What's your least efficient mod?
 

I'm betting there are a few of us here that have done MPG-unfriendly mods. Maybe it's a heavy sound system, a lead foot, heavier wheels/tires, or neglecting maintenance.

What have you done? How bad did it hurt your mileage? Were you able to get your mileage back, or did you care?

I'm running sticky summer tires that are heavier and wider than stock. I went from an easy 43/44 MPG to a difficult 40. She looks really good.....for a commuter.

I started with the heaviest and least aerodynamic 1991 Civic body style. Does that count? :)

Electric water pump.
Its expensive, I don't think it helped MPGs any, caused some cooling system problems and it will make a alt delete more difficult due to the added electrical load.

Honestly? Getting new spark plugs. While I'm still in the 40s for mpg, it's dangerous knowing I now have some leeway in applying the go-pedal :D

Hard to say how much it's actually costing me since I'm in the unusual position of using this as my only family car. I'd say I'm still doing pretty well since a year ago maintaining over 40 using the car as the family car would have been laughable.

Swapping my '88 Civic wagon that died for a '98 Grand Cherokee 5.9 Limited. Went from 40ish MPG to about 11. I don't know if that counts as a mod, but I still regret it, even years later ha ha :snail:

I was the opposite of that with my old Mercedes to my Honda, so I could imagine how you feel. :eek:

I got a block heater and notice 0 effect on mpg. Next to that would of been doubling my starter battery capacity from 35 to 70 amps. Using heel fuel additive didnt help any. Going for cheaper gas actually lowered mpg.

Trading my 96 Civic for the Fit. Overall it's worth it, but I lost some mpg. Best tank in the Civic was 90 mpg, in the Fit is only 73, average down from 70 to 60.

But I gained:
New(er) car reliability
MUCH better cargo capability
Tighter driving dynamics
Working AC (that I don't use :p)

The mod that drives me crazy but I need it for my turbo compound system
(for racing) is my Tilton 40-527 external oil pump. It doesn't help at all with FE and takes away FE from the extra load on the alternator. So I decided to add a secondary deep cell battery to run it most of the time and charge this battery at home and work. I pulled around 200lbs of weight off the car so the extra weight from the deep cell won't be to bad.

Least efficient mod: Taking my truck on road trips instead of the GF's Cruze...

Personally, I'm fine either way. But she says my truck is more comfortable, has better leg room, and she can bring her many "necessary" bags... If we took the Cruze she'd have to pack sensibly... and we just can't have that now :rolleyes:

I buy the gas, she pays for the hotel, food and she carries her many bags herself!

As for the truck itself, I'd say the studded winter tires suck a good 1.5-2 mpg... stupid cold for 5 months of the year doesn't help either...

My neighbor went on a trip in his pickup, leaving his girlfriend's Civic. Both of them are small. They would have fit!

Probably the sound system. When I turn it up, I end up getting 4 bars constant regen, which has a pretty significant impact on the mileage.

It's only a 640w amp powering the rear speakers and a small sub.

How on earth do u get 73mpg on a fit? Teach me your tricks Plz.
 

How on earth do you do it? That's all, how?

How do I do it?

First, that's a single tank in perfect conditions. Summer, so no school dropoff. Summer, so high temperatures. No extra trips besides commuting. I know the route intimately. It's a good route, maxing at 55 mph with multiple lanes so I have flexibility to drive how I want.

Mods: not much. High tire pressure. Scangauge is crucial.

Techniques: pretty much everything in the 100+ hypermiling list at the top. Especially:
P&G - always.
DWB - coast down to stops and turns with absolute minimum braking
EOC - eoc is my primary driving mode, with the engine on for pulses only. I coast, and add the engine only when I need more coasting speed.
Low speed - usually topping out at 45 mph

Add in a generous portion of bullheaded stubbornness and a refusal to accept less than the best.

Fantastic. I'd like even 60 MPG !
 

Great stuff and I truly appreciate your help in explaining. Beyond great!

Hmm, as for "bad" mods:
- replaced reasonable aero front bumper with one that sticks out lower and has a splitter style feature going on to direct more air into the radiator.
- Bodykit that made the wheel arches slightly wider, and made the half-covered rear wheel arches into round arches
- Replacing 155 tires with 195 tires
- replacing the rear drum brakes with disk brakes, and adding beefier brakes up front
- Driving style: driving short trips and doing the speed limit everywhere.
- Adding interior trim bits, negative weight reduction.

Good mods: the wheels that I used are forged aluminium and very very light weight, that must be good for rotating mass, right?

My wife.

Buying a trailer and installing a hitch on the Sentra. While I will lose some MPG, it will still beat the truck (sold) and replace the Fiesta (sold) which saves me hundreds a year in tags, taxes, maintenance and insurance, more than making up for any mileage deficit incurred.

Now to pare down the bike collection.

The folding trailer also fits in my garage, while the truck stayed out in the weather. No extra insurance required on the trailer.

regards
mech

Quadrupling the stock horsepower in one of my cars...

Topping off my AC system. Now the compressor can suck a huge amount of power off of the crank on a hot day.

My scion xa I added a second fan to make the ac cooler and lost 4 mpg. At least my ac was cooler. :thumbup:

https://www.youtube.com/watch?v=rPcaGu70DS0

letting the dealership have a hold of my car. They gave me my worst tank of 44mpg while my second worst is 49mpg, so I had to pay the dealer to work on my car and they gave me a 5mpg drop:mad: