The New Scion 2008 xD

roxy84 · May 2007

my brother in law works in marketing for toyota. fwiw, he says the asterisk next to those mileage figures denotes 2007 testing procedures, and that they will post those as long as legally possible. heck 32/37 for the manual would be higher than the new test numbers for a manual corolla, which i think are 28/37. being that the xd (my opinion here) may well come in heavier than a corolla and be far less aerodynamic, i'd highly doubt 32/37 is via the 2008 testing. the corolla loses about 4 mpg both city/highway, so if the xd does also, that would put it at 28/33. however that would put the auto at 26/30.

hopefully those really are new method test numbers. if they are, a manual xd at 32/37 beats both the corolla and yaris.

eldaino · May 2007

hmm...you can really automatically assume that the milage drop would be so drastic or the same amount of mpg for each car, just becasue one drops four does not mean the xd will.

28/33? the city sounds ok, but i def think it would at least get 35 to 36 on the highway.

eldaino · May 2007

what a good post! i too wish that honda would release the newer version of the fit, i'm a honda man too! But i really do like the xd, and i may end up seeing myself in one depending on when the new fit arrives!

roxy84 · May 2007

hmm...you can really automatically assume that the milage drop would be so drastic or the same amount of mpg for each car, just becasue one drops four does not mean the xd will.

28/33? the city sounds ok, but i def think it would at least get 35 to 36 on the highway.

well, that was a rough estimate on how much of a drop the xd will have. if you look at this site:
http://www.fueleconomy.gov/feg/calculatorSelectYear.jsp

it tells you the old numbers for any car vs the new 2008 numbers using new test methods. i mentioned 4 mpg because that is very close to what many economy cars are experiencing under the new test procedures.

my brother in law was not 100% sure the numbers on that sheet were via old test methods. i, for one, would gladly trade my corolla for an xd if mileage was equal to or greater than the corolla. i had almost traded for a yaris, but i concluded id be giving up some comfort, quietness, power, and a little handling (overall, just more car) without gaining anything in mileage. why bother. the xd, with power locks/windows, 60/40 fold flat rear seats, side air bags, a stronger engine, gauges where they belong, a tachometer...would be so many things the yaris is not. hopefully,it will come in around $14000-$14500.

ohplezz · May 2007

With the new Dual VVT-i engine in the xD, when just considering the engine, you'll get better economy than the old 1.8 engine in the corolla. But having said that, their is more to mileage than just the engine. The body shape of the xD and the short gear ratios, scion has implemented to provide quick response, will have an overall effect on mpg. But this car is not just about good gas mileage for scion. Scions purpose is to introduce the toyota brand to people who would not other wise have purchased a toyota. They have been effective with this approach. But I feel the xD will provide very good mileage with this new engine despite its shape. This engine technology has been proven effective in other toyotas. Look at the toyota tundra. The 4.7 with Intake only VVT-i gets 15/18. The 5.7 with intake and exhaust VVT-i (like the xD motor) provides 100+ horses and gets 15/20. So there you have a motor giving more power and better mileage at the same time just like the xD compared to the xA will hopefully show. Only time will tell the true story but pound for pound, even with its draw backs, the scion xD is going to be a great little car that gives very good mileage. The honda fit second generation is not expected until some time in 2008 calendar year. I wish it would come sooner but its not going to happen. I'm going to be buying a xD this fall. Maybe in 5 years honda will have a couple of diesels for me to trade my little xD in for. :confuse:

roxy84 · May 2007

The body shape of the xD and the short gear ratios, scion has implemented to provide quick response, will have an overall effect on mpg

this is what concerns me. the scion xa was slow anyway, so i felt it was overkill to have the engine revving so high at highway speeds (5 speed xa was booming so loudly on the highway that it became tedious on just a 10 minute test drive) were talkin 3600+ rpms at what should be a relaxing cruising speed of 70 mph. the corolla 5 speed is about 2850 at 70 mph. heck, even the yaris is relaxed at highway speed (about 3100 rpm)compared to the xa. 128 hp cars arent fast anyway, so i hope scion makes the xd a better highway cruiser(keeping the rpms around 3000 at 70 mph.this was the primary deal killer with the xa for me.

jbrahms · May 2007

I have an 2006 xA automatic, and I don't agree with the numbers you quote about rpms vs speed. Here are the figures I have measured in fourth gear: 1750 rpm @ 40 mph, 2100 rpm @ 50 mph, 2500 rpm @ 60 mph, and 2900 rpm @ 70 mph. I don't find it too noisy at 70 mph, but the ride can be uncomfortably choppy at that speed on concrete highways with their expansion joints. On smooth asphalt it rides very nicely at that speed.

I also have a 2006 RAV4 V6 automatic that rides quietly and comfortably on the highway at 70 mph, so that's what I use on trips. However if the xD proves to be a good highway car, I plan to sell both of my cars and "step up" to the xD. I love the xA around LA where I do most of my driving, but I don't really want to own two cars.

roxy84 · May 2007

I have an 2006 xA automatic

yes, but i was referring to the 5 speed xa. id have given up some speed in the xa just to cruise at a resonable rpm at 70 mph. my 126 hp corolla is plenty fast( for my needs) with a manual transmission, and is decent with highway cruising. the honda fit manual has this problem as well at about 3400 rpm at 70 mph.

im just begging scion not to have such vastly different final gear ratios in the auto vs manual.

jbrahms · May 2007

I would have thought the fifth gear in the manual transmission would run at a lower rpm than the fourth gear in the automatic at the same road speed. Isn't that the whole point of the fifth gear?

roxy84 · May 2007

every econo car ive test driven in the past 5 years is the same in this regard. the auto tranny cruises at lower rpms on the highway than the 5 speed counterpart.

on cars like the xa, xb and fit, and many other econo cars, the difference is quite drastic. i disliked the manual fit's gearing at highway speeds so much that i crossed it off my list. the auto tranny was much more pleasant.i guess automakers think it gives more power under foot at that speed or the lower gearing makes it "sporty".xa, xb, yaris matrix, corolla, civic (non si), etc....all these econoboxes are slow and they should never be confused with sporty.

but i am a diehard stick driver, and will remain so until they quick making sticks or my left leg and/or right arm fall off.

i really hope the xd manual tranny is not so punishing to the driver at 70+ mph as the manaul xa/xb. its quite a bit larget engine, so im hoping they wont feel the need to gear it so short.

jbrahms · May 2007

Apparently the fifth gear in a manual tranny is not really an overdrive gear in the subcompacts you mention. I'm surprised to hear that because the EPA gas mileage is always reported better in the manual than the automatic, even under the 2008 measurement system. I guess the energy losses in auto tranny (in the form of heat) must be pretty significant.

ohplezz · May 2007

I would not say that heat losses are the cause for autos poor mileage. A 4 speed auto tranny just does not have enough gears to provide great mpg. It is often left in to high or to low a gear for good fuel economy. Also with manual trannys a 6 speed gives you greater mileage than a 5 speed because the 6th gear is very tall for relative low rpm at hway speeds. For those of you who do a lot of hway driving, and are concerned about high rpm noise, you should get the auto xD. The 5 speed will probably be reving pretty high at 80 mph. I love to drive and that means I've got to buy a 5 speed. Fuel economy and driving pleasue beat out the high speed rpm noise in my book. Don't forget that gas will be over 4 bucks a gallon this summer! :mad:

roxy84 · May 2007

Also with manual trannys a 6 speed gives you greater mileage than a 5 speed because the 6th gear is very tall for relative low rpm at hway speeds.

ideally, but this often is not true. many 6 speed trannys simply make the 6th gear what the 5th would have been and make all the other gears shorter. the nissan versa 6 speed manual is a good example. at 70 mph in 6th gear its rpms are at 3100. this is not as low as id hope with a 6 speed.

i still contend if the corolla 5 speed cruises at 75 mph at 3000 rpm, a similar sized engine in the xd should be just as relaxed. the gearing in the corolla, to me, is not too long or short. it allows me to push when it need acceleration(0-60 times are quite respectable with a 5 speed corolla) and cruises at relaxed enough engine speed to give me consistent 40+ mpg on the highway. the only handicap the xd should have compared to the corolla are the aerodynamics.

719b · May 2007

i thought the axle ratio has as much to do with how fast an engine revs as the transmission gearing does?

ohplezz · May 2007

From my sources the xD is going to have short ratios to provide a quick response. It is going to be reving pretty high on the Hway but not as high as a 4 banger sports car.(my old 96 prelude si 5MT would be at 4k rpm at 80 mph) I don't think the xD will be that high at 80 but buy the auto if you want a quiet yet, boring Hway experience. Overall I doubt the xD will be very quiet in general. I don't think it will have a lot of sound isolation.

iamz · May 2007

Good news. I just read on two other sites that Cruise will be standard on the XD.

ohplezz · May 2007

I read that also on scionlife.com. Where did you read it?

mcmanus · May 2007

Model analysis (engineering, not hollywood) dictates that smaller things move faster/easier than larger ones. So its OK for smaller engines to run faster and OK for them to cruise at slightly higher rpms. But I'd still prefer to see a 1.8L at under 3000 rpm at 70 mph. I don't see the need for a 6M, but 5A would be OK. Most automatics are longer legged in top gear than their manual counterparts so that their efficiency loses are balanced out to provide the same mph.

So glad to read that cruise will be offered. Frankly I'd drive a 1000 miles round trip to get it installed if thats what it'd take. Just my guess, but this implies that the new Corolla will also have cruise.

iamz · May 2007

Autoweek.com and Autospectator.com

eldaino · May 2007

xa, xb, yaris matrix, corolla, civic (non si), etc....all these econoboxes are slow and they should never be confused with sporty.

depends on your definition of fast is. A honda fit with 130 hp would be plenty quick, its not just hp numbers and engine size that determine acceleration.

The civic (mt) is actulally only marginally slower than the si sedan (7.7 sec vs 7.1); better handling is what the latter provides.

I find it odd that some people who have the xa are claiming such low cruisng speeds; my rabbit with a six speed auto still beats it; 2800rpms at 80 mph.

eldaino · May 2007

i know about this site, i frequent it alot. I suspect the civics drop would have to do with the nature of a fairly small engine in a relatively heavy body. I always averaged 28/38 with my ex auto.

the nubmers for the xb are already reflecting the real world 2008 epa tests...i would assume they would be the same for the xd...33mpg on the highway is a little low, the fit mangages about 26 in the city and 34-35 on the highway under the new numbers, i guess the xd is a bit heavier though, and has a bigger engine. (hopefully a nice sized gas tank too.)

i wouldn't mind the yaris if it was cheaper; it would be a good alternative to an older used car, but at 14k, i'll just take a base fit. Or an xa, or an xd.

roxy84 · May 2007

dont know how accurate the info in this piece is, but its about what i expected:

http://wardsauto.com/testdrive/xb_xd_scion/

27/33 mpg for the manual xd. those would be using the new fuel economy standards. very similar to what xa numbers would be with the new standards. as i suspected, the manual weighs in at over 2600 lbs for a manual, so its actually heavier than a corolla and less aerodynamic. the xd will be no mpg leader. gas is creeping close to $4/gallon here this week, so im losing my desire to switch from my corolla to this car. the yaris is the only thing that will give me comparable mileage (non hybrid) as im getting now. i suppose scion buyers may not have high mileage as their highest priority. pricing will be a big factor. anyone seen any pricing for the xd yet?

nippononly · May 2007

is a base price of $15,230 including destination, to be $1000 less than the xB as it is (approximately) now. Or maybe they will shave off a couple hundred more to make the symbolic $14,995 price point.

That would be with a manual, so figure $15,995/$16,230 with automatic.

mcmanus · May 2007

The difference between older xA/xB and newer xB/xD has increased with the bigger engine in the xB. So I'd guess that the pricing would also reflect that. I hope the xD will only be about $1,000 more than the xA so that a 5A x/D base price comes in the low 15's. This would be inline with out the door pricing of competing s. Remember no-negotiation Scion pricing practices.

With the expectation of $4/gallon gas, mileage of nearly all vehicles is very disapointing. Overall mileage figures haven't changed much in decades. Nearly all cars sold in the U.S. weigh about 2900 pounds and get roughly 25 mpg (real world). Thanks go to the oil and domestic auto industries as well as the feds for giving up on the CAFE standards.

BTW its hard to judge aerodynamic performance based on appearances alone. Much of factors into drag coefficient is under the car and in the details. With carefully design boxes can be made to be suprisely efficient in the wind. Crosswinds (especially meeting trucks on 2 lane roads in rain) is another matter.

I know the physics behind low weight leading to better mileage, but I challenge anyone to put 500 pounds in the trunk and measure a difference in mileage. It just doesn't happen. Air temperature makes more difference. Mileage drops significantly when temperature drops below say 40 degrees (lost engine heat) or above 90 degrees (use of A/C). I've measured 30% loss of mileage under extreme cold (-10 degrees) and 15% under extreme heat (100 degrees).

aatherton · May 2007

"... I know the physics behind low weight leading to better mileage, but I challenge anyone to put 500 pounds in the trunk and measure a difference in mileage. It just doesn't happen...

500 lbs anywhere on the car, whether in the structure or the load, will be reflected in additional fuel to accelerate or the weight or carry it up hills. In stop and go driving city driving with frequent braking and throttle, or in hill climbing, there will be a difference in mileage. In steady cruising with no speed changes, there will be no difference, as merely supporting the additional 500 lbs on level ground does not require more energy.

alpha01 · May 2007

I'm sorry this may be off-topic, but what? " Nearly all cars sold in the U.S. weigh about 2900 pounds and get roughly 25 mpg (real world)."

According to data available from Consumer Reports, most vehicles in the compact class (such as Civic, 3, Corolla, etc.) achieve 25 MPG overall or better. And these vehicles weigh between 2700 and 3000 lbs. Sure, they may not top 30 MPG as we'd like, but they are now quicker than near lux/luxury vehicles of years ago, and exponentially safer. To each their own, but I'll take greater safety and more power holding efficiency static, any day of the week.

~alpha

eldaino · May 2007

totally true! heck, the 175 lbs more in my rabbit over the civic i used to have is what keeps its acceleration times roughly the same, despite the huge increase in engine size.

eldaino · May 2007

xA so that a 5A x/D base price comes in the low 15's.

except that there wont be a five speed auto

mcmanus · May 2007

Comparing a Rabbit to a Civic is apples to oranges and meaningless in a discussion of mileage versus weight. There could be hundreds of reasons why acceleration in one is better or worse. Just try running any 100 mile round trip with and without 500 pounds extra in the same car (at the same air/engine temperatures) and see if the mileage varies. I doubt it will.

I drive about 30,000 miles a year and watch my mileage like a hawk. I've also been a licensed engineer for 25 years. I know the physics and the arguments, just have never seen it in roughly 800,000 miles of driving.

Yes nearly all cars are rated for 5 passengers. The little ones are bigger, heavier, etc. due to "model inflation". But the range of choice amoung cars has shrunk. For example on all major specifications (such as interior/exterior size, weight, mileage, configuration, cost) a Civic is 90% of an Accord, so where's the choice there? In Europe there is a much wider range of choices.

My 1978 Rabbit had exposed metal on the inside of the doors. That's OK with me, because I know its made of steel, a form following function design. Beyond auto, air, cruise, and AM/FM most luxuries are lost on me.

Safety comes from alert/non-distracted drivers, roads in good repair, and less traffic (especially tall vehicles you can't see around). ABS, airbags, etc. are compensations for the real risk factors.

Frankly over the past 20 - 40 years I haven't noticed cars being faster or getting much better mileage. In 1973 a high school buddy had a used Road Runner that easily reached 140 mph. How many of today's spoiled high school kids can afford anything that fast? In 1983 my father-in-law and I both got 40 mpg (mostly rural/highway driving) cars, mine was a Sentra MPG and his was a Buick Park Avenue diesel (just as GM "figured out" diesel cars they stopped building them). Neither were fast, but just try to buy a Buick today that does 40 mpg in the real world.

alpha01 · May 2007

That's fine that you haven't observed cars getting faster, but you're basically taking the example of one of the quickest sleeper muscle cars (Ply. Road Runner) and using as the benchmark. (And frankly, lots of cars today could hit 140 if electronically ungoverned and sold with high performance tires - the engine isn't the limiting factor there, IMO).

Note: "Spoiled high school kids"? I don't know, as its been some time since I was in high-school, but if parents had a moderate amt. of money to spend on their kids' wheels, lets say... $25 large - I can think of a whole slew of vehicles from Mustangs to WRXs to even Camry V6s... that would be capable of 140.

Page through Car and Driver, Motor Trend, Consumer Reports, etc... from the late 70s (when gas was a real issue) to now, hold a nameplate (make/model) constant, and check out the acceleration times - particularly the quarter mile. Then check safety features and weight. Cars today offer more safety features, are faster than their predecessors and weigh more.

~alpha

ohplezz · May 2007

This has got nothing to do with the xD but everything to do with MPG. I wish VW would build a reliable car. Their TDI jetta will get 50 mpg. But a VW will brake down at least once a month. Honda has had a civic diesel out in europe for about two years now. The 2.2 CDI. I wish they would release it here. NOW. But I know, emission laws. The xD will get better mpg than what the new epa standards suggest. How good I don't know. I'm going to buy one later this year. I let you guys know then. :confuse:

eldaino · May 2007

Comparing a Rabbit to a Civic is apples to oranges \

why is it apples to oranges? they compete in the same class!!

You do realize i'm talking about the 2007 rabbit right?

Wether your an engineer or not means nothing; 500lbs is A LOT. Ifi i stuck the 2.5 from my bunny into my old civic, i would be going much more quickly then i otherwise would.

Do you really need to be an engineer to understand the concept of weights impact on a car with regards to engine size? Sure hp, torque, redlines, transmissions and gear ratios play a factor as well; but the 2 most important ones, hp and torque, are probably the two biggest determining factors after weight.

Why do you think there is a general consensus that weight is sports car enemy #1?

I drive my car with just me and my wife, and when we fill up the backseat, you do notice it. And we are talking what about 375 extra lbs? (depending on the people of course.) even without timing myself you can tell that the car struggles more to accelerate.

to say that weight has no impact, even a slight one, on mpg OR acceleration, is totally absurd. It does and thats just how it is. You can post 10 pages of why in your experience you think it doesn't, but that wont change a thing.

(i.e. look at edmunds comparo of the gti vs. si. here you have cars with similar hp, but one (the gti) with a lot more torque. But its also carrying about 280lbs more of weight, which translated into ONLY slightly faster acceleration. Pretty sure weight had SOMETHING to do with it there.)

I like the xd. Cant wait for it to come out. :P

mcmanus · May 2007

All I'm trying to communicate is that I know 500 lbs extra should make a difference in mileage, but I've not experienced it making a difference in the real world. Have you (under at least semi-controlled conditions)?

I know weight affects acceleration and handling, I just haven't seen it affect mileage. Please don't put words in my mouth and please try to keep an open mind.

Maybe I'm out of it, but most of the "hot" cars I see kids driving are pathetic little things like a Cobalt SS or an old 70s Novi (former Grandmother's car) with big wheels/tires.

nwng · May 2007

I am thinking this way: when you got 4 people in a car (like my 6 yr old corolla), you'll need to step on the gas pedal deeper and longer to get the car going, compare to a single driver. That means a whole lot more fuel got sprayed through the injectors.

OTOH the mileage won't change much if you stick the same number of people in a suburban.

crabbyman · May 2007

500 lbs does make a difference. It will be less notable the bigger the vehicle. I.E. - 500 lbs. in a Hummer, you won't feel a difference. 500 lbs. in Civic, you will feel a difference.

Heck..my old Geo Metro...one person made a HUGE difference in how it accelerated, gas milage, and cornering. This is even when the person in the passenger seat only weighed ~100 lbs.

So its all dependant on many factors.

eldaino · May 2007

am thinking this way: when you got 4 people in a car (like my 6 yr old corolla), you'll need to step on the gas pedal deeper and longer to get the car going, compare to a single driver

exaclty. Your car has to work harder in general when more weight is added, and yes my mileage did suffer as a result.

Common sense.

Still wondering why a civic and rabbit can be compared though. :confuse:

roverton · May 2007

2008-White
Just picked it on on Friday and too a 324 mile trip for a mpg of 30.1.
This baby rides smooooth and without wind noise. Another reason for liking this is when hitting bumps on the road it is smooth compared to other vechiles driven.
The only complaints are:
- No arm rest for the passenger
- For the driver, the left arm has no where to rest logically as the bottom of the window is to high and the area where the button are is too low. Otherwise this is a great buy.
-The backseat room is great.
? rhoverton@yahoo.com

nwng · May 2007

but your metro can go faster on a highway going downhill with two people

I once had a sub 2000 lb car. I can go to about 70 mph before I felt the air rushing underneath starting to lift the car. With 4 people on board, at 85, the car is still riding solid.

ohplezz · May 2007

http://www.caranddriver.com/previews/13071/first-drive-2008-scion-xd.html

http://familycar.com/RoadTests/ScionxD/Photos.htm

eldaino · May 2007

do you have an xb or an xd? Because you posted this in the xb forum as well....

or do you have both?

ohplezz · June 2007

Sorry about posting in the xB forum. I have a kawasaki ninja :shades:
But I'm thinking about getting the xD when it comes out.

aatherton · June 2007

"... but your metro can go faster on a highway going downhill with two people..."
The acceleration due to gravity is independent of weight. A 5 pound weight and a 10 pound weight would fall at the same speed in a vacuum. So would a feather and a cannonball. And so would a bullet whether it is shot horizontally or dropped. We experience heavier things falling faster than light things only because of air resistance affects light things more.
In the case of a Metro whose air resistance does not change, increasing the number of people inside the car's envelope does not increase the downhill speed. But putting the any people on the roof would decrease the downhill speed.

719b · June 2007

everything you said is accurate, but that metro better have a good set of brakes if it's going down hill with a full load.

ohplezz · June 2007

http://blogs.cars.com/kickingtires/2007/06/scion_xd_first_.html

First Drive: 2008 Scion xD

I got a little worried when I learned the new Scion xD shares its platform with the subcompact Toyota Yaris, a car purely about point-to-point transportation that's not the least bit entertaining to drive. After a brief drive in Scion's four-door hatchback, which goes on sale in August, I can safely say the new xD has a much more engaging personality than the Yaris, and it should definitely be on your list if you're shopping for a small car.

One of the Yaris' biggest problem areas is its weak, 106-hp four-cylinder engine. The xD uses a larger 1.8-liter four-cylinder that makes 128 hp, giving the car sufficient power to accelerate briskly in suburban driving. A five-speed manual and four-speed automatic transmission are offered, with the manual returning EPA-estimated gas mileage of 27/33 mpg and the automatic delivering 26/32 mpg (using the more severe EPA testing procedures that go into effect beginning with 2008 models).

The xD's suspension has a knack for damping bumps in the road while still providing a sporty driving experience. It steers with a light, sporty touch, but the steering wheel could really use a telescope adjustment to better accommodate different-sized drivers. The fabric seats were comfortable during my short drive, and over-shoulder views aren't compromised by the car's large D-pillars.

The standard 60/40-split rear seat slides back and forth and also reclines, but both of the levers that control these movements are located on the top of each backrest. This makes for awkward adjustment when sitting in the seats; levers mounted near the hips would be easier to use.

Overall, the xD is a nice package, with air conditioning, cruise control, side curtain airbags, a Pioneer CD stereo and remote keyless entry among its standard features. Pricing information has not yet been released, but it should start at significantly less than the $15,650 base price of the brand's new xB.

I wish they were reviewing the 5 speed. Auto is boring and does not have the gearing/power for big city hways.

crabbyman · June 2007

I can attest to that!

Don't ask me why I did it but...I once had 5 people in that 3 cylinder Metro traveling about 35 miles. That car neither wanted to stop nor go forward too fast with all that weight in there!

Never really thought of the amount (225+100+300+130+160)..wow approximately 915 pounds of people. I think the max weight occupancy with cargo in the Metro was 300 or 400 pounds. I don't remember.

Although, I would take one of this gen's Suzuki Swift's in a heartbeat!

nwng · June 2007

hmmmm... thanks for the physics lesson. Here's another one: would it take more or less fuel for the said metro to go downhill at the same speed with different number of people on board?

And another one: air travels under the metro at a pretty good clip during this downhill highway run. More air travels under the car with one person than with 4 guys which lowers the vehicle's height.(if you stick 4 adults into any compact car, it will lower the ride height at least an inch). Will that decrease the air resistance(less air goes under the car thus less air resistance) and it allows the car to go faster at the same engine speed?

curious mind inquires

aatherton · June 2007

"... would it take more or less fuel for the said metro to go downhill at the same speed with different number of people on board?"

The number of people in the car does not change the air resistance and so does not affect fuel going downhill. Unless the engine is used to accelerate the car downhill, in which case more people will take more gas to accelerate.

"... if you stick 4 adults... less air goes under the car thus less air resistance... allows the car to go faster at the same engine speed?"

The height of the car off the ground does not affect air resistance unless the car becomes so low that it can push the air aside and have no airflow under the bottom. Adding people won't do it. This takes a very low suspension plus some ground effects panels.

Kirstie_H · June 2007

Interesting physics discussion, but...
anyone have thoughts that are directly relevant to the xD?

eldaino · June 2007

Their TDI jetta will get 50 mpg. But a VW will brake down at least once a month

you sound so certain! 'at LEAST once a month'....

mine has yet to do it! but again its a newer vee dub.

when will the xd's be hitting dealers? anyone know?

ecotrklvr · June 2007

You're right - but only if you ignore rolling friction. An object's weight doesn't affect how fast it falls in a vacuum. And more to the point, with the same air resistance, weight won't change its downhill speed, either. But the force pulling the object down a ramp is directly proportional to its mass - more mass, more force. More force to counteract wind resistance AND the thing you're ignoring - the rolling friction.

When I go biking with my 180 pound friend Matt, and we get to the top of a hill and coast down together, my extra mass shoots me downhill a LOT faster. He has a MUCH more expensive bike with better wheel bearings, so don't assume that it's a friction difference. And he's much more aerodynamic than me, as well.

At the top of the hill, I've got lots more potential energy than he does - that's what's being converted to kinetic energy as we roll.

The New Scion 2008 xD

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