Considering these cars average the same MPG or worse as an LS1/LS2 GTO it's DOD's merit is questionable.

It's also the reason the car took more than a year to get here from Australia and why we can't get a manual with the base V8 like our Aussie friends do.

I would not sweat not having DOD, in fact I would mod the engine to get rid of it. It's pretty pointless in a V8 muscle car like this.

 

This is not really true. The EPA changed its rating method for fuel mileage in 2008 and all cars ratings dropped about 2 mpg. The EPA has rerated all previous model cars to the 2008 test method so you can compare them to the new cars. http://www.fueleconomy.gov/feg/findacar.htm

The G8 is rated at 15/24 mpg while the LS2 GTO M6 would be 15/23 mpg and the LS2 A4 would be 14/19 mpg. Remember the G8 is the heavier car and is an auto. The only GTO that would still have a higher rating would be the LS1 M6 car. I would say that the AFM (DOD) is making a difference in the hwy mileage by a minimum of 2 mpg.

 

what kind of headers? who's making them?

 

Your gonna need new head gaskets as you have to pull the heads to get the lifters out, you will also need a new valley cover plate, as the current one has the solenoids built into it. There is some other things in the oil pan that I have yet to figure out, waiting on an answer now. Oil pressure will go up as well.

 

Have Comp Cam's custom grind a cam that fits under the DOD requirements for the 4 cylinders in question. Also get a set of Yello Terra 1.85's for the L76/L92/LS3 head. This will increase the lift of the valve. Pair it with a set of Comp 918's for .625" lift or there 921's for .650" lift.

The main thing is keeping the cam lift low on the lobe and increasing the rocker arm length (this way you get the lift at the valve).

If one of the cam companies would do this they could offer a performance kit (cam, springs, and rockers) for the L76/L92 market (Truck/SUV/G8 and if it ever hits the ground LS2 09 Fbody with AFM). That is an untapped market that with gas prices constantly increasing is a ripe enthusiast market for the cam companies to look at.

 

American Racing makes a killer header system for the G8 , you can order it here www.neweraperformanceparts.com . Also , Yella Terra does not make anything other than 1.7 ratio currently , it is a typo , I believe they are working on 1.8 right now . I am pretty sure SLP makes 1.8 or 1.85 ratio stock body l92 rockers though . I believe the 921 spring would be too much seat pressure for the DOD lifter also from the people I have talked to . I am testing a DOD cam this week , I will post the results , it is supposed to be close to as big as we can go still utilizing it (which isn't much) .

 

I have Mike @ New Era's NON DOD 228/240 Cam and I love it. I lost 4 MPG over my Tune, but only 2 MPG from stock. I'm over 400HP at the rear wheels and 381 Torque. I'm also in the 12's 1/4 mile time. If you want your G8 to run, call Mike....He'll hook you up!