I'm merely suggesting that you look around at some of the real world results some people on this board are getting with aerodynamic mods. The SRT-8 has lots of room for improvement on that front that would not require swapping to a higher rear end ratio or leaning it out. If only I had one to play with. :)

Ok, I'll grant that this is an issue of perspective and elaborate further:

Virtually every car on the road these days utilizes oversized injectors relative to what is needed to sustain highway cruising speeds. I can't quantify it exactly, but it's clear that most cars can cruise at well below 1/3 to 1/2 of their rated horsepower.

Obviously the injectors are oversized to provide for acceleration. Better fuel economy can be attained by simply sacrificing some of that accelerative capacity with smaller injectors, providing finer resolution. (NOTE: I'm not suggesting that the DIY'r throwing in smaller injectors by themselves will have positive results without remapping the fuel.) It's a simple compromise that manufacturers make to keep performance and fuel economy up to levels that consumers expect.

Virtually every car on the road these days utilizes oversized injectors relative to what is needed to sustain highway cruising speeds. I can't quantify it exactly, but it's clear that most cars can cruise at well below 1/3 to 1/2 of their rated horsepower.

Obviously the injectors are oversized to provide for acceleration. Better fuel economy can be attained by simply sacrificing some of that accelerative capacity with smaller injectors, providing finer resolution. (NOTE: I'm not suggesting that the DIY'r throwing in smaller injectors by themselves will have positive results without remapping the fuel.) It's a simple compromise that manufacturers make to keep performance and fuel economy up to levels that consumers expect.

I don't agree that injectors are too large. Maybe the cars are too large, the engines in them are too large, but making the injectors smaller isn't going to have an impact on FE. The auto manufactures are trying to balance making HP and pass emissions. They are selecting the minumum size injectors that will supply enough fuel at WOT and not be at 100% DC to do it. They also have to keep the car somehwere near a 14.7 AFR to meet emissions. Smaller injectors would just be running harder to do the same job. To get better FE, the cars would have to weigh less, have better aerodynamics, and have smaller engines. So far the comsumers are not demanding this. But considering I just paid $3.57 for regular in San Diego, maybe this will change.

Sigh.

I'm not so sure that you can draft in a way that's legal. Not a close draft anyway - which is the kind that really helps mpg.

My point here is that I believe close drafting is illegal, at least in most states. Legal following distance is usually two seconds worth of travel distance, or one car length per 10 mph of speed. And since the car length version goes back to 1969 when I took Driver Ed., you'd have to count a car length as 18 feet or so. An effective draft at highway speeds is maybe 1-2 car lengths behind a semi, and that's far less than the 6 car lengths that would be appropriate for 60 mph.

I put a premium on safety. I'm much more comfortable with a following distance of 2-3 times the minimum legal basic.

<--- Runs and gets popcorn :D

What I said: "Virtually every car on the road these days utilizes oversized injectors relative to what is needed to sustain highway cruising speeds. "

That's not the same as saying that injectors are too large, only larger than needed to sustain cruise. And yes, injector size does make a difference. Smaller injectors produce finer atomization as well as finer resolution, and that produces a more efficient and cleaner burn.

I think Spinningmarkviii left....

Wow, I have found this thread very enjoyable. I think the $3/gal gas is bringing new people to the site.

Hrmm... That's actually quite interesting... Worth some research methinks... I wonder if the headloss from smaller injectors (thus requiring longer duty cycle) outweighs any losses from "larger" sized injectors (in quotes because I'm not talking about 300cc differences)... Kinda like hydraulics I'd think -- what's more important - Flow or Pressure? Well, both are pretty equal :p

Increasing aerodynamic efficiency will give better FE, some spoilers will do this, some wont. Without a wind tunnel to test, its not easy for average joe to test them. Maybe with FE readings...