Regan, have a tailgate ? for you

[Marv D]

Maybe you have been asked this question a million times, but at the speeds your run NO ONE could possibly offer a better, more definative answer.

We have all heard the Tailgate up / tailgate down argument,, air bubble in the bed, faster with it down, over and over and over.

Care to put the myths to bed? (no pun intended)

[71chevytruckguy]

I vote tailgate down, good for about a tenth. When the tailgate was still on the truck, forgot i put it up one round a ran a tenth off the dail in and got put out by .004. Might have different effects at a higher speed tho. Chris.

[midevil1]

I had a Ranger that was running 9's. It would get really squirrely on the big end when I got to the 140mph range. I put the tailgate back on and tah dah! Straight as an arrow...It was in the "UP" position. I wasnt going to put some huge wing on the back!

[regan wilson]

Good question .... I havent tried in years (like 20) and didnt see much difference I have thought about trying again but my tailgate is bolted shut , the chute mount connects to it and they are such a pain to get off . I think once you get over about 100 mph you probably arent losing too much . I kinda look at it as a stability device .

[Marv D]

Ive never had a tailgate on my 66,, the only one I ever had was a big bent "U" so I built a nylon strap net for a tailgate (popular at the time anyways). Over the years my red nylon strapping has become PINK RIBBON so it's geting changed, redone or something!

I know a few guys using the tailgate to bolt ballast to, and in the 90's there was a Popular Science article that claimed at speeds over 60-70 the tailgate created a 'bubble' of air that forced air high over the bed and actually made the truck more aerodynamic. I'm wondering if that could be some of the stability midevil saw in the quick Ranger???

Don't know, just looking for input on the subject. I was only trapping in the low 100's, Expect mid/high 120's with the new setup (may be optimistic,, we'll see). I'm assuming there was good reason the ProStockTruck series all had a bed cover and no open beds with NO tailgate,,,, and no open beds WITH a tailgate.

[team39763]

Would having a bed cover eliminate the effects of a tailgate?

[Marv D]

Yes, and I probably shouldn't have even mentioned that. Those boys spent big bucks in windtunnel time to decide to not run an open bed, with,,, or without, a tailgate.

I'm just looking for some track testing to support one choice or another. The tenth 71chevytruckguy found is pretty astounding. What was MPH differences???

[Super73]

I've done back to back testing.. The only real difference I have noticed is on the 60'.. But that was on a day where the truck wasn't hooking real good and I have an extra 100lbs in the top most portion of the gate. When the gate goes down, you can see it lower the back of the truck a smidge (1/4" or so).. The leverage ratio is in my favor at that point.

I tend to race with it down, but need more solid data..

[Marv D]

So as far as any MPH difference (a good indicator of air resistance) you didn't see any?
Maybe I'm thinking all wrong here, but if there is a increase in top end MPH,, then there is justification for one, or another. Actual ET shouldn't be effected nearly as much as finish line MPH???
Is that a faulty train of thought?

[Super73]

Marv,

Check this out: http://73-ls1.com/67trucksetlist/Dat...math_rev_2.xls

I have been trying to keep more detailed logs when I go to the track. Unfortunately I did not note which runs had the gate up vs down. However, I do know that the two 113mph runs on 4/4/08 had the mph due to the converter being locked at a different rpm.

Some runs the gate was up, some runs the gate was down. Which ones, don't know. But what you will notice is if there is a difference, it aint much if any. But, I was only doing 110-113mph then.

The more recent runs 3/20/10 gate was down for all of them. But there were a lot of changes, so it's hard to compare.

[midevil1]

The benefits of a tailgate being up is the down force it creates on the back tires. If you arent experiencing traction issues at high speeds, then I dont think you should even run a tailgate up or down. Running with the tailgate up is pretty close to the equivilant of the big prostock wing on the back of the "old prostock trucks" in developing down force. I didnt run a tailgate till I got into 135 to 140 range.

[Genuine GM]

I have been researching the same thing as I am planning on running my 65 C10 at the Texas Mile and the USFRA 130 Club (maybe 150 Club as well). I am a member on Landracing.com and most of the trucks running Production Pickup (PP) and Modified Pickup (MP) at B-ville have some form of bed cover on them.

You have to keep in mind the duration though. In a 1/4 mile blast, even at 150, you are above 100 mph for 5-7 seconds. At B-ville you are over 100 mph for minutes. An open bed may cause more down force, but at sustained speeds, it can be a source of instability.

If you are planning on 125 mph in the 1/4 mile, you are talking 3-5 seconds above 100 mph. I would leave the tailgate off.

Plus, MPH doesn't mean everything. Many a car has been beat by a quicker vehicle with a lower MPH trap speed. When I used to play around at the dragstrip, I was more concerned with 60 foot times. In the 8th mile, my old truck would run 9.90 at 79-81 mph (seriously traction limited). I often got spanked by cars running 74 mph, but a faster ET because they didn't have the traction problems I did.