Aeroing a Pickup Truck

[Atclarkson]

Alright.

So I'm going to build this with semi permanent sides and a removable soft top that clips/snaps/velcros/attaches somehow down.

What I need to know, is if there is an angle that works better for aero as a fastback in relation to my truck that I should be using or does it not matter? (ie- run straight line from roof to top of tailgate, or do I end the angle before the tailgate like below) Do I cut it off sharp or round it to the tailgate? Should it have 2 dif angles in it? etc

[Big Dave]

ATclarkson:

You have a truck that may be excellent for modding.

Long bed should give better Cd than a short bed because you have a longer run to reduce wake area and retain the boundary layer.

I've been reading Phil Knox's sources and they say 10-12 degrees is about as steep as you want to get. Mine is too steep (17 degrees) and it is getting separation and is generating lift (good for airplanes, bad for trucks).

Stay tuned here. I'm working on a newer and more usable top. I'm gonna keep it to 10 degrees and have a snap arangement so you can get it off if you want to.

You truck offers some definite opportunities. Chevy trucks are relatively light. There are millions of aftermarket parts. It looks in good shape, but at twelve years old its time for you to decide to renew or replace. You could "renew" and mod the truck so that 25 or more MPG might be in order but it won't be cheap (although tens of thousands cheaper than a new truck).

PM me if interested.

[Jay2TheRescue]

Take a look at the mileage log on my "Beast" in my garage. I made my first attempt at highway speed gliding and hit 23.9 mpg in a 98 GMC Sierra 1/2 ton extended cab with a 350 V-8 4x4. I'm not sure if my fiberglass camper shell helps or not, but it does not leak so I'm scared to take it off and try without. Certainly a 4x2 regular cab can beat that. I used to pull about 27 in my old 74 chevy 4x2, and my 86 chevy 4x2 on its last big highway trip did about 23 on the highway.

[VetteOwner]

Originally Posted by theholycow

Yeah, the comfort is why I was afraid of getting a small car. I've never been as comfortable as I am in my truck. I cut my shopping short when I test-drove the VW; I sat in it and felt at home, it was almost exactly like sitting in the truck except for the height and the leg angle. The console is low enough that my knees won't get bruised against it (like they did in my '97 Grand Am), the arm positions are perfect, the controls are in reach, etc.

In my truck, the jack is stored unpackaged behind/under the rear seat. It could also easily be placed in empty space under the hood.

ya im about 6'4" and fit in a chevette, kinda pushed aginst the door but in a comfy way where the armrest is. i can reach all 4 dors window cranks and locks from the drivers seat plenty of knee room.

s-10 is nice, wish i had tilt wheel tho (base base base model s-10, i was lucky to get a radio)

jeeps have the jacks stored under the hood and i know theres PLENTY opf room on full size trucks, i could fit mine on my s-10 under th ehood if i wanted.

[Jay2TheRescue]

Originally Posted by VetteOwner

ya im about 6'4" and fit in a chevette, kinda pushed aginst the door but in a comfy way where the armrest is. i can reach all 4 dors window cranks and locks from the drivers seat plenty of knee room.

s-10 is nice, wish i had tilt wheel tho (base base base model s-10, i was lucky to get a radio)

jeeps have the jacks stored under the hood and i know theres PLENTY opf room on full size trucks, i could fit mine on my s-10 under th ehood if i wanted.

The jack is under the hood of my 86 C-10, and was there in my old 74 C-10 as well. The 98 K1500 is an extended cab and the jack is in a plastic toolbox bolted to the floor under the back seat.

-Jay

[Atclarkson]

I'm at 350 kms on a 1/4 tank so far.... (get more on the top half than bottom, but this is still a marked improvement!)

Big Dave you have a pm

[Big Dave]

I read the PM.

You are on the right track. Get the nut behind the wheel squared away first. That is effective and cheap. As you get better, you will get more consistent results.

[Atclarkson]

right on.

thought you had more info to share the way you were talking. Keep me updated on your cap! I'm gonna build one towards the end of the summer (all in town driving right now, no point)


on another note.... I'm at 380kms and still reading 3/4 tank

[Big Dave]

Yeah, I had more to talk about but you made it clear you would be unable to follow up. I understand. None of us are Warren Buffet.

FWIW, I was going to mention that you have a very good candidate for exploring the combined benefits of aero mods and gearing mods. There are scads of aftermarket parts for Chevy trucks where all the maddening little details have been worked out.

For instance there is a company in Virginia that converts Caprices of the 94-96 vintage to manual transmissions using a T-56 six-speed. They even have chips that reflect the fact the automatic is no longer there, so the thing doesn't throw codes. If they can convert a Caprice, a truck would be easy. Maybe in your case a T-56 would be overkill. I have always held that the optimum drive train for a half ton truck would be a Richmond Gear five speed (actually a close-ratio four speed but the top gear is straight through 1:1 to allow hot rods to use economical gearing for street use) and a Buick ten bolt with a 2.73:1 gear ratio. You 4.3 six-banger would push this OK, particularly after you had done some aero mods to reduce aero load.

All this would probably set you back $5,000 to $7,000 and no college student has that kind of bread laying around.

Phil Knox has worked wonders with his Toyota T-100 with nothing but aero mods and good driving. He is stuck there because there is almost no aftermarket equipment for a T-100. He has to do it all himself. GM vehicles lend themselves nicely to aftermarket stuff. The project I described, while it would need some salty parts, is almost a bolt-up. can't say that for many vehicles. even my ford is not easy to find aftermarket parts that promote MPG.

[Jay2TheRescue]

Its not a common option, but you can get a full size Chevy/GMC with a manual 5 speed tranny from the factory.