Serious 1/4 milers......here's a question

[drakesdad]

See if I can word this right.....is there a formula that if you add trap speed that you can subtract ET.......
I ran a 13.51 1.8 60 (with cooper zeons stock width, now I have the SVT rims which are wider with softer compound tires) but my trap was 99....something....
I see other traps around 104 ish and feel strongly that if I can get those extra 4mph I should be real close to 12's.........then again IDKS

 

[bill302]

is this it click on link....
http://www.rpmoutlet.com/dyno.htm

 

[drakesdad]

Bill.....that is CRAZY.....
I went directly off the dyno sheet.....
3400lbs 271.7 rwhp 13.52 1/4 100.79 trap...............but here is the tricky part...
Mine is a Mustang dyno and Don said they run 15 % lower than a dynojet..
so I did the math and put this in....
3400 lbs 312.455 rwhp 12.9080 1/4 105.597 trap

Now the top #'s are right at what I'm running...........but my trans is shifting 1k early 1 to 2 nd and the stall is not locking in 2nd and 3rd..........so I know there is more to gain out of the combo.............GO FIGURE......going to have to do a case study.....

 

[gmkillr]

Only one way to know for sure, go to the track!!!

 

[Killercanary]

I don't know of any "formulas" but based off a given MPH you can guestimate what your ET should be. A 13.5 at 99 is a pretty darn good ET for only 99mph. An EXTREMELY general statement would be that every 1mph is worth at least one tenth.

As for the whole dynojet versus mustangdyno, there isn't a black and white percentage that they differ. It all depends on what is input for drag, load, and weight on the mustang dyno, therefore the numbers can be skewed in either direction. Typically they do report lower numbers than a dynojet, but that's not always the case.


I do think that you should be seeing a slightly hiogher trap speed than you are though.