I have a cammed 2004 Corvette on e85 and I'm not sure on how much timing to pull. The car has a pretty big cam, ls6 intake, stock 241's, racetronix walbro 450 kit w' hotwire kit, 60 lb injectors, and a nx proton plus kit(wet). I'm new to e85 but I'm spaying a 200 shot and I'm not sure if the rule of 2 degrees per 50 hp applies when using e85. Thanks

 

So nobody can ever say how much timing a car will want on a given fuel and nitrous. You can make a good suggestion, but it is best to just follow the 2 per 50 rule... Now, on a 100 shot on my c5z.. (hci, e85, vacuum pump, etc)... I only need 2 degrees out on that size shot. This may not be the same for you though, especially with your heads being stock. I would start the tune with 4 out, do a pull, check the plugs and get the fuel dialed in. Once the fuel is dialed in, then start creeping the timing in. Just don't get greedy with the timing and don't run it to rich. Where most mess up is chasing one issue with another. Find the car is too rich, so you add more timing, and you go back and forth till you lift a ring and break a piston. This is why you get the fueling dialed in with no timing in the car. You may be at the limits of the proton kit with the 200 shot. I would start on a lesser shot and work your way up to the 200.

 

Also, E85 makes the plugs a little more difficult to read in that you need to look at them like a blown alcohol motor basically. Look for a solid 3/4 of the top ring cadmium burnt off for the fuel to be dialed in. NX's chart will be on the rich side mind you, but not by much. If you have a wideband you can also double check against that. Your nitrous afr should only be slightly richer than your motor afr.

 

For the 200 shot though, I would start with 10° out of it and then see where the plugs want to go from there once fueling is good.

 

Thanks I definitely wont be exceeding the 200 shot until I get a plate kit and my tfs 220 heads installed. I really appreciate the advice and I'll post dyno numbers next week.

 

Reason I say to start lower and get smaller shot sizes dialed in is so you can see a trend of what the car likes and it will help you when you up the shot to get the next step dialed in quicker. You can never have enough good data.

 

all you did you increase the shot size from the proton is bought the 200 shot pills right ?

 

Correct I called nx and they gave me the correct pills for a 200 shot and I'm putting them in this weekend.