we set a new best last saturday, but not by much and MPH didn't improve and I have a theory why not.

We ran a mix of 50/50 , 93/110 octane this past Saturday, first time the car has been out in a year (built cage, took wieght out, etc). We'd ran the 150 shot before with our 11.5:1 comp motor on 93 pump w/ booster, 6-deg of retard and autolite 104s gapped at .035. No problems. 11.25 at 122.9mph using the progressive shot.

The 93 in the tank Saturday already had booster in it.

We've gone to a 175 shot, long tubes, true duals, dropped about 150lbs total (net....after the cage).

We ended the day with only 4-deg of retard (not even the slightest hint of trouble) and running 11.16 at 124.6mph. The car felt 'doggish' on motor even with the weight savings. I am thinking that we had a bit too much octane for our mix and tune. Our programming intentionally doesn't has a lower number for full advance because we msotly run this car on spray (motor pases are for bracket racing and we don't care how slow it is there). The plugs...looked absolutely perfect.

For the weight we dropped and raising the shot 25hp (admittedly not much) I'd expected something. Oh, this is a WET shot coming on at WOT and typically launching between 1,000-1,500rpm.

We're going to the local 1/8th mi (I hope) next weekend with a gear change and maybe a little less race gas or maybe just 93 with booster in the tank. Only reason I added race gas this last time was to be on the safe side. Maybe it was a little too safe.

Built bottom end with strong rods and heavy pistons.

 

I dont think you had too much oct. considering you have 11.5 to 1 compression and are running a 150 shot. If your seeing no detonation you might consider opening your plug gap to .038-.040. I wouldnt pull any less than 4* of timing. Keep working with the progressive ramp up and youll see 10.xx soon.

 

Oh , one more thing. DONT trust those octane boosters to boost your octane. Use higher octane fuel. Also , you dont want to run leaded race fuels as they will destroy you O2 sensors.

 

I'm well aware of the leaded fuel and the O2s. Hopefulyl over the winter I will reporgram the car to run open-loop and the O2s can go the way of the Bengals.

So far, we've not seen a problem with the O2s. Truthfully, I think the heat of the exhaust from running spray helps keep the cleaned off.

As for the octane booster, I don't trust them. We've had good luck, but I will always run some retard.