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General Information => Upgrades (non engine related ) => Topic started by: Rising on March 14, 2014, 08:30:45 pm
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Anyone started down any of these paths yet?!
I'm still on a quest to eek the most out of my n/a rabbit as possible. I'm still averaging about 45-46 MPG all the time with a light foot. (mostly city and urban driving though) I've read alot over on ecomodder and also on the project sipster (USA top gear ::) But... effective) to try and gather some ideas. Project sipster opted for the clipper kit and a mk2 front bumper as a way to decrease CD. I'm wondering this though: Would the clipper kit ( i have it equipped currently) reduce enough drag to overcome the weight gain of huge metal bumpers as opposed to some small plastic euro bumpers?
What about a full underbody tray. A smooth panel running front to back. Think this might squeeze an mpg or two out on the highway? Or cause my rabbit to fly off the road with a slight breeze?
Anybody done anything like this around here?
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A Giles super pump will raise your mpg by 10-15%
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A Giles super pump will raise your mpg by 10-15%
Not if you know how to use it ;D
Delete passenger side mirror, get some of that stripping to seal up your hood, a spoiler would probably be quite effective on a rabbit? Those are easy things. Have you done a lot of weight reduction yet?
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There was a guy that posted some on here, I think in the general section, that made some crazy looking stuff. A rabbit that was about 2x as long as normal with this taper coming off of the hatch. Another guy had a jetta with 2 box looking things on his trunk that made the air flow better and he could still use the trunk.
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My brother did a full belly pan on his Chevette and he said it gained him some MPGs.
I'm hoping to start playing around with making my car look ridiculous, but first I need to get a car.
As for the weight, I would think it would have most of it's advantage at higher speeds, and accelerating is when weight is going to have the most effect on MPG so if you are just around town doing under 50 it might not be worth it.
Don't forget about safety. Those euro bumpers do as close to nothing in a minor collision. Also body work is a lot more expensive than diesel.
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Yeah I definitely don't want to ditch safety just for a few mpgs. So I'll stick with the clipper look. Good to hear confirmation on the belly pan though. Seems like a worthy cause.
As far as the other stuff, I'm not sure im shameless enough to try building a paper machet kammback yet.. But im probably close. I saw in hyper miler competition they use painters tape to cover all seams and crevices. Seems clever.
The weather stripling and maybe a partial grill block in the winter seem like good ideas. Weight reduction doesn't seem very feasible for Me but im always up for suggestions. I drive a mk1 rabbit l with no rear seats carpets etc, no big sound system, no ac, no PS, manual windows and locks... The only heavy thing I could really lose from here would be my bumpers but that scares me. Unless there is farther I can go with that.... Oh and no passenger side mirror either!
Giles pump is out of my league for now. If the pump starts acting funny or leaking it will probably go to him though. I also just found a guy whose going to help port my head and intake manifold (replacing with mk1 Gasser manifold) hoping the port n polish will squeak out some efficiency. And then get the vnt rigged up for high boost with low fueling. But those aren't really aeromods ;)
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Shave drip rails, those things are an aerodynamic abomination.
But they do keep it from dripping on you leg when it rains.
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Sounds like you're pretty much there with weight savings. A belly pan under the motor and a spoiler might help.
What are you running for tires?
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Shave drip rails, those things are an aerodynamic abomination.
But they do keep it from dripping on you leg when it rains.
Bahaha. Excellent description. Ya I've thought about shaving them before but ive heard that's actually where the roof joins to the rest of the body so you have to smoother and weld up the panels and possibly fabricate new panels. Scares me. Could probably beat them flat though :/
Yeah weight savings was mostly accomplished by purchasing a rabbit L! Oh I forgot to mention I've already ditched the spare and jack in favor of a can of fix a flat. For tires I'm running bald 195 fallen ziex 912s which is probably a part of my bad mileage. And they wore out in less than a year of normal driving :(
Hoping to go to skinnier tires with lower rolling resistance in a few months. Any suggestions?
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My favorite size to run on these has always been the 175/70-13 but in theory the 155/80-13 will be the best tire for mileage.
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I was planning to drop to 165s or 175s depending on what I can find at a deal. Any preference for brands etc. I know falkens are cheap and sticky (good for cornering bad for mpg) so I'm more looking for something with a high tread life and good wet/snow traction with some low resistance. Are those things compatible?
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We just put some Kenda Kenetica tires on my FILs 93 Protege. We did notice a few extra MPGs over the old mixed/worn set. Price was pretty good to, $250 installed I think.
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my mpg and how it handlefew examples from what i have experianced.. in past yes.. but valid..
81 diesel bunny.. stock ride height, 185/60 r 14.. turbo bogie on stock springs... add kamie front spoiler.. much more stable at speed.. 2mpg improvement.. but i had heavy foot and way too many 81 in 65 tickets that i cannot even guess how many left court at that...
82 jetta coupe into 84 coupe (lowered jetta square up front like kamie on bunny).. cutting a coil off th egti springs on it, increased gas milage and i gained 14mph more stilibilty in tripple digit speeds.. it alowed for enough speed to make top of doors fluder at speed (th e82 was reallty rusty).. :D again.. i was way too yung to admit how dumb..
so th ekey to better is keeping air from under front of car..
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Yokohama AVID Ascend
That is the best tire I have ran since the spectrum was discontinued.
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Prius OEM tires are great for MPG and can be had cheap because they drive kinda crappy.
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I forgot about lightweight wheels, those can net you some gains as well, find a set of decent 14" rims in the junkyard? Going 185/60-65r14 will open up your tire options tremendously as well. There are documents out there that list the more common junkyard alloy wheel weights if you do some searching, people have compiled extensive lists of potential weight saving bits for all the lemons races.
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The 13" steels I have are lighter than my 14" snowflakes and the snowflakes are supposed to be the lightest alloys VW made. Also, it takes a ton more to turn the 185s than it does a 155, there is 30mm of extra rubber making contact.
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14" lacastlets are lightest stock 14 i know of... passat/jetta/cabby come stock... passat syncros got 15" version that one day ill own a set of...
they supposedly a funch and forged... people polish the faces into a mirror... even has aluminum center caps ($60/each new years ago) but plastic ones from snow flakes fit nice.. but if you have 4 caps.. well worth polishing effort.. just most are missing 1.. :P i have 5 due to matching spare.. but my 5th one is discolored.. i bought a set of wheels with a melted one for caps one day.. :P
also the inners have different colors.. of my 5 2 are one shde of grey.. other 3 are really light colored..
the lightest made were 13x5 mk1 rocco wheels... here.. in europe they came in a more common 13x 5.5 and usa got as option for 80-81.. and jetta only.. ive seen only 1 in real life.. 1 not set of 4.. 1.. and imo of all the 13" my fav.. id rock a set.. seen a few pop up on poortex on "just picked it up" type of cars.. the owners always feel its just a rocco wheel till i point out i want to own.. then they relize its not "common" and never see again... vs the 5" wide wheel.. the face is almost flat.. i got pic somewhere..
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(http://i.ebayimg.com/00/s/NDE2WDY0MA==/z/LWoAAMXQVERStMzc/$_20.JPG)
To my knowledge, these are the lightest rims VW ever made. They are 13". I own a set, well I guess my brother does and I know of one set for sale. I have no before and after mileage report though.
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(https://driiive.com/assets/cars/380cbb69fd4573539d6b334deed5495b93c506c9/photos/6708851395170499-16ddf172d1.jpg)
13x5... and i think weight less then above turbine fin wheels..
(https://driiive.com/assets/cars/380cbb69fd4573539d6b334deed5495b93c506c9/photos/8451001395170491-49b76d491b.jpg)
is the rair 13x5.5 ones.. see how flat they are?
my atp spa(brand long gone that i got in 98) on my 84 coupe on a b3 kill milage by 6mpg vs the 14"castlets.. but what funny.. the phone dials even with adapters did not change its milage at all..
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Yeah I think you are correct CRSMP5, I've gotten them mixed up.
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I'll be darned. I never knew any of those good ol' Sca-rocco wheels were 5's!
Man, it's GREAT to have cramps back! ;D
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id almost swear they were magniesium they weigh so little.. but the bubble butt effect the 5" wide has vs the 5.5" flat has always put me off.. the 3 piece 15" ones the guy is building look sweet... but i bet the flate face with less dish would look much better..
http://meister.us.com/
would be a guy to ask on weights..
(http://meister.us.com/wp-content/uploads/2013/09/1233617_10201611583993021_1578073096_n.jpg)
i know there a tranchula cut up.. few "man holes as they call them" but he has a set of 13" snowflakes, guess mexico option, seen set of turbines someone wanted him to do.. so id ask them if your dead set on wheel weights..
now imagine less lip, flat face... no way ill ever piss away $3k on wheels.. id buy a mill and make my own first.. but they pretty..
:D thanks on the welcome back.. but a majority of us were only 13x5.. the 13x5.5 were jetta only option in usa for 80-81.. then they got turbines, rocco/cabby got a 1 year only really soft bend if 5ft from pot hole wheels.. 83 tranchula replaced.. then snows, bottlecap, teardrop, p spoke was 87 gli option here, cross pond had on mk1s.. castletts started in 88 along with steel 14s..
so to me growing up with new just out.. yea till mk3 i know them.. :P sadly the only 1 of the 13x5.5 i have seen was so bent i thought they bent the face.. tire shop fd up and was looking for one.. hell this was 84ish.. only one ive ever seen in person.. :(
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Oooo those are shiny. Yeah I need to invest in some cheap light rims sometime. I'll keep my eyes pealed. Id love to make my own wheels sometime. A light one off design would score me points for having one of the kind rims and be killer for mileage ;) too bad that won't ever be haha.
How do you guys drive in town for best efficiency. I catch myself compression braking and riding in third too much. I really need to take advantage of that 3+E ;) in computer cars (at least scubies) compression braking shuts off the injectors and saves fuel. But in our cars it would use up energy with no fuel savings so I should just clutch in coast right?
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no the way the gov. works in our pumps if you coast in gear it limits the fuel. If you clutch in, not only are you riding your clutch, you are wasting more fuel.
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no the way the gov. works in our pumps if you coast in gear it limits the fuel. If you clutch in, not only are you riding your clutch, you are wasting more fuel.
How so?... control collar is at idle position if foot is off pedal...
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At 3,000 rpm or so if you let of there will be little to no fuel injected. If it were, you would never slow down coasting. It is something about the flywheel weights. IIRC rabbitman or someone had a test with their tiny tach that around 3,000 rpm when they let off the tach quit since there was no line pressure activating the pickup.
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Ok, I follow you now... idle fuel quantity at 3000rpm, vs idle fuel quantity at idle rpm (coasting).
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Descending a hill , I get EGTs around 200F as long as it's steep enough to keep it over 2800 rpm I think.
Burn and engine kill is going to be more efficient, but the factory ignition switch can make it a pain.
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Okay so our pumps DO limit fuel at around 3k Rpm idle. Now if only I had a tach so I didn't have to do calculations on the fly haha.
Any other big increases in mpg? I know the driver is the biggest factor but making these things slippier has to help.
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Anytime you are in gear and not on the pedal the pump limits fuel.
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No tach needed... the IP spits fuel with each revolution: with no pedal, a little at idle (e.g. 800rpm), same pedal at 2400rpm (engine braking)... 3x as much. The cc per injection doesn't change, but the number of spits does, and for nothing since you're braking.
As for aero, the blunt rear is the big offender.
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Fuel is limited in decel, but I think it only stops above 300 or so.
An EGT gauge can help a lot, and mostly driving slow.
http://cumminsengines.com/uploads/docs/cummins_secrets_of_better_fuel_economy.pdf
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I think the fly weights on the gov shaft pull it in harder when the engine is spinning faster than idle, but you are off the pedal.
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No tach needed... the IP spits fuel with each revolution: with no pedal, a little at idle (e.g. 800rpm), same pedal at 2400rpm (engine braking)... 3x as much. The cc per injection doesn't change, but the number of spits does, and for nothing since you're braking.
It's not quite that simple because the throttle pedal is not directly connected to the control sleeve that determines how much fuel is being injected.
With our pumps, engine braking uses 0 fuel. Fuel will start being injected again once the pump RPM approaches idle speed. The reason why you would see 200F on a pyro is because of the compression of the engine, not because of burning fuel.
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Ok, that makes sense, but that would also mean that fuel consumption might not differ much between coasting and engine braking.
From the Bosch book:
Overrun
When the vehicle descends a steep gradient, or when the accelerator pedal is released at high speeds (overrun), the engine is driven by the vehicle's inertia. The sliding sleeve responds by pressing against the starting and tensioning levers. Both levers move the shift the control collar to decrease delivery quantity; this process continues until the fuel-delivery quantity reflects the requirements of the "new" load factor, or zero in extreme cases. The response pattern of the variable speed governor described here is valid at all flow control lever positions, and occurs whenever any factor causes load or rpm to vary so substantially as to shift the control collar all the way to its WOT or "stop" end position.
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I don't seem to coast nearly as far while engine braking though.
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Regarding aero-mods: trailer-tail perhaps...?
(http://static.commercialmotor.com/big-lorry-blog/2010/06/24/Trailer%20tail%201.JPG)
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Ok, that makes sense, but that would also mean that fuel consumption might not differ much between coasting and engine braking.
From the Bosch book:
Overrun
When the vehicle descends a steep gradient, or when the accelerator pedal is released at high speeds (overrun), the engine is driven by the vehicle's inertia. The sliding sleeve responds by pressing against the starting and tensioning levers. Both levers move the shift the control collar to decrease delivery quantity; this process continues until the fuel-delivery quantity reflects the requirements of the "new" load factor, or zero in extreme cases. The response pattern of the variable speed governor described here is valid at all flow control lever positions, and occurs whenever any factor causes load or rpm to vary so substantially as to shift the control collar all the way to its WOT or "stop" end position.
Exactly. Coasting means you burn whatever fuel you burn at idle, which is not much.
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Duckbill and A pillar spoilers...
(http://i1117.photobucket.com/albums/k596/Jetta_GTD/VWVortex/vw-golf-gti-mki_277_zpsa444a053.jpg)
Rear upper spoiler...
(http://i1117.photobucket.com/albums/k596/Jetta_GTD/VWVortex/6151083112_851ec17ccc_b_zpsdb0f8b51.jpg)
Rear lower spoiler...
(http://i1117.photobucket.com/albums/k596/Jetta_GTD/VWVortex/FOHA_zps13c88344.jpg)
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Woah those a pillar spoilers are wild! I've never seen those or the lower spoiler either. I imagine those a pillars might actually reduce drag a bit. Though I think the rear spoiler might increase it... Those are super rare at any rate. Wish I could find a zender 3 PC just for looks ;)
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The rear spoilers decrease drag a lot, they aren't there to provide downforce. I'm really not at all a physics guy and know little about automotive aerodynamics someone explained the rear spoiler once, something about directing the airflow away from the pocket of low pressure behind the vehicle and reducing turbulence IIRC. You could probably make one or modify a common junkyard lip spoiler, e30 comes to mind, maybe the Impreza (mid-late 90's) with the spoiler just beneath the glass could be shortened?
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Glad I stumbled on to this thread. I have been going to the Ecomodder site for quite some time and truly believe that mileage starts with areodynamics. The best example would be for anyone to type in 'basjoos' on google & see his 100mpg 92 honda vx. He's done just like a wing: blunt at the front & pointy at the back, so the air flows back together with no turbulence. I have been thinking if a Caddy was to do something like basjoos did, 80+ mpg would be possible, albeit it would look completely alien. A flat bottom has also been shown to be very effective and is incorporated in basjooses work. I think it will be worth a try.
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Most of the "aero" benefits are at the back of the vehicle. But some are available at the front. Blocking off the grill helps. I have about 3/4ths of the radiator covered. Narrow tires help. Putting spats in front of the tires helps.
Look at almost every newer SUV and van, they all have a rear window deflector. Its purpose is to help the air stay attached longer. I have a 12" long deflector on the back window of mine.
(http://veloliner.com/vw/vw12312b.JPG)
Taking it to an extreme, this guy gets 60-70 mpg on his diesel. Besides the obvious he has a full underbody covering and a nearly full grill block.
(http://www.veloliner.com/vw/tailconejetta.JPG)
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Perhaps y'all are familiar with Flow-Illustrator? It makes videos online, or a version of the program can be downloaded.
(http://www.flowillustrator.com/images/3.jpg)
http://www.flowillustrator.com/
Not a 3D flow modeller, but interesting.