New Best!

It was a cool night at Atlanta Dragway and me and David (ga289stocker) were there. It was also the last race of the year. We both had only made one pass this year and that was for the show Pass Time that was filmed back in May.

Putting the "newby feeling" nerves aside I went ahead and pulled down my new best time on my first pass. My burnout was good but I got into the throttle a little too slowly as I think it would have hooked with the pedal to the floor. Anyway, the pass looked like:

60' ... 1.642
330 ... 4.661
1/8 ... 7.211
MPH ... 96.09
1000 ... 9.446
1/4 ... 11.383
MPH ... 115.59

Oddly, the car ran over 96 mph in the 1/8 on all three runs which it had never done before but LOST mph on the top end. I have some 116.8 mph or so passes. It acted like it was starved for fuel on the top end??

I backed this run up later during "Power Hour" with an 11.48. This won me the $50 Year One gift cert. and a $50 NAPA gift certificate for quickest street legal car. I was actually surprised by this as there were LOTS of fast cars there tonight. Old and new Mustangs, Camaros, some speedy RICE, Z06, Nissan GTR, Challengers, etc..... Big turnout for the final race of the season!

Nothing broke, set a new best and got some spending $!!

I just need to figure out what is happening on the top end of the track. I would have loved to jetted up tonight to see if it made a difference. My 750 Demon uses 79's and 87's. Does this sound close for 1000 ft elevation, 6500 rpm shift points with full exhaust???

Well if the jetting was close when the air was, for instance, 80 degrees, 75% humidity, and this last race was cooler, dryer air, chances are that the jetting could be a bit on the lean side (which may be a possible cause for it "laying over" a little). Generally speaking, I always had to go up about 5 sizes on all 4 (I run them square...all 4 jets same size) when the air got "good". Good meaning a density altitude (DA) of 500' or better. Last race day it was -238'. That's 238 below sea level. Our altitude at the track is 360' so we're lucky anyway BUT in the summer, DA can get up to around 6000' so there is a big difference in air quality. If jetting wasn't such a pain on my Mustang I'd play with it more often. I guess I'm spoiled...the Maverick...one jet and it takes 15 sec to change it.

Congratulations on the new best and taking the win.

I agree that you had a strong 1/8 mile and it appeared to fall off some on the upper half. Could be fuel delivery, weakening valve springs, or not enough air in the rear tires causing drag.

Congrats Vinyl-time to update the sig!
Pretty sweet to get the fastest street legal car recognition also.

Dumb question,but how much gas did you have in the tank?

What was the factory jetting for the carb? I think I remember BigJoe saying the Demons usually run lean out of the box.
Like Mavman said,if you were running the same jetting last night as you do during the summer, there's no way it was optimum both times.

I remember hearing 76/83 jetting on a BG 650 runs well. I would think the BG 750 should be a tad higher. What rpms are you crossing the lights at??

I don't know what the DA was last night but it was a nice calm and cold night.
My Mighty Demon came with 76 and 84 jets and I currently have 79 and 87 in there. I know I should have jetted up because I ran right at 117 in the summer heat with the same jets. I have also added a 1" open spacer since the last time out too. mavman: No doubt I would have changed jets if I could do it in 15 seconds. That would be sweet!

I'm not so good at the tuning portion of the "Test and Tune" because I usually walk around the pits talking to people about their cars instead of actually tuning mine. Oh well, it's still good clean fun!

68fastang: My gas gauge stopped working recently so I filled up and was running with a full tank last night. And yes, finally time to update my sig

Spali: I don't even know what rpm I crossed at but I do know it is WAAAY too low because I am running 3.55 gears.

Damn, slap some 4.30 gears in that baby and watch it hit the 10's.... Your probably crossing the lights at like 4-4.5K rpms. If that is the case, you have much to gain going to 4.30's.

Check the basics, like the fuel filter and especially the float level. A low float level can do that. Plus, you may want to make sure your gas tank is venting. Tank doesn't make noises when you take the cap off, does it?

Nice to be able to update you sig!

Spali: I have been thinking about going to a lower ratio but I do drive the car on the street and 60 miles to the track so I don't wanna go too low with no overdrive. Although......I am very tempted to swap the gears and get an 8" converter so I can finally get some respectable 60's. I've seen low 13 second cars run the same 60's as mine!

n2omike: Float level sounds exactly what it felt like! I have actually run the floats too low years ago on another carb and raised them at the track and picked up between 1-2 mph. It didn't even occur to me the other night to check it.

If you drive the car much,4.30s with no OD is gonna get old real quick IMHO.

I wasn't even thinking about the fact that you are using 3.55s and a 235 radial.....those are definitely very respectable 60 fts and Ets!