|
Fords have always been good at it in my experience. I'm pretty sure I've driven every single one of their four-speed electronic RWD autos and all of 'em were great at engine braking. Manually dropping a gear on the highway to hold speed for a downhill could easily send unrestrained things on the seats to the floor. The KJ Liberty, not so much. You could drop that thing to second at 70 MPH and the RPMs would rise while you felt basically no change from the driver's seat. I did not like driving it in the mountains.
|
#
?
Jul 21, 2016 23:30
|
|
|
|
| # ? May 30, 2024 10:23 |
|
|
0toShifty posted:The most batshit thing a Prius transmission does is how it implements overdrive. Prius enthusiasts (yes) call it "heretic mode" - Toyota calls it "power recirculation mode" - at highway speeds - the gas engine is spinning all the time. To make overdrive happen, one of the motor generators takes power off the output of the differential, and drives the other motor generator with that power together with the engine - which in effect slows the engine to a more efficient RPM. Seems kind of like a perpetual motion machine. On the second‐generation Prius, this mode happens at and above 42 mph. Even if no gas is being consumed, the ICE’s crankshaft must rotate. If you put the car into neutral below 42 mph and coast downhill, you can exceed 42 mph without the car switching into recirculation mode. This results in overspeed on one of the motor‐generators (I think it’s MG2). I don’t know if this flaw was fixed in later models. Another quirk of Toyota’s HSD is that in reverse, more power is available when the ICE is stopped than when it is idling. To back up a very steep hill, or just a lip of pavement, it is sometimes necessary to wait for the warm‐up cycle to finish so the ICE will stop (or put it in EV mode, if available, to pre‐empt it). Platystemon fucked around with this message at 02:10 on Jul 22, 2016 |
|
#
?
Jul 22, 2016 02:06
|
|
|
Impending mechanical failure, and a horrible mechanic failure. Apparently the guy that built it is only 15, so mad props...but I think maybe an adult should have stepped in at some point.   quote:First I started with a drawing, kind of a rough sketch to just get my ideas on paper. I then went to my neighborhood metal store and bought around 30ft of 1 inch tubular steel. To bend it I would clamp it in a vice and hit it with a hammer. Once I had the desired angle I welded the kink to strengthen it. I then welded all the pieces of bent steel to form the main part of the frame.  quote:I then mounted the gas tank inside the frame by welding mounts and bolting it in.  quote:After the main frame was built I decided to build the swingarm. I used a wrench and chain links welded together to make mine. But of course you can use steel tube or many other things Emphasis mine. He doesn't go into the forks a whole lot, but it really looks like there are two butt welds holding them onto the frame.  The whole gallery is here https://imgur.com/gallery/sMfWj#UorSavc
|
|
#
?
Jul 23, 2016 16:53
|
|
|
I know I'm several pages late but BMW did something even more hideous with an E21 back in the early 80's 
|
|
#
?
Jul 23, 2016 17:43
|
|
|
NitroSpazzz posted:I know I'm several pages late but BMW did something even more hideous with an E21 back in the early 80's Kind of funny, but that's what you would think is more aerodynamic with no experience in it, but it's really not. Kind of like how the guy who designed the 68 charger thought the flying buttress thing on the charger would be aerodynamic because it looked aerodynamic, but it was nearly the worst thing he could have done. What's strange is paul lewis seemed to have gotten it right in 1974, and the big automakers still moved backwards for 2 decades. 
|
|
#
?
Jul 23, 2016 17:55
|
|
|
Nubile Hillock posted:Impending mechanical failure, and a horrible mechanic failure. Apparently the guy that built it is only 15, so mad props...but I think maybe an adult should have stepped in at some point. Kid owns and this a good and cool thing to do. I hope he survives the swing arm snapping off though.
|
|
#
?
Jul 23, 2016 19:43
|
|
|
Don't get me wrong, I'm not trying to rag on the kid. He's definitely got his aesthetic down and some top-tier wrenching is in that project. I'm mostly impressed by getting the brake mounts welded/brazed on all aligned n poo poo...but there are going to be some hard lessons learned about frame design and gusseting sometime in the near future.
|
|
#
?
Jul 23, 2016 20:12
|
|
|
This was posted in a local car group today.     
|
|
#
?
Jul 24, 2016 03:30
|
|
|
That's...that's the teeth for the flywheel out there unzipped, isn't it? The big thing that got me about rotational energy is the phrase: "The faster you move, the heavier you get. The energy of motion turns into mass."
|
|
#
?
Jul 24, 2016 04:42
|
|
|
NitroSpazzz posted:This was posted in a local car group today. I misread this as, like, posted for sale in a local car group Like these were the photos for the auction listing "I DARE you to bid on this!  "
|
|
#
?
Jul 24, 2016 06:47
|
|
|
NitroSpazzz posted:This was posted in a local car group today. https://www.youtube.com/watch?v=f4Mc-NYPHaQ
|
|
#
?
Jul 24, 2016 06:57
|
|
|
Powershift posted:Kind of funny, but that's what you would think is more aerodynamic with no experience in it, but it's really not. There a fantastic set of NASA papers available from the 70's I think, detailing aero experiments on a box truck. Nothing they did at the front no matter how extreme matched the benefit of lightly fairing in the rear. I think they also started with a full aero tail and progressively chopped more and more of it off with little negative effect down to a couple of feet. Aero is fascinating and I wish I'd studied it.
|
|
#
?
Jul 24, 2016 08:28
|
|
|
Cakefool posted:There a fantastic set of NASA papers available from the 70's I think, detailing aero experiments on a box truck. Nothing they did at the front no matter how extreme matched the benefit of lightly fairing in the rear. I think they also started with a full aero tail and progressively chopped more and more of it off with little negative effect down to a couple of feet. Aero is fascinating and I wish I'd studied it.  Overview: Aerodynamic Truck Studies - https://www.nasa.gov/sites/default/files/atoms/files/fs-100-afrc.pdf A Reassessment of Heavy-Duty Truck Aerodynamic Design Features and Priorities - http://www.nasa.gov/centers/dryden/pdf/88628main_H-2283.pdf Drag Reduction Obtained by Modifying a Standard Truck - http://www.nasa.gov/centers/dryden/pdf/87898main_H-977.pdf
|
|
#
?
Jul 24, 2016 11:52
|
|
|
Powershift posted:Kind of funny, but that's what you would think is more aerodynamic with no experience in it, but it's really not. Belly tankers have been around since the 40s or 50s mate. http://www.autoconcept-reviews.com/cars_reviews/gm/GM-belly-tank/cars_reviews-gm-belly-tank.html
|
|
#
?
Jul 24, 2016 12:53
|
|
|
xzzy posted:What cars need is the ability to read your speed when in low gear, and when you release the brakes it maintains that speed as best it can with gear selection and engine braking. Seems like CVT's would be really good at it. Page back but I can confirm that 2015 and higher Honda CR-Vs with the CVT standard do this. It is great when you are in cruise control, terrible when you aren't. You lift your foot off the accelerator when going downhill, expecting mild engine braking, and the CVT panics and aggressively engine brakes. Took some getting used to.
|
|
#
?
Jul 24, 2016 14:04
|
|
|
Geirskogul posted:That's...that's the teeth for the flywheel out there unzipped, isn't it? Yup. The flywheel is usually cast iron, the ring gear is steel, and merely pressed on. You can sometimes even freezer/oven the parts and slide it together. So when the flywheel splits in half and the halves want to assume a straight line path as quickly as possible, the ring gear really doesn't contain it very well.
|
|
#
?
Jul 24, 2016 15:49
|
|
|
skybolt_1 posted:Page back but I can confirm that 2015 and higher Honda CR-Vs with the CVT standard do this. It is great when you are in cruise control, terrible when you aren't. You lift your foot off the accelerator when going downhill, expecting mild engine braking, and the CVT panics and aggressively engine brakes. Took some getting used to. The earlier 2012-2014 (and probably the generation before that too) with the 5-speed does it too. Actually works perfectly coming down I17.
|
|
#
?
Jul 24, 2016 16:37
|
|
|
NitroSpazzz posted:
That's the one, I got some of the details correct 
|
|
#
?
Jul 24, 2016 16:53
|
|
|
I'd like to see the testing re-done in an era where the analysis isn't on pictures of cars with chunks of string taped to the side. Not that their study and results are invalid just because they're old, but with modern simulations it seems like you could experiment with a lot more variants a lot more quickly.
|
|
#
?
Jul 24, 2016 19:53
|
|
|
Apparently there is a recall for this in US salt states, but not in canada. Because apparently your valve stem exploding and your tire rapidly losing air isn't a safety issue once you cross the 49th parallel.   Chrysler went out of their way to find an aluminum that turns to dust instantly in the presence of salt, and used it to make everything on the jeep liberty.
|
|
#
?
Jul 24, 2016 21:36
|
|
|
My entire life has become fighting corroded TPMS stems.
|
|
#
?
Jul 24, 2016 22:38
|
|
|
I've been told by folks who work at dealerships that those TPMS modules never got sold up here, we only have those ABS module based inflation sensors. So maybe they weren't recalled up here because nobody has them unless they imported the car from the U.S?
|
|
#
?
Jul 25, 2016 00:03
|
|
|
Nubile Hillock posted:I've been told by folks who work at dealerships that those TPMS modules never got sold up here, we only have those ABS module based inflation sensors. So maybe they weren't recalled up here because nobody has them unless they imported the car from the U.S? Nope, it's a canadian model 2008 jeep liberty.
|
|
#
?
Jul 25, 2016 00:06
|
|
|
Oh dear
|
|
#
?
Jul 25, 2016 00:11
|
|
|
Powershift posted:
Problem identified.
|
|
#
?
Jul 25, 2016 00:20
|
|
|
Well there's at least one argument for using nitrogen in your tires instead of air. ...or at lest for getting a desiccant on your compressor.
|
|
#
?
Jul 25, 2016 16:33
|
|
|
Why in the gently caress did they make something as thin and delicate as a tire valvestem out of aluminum? I guess it must have saved a few cents over making it from brass or stainless.
|
|
#
?
Jul 25, 2016 16:39
|
|
|
GnarlyCharlie4u posted:Well there's at least one argument for using nitrogen in your tires instead of air. Those corrode from the outside in, even here in Florida I've sheared a couple and the threads were always pristine from the tire side and hella gunked up and siezed on the outside... side. The small amount of water that could get inside a tire is nothing next to the rain, road grit, UV and (in places) salt combo that the outside sees. Besides, all tires are filled 4/5 with nitrogen anyway.
|
|
#
?
Jul 25, 2016 17:51
|
|
|
But that extra 1/5 means you get predictable pressure changes with temperature and gain microscopic fuel efficiency improvements!
|
|
#
?
Jul 25, 2016 17:54
|
|
|
Enourmo posted:Besides, all tires are filled 4/5 with nitrogen anyway. Yeah, atmospheric air is 90ish% nitrogen. But, air from a compressor can contain a lot of moisture (depending on the temperature, and if you drain the tank) and if you don't have a desiccant on it.
|
|
#
?
Jul 25, 2016 18:21
|
|
|
GnarlyCharlie4u posted:Yeah, atmospheric air is 90ish% nitrogen. 78% is not "90ish%", I'd hazard a guess. Costco puts nitrogen in anything they install and I've been getting my tires there. But I don't go out of my way to keep 'pure' nitrogen in there.
|
|
#
?
Jul 25, 2016 18:34
|
|
|
Wait, just get rid of the like 20% of oxygen out of the air on one side of the wheel? That seems like a whole lot of effort for not a lot of benefit
|
|
#
?
Jul 25, 2016 19:16
|
|
|
The N2 molecule is a little bit bigger than the O2 molecule, results in a little less leakage over time which helps fuel economy as well. e: by something like 2%... yeah I agree it's pretty pointless for 95% of cars on the road
|
|
#
?
Jul 25, 2016 19:20
|
|
|
Maybe like long haul truckers would benefit, but that sounds entirely pointless for almost every other vehicle I can think of. Unless getting pure nitrogen is as simple as turning on a compressor, then emergency service and some commercial vehicles could benefit too, but yeahhhhhhh
|
|
#
?
Jul 25, 2016 19:35
|
|
|
It is basically pointless and changes nothing unless you are a trucking firm with thousands of long haul truckers who get a very repeatable fuel economy number every time and log millions of miles a year combined. I drive 50k miles a year at ~$2.50/gallon gas and 24mpg. Difference over the course of a year is apparently 1.3psi lost. N2 only lost 2.2psi, air lost 3.5psi. The EPA says you lose about 0.3% for every 1psi dropped... if I ran the entire year at 3.5psi low (let's ignore the fact that N2 still loses 2.2psi here) I'd reduce my fuel economy from 24mpg to 23.748mpg. That works out to a savings of 22 gallons of gas, or 55 bucks. If you take into account the fact that N2 tires still lose 2.2psi so the difference is actually only 1.3psi (and still ignore the fact that it'd be a gradual loss over the whole year, not running the whole year 1.3psi low) it'd be a savings of $21 per year. And I'm an extreme case, I drive about 4x what the average driver does, in a car with worse fuel economy. And that's still assuming running the whole year 1.3psi low instead of a gradual loss over the course of a year or checking every month and refilling as needed. Check your tires once a month. Now it literally does not measurably affect your fuel economy either way and you can refill at any gas station instead of having to pay more than you will even save in nitrogen topoff fees. e: http://www.edmunds.com/car-care/should-you-fill-your-cars-tires-with-nitrogen.html
|
|
#
?
Jul 25, 2016 19:37
|
|
|
The Door Frame posted:Maybe like long haul truckers would benefit, but that sounds entirely pointless for almost every other vehicle I can think of. Unless getting pure nitrogen is as simple as turning on a compressor, then emergency service and some commercial vehicles could benefit too, but yeahhhhhhh Nitrogen is a waste product from some process for like welding gas or some other widely-produced chemical. If you have the facilities to accept and store it, it's cheap, and you can up sell it for way more than the cost.
|
|
#
?
Jul 25, 2016 19:50
|
|
|
50k a year? holy poo poo
|
|
#
?
Jul 25, 2016 19:51
|
|
|
The real "holy poo poo" is the quote from the edmunds link:quote:The "nitrogen upgrade" was a $69 item on the supplemental window sticker. Another forum member later posted that his dealer was charging $179 for this same "upgrade." Haha, what a bunch of dirtbags.
|
|
#
?
Jul 25, 2016 19:58
|
|
|
Nitrogen's not really a waste gas, but it is the most common gas produced in air liquefaction because, well, it's 78% of the atmosphere. If you condense/compress air you get 78% nitrogen, about 16-17% oxygen iirc, 1% argon (used for welding), and a couple hundred ppm of CO2 plus other traces like neon and methane. Common welding mixes are 75/25 Ar/CO2, 100% Ar, plus some helium and other specialty mixes. Helium is only found underground though, resulting from radioactive decay in rocks below nonpermeable rock formations that trap it. The N2 and O2 are products in their own right since they are widely used in industrial, scientific, and medical processes. Other fun facts: almost all of the argon we have today comes from radioactive decay of some isotopes of potassium. The only reason we have it is because it's heavy enough to remain in the atmosphere, unlike helium, which escapes into outer space. BraveUlysses posted:50k a year? holy poo poo The shortest my commute gets is 140 miles roundtrip, about 34k miles a year. If my GF and I carpool it becomes 173 roundtrip, around 43k a year. There are evenings where I come home from work after driving 70 miles there and 70 miles back, and just go hoon around on back roads for a couple hours, putting down another 50-80 miles for the hell of it. Add in the amount of driving I do on weekends and it easily hits 50k a year. I think I'm coming up on 300k miles driven lifetime now.
|
|
#
?
Jul 25, 2016 20:08
|
|
|
|
| # ? May 30, 2024 10:23 |
|
|
I fill my tires with hydrogen so they are lighter and I go faster, (for a little ways anyway).
|
|
#
?
Jul 25, 2016 20:12
|
|
