Ok.. last Saturday I made my way back to the track. This time with the knowledge that I needed to bump up my timing from 0* to 6* BTDC (it was at 0* the previous race weekend)

I was happy with the results (somewhat) and I want to hear some opinions on where I am going wrong here....something is still not coming together right...

For some background on my previous trip to the track... my best run was 15.03@89MPH on a 2.169 60 foot

OK... breakdown of the runs...


1st run of the day my timing was set to 6 * (stock setting) and stock Fuel pressure of 43 psi... ran a 14.895@90.14 MPH on a 2.143 60 foot

2nd run same timing 14.905 @ ?? (traps screwed up and never gave me a MPH) on a 2.135 60'

3rd, 4th, 5th, and 6th runs were all made during the warmest part of the day with a slight wind blowing up the track...everyone was running slower (or so it seemed)

3rd run (ambient air temp was starting to climb), this time I bumped my timing to 8* and left the fuel pressure at stock.

14.989 @ 97.5 MPH on a 2.199 60'

4th run (timing at 8* and fuel pressure bumped up to 48 psi)

15.000 @ 98.31 MPH and a 2.305 60', awful 60 ' but MPH is on the rise!!

5th run (left the timing and FP alone) and slapped on a set of ET Streets (was able to get a loan of them from my buddy)...

14.890 @ ?? (again a trap speed screw up) on a 2.003 60 '

6th run (took off the sticky's and left everything else alone)

15.202@98.10 MPH on again a terrible 2.381 60' ... spinning all through first all through the 60 foot

7th run (last run of the day around 5:00pm) never touched anything, 8* of timing and 48 psi.

14.830@91.13 MPH on a 2.125 60'

The air was cooler and the car felt strong off the line. Not sure why my MPH dropped off though

I also found out that I was running the whole day with over 3/4's of a tank of gas! Stupid gas guage was saying less than a 1/4 tank. I only found out when I stopped to get gas on the way home and could only squeeze in $14 ... not that it would have made much of a difference though

What am I doing wrong here? I was concerned about the MPH the previous weekend (could only get a 89 MPH out of all my runs) but I seem to have found the MPH this weekend.

Power Mods (well some could be considered power mods)

Headers
No Cat/Smog
Flowmaster 80
Beefed up and rebuilt 700R4 tranny
ported air plenum
K&N filters over a chopped air box
Rear LCA Re-location brackets
Tubular rear lca's
Adj PHB
Stiff Drop Springs
Subframe connectors
3.27 rear gears with a posi that works
5.7L engine that runs strong (100,000 miles on the engine)

 

just need to get that 60 foot tame, u definitely could get even better numbers.

 

Yeah I hear ya... I mean I have the MPH that should translate into a low 14 sec ET... I just have to get it all together and get more practice...

 

Something is funky with the timing.

You gained almost 10MPH, and even with similiar 60ft times you saw a marginal(if any) difference.

You don't gain 8-9 MPH and don't ET any faster unless you get like a 3.0 60ft time. 8-9 MPH gain is a considerable amount of horsepower(at least 40-50HP) and with the slight changes you did i somehow doubt gaining that much.

A true 98mph is nearly always good for a mid/low 14 second run, even on street tires with anything less then a 2.3-2.4 or so.

And then your last run in better weather you 'lost' 6-7 MPH.

Timing is funky somewhere.

 

That's why I'm here trying to figure this stuff out.... it has me baffled....

 

There are soooo many variables in this sport. Air density altitude (and the individual components of that - some cars respond more to humidity than they do to air temperature, for instance), wind speed and direction (some tracks shield the car from wind from one direction for a different part of the track than they do from another direction, for example), engine temperature, drivetrain fluid temperatures, track temperature, tire temperature, tire pressure, etc., etc., etc. And, feedback control engines will change the engine operating parameters with varying conditions. Documenting and tracking each of those is the only way to get meaningful data.

This year, I've had an issue from time to time with the car pushing out of the staging beam when stalling up the converter (new front disk brakes). I have noticed that when it pushes far enough to turn off the prestage light, my 60' and ET can be affected (increased) by as much as .03 sec - that's huge.

So, in addition to the condition variables above, add to that the driver variables - staging position, staging RPMs, shift RPMs, etc., etc., etc.