MPH V's ET

[JG33RD]

I'm a bit confused, went racing saturday and mph is down but et's roughly the same. Bit of history, have been running 13.5's@100mph, have run a 13.2 same mph but last runs were, best 13.6@95 and 13'6@89mph. The first two runs on the same day were 14.04@98 and 14.07@100mph, the quickest passes I had issues in the deep end where the car lost power, I'm thinking fuel shortage, but I'm confused that with losing power I still ran quicker but lower mph. Any ideas what's happening here?

[GTP owner]

The et is a guide to how well you get the power down. The mph the horsepower you are making. I would suggest that either you are over-revving it, making you slower, or the less horsepower is allowing you to get the tyres to hook up better - and the, run a quicker et. What were the 60foot times with the runs? That will give you more of an idea of what is going on

[XR.1967]

You could be getting out of the hole better and you will see that with your 60ft times and like you said running out of fuel..
So at 1/2 track you should be faster then your 14 second pass but you run out of fuel=power and down on MPH..
When you did your 14 second pass you will be slower at 1/2 track but will not run out of fuel till you are past the line so it's still pulling..
So on your 13 second pass you might have got to 105MPH b4 the line but run out of power..
Like it was said b4 look at you 60ft times and then 1/2 track times and MPH..

If you look at a door slammer when they get a good drive off the line and then something goes wrong 1/2 track they roll over the line say under 10 seconds but the MPH will be real low..
You would need to do a heap more MPH in a street car to get the same time because you wont get out of the hole as well..

Hope that makes sense lol..

[XR6_661]

Sounds like your 60ft may be coming into play a bit…Getting out of the hole faster, spending less time on the track hence the low mph…

That’s how I see it.

[JG33RD]

Thanks for the replies, it does make sence what you have all said. I did rev it harder in the two 13.6 passes changing into 2nd at 6500 instead of 6000 for the 14's and around 6300 into top for the 13.6's agaisnt 6000 for the 14's, so approaching the line I was a little bit higher in the rev range, I don't have 1/2 track speeds but the 60ft's in order were;2.229 14.07@100.67 ;2.048 14.049@98.68 ;2.086 13.656@89.28 and 2.035 13.625@95.74. That first 13.6@89mph, it was like I had turned the engine off for a sec or two, there was just nothing till I backed off then it coughed and I fed it again so, after reading your comments, it seems pretty clear to me now, the extra revs must be enough to starve it so I will have to look at a new pump and maybe bigger lines. Thanks again

[Quadcams]

Originally Posted by XR6_661

Sounds like your 60ft may be coming into play a bit…Getting out of the hole faster, spending less time on the track hence the low mph…

That’s how I see it.

Mph wont be affected by your 60ft, your half track mph yes, the better the 60ft the better the 660ft mph will be, your 1320ft mph can very from a number of things from wheelspin, how well you keep momentum in gears (with manuals), drivers right foot and of corse your power.

Wade