1st Gen Toyota Tundra Aeroshell Build

[Macskyver]

Originally Posted by dothadance

dude, yes!! i have to see this thing in real life. i'm up in austin and go to san marcos pretty frequently. i've actually been trying to figure out how to build my "final draft" aerocap for the past week or so and you just led me to the answer

Sounds good. PM sent..

[Macskyver]

Originally Posted by aerohead

Texas A & M has 5-wind tunnels in College Station.I'm not sure how large a structure can be accepted into the available test sections,but a phone call to the Engineering College could take care of that.

That is a great idea/lead. I think I am going to just drive it a while and get a bunch of MPG data before doing any other tests. I have other projects that have been severely neglected that need my attention, I'll be posting MPG data as it comes in, but so far it feels like it is pretty good.

[ByDesign]

I'm late to the party on this one, but wow! Awesome work. I showed my wife too. We love the look -- oh, and the potential aero improvements! Good luck with the testing.

[Macskyver]

Originally Posted by ByDesign

I'm late to the party on this one, but wow! Awesome work. I showed my wife too. We love the look -- oh, and the potential aero improvements! Good luck with the testing.

Thanks, I am glad you like it. So far I have gotten nearly two full tanks of gas through it. The first tank had a lot of highway and freeway miles and was 16.5 MPG. The current tank is pretty much all colder weather short trip stop and go. Even though I haven't filled up and calculated the fuel economy, I can already tell it is much worse, but not unexpected.

[ByDesign]

Well that's the rub with fuel economy. Add some nice aero like your shell, but it adds weight. Aero is king at speed, and the faster you go the bigger the difference it makes. Weight is king for stop and go. The more you accelerate, the bigger the hit because of the weight. Of course you know that.

At Ford several years ago, weight was valued at (I don't remember the exact numbers) 1 pound weight savings in the car was worth $100,000 for their high volume family cars like the Taurus. Part of that equation included the tax and fleet ramifications of corporate fuel economy numbers. The $100K had more to do with facilities than car cost, of course, and the number was different for different vehicle models based on volume and fleet positioning. Anyway, I mention that because I'm guessing your cap probably weighs 80ish lbs. That doesn't seem like much, but if you think about the energy it takes to start and stop that mass over and over, then it adds up.

The interesting part, and one of the reasons I'm attracted to Ecomodder, is you can control what you do on the acceleration. I have to admit I love a WOT accel, and I have a car with more engine than sense, but I understand the consequences, so mostly I'm in the granny category. Size is most important (though that's often dictated by function), then technique, but after that, aero is the big fish -- which you've attacked with style.

Your shell should serve you very well as time goes on. The payback won't be fast in terms of savings, but you probably already have full payback in pride of workmanship and accomplishment! Congrats again on the great work! It's absolutely delicious.

[NeilBlanchard]

A little weight makes a very small difference, and aero matters at slower speeds than you think. A truck has higher drag than an average car, and average cars hit 50% of the load from aero drag at <30MPH.

Pretty much everybody drive at least 30MPH much of the time - so aero matters to everybody, much of the time.

[skyking]

^What he said, aero is all the time. Like baseball, you can have an up or down day at the bat, but speed never slumps
Winter is also a crappy time to collect data in general. All my rigs suffer variably with the cold temperatures and wet, sloppy roads. Tough to get a good read sometimes.

[Macskyver]

Yeah, the jury is still very much out on what the effects of the aeroshell are. The first tank was slightly above average, but that is just one data point. The second tank is in much colder weather and the majority of the driving is with the vehicle not up to operating temperature as my commute to work is extremely short. I also haven't even finished with the second tank, so who knows what it really is at. Qualitatively speaking, the truck feels less encumbered and seems to track more solidly at freeway speeds, so I am pretty sure there is a positive (or negative depending on how you look at it) aero effect.

[skyking]

LOL, man. You are killing me!
Don't worry about it until you get :
A) decent weather.
B) a chance to do a couple of controlled road trips.
I have absolutely no doubt of the outcome, mind you. It will be nice to see.
Go out a couple of hundred miles and back with it on, then repeat without. I prefer not just driving to see what's up, so sometimes I wait for a purpose for the trip.

[aerohead]

Originally Posted by Macskyver

Yeah, the jury is still very much out on what the effects of the aeroshell are. The first tank was slightly above average, but that is just one data point. The second tank is in much colder weather and the majority of the driving is with the vehicle not up to operating temperature as my commute to work is extremely short. I also haven't even finished with the second tank, so who knows what it really is at. Qualitatively speaking, the truck feels less encumbered and seems to track more solidly at freeway speeds, so I am pretty sure there is a positive (or negative depending on how you look at it) aero effect.

Your shell should reduce rear axle lift significantly,and she should ride as though she's got hundreds of pounds of load back there,improving your effective front/rear weight distribution.
At 114-mph mine feels like my CRX running on cork.