truck intake
LS1 intake
LS1 intake