sprucetop
04-05-2007, 08:00 PM
Hi... Please forgive any repetition of previous posts. I've been reading and trying to absorb it all. It's been very helpful thus far, bumping the mpg of my '02 Mazda Protege from 25.3 to over 32 mpg. That's without the use of the Scangauge that I should be receiving very soon.
Wayne has been very helpful in answering questions and has encouraged me to post here to get the input from many here. I'm wondering about a few things.
1. 50 psi... (with a rec max of 44)... is there anything at all to be aware of/concerned about? In moving from 35 to 44 I noticed all the improvements you guys list. Will moving up to 50 present any "concerns" or anything I should be aware of? What improvement in FE would I expect from 60psi (if any)? What caveats would present themselves at 60?
2. Drafting... I'm sure I'll get some great feedback from my Scangauge... but I'm curious what you guys have learned. Is 30-40ft back (about the closest I feel safe) from a 55-60mph semitruck beneficial? HOW beneficial? 10% improvement? 50%?
Thanks! You guys have saved me a boatload of gas (aka money).
Bob Hicks
tbaleno
04-05-2007, 08:37 PM
1. 50 psi... (with a rec max of 44)... is there anything at all to be aware of/concerned about? In moving from 35 to 44 I noticed all the improvements you guys list. Will moving up to 50 present any "concerns" or anything I should be aware of? What improvement in FE would I expect from 60psi (if any)? What caveats would present themselves at 60?
It will be more of the same going from 44 to 50. There shouldn't be any problems as many of us run them that high, however, you should be the final judge. All I can say is that I have hit massive pot holes and the tires and rims have held up fine. Same thing going to 60.
One thing is that the higher you go the less of a return you get back.
2. Drafting... I'm sure I'll get some great feedback from my Scangauge... but I'm curious what you guys have learned. Is 30-40ft back (about the closest I feel safe) from a 55-60mph semitruck beneficial? HOW beneficial? 10% improvement? 50%?
Bob Hicks
As far as drafting goes you will get better improvement the closer you get. I personally draft from a distance. I don't feel the need to push for every drop as important as being safe. And while many people safely do a close-in draft, I prefer a little distance just to be safe. Again, this will be a judgment call on how close you want to get.
Every thing you need to know about drafting:
http://www.cleanmpg.com/forums/glossary.php?s=&do=searchresults&search=draft&searchoptions=1
philmcneal
04-06-2007, 06:24 AM
1. 50 psi... (with a rec max of 44)... is there anything at all to be aware of/concerned about? In moving from 35 to 44 I noticed all the improvements you guys list. Will moving up to 50 present any "concerns" or anything I should be aware of? What improvement in FE would I expect from 60psi (if any)? What caveats would present themselves at 60?
I"ve ran 60 psi in my civic for at least 8 months or 15000 km as you will, and I live in the nastest roads around here, only serious issue i went through was a small puncture but with the massive air I had, managed to go home before the tire ran out of air. Got it patched and ran it 50 psi till I sold the car (tires say 51 psi max)
got the classic prius ran 60 psi on them for 8000 km before I sold it again (again 51 psi max for the tire spec)
got the NWH20 now 55 psi all across, its been 5000 km, my tires look like they were when I bought them. (44 psi for the tire spec)
you be the judge, i honestlly can't say "GO DO IT because it worked for me!" type ordeal since you'll probably sue me for some X amount of dollars IF your tires does go boom, but remember you can always increase it in baby steps. I didn't go super high psi in the beggining... but try increasing 1 psi on a daily basis and see how far you can go before you can't handle the stiff rock ride of pure fuel economy! ANd once again, I'm the professional and you are not, so don't go nuts if you do decide to go for high psi pressure, I drive in a cautious state to ensure I don't have to change the tire because frankly I just don't have a spare.
2. Drafting... I'm sure I'll get some great feedback from my Scangauge... but I'm curious what you guys have learned. Is 30-40ft back (about the closest I feel safe) from a 55-60mph semitruck beneficial? HOW beneficial? 10% improvement? 50%?
lets just say, 10% for two or three car spaces, 30% if your willing to half one car space or less, but drafting skill is required, you just don't mindlessly follow the truck but more like trying to keep behind it with using as little throttle as possible, since the object in front of you is eating through the air, you should use little as possible gas to maintain your velocity without the distrubance of the air.
in the end it comes with experience, you learn a few things and you get confidence in your hypermiling skills, able to pull all the techniques without thought and of course not pissing the locals around you... after all its them that you need to worry about when trying to get that magic number on your odometer.
psyshack
04-07-2007, 09:29 PM
Tire psi your just going to have to find your own way. I run mine on the Civic at 50 psi. Max side wall is 44 psi. Above 50 psi the car gets to loose for me.
Drafting is going to be much the same way. Your going to have to find your own way on it. Im not a big drafter. I will use it if fighting head winds and a semi wants to run my speed. I will share with you how I work a draft and feel it. I find me a target semi, large motor home or like wise target. I start easing up behind them. Once I feel a lot of buffeting. I know then where the draft points are. If I want a close in then I bust thru that buffeting. And I'm in. I can also feel the air pressure change in my ears. If I want a distance draft I back out of the buffeting a few feet and get that gravy. It wont be near as good as getting in and past the bad buffeting. But it does put you in the second bubble of calmer air.
Something else. Trying to put a % on something will drive you crazy. Well it does me anyway. If I looked at % on my daily grind and tried to make since of it I would be sick and banging my head on a rubber wall in a hospital. As you bag of tools gets bigger and your skill level gets higher. The mpg will go up. % wise I don't know how much. Alot of this even with instrumentation. Is still seat of the pants and bottom of the foot work and feeling.
Have fun
psy
