Cecil County 9-13-24

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SpeedThrills

SpeedThrills

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I'm going to try out a few things tonight. Anyone else going?

These two threads have the info:
How To Measure Fuel Volume.

Advancing Cam Question

But basically, I'm going to:
-See if the cam advance affects it. (From straight up 108, to 104.)
-Check trap RPM for the effect of the 2" taller tires.
-Check convertor flash RPM off of the line to see if it's the same as I've seen on the street, power braking. (3200)
-I have the lift-off hood pinned in a way that I can let the back of it float. I want to see if it's faster in the "float" position.
-Take off the dumps, and put 18" collector extensions on. (If I have the energy. :rolleyes: )

One other thing I did that's not mentioned on either of those linked threads is, I put vent whistle baffles in the Holley. Not sure there's a problem, but it can't hurt. I put the rear on too, because I'd probably lose it anyway.

I'll check here to see if anyone adds something else to try.

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I will be there for the SSCS Sept. 27-28 and again Nov. 1-2 , I haven't gone yet this year due to rain in their forecast and its a 2 1/2 hour tow .. too far for an iffy forecast. Good Luck with your test and tune !
 
BVoelzke said:
I will be there for the SSCS Sept. 27-28 and again Nov. 1-2 , I haven't gone yet this year due to rain in their forecast and its a 2 1/2 hour tow .. too far for an iffy forecast. Good Luck with your test and tune !
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I will probably go one more time. This was my first trip since last year when I met you. A 2 1/2 hour tow for me also! My closest choice. :(
I'll look for that pretty Dart if I make it one of those two weekends.
 
The results are in!

I didn't have the chance to try anything except to try to get consistent runs.

The main differences from last trip were:
-The air was "Summery". Last trip it was very "Autumny", for lack of accurate numbers.
-2” taller tires, (235's vs. 265's)
-I advanced the cam from 108 to 104.
-Last trip's runs before these differences were 11.80's at 110, 111.

I left at about 1500 rpm.
Shifted by light, set at 5800, probably occurred at 6000?
(Both the same as before.)
I dropped the air on the M/T ET Streets from 18 to 15 after the 1st run, it may have spun a little on the first run.

It trapped at 6200. It still runs out of breath, but closer to the finish line.

It seemed to flash to about 4000. Hard to say because it's already moving, and climbing. It power brakes to 3200.

I used this site for D.A. Cecil County Dragway - Rising Sun, Maryland - Engine Tuning Weather I didn't think of it until the 2nd run, and I've never used it before.

D.A.
-2nd 1861'
-3rd 1719'
-4th 1457'
-5th 1303'

Water Temp:
-1st 160
-2nd 170
-3rd 170
-4th 160
-5th 170
I only have the stock water pump and a flex fan and shroud, so the temps might not be accurate. (Autometer mech. gauge.)

It pulled smoothly all the way down. Before it sometimes felt like the secondary spring opened at different times. That's why I put the vent whistles in.

I don't know if it's faster or slower! The 3 changes I listed above added too many variables. I will probably go again when the air is better.

Each run was pretty much slower than the previous, even though the D. A. was getting better. Maybe jetting isn't right? (72 and 75 as it usually is, but the jetting was 74, 77 last trip, another variable!)

I'm an old bracket racer, and I didn't build this car to race, but I can't help but fiddle to try to figure things out.

Idea's and comments, please!

No pictures, I was by myself. I'd love to get a video of it coming off the line.

P.S. Yes, lights were terrible. I was watching the tach for the flash speed. That’s my story and I’m sticking to it!

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Were the 60’ times better or worse than before?

My thoughts for the early part of the track is that advancing the cam and the taller tires are somewhat cancelling each other out.
 
Anecdotal taller tire story…..

My dad used to have a 79 Cordoba as a bracket car.
Full bodied, full interior car.
A bit over 3900lbs race weight.
Bracket race type 360 in it.
5000 stall, 4.56’s, 28x10.5’s on it.
Ran high 11’s in decent air.
Slicks wore out……he never liked the looks of the 28” tires in the giant wheel wells so he put 29.5x10.5’s on it.
Slowed it right down.
Never ran an 11 with those on it.
 
At this point I’d say, between the changes and the weather………it doesn’t appear to be a “win”.

On the plus side, you got to make some runs and didn’t break anything.
 
PRH said:
At this point I’d say, between the changes and the weather………it doesn’t appear to be a “win”.

On the plus side, you got to make some runs and didn’t break anything.
Click to expand...
Definitely. I’ll do my best to get back in better air. And continue to keep track of the weather.
I need runs in the car. Haven’t run it that much since I built it.
Plus, my shifter was for a forward valve body and I modified it to work on my reverse pattern, and it works great.
 
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