the publics opinion of what good mileage is

[SVOboy]

Well, if you go from 3k to 2k, you'd be burning roughly 2/3s of what you were before simply in terms of revolutions. I wonder how that would affect load though.

[budomove]

Will someone answer this riddle? I know I can't.

[SVOboy]

Just do a consistent highway run now, then do one after the swap, and have a vacuum gauge hooked up during both, and you'll've figured out the riddle.

[budomove]

Ingenius!

[JanGeo]

SVOboy

Why can't they make a manual with tall gearing anymore, *cry*
But it's okay, because I can rub my hf tranny in everyone's face,

They have to give the xB enough torque to get up hills in 5th and it redlines at 6500 so that gives about 120mph top speed. Max torque is 4200 puts it at about 80mph. Max torque usually means highest efficency. The automatic is geared taller btw.

[MetroMPG]

Originally Posted by JanGeo

They have to give the xB enough torque to get up hills in 5th

they don't *have* to.

i don't care if my tallest gear can't get me up a hill - that's what the next lowest gear is for. the tallest gear should be for maximum efficiency under light loads.

i suspect it's marketing more than anything. a car that required downshifting at highway speeds in "normal" driving (for hills, or passing) would be ridiculed by driving "enthusiasts". the motoring press (which is generally biased towards speed & acceleration) wouldn't like it.

but i also know that my (our) views are not shared by the majority of the motoring public.

and automakers seem to feel that once we've reached top gear, our arms are now broken and we're incapable of shifting any more. please.

[JanGeo]

they don't *have* to

Well to make it more drivable they need to - the aero in this thing is not that of a small car and if you are driving alone then it goes ok but as soon as you add a couple of people and luggage then if 5th was any taller you would not be able to use it. Cars are designed to be able to make it up certain grades on highways and highways are designed with a certain maximum grade so that cars can make it up the hills without slowing down. Remember this is a van sized vehicle with a 1.5 liter engine. It does ok as it is and I would not want to have 5th any taller than it is or else I would be shifting more. Actually I am not sure that the whole 5th gear overdrive thing is a good idea when you think about it there is a little efficiency loss from that like in the Geo tranny. What happens is that the Geo is geared for about 135 top speed at redline if you crunch the numbers and you never get there. The xB on the other hand I have heard gets to redline in 5th at about 120mph - not sure if it was a turbo or not however. The automatics are geared a little taller and have trouble on highways on steeper grades - I hear they turn 2800 at 60-65mph. They also start playing with the valve timing under loads and I would rather have it operating at max efficency at a higher rpm instead of more power with higher losses when under a heavy load. Ocean Drive 11.9 miles last night at dusk with lights on 48.6mpg with a cold start.

[MetroMPG]

Originally Posted by JanGeo

I would not want to have 5th any taller than it is or else I would be shifting more.

whereas i don't mind shifting more to get good mileage - including occasionally at highway speeds because of a taller top gear. if i didn't want to shift, i would have bought an automatic.

[krousdb]

Originally Posted by budomove

When I swap in the hf tranny to my 91 std civic hatch (with SVOboy's help of course), i will have reached a decent baseline of I'm hoping 45mpg highway. With the 4spd std I get 40mpg highway. I will be running over 1000rpm less than what I am at now on the highway! I got coroplast, and want to do some aero, and add vx rims = good for 50mpg? I am with DaX on 50mpg...a good round number.

Actually, I would recommend the 14" HX rims and the 165/65/14 Potenza RE 92's. You will end up with the same tire diameter and same unsprung weight but you will have the lowest rolling resistance tire available (that I know of). This special tire is OEM on the Insight. I have noticed 3+ MPG by swapping my 15" for this setup. Once the tires are broken in, thier performance is quite good, both on dry and wet pavement (not for the snow however). But since i drive conservatively, you should take that statement with a grain of salt. Oh, your mileage may vary.

[Matt Timion]

Originally Posted by krousdb

Actually, I would recommend the 14" HX rims and the 165/65/14 Potenza RE 92's. You will end up with the same tire diameter and same unsprung weight but you will have the lowest rolling resistance tire available (that I know of). This special tire is OEM on the Insight. I have noticed 3+ MPG by swapping my 15" for this setup. Once the tires are broken in, thier performance is quite good, both on dry and wet pavement (not for the snow however). But since i drive conservatively, you should take that statement with a grain of salt. Oh, your mileage may vary.

This is making me regret getting the 13" VX rims and selling my 14" HX rims.

Then again, from an economic standpoint I did end up saving money in the whole process, so I guess thats' worth something.

14s do look a little better than 13s though.

Maybe it won't matter when I put the pizza cutter hubcaps on these guys.