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05-11-2010, 12:04 PM | #1 |
Registered Truck Offender
Join Date: May 2008
Location: hells training ground (aka Ariz)
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Regan, have a tailgate ? for you
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)
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Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. |
05-11-2010, 01:33 PM | #2 |
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Join Date: Jul 2005
Location: Kernersville, NC
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Re: Regan, have a tailgate ? for you
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.
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its a work in progess. 71 c-10 lwb, in the middle of frame off restoration. 69 c-10 swb, drag truck, 406 sbc, balanced, comp 292 cam, ported, polished, gasket matched, and bowl blended pro comp 210cc heads, 2.02/1.60 ferrea valves,1.6 roller rockers, re curved hei with msd 6al box, 2-step rev limter, accel 300+ wires, ported victor jr intake, holley 750 double pumper carb, dynomax 1 5/8 headers, 4 spd munci m-20 with super case and iron midplate, mr. gasket vertigate shifter, 5.38 pro gears with full spool, 33 spline moser axles and c-clip elimators, line-loc, 5 gal fuel cell, holley blue pump. 7.807 @ 88.37mph 1.60 60FT 80 g-20 van, tow rig, cammed 305, th350, 10 bolt 88 jeep wrangler, dd, 258, ax-15 swap, 4.5" lift, 33x12.50's, lockers, 3.55's |
05-11-2010, 09:04 PM | #3 |
ShortBus KingPin
Join Date: Feb 2010
Location: houston texas
Posts: 146
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Re: Regan, have a tailgate ? for you
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!
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67 shortstep prosteet. 505 BBC, FULL BILLET TH350, Owner built EVERYTHING.... (My RIDE) 2008 GMC Yukon DENALI, 425 AWHP, 5700LBS, 12.40's at 109mph. (Her RIDE) 2006 Kawasaki Brute Force, 916cc, 80 shot, 6.20's at 111 mph. (Her RIDE) Last edited by midevil1; 05-11-2010 at 09:06 PM. |
05-12-2010, 07:33 AM | #4 |
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Join Date: Mar 2008
Location: tyler texas
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Re: Regan, have a tailgate ? for you
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 .
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NHRA Super Street 469C It only runs 10.90 at 156 mph |
05-12-2010, 11:07 AM | #5 |
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Join Date: May 2008
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Re: Regan, have a tailgate ? for you
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.
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Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. |
05-12-2010, 07:58 PM | #6 |
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Join Date: Feb 2007
Location: Texas
Posts: 469
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Re: Regan, have a tailgate ? for you
Would having a bed cover eliminate the effects of a tailgate?
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1982 Silverado - SBE, cleaned up GM heads, small cam, TH350, 850 Demon, 4.56 gears, and caltracs. Best time so far 11.8@XXXMPH |
05-13-2010, 11:05 AM | #7 |
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Join Date: May 2008
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Re: Regan, have a tailgate ? for you
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???
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Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. |
05-13-2010, 12:34 PM | #8 |
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Join Date: Nov 2007
Location: Bay Area, Ca
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Re: Regan, have a tailgate ? for you
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..
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------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 |
05-13-2010, 04:50 PM | #9 |
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Join Date: May 2008
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Re: Regan, have a tailgate ? for you
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?
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Still playin with trucks, even at my age! When you're dead, it's only a problem for the people around you, because you don't know you're dead. .....It's kinda the same when your STUPID. I just did my taxes and reviewed my SS statement. Thanks to the current administration it looks like I will only have to work till noon on the day of my funeral. |
05-13-2010, 06:56 PM | #10 |
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Join Date: Nov 2007
Location: Bay Area, Ca
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Re: Regan, have a tailgate ? for you
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.
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------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 |
05-13-2010, 09:30 PM | #11 |
ShortBus KingPin
Join Date: Feb 2010
Location: houston texas
Posts: 146
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Re: Regan, have a tailgate ? for you
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.
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67 shortstep prosteet. 505 BBC, FULL BILLET TH350, Owner built EVERYTHING.... (My RIDE) 2008 GMC Yukon DENALI, 425 AWHP, 5700LBS, 12.40's at 109mph. (Her RIDE) 2006 Kawasaki Brute Force, 916cc, 80 shot, 6.20's at 111 mph. (Her RIDE) |
05-18-2010, 01:37 PM | #12 |
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Join Date: May 2009
Location: Unincorporated County, TX
Posts: 172
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Food for Thought.
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.
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Don't let my username fool you, I have become brand blind. Cool is cool, period. 1965 C-10 - "Whipping Post" 1958 Biscayne - "Ruby" 1961 IH Scout 80 - "Gaucho" (My wife's new project) 1938 Chevy - unstarted project. |
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