Built-in FE
 

After a few years of hypermiling, it begins to wear on you. It is especially difficult when you hit a wall that you can't seem to get past. While I am not there yet, I fear that this summer I will indeed hit that wall. Hopefully it will be north of 70MPG. :)

Anyway my point is this. There are several factors that influence FE. Technique is related to the driver while vehicle weight, aerodynamics and rolling resistance are related to the vehicle and route. Anything you can do to your vehicle/route to increase FE will still be in effect should you change your driving style/technique. That is why I am concentrating on aerodynamics, weight and rolling resistance, or Built-in FE. If anyone can drive my car and get 50 MPG, that is quite an accomplishment.

So my next area of concentration is rolling resistance. My current tires did great in the snow but are not optimal for summer driving. So I have done much research on LRR tires. Within the next few weeks I should have new HX wheels with LRR tires and hope to see some improvement from them, although tires need a few thousand miles on the to begin yielding the best results. The new tires are back to the stock diameter so my ride height will go down another inch which should also help with aerodynamics. Each wheel/tire will wheigh less than 25 lbs so that will be a 36 lb weight reduction of unsprung weight.

I hope this makes a significant difference. Prolly good to do a sidce by side comparison with the different wheel/tire setups.

you haven't hit anything.
 

you haven't hit anything. You are far from maxing out your mpg. There is plenty you could do.

Have you thought of a different engine or using lighter engine components.

I doubt you are even using aluminum brake drums.

Why not do a Full LED conversion? there is 1-2mpg improvement in that alone. You don't have to do the whole car. Just do brake lights, turn signals, instrument cluster.

Lighter driver's and passenger seat. You don't have to get a sparco seat. Just get a $60 racing seat. Their light like crazy.

Lightened flywheel, even if it's lighter by a pound a rotational mass multiples this.

There is so much stuff you do that 70mpg can turn to 90 or even 100mpg easy.

Also do you have a citi card
 

Also do you have a citi card credit card with 5% off on gas, grocery and parmacy purchases. Every time you purchase gas that adds up and when it gets to $50 you can ask them to send you a check. I made $60 in 4 months.

There is many ways to skin a cat.

Re: you haven't hit anything.
 

Compaq, there is a point of diminishing returns. All of the weight reduction that you speak of might be worth 1 MPG at best. At $2.50/gallon for every $100 I put into weight reduction, it would take me 150,000 miles of driving to recoup the money spent. Hell, I have already spent more money than I will recoup, but I just needed to find out for myself.

You are also being optimistic about FE savings from LED's. Another 1 MPG at best if you always have your lights on. Since my lights are rarely on in the non winter seasons, there will be no difference at all.

Re: Also do you have a citi card
 

The way I skin the cat is to use my discover card (1% cash back) to buy groceries (and everything else for that matter)and for each $50 in groceries I get 10 cents off per gallon. I save about $25/month on gas and $300/year cash back.

gas is $2.80 for regular
 

gas is $2.80 for regular here. I could buy a civic and save myself gas money but I'd waste a good amount of money and that will never pay off. And the fact that I'd be downgrading.

Have you considered boosting your spark energy??? It will make a more complete burn.

I've considered this myself
 

I've considered this myself krousdb. There comes a point when so much effort and work starts to wear on you. I just view it as an ebb and flow thing.

I've been a little out of modififying my car for the last few months, mainly b/c it's winter here (yeah, it lightly snowed yesterday, wtf?). It's really difficult to be motivated to work on my car when it's freezing outside.

That being said, I can't wait for the engine swap. The notion of "built-in fuel economy" is an excellent one. Sounds like a wiki entry waiting to happen. When I get my new engine put in, with the new tranny, I should *in theory* be getting upper 40s and lower 50s without much effort. then the aerodynamic modifications can begin like the belly tray and the wheel skirts, both of which I plan on accomplishing this summer.

I honestly don't care how my car looks, I just want to be able to go for a drive and not have to worry about refilling.

Oh, and I spend about $20/mo on gas, sometimes even less than that. That's how little I drive. For me ANY modification I make is essentially already never going to pay for itself. Heck, I havn't even really broken even on the engine repair I had last May that led me down the road of never going to a mechanic again.

IT's a hobby though, and a fun one at that.

I think we'll all hit a wall for a while, and then something new will come out and we'll all be excited.

Ebb and flow baby, ebb and flow.

Re: gas is $2.80 for regular
 

Again, Im not gonna spend $ on something likley to be worth 1/2 MPG or less. Show me some data on greater than 1/2 MPG improvement and I would consider it.

I got data that it makes the
 

I got data that it makes the motor get more power, nothing of fuel economy. But when you make more power you can press the gas less.

hondas ignition system needs
 

hondas ignition system needs little to no modification. it is already wonderfully efficient and many tests have been done with aftermarket plugs, wires and msd stuff. all results have shown no improvement and that new oem parts are just as good, if not better than the aftermarket goodies.

the side gapping and indexing of spark plugs is still undetermined however. i have not seen any data supporting or denying its claims.

anyway, back on topic: i feel the same way about having the built in efficiency, thats also why i drive my car just like any other person would, and perhaps more agressively on the throttle. yes it costs money for some of these modifications, but the reason we do them(within a budget) is because its fun to learn. i am willing to break even with $ spent on mods vs $ spent on gas. but thats also because all my mods have another motive: performance.

i have also wondered where my 'glass ceiling' of fuel economy lies. when i approach it i will tattoo it on my left bicep....er... maybe not, probably just make a sticker out of it and have it be my number for auto-x.

in short, i agree with your philosophy and support it :)

This is what I'm mostly
 

This is what I'm mostly about now - adding built in FE. Once I get the built in FE (for me, in the form of HF transmission, OBD-1/MPFI conversion w/Hondata), then I'll really start stressing on things like technique.

This is prolly the best
 

This is prolly the best thread to put this in. My latest built in FE mod was to replace the 15" wheels and tires with 14" HX and Insight rubber. Here is what the car looks like now...
https://img90.imageshack.us/img90/3208/dcp60343ci.jpg

The tire diameter is 2" less than the previous tires so the car is 1" closer to the ground as a result. The old wheel/tire weighed 34.5 lbs each, the new ones are 24.4 lbs each for total unsprung weight reduction of 40 lbs!

I made a quick calculation and changed the SuperMID distance parameter before going out to finalize the calibration by 40 miles of highway driving via the milepost method. After another small tweak, methinks I am calibrated.

Initial driving impressions...
Good stuff
- Easier to steer, less rubber on the road
- Easier to start from a stop and easier to accelerate according to the buttometer
- Quieter ride, bumps are less sharp even at 62 PSI.
- Rolls much farther when coasting
Bad stuff
- Less rubber on the road
- Cornering ability greatly diminished, oversteer !!!
- Nearly spun out on two occasions, need to reduce speed on curves
- I can only imagine what it will be like in the rain.

Initial FE impressions...
- Good stuff
- The trip to the inlaws was 73MPG (warm start) vs 62MPG (cold start) (pre belly pan) similar temps (52F) and winds.
- The trip around the park was 82.9 MPG vs 72.0, again similar conditions although I made one of the lights this time.

So far I am happy as long as I don't kill myself on a guardrail. We shall see what the commute data looks like. Next two days should be dry and moderate temps. I will update in the FE update thread.

Since the wheels are thinner
 

Since the wheels are thinner now you can make a better wheel skirt for the rear wheels. It can go further down.

Quote:- Cornering ability
 

How did you manage that? You're lucky!

Anyway, if you want I'll find you a front sway bar that's a little bigger than stock to reduce your oversteer.

I wouldn't do that if I were
 

I wouldn't do that if I were you. Yes the bigger sway bar will improve his handling but you need to make sure the tires hook up. Since his tires are thinner and overinflated a bigger sway bar will make him oversteer like crazy if he has traction or make him crash.

My advice is keep the stock swaybar and slow down a little. Bigger swaybars are meant for cars that have grip, using thinner tires and overinflated will just fuel the fire.

Re: Quote:- Cornering ability
 

Many of my long engine off downhill coasts have curves in them. Approaching those curves at the highest possible speeds means in some cases that I will have enough momentum to get me over the next hill and onto the next downhill without bump starting, thusly increasing FE.

The culprit might be that there is very little weight on the rear tires and the coilovers. If I hit a bump rounding a curve the coilovers bounce and cause the wheels to lift. Another time it was prolly because I was braking also and the tires started to lock up. I took the corners slower today and had no problems. Because of the decreassed RR, I still had the momentum I needed to get over the next hill. I might go back to the stock springs now that i have smaller tires. Unfortunately with the smaller tires i am constantly trying to shift into 6th gear.:(

An example of the decreased RR. I normally take one curve at 35mph, engine off and then coast down a gradual hill for over a mile before bump starting. At the very end of the coast, at the 25MPH speed limit sign, my speed has dropped to 27MPH with 40-50F temps and as low as 20MPH in 20's F. Today, at 32F I took the curve at 33 MPH and ended up actually gaining speed to 35 by the time I got to the speed limit sign. That is quite a significant difference.

Here is my route...
 

Here is my route...

Elevation at home:1187 ft
Elevation at work:1056 ft
High point:1260 ft (top near where route crosses I-79 for the first time)
Low point: 692 ft (Bridge over Ohio River)
Distance: 39.83 km, 24.69 miles.
https://img102.imageshack.us/img102/4682/route7ug.jpg

Elevation at home: 56
 

Elevation at home: 56 feet
Elevation at college: 36 feet
Distance: 3.55 miles

Trips to college and back on a single tank 44.788
1 tank of gas is enough for 14 weeks of college.

Re: I wouldn't do that if I were
 

How will a bigger front sway bar increase his oversteer. Possinly a bigger rear bar would do this, but he has no rear bar and I am not suggesting he get one.

I never knew google earth
 

I never knew google earth had the elevation on it. I just redownloaded it.

The first time i used it i never really liked it (i didn't think it was any better than google maps). But seeing the elevation is really cool.

Re: I wouldn't do that if I were
 

With his new setup he needs more body roll than stiffness. He just doesn't have the tire patch for a stiffer sway bar.

body roll is badpicture a
 

body roll is bad
picture a slalom course...recovering from the momentum each time is costly on performance...
corrected with swaybars and/or stiffer springs puts the requirement more on the tires for adhesion...
so its a give and take...body roll puts alot of load on the outside tire adding traction to it...
steering must be compensated in either case
it comes down to driver preference given a single car
how they like it to feel...and how much sacrifice they will make one way or the other...

swaybars are useful in that you can use a softer spring for better strait line feel over bumps etc...less feedback...
then in cornering you get the added spring rate of both springs...

incorrect assumption about
 

incorrect assumption about the sway bar. body roll is never good. and you really cant assume anything without knowing his spring rates, regaurdless of contact patch. it depends on if the car has a front swaybar. i doubt it has front or rear.

the cause of such oversteer, if there is the severe weight balance, is either brake, or throttle lift oversteer.

bottom line: stiffer front sway bar (or more lose rear) will help cure oversteer. if it has no rear bar, then the front is the only solution unless you wish to get stiffer rates in the front(my recommendation) but it seems comfort is prefered?

I think he has 400 rate
 

I think he has 400 rate springs, but that's 100% guess.

Anyway, the sol should have a front bar, all the CRXs did, even the damn HF (I'm looking for an hf bar to put on mine). Only the CRX Si came with a rear (also looking for this, :p).

whats my incorrect
 

whats my incorrect assumption
there is no assumption in fact...
lol

not you eiger, i agree with
 

not you eiger, i agree with you. refering the c888.

could we get some solid numbers on the spring rates? by 400 you mean lbs/in? and are they linear or progressive? factory is something like 198\96. these things definitely matter, especially if there is a problem with oversteer. usually oversteer without sway bars is cause by swapping the front and rear springs....

i have 450\360 progressive lbs/in on my hatch with a 21mm\22mm swaybar setup front\rear and the i could probably get mildly stiffer bars.

They are ebay type springs,
 

They are ebay type springs, linear, 400 is just a guess. I'm getting skunk2 450/350 soon, excited, :)

400lbs/in is a pretty high
 

400lbs/in is a pretty high guess for an ebay spring. those skunk2 rates seem pretty fun though, very similar to mine, and with those rates you will be happy you have nice fat gushy sidewalls

, I'm excited to get the
 

:), I'm excited to get the ****, need to whip up an ecu right now to pay for them, :p

Every little bit helps. I
 

Every little bit helps. I have not waxed my car in 5 years so I'm going to hit it in a couple of days. Also my wipers are in the airstream on the windshield. I thinking of using rain-x, which works good in light to moderate rain, and removing the wipers and putting them in the trunk and if I need them I'll stick them on the drivers side.

I've also notice according to the scan gauge that with the belly pan and grill block I've now got a 25 degree increase in intake air and a 5-10 degree increase in water temp. With a 180 degree thermostat the water temp is 197 now even though the gauge runs where it always does. Now to figure out how to get my EPA image posted.

i think rain-x works the
 

i think rain-x works the best when its pouring down. when its like misting its the most annoying. i keep on toying with the idea of pulling the wipers off.....

krousdb, although a 500
 

krousdb, although a 500 pound weight reduction would only yield 2-3 more overall mpg, the benefits to performance would be astounding.

How would you like to drop your 0-60 mph acceleration to around 9 seconds(from like 12?), and still manage 70+ mpg if you maintain a light foot?

You could show many people that fuel economy and better performance could actually go hand in hand if you design for it.

Not to mention, if you eventually cut Cd from to .26, your top speed would be much higher given your taller gearing. Imagine having a 70+ mpg car that can hit say, 140...

After the aeromods, the next biggest benefit you could have would be an engine swap. Get rid of the gas engine, and place in a turbodiesel. Would require a lot of custom fabricating(motor mount, transmission adaptor, ect.), but the potential for 90+ mpg with a 130 horsepower turbodiesel is there if you have the aeromods, LRR tires, ect. in tact.

Re: krousdb, although a 500
 

Yes, I have often thought about a deisel in the del sol. But like you say, lots of fabrication and adaptors and stuff. I'm not up to that level of complexity. Not yet anyway.
Now back to weight reduction, can you tell me how to get 500 lbs out of my car? Hell, even 100 would be nice. :)

Quote:Now back to weight
 

Indeed indeed, looking to hear your insight on this topic.

Re: Quote:Now back to weight
 

I BELIEVE that Bunger has his CRX HF down to 1600lbs if I remember correctly. He might be the person to ask about this.

C'mere, bunger, you're
 

C'mere, bunger, you're needed!

I hope he hears that.

I think it is 1730. Give
 

I think it is 1730. Give me a second to look it up.