Why would MPH be down?

[Stl376]

I log all my runs in excel. This past Wednesday I hit a PB on the 60ft, 330ft, 1/8 et, and 1000ft. However my traps were down 3mph in the 1/8 and almost 2 in the 1/4 than my previous PB run back in November. DA was better than the previous. All other varibles were the same. Stock Cat with a little weight reduction.

 

[BULL]

I log all my runs in excel. This past Wednesday I hit a PB on the 60ft, 330ft, 1/8 et, and 1000ft. However my traps were down 3mph in the 1/8 and almost 2 in the 1/4 than my previous PB run back in November. DA was better than the previous. All other varibles were the same. Stock Cat with a little weight reduction.

View attachment 41699

God is punishing you for racing in DAs that aren't in the neighborhood of 7500+

Just saying...

 

[John G.]

I've noticed the same thing. My best ETs are not my best MPH.

 

[vortecd]

I log all my runs in excel. This past Wednesday I hit a PB on the 60ft, 330ft, 1/8 et, and 1000ft. However my traps were down 3mph in the 1/8 and almost 2 in the 1/4 than my previous PB run back in November. DA was better than the previous. All other varibles were the same. Stock Cat with a little weight reduction.

View attachment 41699

I have been seeing a lot weird stuff like that at my track the last few years. One year the left lane has more mph then the right lane then the next year it is the other way around. Are both lanes giving you the same mph on the same day?

 

[vortecd]

I like to run both lanes if possible just because of this. I have seen 3mph difference on the same day running the same time

 

[MiHiHemi]

You have to lower MPG for higher MPH

 

[Marc W]

Make sure you are running it past the finish line and not shutting off before you reach the last mph light. If you get off the gas right at the finish line it will impact your mph.

 

[BULL]

Make sure you are running it past the finish line and not shutting off before you reach the last mph light. If you get off the gas right at the finish line it will impact your mph.

This is especially true for Standing Mile.

I stay in it for several car lengths before I start shutting down.

 

[Jack_Toepfer]

Stock Cat on DRs? Is the PSI the same in the tires for every pass?

 

[SilverBillet]

Does the depth of how you stage affect the mph? Maybe staging shallow one time and deeper the next?

 

[droptopp]

The more tires spin, the faster MPH has to be for the same ET. This is not the same as saying more tire spins results in higher MPH. Actually, the exact opposite is true. The more tires spin, with power and distance constant, the slower the final speed will be. ET slows right along with MPH when traction is reduced over a fixed distance, although traction generally affects ET much more than MPH.

One fact of the quarter mile is; no matter how slow or fast your car is, the mph multiplied
by the ET will pretty much be the same number every time - @1380-1400.

 

[Stl376]

Thanks for the input all. Stock car on DR's... tire PSI was about the same, 18-20 depending on how hot the tires were. They were probably hotter on the faster 1/4 trap. I stage the same everytime (shallow) and run it past the finish lights.

 

[SilverBillet]

It could just be the way the lights are setup and what lane you were in

 

[Mean Cat]

I log all my runs in excel. This past Wednesday I hit a PB on the 60ft, 330ft, 1/8 et, and 1000ft. However my traps were down 3mph in the 1/8 and almost 2 in the 1/4 than my previous PB run back in November. DA was better than the previous. All other varibles were the same. Stock Cat with a little weight reduction.

View attachment 41699

What was the humidity % for the 2 passes ? the DA can be lower but if humidity is higher that makes a difference.