+1

I drive an 18 wheeler a couple times a year when i go on tour with my company. We get few guys that try do exactly what your doing. In traffic, its unavoidable but on the open road its a PIA and dangerous. It's not worth it. Get a Prius

 

+1 very true

 

Slow_evo, perhaps aerodynamics play a big part, turbo vs. NA...i haven't a clue why your camero keeps up in the MPG dept.

Evo Tengoku, tis true. But I still think (hope?) I got over 25.3 mpg this tank. We'll c.

 

Why are soo many many people against wanting to have best of both worlds performance and good mpg's? Its almost as if your better off putting stickers and unnecessarily loud exhaust on your car then aiming for better mpg's here in this forum.

I'm pro saving gas, but I wouldnt drive behind trucks because they can kick up soo many rocks and or parts that might break off and fly at you (such as tires etc..). I wouldnt be soo much worried about the truck making a quick stop because no matter what your evo will stop faster than that truck, unless your literally 1 foot behind it before your reaction time kicks in.

I've been reading that the only reason cars stoich a/f ratio is 14.7 is because that is the required ratio to keep the catalytic converter at optimum temps to do its job with emissions.

I am not a tuner, engineer or an engine builder but I would guess to increase your mpg's we need to do the following: (besides driving technique)

-Increase timing
-removing/replacing restrictions (exhaust, intake etc...)
-lean out idle/normal driving a/f ratio to about 15's-16's
-Improve aero dynamics of the car

Who said your only saving 3 dollars per fill up?

CAR 1 : 20 MPG * 12 = 240 miles driven
CAR 2 : 27 MPG * 12 = 324 miles driven

I drive about 13,000 miles a year and fill up 12 gallons every week.

http://www.fueleconomy.gov/feg/savemoney.shtml

Yearly savings of 556 dollars, sounds like a pretty good mod you can get for your car.

556 / 52 weeks per year = 10.69 savings every week from a 7 MPG increase which you can use to watch a movie, eat fast food etc....

 

BlueEVOIX..I think having the best of both worlds is difficult, unless you could have an EVO in which you selected which map (Econo, Normal, Performance) to run b4 you took off for a trip. I believe the way tuner's increase power on our cars is to increase the air (drop in or intake), decrease the back pressure (exhaust) and tune the AFR closer to 11 or 12 (dump more fuel than stock to match the increased air inflow). Can any more kniowledgeable members comment on this? Is it possible to load an econo map vs. performance map b4 u start your car short of hooking up your laptop and using ECHFLASH, flash your rom ever time?

 

Wow, 7-11% gain, I sure slept through that one.

I guess your just someone who takes a lot of risk for little reward, more power to ya!

 

 

yep....100 feet (6.6 car lengths behind) behind an 18-wheeler sure is a WHOLE lotta risk for ~10% improvement in gas mileage...PM me to get your life insurance policies started on me, you could really cash in there buddy.

 

On a forum that's mostly about 42R's, 1/4 mile times, dyno numbers, 1000cc injectors and pushing performance to the limit, I think it's safe to say that while some people may think like you and want to go out of their way to get a few more mpg out of their car, most people here would spend $250 on Ti Spark Plug Covers and $1000 on a 6 foot piece of 3" pipe without blinking so what makes you think they would tailgate a truck for 300 miles to get an 11% increase on a tank of gas? More power to you as you continue looking for ways to "pmprovrd" your fuel economy, though.

 

No matter the power level, almost all cars idle and normal drive with an a/f ratio of 14.7 . But having best of both worlds depends on how much power your goal is because certain factors/modifications would work against the MPG's such as cams. Unless we had V-tec with cams that have 2 profiles low econo and high rpm power lol.

For me 330-350 whp with 30 mpg is more than enough and I would be done with the mod game.

Opening up the exhaust flow (less back pressure) and intake flow would increase the efficiency of the motor. Under normal driving there wouldnt be more fuel consumption because you would use less throttle for the same acceleration and the o2 sensor/maf would adjust the a/f ratio accordingly.

That 11 a/f ratio you are talking about is only during Wide Open Throttle or open loop mode. During normal driving the a/f ratio is always around 14.7 (whether tuned or stock) . Stock a/f ratio during WOT (open loop) is actually more in the low 10's, so tuning your car actually leans out the fuel ratio to make more power but still rich enough to keep the EGT's (exhaust gas temperatures) low.

I could be wrong but I'm pretty sure my above statements are pretty accurate or close to the truth. So any one can feel free to share their thoughts, opinions, and knowledge to add on or correct me.

 

gas millage for evos suck. we all get 16-19mpg. just deal with it

 

18-wheeler drive to slow any way. Granted there are a few that move along at a good speed. But I would end up shooting my self going that slow all the way just to save a little bit of gas.

 

You guys never play mario kart? Gotta draft your competition!

 

If any of you have seen the carnage of an auto/semi accident, you wouldnt think twice of this idea. It is far too dangerous to even consider. Semis can stop quicker than you think, especially unloaded. At 55MPH, you are traveling 74 fps, Even if you were focusing 100% of your attention on the semi in front of you (and you know when you're driving on the highway, the most you give is 80% attention) with a typical half second reaction time, you've already traveled 37 feet before your car even attempted to slow down. Tap the rear of an unloaded semi which is hard on the brakes, and you've now caused a jack-knife, which not only damages you and the semi, but now will cause a chain reaction accident with every other car on the road.

Drafting a semi is just plain stupid, and not worth the risk for the reward. The juice is not worth the squeeze.

 

Thx for proving my point...you said 'mostly' not 'entirely.' It's a free country and a free msg board. Just because someone is into efficiency does not mean they can't appreciate performance and vice versa. (and from the looks of this thread, I'm not the only one) If u're not into efficiency, that's fine, I'm not laughing at u at the pump as I drive by, am I? To each his own to enjoy their EVO how they like.

(as yes I made a spelling mistake when I originally posted. Kind of a PIA to type as well as I used to with one functional hand <motorcycle accident this past summer> these days. I'd like to see you try it, or better yet stick to the topic of the thread instead of making fun of forum members behins your computer.)

BLUEEVOIX- Thx for the info. I'm late to the tuning game and reading the tuning forum as fast as I can. Wideband here I come.

TempeRacerGuy- I beg to differ. Using Mythbusters testing results, traveling 100 feet behind yields 11% increase in mileage. I'd bet my next paycheck 99% of EVO owners, heck all automobile owners, don't leave that much following distance behind any car. Also, one might argue following a semi is safer in that at least 50% of the time (prob. more if the trucking industry has any sort of decent logistics) the truck is fully loaded, and as a result your evo can stop easily in time, being 100 feet behind. Also, one might argue following a big SUV with tinted windows gives u almost as crappy a view of traffic situations ahead, and I trust a trucker to be much more consistent and safe in their driving that an SUV soccer mom, trying to take care of 2 kids in the back, talk one-handed on their cell phone, with less miles under their belt, and driver training than a big rig operator. Plus that more experienced, big rig operator generally leaves more following space between himself and the automobile ahead of him than u're average SUV driver. Again it's all just opinions and theories, just giving another point of view. Not sure who is corect, or if there is a 'right' answer.