Why is my truck not running hard anymore?

Mooring Product

Mooring Product

I just don't care
Joined
May 10, 2006
Messages
3,198
Back in December we went to the track and I ran 14.1X all night long. I even did three hot laps because the track was dead. About a month later I changed tires, I went from A Mickey Thompson ATZ to a Toyo Open Country. After putting the new tires on the truck got 1 extra mpg. I was thinking I should be very close to running in the 13's. Nope...we went to an 1/8th mile track and I could only run a 9.5 all night. So this past weekend we went up for the NHRDA and sure enough the truck only ran 14.8X.

The fuel filters are 6 months old. Oil in the motor and trans changed 2000miles ago. Boost is good.(30PSI) Motor sounds great. I launch at 2000rpm.

Any ideas. Weight of new tires? Injectors? Turbo?
 
Did the truck run High egts on those hot laps?
Maybe you need to try some different tunes.
 
What was the DA on the later slower runs? Track prep? Assuming same stated tire size, what is the measured tire size? Toyos seem to run to run pretty close to stated size while other brands (don't know about MT) can be off as much an inch or so. Alot of 35's are really 33 and change or 34 and if they were worn to new tires you could have gained a fair amount of new rubber.
 
Pete,
Do you run any additives? My truck was running slower, and I put in additives with every fill up and my truck ran better that ever last weekend! I wondering if the low sulfer fuel is doing somthing? any one else notice anything?
 
Shambo said:
Pete,
Do you run any additives? My truck was running slower, and I put in additives with every fill up and my truck ran better that ever last weekend! I wondering if the low sulfer fuel is doing somthing? any one else notice anything?
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No I don't. You and I talked about this at the track together and will try this.
I just find it hard to comprehend how I could lose that much time.
What brand did you use?
 
I just use the Stuff in Walmart, are your fuel pressures O.K.?
 
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