New Mileage nut, Long-Time efficiency seeker.
 

Actually, I've sought mileage for a long time too, but
it took a back seat to performance. I have been a major
player in the V6 Mustang modifying arena -see SIX OFFENDER
in the February issue of Muscle Mustangs and Fast Fords-
but now I am hotly in pursuit of maximum efficiency and
approaching it with greater T.E. in mind. If we could get
gas engines up near diesel eff. levels then power would be
easy to come by. I have a couple of engine ideas I'm working
on, one is the "Optimized Otto Cycle" engine https://www.eng-tips.com/viewthread.cfm?qid=141129&page=1
and another is a top-secret exhaust heat reclaimer that
could boost any diesel or gas emgine's efficiency quite
substantially, to the point where one could conceivably
start retaining coolant losses using higher thermostat
settings and channeling most waste heat to the exhaust
system and through the reclaimer for yet higher gains.
Still in the planning stages. Perhaps FORD will buy it
and save the company :D
I will pursue a patent on this if testing shows a good
increase in T.E.

Back to the car-du-jour, '89 Tracer, the prior owners
claimed 38 MPG (best I presume) and I have gotten 42.8
once and backed it up with a 42.6 and several tanks over
40 MPG. So far I have used clean plugs, timing advance,
new tires (+1 sizing) 40 PSI (Diamond Larry, is 55 PSI safe???)
and acetone. The acetone on very similar runs (70 MPH avg)
showed a 25% gain on a tank, only change made except I
was driving on a much rougher and hilly, curvy road for
the higher MPG run. I'd like to compare it on the same road
and I will get the chance soon.

I hope to use many more tactics like fixing my fuel leak
and maybe some aero add-ons but I need good info on what
works for aerodynamic improvements. I can probably make
most anything, I have good fab skills and resources.

Glad to be here and hope for great MPG for all!

Sincerely,
Robert Greene Racing
(RGR)

Quote:new tires (+1 sizing)
 

I would say that for the average driver, 55 psi might be too high. Since I'm always driving for max efficiency I generally drive much slower than the average driver so handling doesn't seem to be an issuse. I have never had any loss of traction in a turn/curve at 55 psi. My tires are rated at 44 psi max and I have heard that there is a very healthy reserve built into that max pressure rating. It's good to see another long time mpg fan. Welcome and enjoy the good info!

55psi???
 

Is that how you are getting the mileage on that Saturn?? 55psi is going to really blow that tire to pieces if you ever get punchured. Keep an eye on the tire bead and sidewall cracking as they age.

I thought the 42psi I had in my new Scion xB was a little hard so I lowered them to 38.4 psi - yeah a weird number but I just lowered them with the digital gauge to the lowest of all four tire pressures after I started letting it out with a less accurate gauge then decided to split the difference of where I should be and where I was in pressure. Will need to check them soon to see how they are holding in the air at that pressure. Been almost 2 months.

Re: 55psi???
 

which reminds me to add: the master pulse & glider i've referred to in other threads runs his tires at similar pressures - no doubt a great contributor to his numbers.

i run at 38ish. any more than that and it's just too harsh. and i don't mean on me. all that pounding that would normally be absorbed by the tires is transmitted into the suspension - i cringe for the poor ball joints whenever i drive down a rough road, even at "just" 38 psi.

I run 45 and I have my
 

I run 45 and I have my friend's 01 civic at like 52, never hard any trouble with that, but then again CRX and Civic have kick *** suspensions. I even managed to drift a 180 turn in my friend's civic at 40 mph with the tires that high. Surprised we didn't die.

hi pressure
 

Yeah you really feel the extra pressure with a new car - everything is stiff already and then add extra pressure . . . I remember the Geo when I went to 34 psi I could feel every crack in the road as I drove over them. One thing I don't miss from the Geo is the big bumps where I would bottom out the suspension and I am talking "paved" roads. Seems the xB has more travel and stiffer springs but still only 6.1 inches of ground clearance.

I have yet to bottom out
 

I have yet to bottom out mine, with 6 inches I believe. I'm dropping it to 4 soon, we'll see.

also it's more noticeable in
 

also it's more noticeable in the cold. i think i'll be able to tolerate more pressure in the summer. when everything's warm & supple, the suspension doesn't feel as brutal.

and despite being 8 yrs old, my car is essentially new - i just passed 5k kms/3k mi last week. so the suspension is much firmer than it has any right to be for its age. it should mellow some as i put on the miles.

Are you serious? 400 miles a
 

Are you serious? 400 miles a year?

3k miles?
 

That is not even broken in yet! Heck I did more than 400 miles on my electric scooter last year!

i'm serious. i bought it
 

not 400 miles a year - 1500 miles in its first 6 months, then parked for 7 yrs.

i bought it this fall after it had been in storage. the orig owner drove it in the winter of 97/98, then got sick and stopped driving altogether. it was in the family's garage gathering dust, and they just sold it to me this fall (i found it in the auto trader).

oh
 

Sweet deal - I always thought that buying a new car and then storing it would be a better investment than money in the bank - you get a new "old" car and the excize tax around here goes to zero if the car is old enough. Just have to keep the rubber in good condition.

I was going to make a thread
 

I was going to make a thread about tire pressure and saftey. It snowed 4" today and my 40-45psi tires didn't have much traction. 30psi would have been better in the snow.

high pressure and snow
 

HA HA HA Yeah too much pressure!! I have to start thinking about that also at some point we will get some snow around here in Newport RI. Looks like maybe an onboard engine powered air compressor to charge an air tank during braking is also in order to have air to reinflate after the snow melts. Sure wish I had the room under the hood in the xB that I have in the Geo for all this stuff. I still have not even seen the transmission so I can find the filler plug to add some Slick50 gear lube to it. Actually I better find out what they have in there for oil in the first place to make sure it is 80/90 weight.

Re: Quote:new tires (+1 sizing)
 

MOST things that are de-rated for safety and durability have
a 20% reserve or more, or looking at it another way, one could
increase the pressure 25% and get to the 100% (not de-rated)
pressure rating. My _current_ (pun intended) profession is
Electrician and we derate most electrical items to 80% almost
across the board, like conduit sizing, amp ratings, etc. for
surges, safety factor, uneducated users and the like.

Thanks for all the replies everyone, and I hope to make some
contribution here and learn alot in the process!