tailgate weight?

[Pos]

Hi everyone, still a bit of a newbie to this forum but feel like I'm home, being surrounded by all these Commodore fans What I'm wondering is how much would the tailgate & passenger seat weigh on my VR ute? I'm thinking of taking it off for the next round of the Track Championship Series at Sydney Dragway & possibly the passenger seat too. She's just a stock 5l at the moment, but I also use it for work so anything I do to her has to be reversable lol. Do you guys think that removing the tailgate even though it's lightening up the car it maybe too little weight over the back wheels? I am saving my spare change to eventually get a "Greenfoam Tune" lol. The best it's done so far is 15.2 @90mph with a 0.05 RT. I'm not sure whether thats good, bad, or average for a stock 5l with 250k on the clock & that was on normal street tyres. Thanks for your time in reading this.
Cheers Pos

[alien]

I probably wouldn't remove the tailgate at all.

If you have a cover and remove the tailgate it will create different pressures as the vehicle has air going over it, that pressure will try and pull you back (how many jet engines do you see with holes in the rear NOT for engine exhaust).

If you dont have a cover:
Watch this: YouTube - Insert from MythBusters - Tailgate Up or Down 2 (from More Myths Revisited) fuel consumption test

When you watch it, the way with the best fuel efficiency is what you want. This means your putting less fuel into moving the vehicle the same speed, meaning you can also pump more fuel in to get it moving quicker.

[Pos]

Thanks Alien, that's a pretty good mythbusters link. I understand what your getting at, but I'm looking to knock off some weight to accelerate quicker over the 1/4ml. Fuel consumption is nothing to worry about. I do see your point as far as less fuel =slippery shape, but I'm still thinking over the 1/4 the weight saving will still outweigh (pardon the pun) the savings of aerodynamics. It'd be interesting to do all of the tests the myth boys did back to back on the dragstrip though. Cheers Pos

[brockee]

hey mate if seen alot of guys just take em off ???must help some where along the line hahah... as u use for work just drop the tail gate down when u go ...thats if they allow ??

[alien]

Pos, thats the thing, the tests show which are most aerodynamical, by having less fuel usage because of aerodynamicness you can accelerate quicker.

If you grab a piece of carboard and having it perpendicular to the ground push it along the air you'll feel the drag, but making it more aerodynamic by using it parallel to the ground it's alot easier to move, you put less force into making it move, meaning if you put more power or force into it it will go quicker. Same physics apply on the drag strip. 1/4 mile or 500 miles, same physics apply.

[Not_An_Abba_Fan]

Leaving the tailgate on will be better as you increase speed. The turbulence inside the tub deflects the air over the tail gate and will be more aerodynamic than if you took it off. Once it is off the air flow over the cab will get forced down into the tub that now has a lower pressure area than with the tail gate on, so it will drag on the back of the cab slowing you down.

Leaving the tail gate on will be better than the weight saved by taking it off.

Just as an experiment, the next time you are there, do two runs each with it on and off and see what happens. A practical experiment will give you more accurate results than asking on here.

[Pos]

Yeah thanks guys, it does make sense about the low pressure area in the tub. I was just thinking that over the 1/4 with a stock 5l ute it wouldn't make that much of a difference compared to losing 20-30kgs in weight. But my luck it would cancel each other out lol. To remove the tailgate you have to remove both bumperettes to access the hinges so mucking around like that at the track isn't really feasible. You wouldn't even leave a spare with the steel belts showing lying around, someone would knock it off!