Increasing gas mileage with bolt-on parts?

[Throckmorton]

I didn't think it was possible to increase gas mileage by improving intake, because the more air you stuff into the engine, the more fuel the ECM sends to it. I don't buy the restrictiveness thing either, because what a throttle does is restrict airflow with a plate.... So a freer flowing intake would only help at wide open throttle.

But these guys had success. Maybe it's a placebo effect

http://www.4wheeloffroad.com/b...kee_mileage/index.html

 

[olds]

Originally posted by: Throckmorton
I didn't think it was possible to increase gas mileage by improving intake, because the more air you stuff into the engine, the more fuel the ECM sends to it. I don't buy the restrictiveness thing either, because what a throttle does is restrict airflow with a plate.... So a freer flowing intake would only help at wide open throttle.

But these guys had success. Maybe it's a placebo effect

http://www.4wheeloffroad.com/b...kee_mileage/index.html

Placebo effect with an inanimate object?

 

[JulesMaximus]

I would say that that article is a big steaming pile of literary bullshit...someone feel free to prove me wrong.

Don't believe everything you read.

 

[AnnonUSA]

You can save a lot of gas with proper usage of your right foot. (and I don't mean by driving slower, I mean by driving smarter.)

 

[jagec]

Well if you consider a differential to be a "bolt-on" part, then sure, you can save plenty of gas that way.

But a modern EFI engine is a pretty efficient beast. A different throttle body and coil isn't suddenly going to improve your mileage by over 20%

 

[Throckmorton]

Originally posted by: oldsmoboat

Originally posted by: Throckmorton
I didn't think it was possible to increase gas mileage by improving intake, because the more air you stuff into the engine, the more fuel the ECM sends to it. I don't buy the restrictiveness thing either, because what a throttle does is restrict airflow with a plate.... So a freer flowing intake would only help at wide open throttle.

But these guys had success. Maybe it's a placebo effect

http://www.4wheeloffroad.com/b...kee_mileage/index.html

Placebo effect with an inanimate object?

Yeah, I mean you do the mod with the intent to improve gas mileage, so you drive with a slightly lighter right foot.

 

[SoulAssassin]

Take a block of wood and bolt it underneath the skinny pedal. Bam! Bolt on gas savings!!

 

[feralkid]

Is there any chance that many of the parts they replaced were worn out, leaky and by replacing them, they merely returned the mpg to where it was when the vehicle was new?

 

[Howard]

You could install an underdrive pulley... or bolt-off unnecessary items like seats.

 

[potato28]

Originally posted by: SoulAssassin
Take a block of wood and bolt it underneath the skinny pedal. Bam! Bolt on gas savings!!

:laugh:

 

[exdeath]

Bolt ons increase efficiency. Why? Because you are getting more power without increasing the displacement of the engine.

A intake and exhaust allows the engine to breath better under WOT, which means more air and more fuel. But you still need to floor it to get that extra air. When not flooring it it doesn't consume any more air than it did before, it requires slightly less work to suck in a smaller amount of air, resulting in better mileage, as long as you're not flooring it.

Most stock tunes are pig rich to provide a margin of safety for reliability and liability. Flash tunning to lean it out a little results in more power, and less fuel consumed.

The added power and efficiency from bolt on's means you can achieve the same acceleration and speed with less pedal effort. If you make a 100 HP engine have 200 HP, then its going to make 100 HP at 50% of pedal position instead of 100%. Problem is once people feel that 200 HP they won't stay at 50%, they will continue to go 100% just like they did when it only had 100 HP.

People get addicted to that new found power, and prefer to exploit the power gains at WOT more than the efficiency gains with no WOT, so they won't ever see any MPG gains.

 

[mooseracing]

And yet they put the crappy platinums on it. IF they were going for the most effiency over the short term they should have put coppers on it.

 

[PlasmaBomb]

Our conservative estimate is that we improved mileage by 10-15 hp

 

[PlasmaBomb]

Originally posted by: mooseracing
And yet they put the crappy platinums on it. IF they were going for the most effiency over the short term they should have put coppers on it.

?

 

[XMan]

Anyone ever try one of those electrolysis devices that put hydrogen gas into the intake? Supposedly it can greatly increase your mileage. A guy I work with is building one for his truck.

 

[jagec]

Originally posted by: PlasmaBomb

Originally posted by: mooseracing
And yet they put the crappy platinums on it. IF they were going for the most effiency over the short term they should have put coppers on it.

?

Copper plugs are better than platinum, they just don't last as long. Check out the relative conductivities between the two...copper is over six times as conductive.

Originally posted by: XMan
Anyone ever try one of those electrolysis devices that put hydrogen gas into the intake? Supposedly it can greatly increase your mileage. A guy I work with is building one for his truck.

BEEP BEEP BEEP BEEP BEEP


...sorry, that was my BS meter going off.

Those devices are thermodynamically unsound. You will NOT improve your gas mileage with such a scheme. Electrolysis is a horribly inefficient.

 

[SoulAssassin]

Originally posted by: PlasmaBomb

Our conservative estimate is that we improved mileage by 10-15 hp

:music: One of these things is not like the other...one of these things...doesn't belong.

 

[Kadarin]

You'll have much better luck by putting an extra few PSI in your tires, and by driving carefully. Plan your trips, too, to avoid unnecessary travel.

 

[PlasmaBomb]

Originally posted by: jagec

Originally posted by: PlasmaBomb

Originally posted by: mooseracing
And yet they put the crappy platinums on it. IF they were going for the most effiency over the short term they should have put coppers on it.

?

Copper plugs are better than platinum, they just don't last as long. Check out the relative conductivities between the two...copper is over six times as conductive.

It does indeed, but I didn't think that conductivity was king. I thought that the point of precious metal plugs was that they had a smaller point, yielding a higher field strength (and therefore a better spark). They also have higher melting points, so you should be able to run them at higher temps, increasing the thermionic emissions (think incandescent light bulb), again increasing the ability to provide a good spark.

However I am not a spark plug engineer, so I could well be wrong...

 

[PandaBear]

Unless the design from manufacture is not optimal and you redo a fuel/ignition map tuning afterward, bolt on don't improve fuel economy.

Today's engine adjust fuel and ignition to compensate for all temp/pressure so this device won't do you any good in economy, but may improve your throttle feel (butt dyno).

 

[OS]

i never noticed any difference with aftermarket intake and exhaust manifolds.

i doubt car manufacturers would leave anything of significance on the table, CAFE penalizes fleet averages something like every 0.1 mpg or whatever, definitely not without sacrificing something else.
Alot of car makes even switched oil weights to 5w-20 just to save a couple more tenths of mpg.
If a factory car runs rich and is retuned, that is engineering margin that you are eating into.

for sure driving style affects fuel economy more than boltons.

 

[JJ650]

Originally posted by: OS

i never noticed any difference with aftermarket intake and exhaust manifolds.

Really!? I have noticed (butt dyno and a real dyno) and seen gains with a high flow manifolds.

Now...I have noticed a decrease in performance/mileage when going to dual exhaust (without changing manifolds) at certain rpm ranges.

A lot of that is engine dependent. Some will respond diffrerently to mods. Some more show good performance gains or none at all.

A lot of stuff is gimmicky too (ie. 'helix' style risers on EFI cars) and do absolutely nothing.

 

[OS]

oh i only meant in reference to gas mileage,
yeah horsepower there was almost 20 whp gain on a dynojet