What's seen as the optimal highway speed..?

[guest001]

I agree with a lot of what everybody's saying. I myself haven't seen people slowing down at all. Hell, when I go 70 people are wizzing by me.

you def. wouldn't drive 55-60 if your had a 200+ mile trip. it would take forever to get there. plus time when your actually in a hurry. but it seems like the majority of people drive ridiculously fast ALL the time.

The question is how if everyone drove 60mph, its effect on traffic. most of the traffic I see is people leaving huge gaps in front of them, super quick acceleration and slamming on brakes, I dunno what it is exactly but like exit are all way bunched up, you wouldn't even have to stop if your moving steady and intecipating everything. looky luu's kill it. everyone slowing down to look at any and everything on the side of the road.

[TrebGreb]

On freeways, I think it depends on traffic and slipstreaming opportunities. With little or no traffic 50-60 seems best. But with traffic and vacuums--love getting behind bigger newer SUV's like explorers and navigators-- my scan gauge indicates 30-45 mpg at 65-70 mph. I've also noticed with moderate traffic and no slow downs, there's a huge draft and I see 30-40 mpg on the scan gauge at 65 mph.

[DRW]

Rayme wrote: "I know some of you have scangauges, what's the average optimal speed that you get the highest MPG.."

Otimal speed is actually very slow. When the fuel economy competitions take place the top competitors will average around 25mph. Of course they're not trying to get anywhere, and they're not holding up traffic. In reality I like to go about 5mph slower than the flow of traffic in the slow lane.

"...and at what speed you get the EPA rated MPG.?"

Gadz, I haven't gone that fast in a while! I'd guess around 80mph. FE mods work!
Nice to see another turbo car on these forums. With some good mods you can have the best of both worlds; good FE and good power.

[guest001]

Originally Posted by Tribor

On freeways, I think it depends on traffic and slipstreaming opportunities. With little or no traffic 50-60 seems best. But with traffic and vacuums--love getting behind bigger newer SUV's like explorers and navigators-- my scan gauge indicates 30-45 mpg at 65-70 mph. I've also noticed with moderate traffic and no slow downs, there's a huge draft and I see 30-40 mpg on the scan gauge at 65 mph.

interesting, what about 55-60 with no or moderate traffic with no slow downs??

[guest001]

^^ turbos are the ****. normal if not better DD FE and power on demand.

[101mpg]

Optimal FE speed on my wife's Malibu Maxx is around 35 MPH. Easily in excess of 40 MPG, sometimes 45 if the weather is right.

That said, on the highway the "sweet spot" is about 62-63 MPH. I get about 35.6 at that speed regardless of terrain, meaning normal driving INCLUDING big hills and such around here, 1 hour + drives. Get up to 70 with hills and it's about 29.7. Nebraska or Kansas in the summer - can get 38-40 MPG at 85 MPH, better than that at 60.

However, dropping to 55 on the same "normal" terrain around here it only gets 35.9. Dropping 8-10 MPH is not worth it timewise for .3 MPG. That means it would take me ten minutes to save 9?, not worth it. Basically I can save an entire gallon of gas in an hour by adding about 5 minutes to my one hour drive and THAT is worth it.

[white90crxhf]

Originally Posted by baddog671

In my car, I think anything over 50 is excessive. But thats just my gearing and if I did that on the interstate I would get run over. I try to stick to the backroads for just that reason.

And I disagree, I think the educated people on the streets will slow down if we get another unexpected gouging at the pump. I remember like a year ago when we hit a record high in this region, everyone was driving about 50. EVERYONE...

i have yet to see anyone slow down when their driving unless they're on their cell phone. It's always funny to see a prius fly by me.

[GasSavers_RoadWarrior]

Depends a lot I think on the vehicle and gearing and how your auto behaves if it's an auto. For example I need to go over about 75kph in the voyager, otherwise the TC lockup is dropping in and out. Can get it to kick in at 65, but it's real difficult keeping it on, slightest twitch of the pedal and it's out again, and I'm only getting 90% power transfer again. (Guess I could rig an override...) Likewise many modern electronic autos will modulate lockup and/or the overdrive gear. Typically, cruising along on the torque peak will be quite economical and vehicle should be less affected by grades and gusts. However if your torque peak is in the top half of the rev range, you are probably going to have to row it along with the shifter, lugging in 5th on the flat, and kicking down to 4th for the grades.

Aero is a big concern too of course, if you've got a brick, keep it under 100kph-ish, if it's a bit slippier, you might be okay at 120kph if that's where your torque is good. Typically, I'm staying just under 100 on the highway, unless I'm drafting semis at ~110. Going much below 95 on the highways around here feels dangerous, and you seem to use up a lot of gas continually flooring it to move over for merging traffic (i.e. getting up to 110ish that everyone else is going in the next lane quickly) whereas at 100, you can generally get over safely without much extra gas, just by catching a draft.

In tight traffic situations at higher speeds on the highway, I seem to get good mpg on a modified pulse and glide technique, meaning I just keep pulsing the gas, but every few seconds rather than gradual acceleration then a long coast. This is dependant on how your ECU behaves, if it cuts fuel above X rpm when throttle is closed, then it may work out for you. This is only really useful in real "cut and thrust" busy highway traffic in full defensive driving mode, when the speed is +/- 20kph all the time and you have to maintain the space around your vehicle. Just give it quick squirts to hold the right gap in front of you and let it coast and engine brake as you get slowdowns, you can anticipate those quite well by looking a few cars ahead, even behind trucks you can often see brake light shine off the asphalt underneath.

[GasSavers_James]

For my VX I would guess its around 30-35 mph in 5th gear. This is about 1300rpm. If i could survive without being run over I would get 85-90mpg.
Recently I have been trying to drive slow and have noticed a big difference. I used to go 55 in a 55 zone, but have dropped that to 47 when no one is behind me. In the summer, the FE should be nice at that speed.

[s2man]

Best milage @ 45mph, below that the torque converter unlocks on hills. I guess I get epa at around 70mph, but I haven't driven that fast in a long time either.