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Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

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Old 11-21-2006, 08:06 PM   #11
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Quote:
Originally Posted by Headshot Zod
I can save money on building big horsepower by spending money on aero mods first. Plus I love the idea of a full size Insight
Oh, I'm looking forward to this. Keep us posted!
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Old 11-21-2006, 08:20 PM   #12
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lol.............
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Old 11-21-2006, 11:42 PM   #13
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Originally Posted by theclencher
Does it have to carry or tow heavy stuff?

You well know that most trucks dont get used often for utilitarian service
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Old 11-21-2006, 11:43 PM   #14
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oh.....its getting the "knoxification" alright. I've been looking at his and the one at maxmpg and I'm going to try to shoot for for more of a Prius or Insight shape. I was actually thinking of using the fastback from a 1966 charger for a while. I thought it would be sweet and I could still have real glass.
This is exactly what I was going to ask.

'Knoxify' it, and without new driving technique, just the aeromods alone will push you into the high 20s/low 30s if done right. Add in gear changes, LRR tires, synthetic transmission oil, and other efficiency mods along with driving technique, and I have little doubt about the high 30s or low 40s being possible.

160 hp and 400 lb-ft is not that bad. How much does this monster weigh?

After the Triumph is finished, I am considering a truck of sorts. Mine would be mostly electric though, with nearly 1.5 tons of lead on board for 200 miles range on golf cart batteries with aeromods and efficiency mods, maybe a high power diesel engine powering it as well if both powertrains can fit. I want a high performance sports car and an armed muscletruck both running on renewable fuels, two vehicle archetypes that few dare to even associate with eco-friendly.
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Old 11-22-2006, 12:58 AM   #15
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Notice how some garage doors, window blinds, and what have you are built of many horizontal slats with hinges, which allow them to be vertically lifted or rolled?

One of my ideas is to build an aeroshell using this principle. When you want to haul stuff in the truck bed, just unlatch the lock that sets the shell in place, and roll it up. It would slide along two angled walls of sorts on each side of the truck bed, and wouldn't be near as cumbersome as a full piece shell that would have to be removed and stored somewhere. The downside, of course, would be the blind spot caused when deployed and the less than perfect aero benefit over a 100% smooth and tapered shell. Utility would not be sacrificed, and ~80% or more of the aero benefit of a perfectly tapered aeroshell would be retained, however. But then again, any truck worth its salt optimized for aero wouldn't be worrying about a blindspot. It would be using cameras and screens in place of mirrors, to make a rear window perhaps fully unnessesary. I've seen a lowrider truck with no rear window and roof mounted cameras that allowed a full 180 degree view of the rear from inside the truck.

Further, this aeroshell would also extend utility a bit. If it's raining out and your load needs to be kept dry, and the inside of the truck doesn't have the space, but the load isn't so large that the aeroshell couldn't cover it, then you could use the aeroshell to protect the item in question from the elements.

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Based on...
It's a guess based on the results of others I've seen on various forums. The maxmpg yahoo group has lots of info.

While this truck has a larger frontal area than Phil Knox's, the overall percentage change in Cd*A won't be too different. This diesel is not as innefficient as a V8, either, and given its current economy, it really can't be called a guzzler. Phil's truck at 70 mph got 25 mpg with no mods. Just the extensive aeromods raised that to like 32 mpg. If he'd slow down, mpg would increase.

A 20 mpg truck with a similar percentage reduction in Cd*A could be expected to see a similar percentage increase in mpg. Going from 20 mpg unmodified to 25-26 mpg from just aeromods alone on this truck seems reasonable, but the possibility exists for even more gains given this particular truck has even worse aero unmodified than Phil's T100. He mentions he could get 25 mpg by timing adjustments and such, and assuming this is correct, those two things alone would get him to the low 30s.

Add synthetic transmission oil, taller gear ratios, LRR tires, alignment, and the like, plus the dramatic improvements than can be made when hypermiling a vehicle, and that guess doesn't seem too unreasonable.

Unlike that V8 monster you mention, I don't think his pumping losses and such are so high as to make efficiency mods negligable in effect. I do know vehicles where it would, and these are 350+ cid musceltrucks that get 6 mpg, with race-tuned engines where the idling and fuel pumping losses are so large that fuel economy won't change much from 40 mph to 80 mph. These trucks just guzzle fuel like crazy.

A 20 mpg vehicle really doesn't behave like that. That slow POS Suzuki I drive, for instance, might get 16 mpg going ~65-70 mph, but gets like 25-30 mpg if I keep it in 5th gear and go ~40 mph. It has a .48 drag coefficient, which is pretty nasty.

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I think your local recruiter can set you up!
No thanks. As far as our founding fathers would have been concerned, the neocons are a domestic enemy to this nation. I thought of going into the Marines during high school. Very glad I didn't.

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Seriously, I liked Mad Max too, but what does one do with an armed muscletruck?
Lots of things that I wouldn't describe in any meaningful detail on a public forum. I'll just say it may involve a homeade gatling gun, Lynard Skynard, a dirt road with no traffic, and a few bottles of Jim Beam.
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Old 11-22-2006, 02:00 AM   #16
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Percentage change could possibly be identical but the CdA will be higher.
Yes, as his is higher to begin with.

But lets say hypothetically that Phil's truck went from needing 24 kW at the engine to maintain 70 mph to needing 18 kW to maintain 70 mph from aeromods. A similar percentage reduction in Cd*A would result in a similar percentage reduction in power required at these speeds. This big truck, with more weight, area, and higher Cd here might need 36 kW to maintain 70 mph, and aeromods might make it to where it only needed 27 kW at the engine to maintain that speed. These assume no significant loads running, which could add a bit more(I do believe Phil Knox paid attention to economy on his runs). Aside from the shift in engine operating point and a few other small but significant factors, you'd expect fuel consumption per mile to drop by the same percentage for each truck based on power requirement dropping by roughly the same percentage. As the engine gets larger and pumping/idling losses increase, then you expect the results of the larger pickup to be skewed much more downward.

I could try to run a simulation of it and illustrate this, but it could just as easily be said. That, and simulations have a large degree of error when you don't know all the specific parameters of the two vehicles being compared.

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He's got his work cut out for him just breaking 30 mpg. If that thing made it to the low 40's I'd eat my shorts!
We'll wait and see. I'd expect given his best of 23 mpg, with 20 as average, hypermiling will give him about 15% gain. LRR tires, probably 2%. Synthetic tranny oil, alignment adjustment, and other less obvious, cheap, and simple mods, ~5%. Engine timing he estimates 25% increase(20 to 25 mpg). Aeromods, estimate another 25%. Works out to 38 mpg.

This would be a crazy feat, but I'm more than open to the possibility of it being doable. I know of Mitsubishi Mighty Max pickups that have had ~15% FE gains from tapered bed covers alone. Phil Knox's truck went all out on aeromods. He cut his drag coefficient by an estimated 40%. At these speeds, even for a 5,000 pound hunk of Detroit Iron needing 40 kW at highway speeds, aerodynamic drag will be accounting for about as much horsepower needed than all other sources combined. A 5,000 pound truck with .015 Cr studded tires will only need about 10 kW to overcome tire rolling force at 70 mph, not including sliding friction. If this truck uses another 5 kW at the engine for overcoming sliding friction, brake drag, alignment drag, another 5 kW for accessory loads, and you'd basically have aero drag accounting for the rest.

Cut the Cd*A by half, and you'd roughly cut the power needed by a fourth for this monster. It would actually be less, counting in the new engine operating point at lower load and less efficiency. But not too much so.

It goes without saying that a smaller truck has less accessory loads, so I can certainly see your point that the effects may not be as much as on Phil's truck, but I don't think it will be too dramatically different. Zod's truck does have quite a bit more room for aerodynamic improvement than Phil's truck, for certain. The grille opening, mudgaurds, and exposed axels alone may contribute more aerodrag than an entire midsize sedan sees!
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Old 11-23-2006, 08:40 AM   #17
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Quote:

He's had a best of 23 and an average of 20.


He's got his work cut out for him just breaking 30 mpg. If that thing made it to the low 40's I'd eat my shorts!
Really?! Well, keep those shorts handy... 'cause if Matt gets my "stuff" posted, and he decides to 1) look into this matter further , and 2) decides to try my gasoline modifier... do you prefer ketchup with your cotton? Or, just plain? LOL!
MPG is a function of torque ; raise the torque (by some means), back out of the throttle to maintain the same work being done (at the same speed)...using less gas.
I don't mean to start an argument on T'giving Day ; but this whole HP / torque / MPG thing doesn't sit too easy with me...ie, a big (!) engine generates exactly the same HP to move a select body shape / weight as a small engine, under the same conditions. The power requirement is not a function of displacement, but of fuel used to "make" that number!
Don't forget...we are talking flywheel HP, imparted to the "same" bearings, tires, coefficient of drag, terrain, wind, etc. Burning gas is a trip!
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Old 11-23-2006, 09:01 AM   #18
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I just went through the forums on the Turbo Diesel Registry @ tdr1.com.

The best mileage for a non-intercooled version of my truck is 26.8. That is with no aero mods. Diesels are very much different then gassers. Aside from the fact that they are 30% more efficient per cubic inch size when you mod them the generally pollute less and get better mileage. When you modify gasser motors for better HP they pollute more.

quickie lesson. larger turbo on a stock truck will drop NOX emissions by dropping egt's. It may lag a bit more though.

I'm thrilled to death to see all the mods here. But I'd also love to see somebody take their engine apart and make it more efficient from a combustion standpoint.

Thermal coatings, exhaust wraps, "knifing" the crank, extrude honing. There's a lot of potential locked up in there.

Glad to see this thread take off.
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Old 11-23-2006, 05:08 PM   #19
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Pre-94 and Cummins

I agree as well -- the pre-'94 Dodges LOOK like trucks, before they got all "perty".

Also, that Cummins is my favorite Diesel pickup engine -- bullet-proof with a half-million mile+ life expectancy. Without mufflers, it sounds just like a Semi-Truck. What a machine!

By the way, belated Welcome to GS -- I passed out from overeating and here we are...

I'm a bit confused on the vehicle choice -- is it for the challenge, you like trucks, etc???

RH77
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Old 11-24-2006, 04:47 AM   #20
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No Throttle

OK wait a minute folks, how easy we forget...

Diesels don't have throttles. You're running around at WOT all day and pumping fuel with the "go-pedal".

RH77

Quote:
Originally Posted by theclencher
Your magic stuff works on diesels too?

MPG is more a function of efficiency than torque. Raise MPG by either reducing torque requirements or producing torque more efficiently or both. Making more torque by itself may/may not increase FE.

That's the thing about the big engines- efficiency decreases away from WOT so usually a big engine loafing along just off idle will be less efficient generating that modest amount of torque than a small engine generating the same amount of torque with more throttle/loading. Yes, new gen engine controls have narrowed the gap greatly over the old stuff but it's still true.
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