Dropping slower times at drags

[VZSSCHASE]

I need some help on why I seem to lose mph when racing, just recently I have dropped from 117mph doin 11.4s to 113/114mph doin 11.6s in a vz SS 6litre my 60 fts are 1.634, my reaction is around .040 running street ets on 15psi, I just seem to be going down in mph my engine sounds normal and not getting much wheel spin and launches well but I'm at loss on why my mph is dropping when I'm pretty much racing with the same setup, the only mods is a cam and stall with 3.9 gears any help would be appreciated, I'm thinking of doin a compression test but the motor was built early 2015 thanks.

 

[Immortality]

Could be any number of reasons. Don't just assume it's an engine fault, track conditions, weather and many others can effect the times you run on the day.

When was the last time you serviced the engine, trans, diff etc? Cover off all the basics before you start digging deeper.

 

[gtrboyy]

Put a gopro on it to record speedo/rev tacho..might help work out if auto or convertor issue & efficiency.

Go through all basic things first to check all is ok.

 

[Deuce]

What was the wind doing on that day?

 

[LYV Y R]

Air temp knocks power around a fair bit.
I used to notice quick in the morning, slower in arvo, then quicker again night.
Catches a lot of people DYO break-outs.

 

[Deuce]

Air temp knocks power around a fair bit.
I used to notice quick in the morning, slower in arvo, then quicker again night.
Catches a lot of people DYO break-outs.

On the bike my mate and I would always dial quicker and quicker until around 2 or 2:30 in the arvo. Then we would start pulling them back a bit.
But bikes are a lot different to cars on the track.
And I won't say that rule worked for any other than our local track.

 

[mpower]

another zombie thread rises from it's grave!