To draft or slow down?

[1993CivicVX]

Originally Posted by theholycow

To re-clarify, that was not my post, but a post I brought in from another forum.

I couldn't find the original post. Google search only returned results of it on gassavers, not on the original site!

But, yeah, that was sloppy on my part to cite you.

[R.I.D.E.]

Another thing about this type of draft. Find a trailer that has a provision to haul a tandem trailer (one behind the other). The hitch area is reinforced, with a steel plate from wheel to wheel,between the trailer wheels and the air flow under the trailer is blocked down to about 6-8 inches from the pavement.

The one I remember was a UPS owned rig (tandems are legal in VA) with two trailers, and the blocked area between the rear trailer axle.

This made a difference I could feel, at least that is how it seemed.

Filled my tank today 365 miles on 6.029 gallons, thats local driving. Learning to use downshifting to kill fuel delivery to the engine when I need to slow down. It seems to make a difference. Went past the station ten minutes later and they raised the price by 20 cents to 356.9 per gallon.

60.5 MPG, man I love this car.

regards
gary

[1cheap1]

Drafting, dose drafting help the truck? Today as i was going downhill in EOC at 62 mph in the slow lane i was tailgated by a camero who was very close to me. I noticed a noticeable push and slight increase to 63 mph. He exited and later another person tailgated and i also noted a push. I think with my engine on and in gear i would not notice the slight push. Also did P & G while drafting trucks and i think the faster the truck the better the glide.

[1993CivicVX]

1cheap1: I think the consensus is that it does help the truck, as you experienced.

Gary: your local tank--do you do EOC? P&G? What measures are you taking to save gas?

[R.I.D.E.]

1993civicvx;

I don't do engine off. Thats a little too much for my old brain with some of the moronic drivers around here. The VX doesn't respond well to engine off, loosing the lean burn for some time after each engine off cycle (Read that on this forum). With probably the lowest idle consumption of any 4 cylinder engine, I try to keep my average speed as high as possible, usually close to 40 MPH.

Been P&Ging long enough now that its natural about 1 to 3 ratio at 40-45mph.

Driving interstate (very little under 5%) drafting, some P&G when it doesn't aggravate other drivers. 5th gear pulse at anything over 35 MPH.

I usually use the back roads (years of local knowledge) avoid left turns at lights. P&G on those roads almost all the time, slow down quite a bit when there is no one behind me. Smaller pulses when I am in traffic.

I drive like there is a 2k RPM governor on the car about 1500 to 2000 in each gear during acceleration, coasting in draft and using transmission downshifting to keep fuel shutoff engaged to the greatest amount possible.

Traffic here can be very heavy at times. I am retired and I avoid the really bad times as much as possible. A lot of times the interstate is crawling and if I get stuck in that I try to P&G even them.

I coast anytime the opportunity arises, I coast almost 1.5 miles when I am almost home with only two pulses and the speed drops from 65 to 55 to 45 to 25.

I think the war air intake made a significant difference, in cooler temps. I wonder about warmer temps, but soo far I havent reversed the intake snorkel.

Remember this is a low mileage car, I hope to drive it for the next 8 years, so I am not interested in any action that I think might shorten life expectancy. The type of driving I do now puts my wife to sleep, except for some of the drafting.


regards
gary

[1993CivicVX]

Cool Gary. Yeah, you should easily get 8 years out of the car. The only time I feel bump starting is hurting my car is second gear. I cannot for the life of me make a smooth 2nd gear bump start. All the other gears are seamless. Yes, I've read about the trade off of EOC to leanburn on this forum. I find EOC outweighs loss in lean burn. One member on here would get 65mpg regularly in his VX because he lived in a hilly region and was able to do lots of EOC down hills and lean burn up them.

[monroe74]

I apologize for veering off-topic, but maybe it's not that far off-topic.

"he lived in a hilly region and was able to do lots of EOC down hills and lean burn up them"

I'm trying to assess the relative merits of low-throttle settings, as compared with high-throttle settings.

Lately I've been doing lots of P&G, and it seems to be yielding great results. For me, the essence of this technique is that I avoid any throttle setting other than about 70%.

But this kills my lean burn, right? Because lean burn generally works only at relatively low throttle settings, right?

I think the benefit I get from a large throttle setting (reduced pumping losses, and therefore reduced BSFC) is large enough to more than offset not have lean burn working for me (in that moment).

Although lean burn is helping me when (if I can't P&G, for some reason) I'm maintaining a constant speed with a small throttle setting.

So if you "lean burn up them" (use a small throttle setting while climbing a hill, or at other times) aren't you missing a chance to reduce pumping losses, by using a larger throttle setting?

In a way, what I'm saying is that I'm very suspicious of DWL. I think the fundamental BSFC principles that make P&G work also make DWL not a good idea.

Some very smart people in the room, so I'm interested in getting help improving the way I think about all this.

[occupant]

Originally Posted by racertim

While traveling at 62mpg for an entire week, 130 miles round trip, I passed ONE vehicle. It was a beat up Oldsmobile that I don't think was capable of 60mph.

LOL. My Olds is perfectly capable of burying the speedometer needle into the fuel gauge. I CHOOSE to drive between 49-59mph because that is the most efficient piston speed for my engine, considering gearing and tire size.

But it probably wasn't me. I haven't driven the car in about a week because I haven't needed to.

[mkiVX]

Originally Posted by 1993CivicVX

My tire size is the same as you my friend, and oft is the time I have felt the same way that it would be nice to have stock tires for these reasons.

i have owned alot of vx's
i have tried all sizes of tires. nothing works better then the 165/70 13
people on this board think that skinnier tires like the 155 80 13 will get you better mpg
what they dint realize is that they are over all taller and require more push of the pedal to get going...
the best tire i have bough up to date are 165 70 13 sumitomo htr t4 at 60 psi

In the states the correct tire size is super hard to find....
how ever in mexico there is no shortage of LOW rolling resistance 165 70 13.. my brother lives in cabo and i have ordered a set of michelin energy 165 70 13



tire rack has 165 70 13 all day long. if you get these i guarantee you about 3-4 mpg more!!!

[R.I.D.E.]

mikivx could you get me a set?

regards
gary