The weather last night was optimal so I decided to head out to the midnight madness runs at the 1/8th mile track in Sanger, TX -- It was low 60F's w/ Barometric Pressure @ 30.23 -- Perfect!!

I was not happy though, as the car was hooking okay, but pulling some seriously crappy trapspeeds -- I was only hitting 76-77mph whereas a few months back in the summer heat(85F) I was trapping 80mph through the 1/8th mile. I'm trying to figure out what could have happened.

Here is my guess?
I normally run 93 Octane b/c I have my timing advanced to 17*, however when I got up to Sanger just before the track my gas light was on so I stopped to put a few gallons in. All they had was 91 Octane. The car seemed to feel OK? However my friend ran against me a few times noted that it didnt sound to him like my intake-sound was as loud as usual.

Could the lower Octane have caused the car to pull timing and really affected my power/trapspeeds that much or should I be looking elsewhere?

Thanks for your suggestions.

 

Maybe the trap boxes were off back in the summer?

 

Doubt it, i've trapped 80mph before at this particular 1/8th track, as well as texas motorplex nhra 1/4 mile track. My friend who went w/ me was about the same in his Titan (74-75mph) which is the same or within 1mph he normally traps.
It's got me down on the car -- I picked up a beltronics fx2 g-timer yesterday from craigslist real cheap to play around w/ to try some different things w/ the car till I can get back to the track.
Starting to think maybe the power valve (vias) isn't functioning properly or opening up all the way as I had some issues with that recently but thought I fixed it...

 

maybe you got better traction this time

 

plano - i think either of your ideas are reasonable.

 

Thanks Nealoc - I've got 93octane in there now and am going to play around w/ the IM later on. I made some passes on the G-Timer early this morning and my 1/8th et & traps were in line with what I ran at the track Friday Night. I even made a few 1/4mile passes on there to find that I'm barely gaining 19mph on the back half -- did a 14.4 @ 96mph -- ouch. I know it's just #'s from an accelerometer, but it's fairly accurate from what I've seen. Anyways, If I figure it out i'll post up what I believe caused the loss in power/trapspeed.