am very happy with the 60 ft times (considering the best 60 ft in street tires was a 2.1) but I am wondering why my mph is so much lower than last year on street tires? I was in the 96-98 mph range last year...do slicks slow your MPH that much? It was a nice cool night and I had about 45 minutes between runs so I know it was not becuase of being hot.
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There are several reason why your MPH may have slowed down one of which is the traction. Generally, A car that spins then finally hooks will run a couple MPH better than one that dead hooks on slicks. The E.T may be quicker when it hooks better but NOT necessarily the MPH. That is normal. In your particular case on this day, that was NOT the case.
The second reason is what are the size of slicks compared to street tires. A taller tire reduces gear, a shorter tire increases it. If its a shorter tire then it is highly likely that it had more gear, better E.T and again less MPH.
Thirdly conditions and track location. Is this the same track you ran at last year and were the conditions the same. I've noticed variations of as much as 1-2 MPH from track to track. Keep in mind conditions and temps, humidity, air density, weight all come into play here too. On a pretty typical street application its not uncommon due to any of those reasons to see a MPH or two lost at top. Especially in bad heat or higher elevation.
Fourthly, if you've added additional weight, ie stereo, heavier wheels and tires or other goodies, that will shave MPH as well.
Lastly, shift points and rpm could very well have something to do with it too since you have a stick car. The harder you leave in the RPM the better the 60 ft will be if it can hook it. Shift points should try to be completed the same every time. Unless you race it a lot at the track I'm sure some of its that. A early or late shift in the power band WILL affect both ET and MPH. Your last run was obviously better than the first and I suspect better shift points and maybe leaving harder on the launch had something to do with that.
A 14.0 pass should be in the 94-97 MPH range in these cars. I'm in agreement with your observation that its likely running rich at top. I think a tune will put you in the 13's and a much better running car on the top end of the track.
These are just some things to consider. Get it tuned and do a lot more test and tune running at your track and data log what you do and how it affects the car. It'll get you in practice as well at driving the car on the track. You will certainly see improvement in both ET and MPH ,especially come Fall, in cooler temps.
I hope this helps you and good luck.