Quote:
Originally Posted by niky
As for buying a piggyback for fuel economy, you have to do a lot of research. Many cars will "relearn" around a piggyback, adapting to the change in fueling parameters by altering the fuel maps over time. Which means you need an O2 sensor intercept, which will cost extra.
And the amount of money spent on a piggyback will often not be recovered through fuel savings. A piggyback that works properly costs a bit of money, as do the dyno-tuning or street-tuning required to get best performance (alternatively, you could tune it yourself, but that means spending more money on a wideband O2 and software).
Aero modifications will net you similar gains, for less capital outlay. Possibly even more if you go crazy.
And... driving habit modifications (which includes your choice of tires and daily tire pressures) have the potential to net you even more gains than that. If I recall right, some authorities claim gains of 30% or more are possible simply from driving habits.
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Yup, doing a LOT of research on the subject, luckily there's a bit of data out there to work off of, pretty much all the answers are out there if you look hard enough.
If the piggyback costs $300 and will never recover that in savings that's fine with me. I really plan on this vehicle being "the one" that I carry for many years, I hope to own it a decade from now. I'd rather spend a lot on it now, but not willing to overspend needlessly. If the electronics for the piggyback end up costing $600-700 and they will perfect the gains of the header, it's worth it. But if tuning ends up costing $2000, I might as well have spent that in other areas.
Basically, I also have a 1993 Honda Accord. Bought it with 278k on it, drove it for a year or so getting 23-24 mpg in the city, loved the thing. Then I borrowed it to someone, uninsured, and there was a freak flood on that person street and the whole car was underwater for a brief period of time. Past the hood, halfway up the back of the seats. Basically it was a miracle to get it running again. Then it was basically just a beater, could barely even rev the engine to get the car to drive, getting 16-18mpg but I used it for 5-6 years like that, never really thought much about fixing it. Brainwave, the ECU is dead! I bought a new ECU and suddenly, the engine worked decently again. Got like 23-24 MPG again. Got new exhaust in 2012... Still 22 mpg.. Then we changed something. And it started getting 36 mpg. After all these years... I think it was the distributor cap.
Now, with 350,007.1 km on it, the car is physically shot. To demonstrate,
's a video of me amputating a section of rust that was falling off. The other side is just as bad, and there's a big horizontal split alongside the side of the trunk. Literally every part of the car is rusty. I don't know how long I could legally drive it anymore, but it's my emergency car if I need. Thinking about it though, the 72,000km I put on it, according to this mpg calculator, would cost $8,337 at 26 mpg and $6,021 at 36 mpg. I basically wasted 2 grand on my fuel car because I never really cared enough to fix up the problems.
So the Vitara comes into place in the winter, the tires on the Accord are completely bald, I have to drive highway speeds on sheet ice for half the year so I had to do something. I had the choice of $500 on tires or buy a new vehicle. I took door #2. I researched literally every vehicle on the market, I had to have a 5-speed manual and it needed to be a true 4x4 with the transfer case, something I could disable and have rear wheel drive all summer. I also needed it to be as efficient as possible, so a 4-cylinder would be preferred. I love the Vitara so much that when I saw there was one in the city I just instantly bought it that day. I didn't even look under the car, and.. it's already pretty rotten, I basically acted on impulse and should have looked for a cleaner one. My $2800 Vitara is now a $5600 Vitara with the repairs I've had to do to get it to this point. A lot of these repairs dramatically increased my fuel mileage, instead of adding power I'm just trying to get all that power back, and I'm almost complete with that. Fuel filter, spark plugs, diff fluid, and a couple other things on friday, then it will be basically as good as it gets. In a couple years I want to get the timing chain replaced and put in a new water pump, oil pump, and anything else that could theoretically hinder it's performance.
Now I'm at a point where I don't need to change anything, the truck just works and runs great. Now I'm thinking about actual mods, basically I want to plan on modifying/upgrading every component possible, but prioritize them in such a way that they are 2-3-4 years down the road and may not ever do them, but just to have a roadmap of what I want to do with it and be aware of every upgrade that I could theoretically purchase and install. Price determines priority in a lot of cases.
Now when I bought the Vitara it was giving me 20-21 mpg, now my last update was 27.3 mpg but city driving, it's probably easy 28.5 mpg if all highway. Every week or so spending $300-400 on it to try recover another 0.5 mpg is basically the plan. I think the thing will cap out at about 32-33 mpg before aero mods. With a few other mods I might be able to get it close to where my rustbucket Accord is now. It sounds like being a "modern vehicle" I won't have much to gain but there is. This thing has a mechanical fan on the engine, I'm swapping it for an electric and there is basically a guaranteed increase in mileage. Putting an thin belly pan plate under the body could help quite a bit too. I bet if I put $2000 more into the truck in specific areas I could come out at a net gain in 3-4 years. Plus that whole time, I have a very efficient truck that can haul ass in 3 foot of snow. Worth every penny.
Not particularly interested in skinny tires though! Rides good enough on stock sized rubber! Also, my driving tactics are already hypermile-focused.
