Competition poor track times..

[AMcKee]

Ok 3rd gen. drag racers, how did you get your 60' times down to the 1. 7-1. 8 range?

 

[JasonCzerak]

my truck, full of fuel is 7400 pounds I think weight is the answer here.



I plan on getting a number at what I race at sooner or later:



drop the spare,

3-6 gallons of fuel

no nothing under the seats

no wheel bolt cover caps.

one battery

no tail gate



If I run across some slicks, This is a biggie, no front drive shaft (top end speed rotating mass... )



I will need to independaly weight the tail gate and front drive shaft. Based on the situation, one or both may be needed.



And a bit off topic. tail gates. Everything I read says leave them on. The make that air bubble. But half of the videos I see the fast guys run with out the gates. Has anyone ever done a controlled experiement with the tail gate on and off and note any improvements? Would the cab and ben sizes matter also? when I was stock and did some base line runs last year, I noted . 2 faster with it off. I did not run 10 runs in the same manor tho, but I will this year at a Test and tune day.

 

[Rhondasway]

And a bit off topic. tail gates. Everything I read says leave them on. The make that air bubble. But half of the videos I see the fast guys run with out the gates. Has anyone ever done a controlled experiement with the tail gate on and off and note any improvements? Would the cab and ben sizes matter also? when I was stock and did some base line runs last year, I noted . 2 faster with it off. I did not run 10 runs in the same manor tho, but I will this year at a Test and tune day.

Tailgate off. My own experience has shown to remove it. That air pocket thing is interesting, but I think you just end up moving the "dirty" air behind the tailgate. I believe the wind-tunnel testing was done at 55mph; maybe there's a difference at 100+ (as we see on the track)...

I'm hardly an aerodynamics specialist, but also experimented a few years ago on a long drive I was doing twice weekly of 500 miles. I ran multiple times with the tailgate up and down, with noticeable mileage improvement when down. Must mean something.

I think Paul hit the nail on the head with the weight idea.

 

[AMcKee]

I know she's a heavy pig, its just hard for me to fathom. Whether your truck weighs 7000-7500# (like other quick third gens) or it weighs 8000# (like mine), it's hard for me understand why there is such a drastic difference in track times. I have to think that there is some component that i am lacking.

 

[RacinDuallie]

Are the tires spinning? or are they planted and hooked?


On the tailgate, my truck liked it better with the tailgate on, but down. I tried it on, off, left up and left down. Seemed to like the little bit of weight hanging back past the bumper.

 

[JasonCzerak]

I have a cat certified slip with 7400+change as a total. With 4700+change on the front axel.



I dunno the exact numbers but 7400 is close enough

 

[AMcKee]

Are the tires spinning? or are they planted and hooked?





On the tailgate, my truck liked it better with the tailgate on, but down. I tried it on, off, left up and left down. Seemed to like the little bit of weight hanging back past the bumper.

Its dead hooking in 4x4... I take it out of 4x4 once im past the tree and it never spins.

 

[paulb]

Its dead hooking in 4x4... I take it out of 4x4 once im past the tree and it never spins.

Those extra couple of tires are helping you hook... I can spin all four tires off the line.



One other question... Are you still in 3rd when you cross the 1/8 mile? What rpm?



Paul

 

[JasonCzerak]

Its dead hooking in 4x4... I take it out of 4x4 once im past the tree and it never spins.

Short of test drives, I have never driven an auto CTD. BUT, if you have the same manaul transfer case that I have. Knowing how automatics don't disenguage 100%, even for a moment between between shifts, I'm lead to believe that even tho you moved the lever from 4x4 to 2x4, it's not really out of 4x4.



My truck (and my jeep) will not disenguage 4x4 until the load is released off of the transfercase. If the auto doesn't release the load (like pressing the clutch). Then your prolly in 4x4 the entire 1/4 mile run, once you left off at traps then it disenguages.



With a manual, I'll do a 2nd gear launch in 4x4 and as soon as I start moving hit the lever, as I grab 3rd, it drops to 4x2.

 

[AMcKee]

Paul, I believe im into OD by the traps in the eigth. I trap about 80 mph, not sure of the rpm.



Jason, I never really thought of that. I always assumed that once i manually disengaged the 4x4 it just went back to 2x4.