better gas mileage....v8

K

Kro781

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I found a way to squeeze a few extra mpg out of the beast. If you open the air filter box there is a second carbon air filter. Drill the rivets and pull. Got the idea from my taco xrunner it had the 4.0 v6 and it gave a few extra on that. my mileage went from 15's to now high 17's and 18's. I do alot of city driving and my trires are 275/65 17's. there has been no other changes in the truck since I tried this. and my foot has never been light.

Kev
 
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Obviously life is a give and take senario.

Can some expert on engine intake explain what just happenned. The good is the obvious increase in MPG. What about the bad??

I mean what do that second carbon filter prevent from entering the combustion chamber. Typically carbon is use for filtering chemical fumes.
 
I don't know about the V8, but folks on the Tacoma forums with the 4.0 V6 say it's just for emission purposes.
 
Definitely could use a little better gas mileage. I get 15-16 in town, 18-19 highway, and 9-10 towing on flat Florida highways.

Be nice to find out the story on the carbon filter. I can't lose any power towing. I am pushing the envelope now

mike
 
According to the Toyota tech manual it's strictly for emission control on the 1GR-FE (4.0 V6), I'm sure it serves the same function on the V8. Attached is a PDF with the info.
 

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"adsorbs the HC that accumulates in the intake system when the engine is stopped, has been adopted in the air cleaner case in order to reduce evaporative emissions"

sounds like it has two functions?
1)adsorbs the HC that accumulates in the intake system
2)reduce evaporative emissions

I'm not sure what HC is but I am sure thinking about ripping this thing out.

Thoughts?
 
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also, im thinking that instead of drilling the rivets, I would want a way to put it back in for the eventual emissions tests (btw, since I have a sticker that says "emissions exempt vehichle", does that mean for life?)
 
So I just spent an hour reading posts at CT and TN and the general consensus is this:

1) The filter is restrictive and should be removed
2) removing it leads to better response
3) dyno tests say no difference.

Hmm. I'm thinking I'm going to remove it. Restriction is bad in my opinion.
 
keylay31 said:
So I just spent an hour reading posts at CT and TN and the general consensus is this:

1) The filter is restrictive and should be removed
2) removing it leads to better response
3) dyno tests say no difference.

Hmm. I'm thinking I'm going to remove it. Restriction is bad in my opinion.
Click to expand...

CT? TN? Could you please post the links to these threads? I'm also interested in removing it, if it really does improve response, assuming throttle response.
 
I'm ready to jump on the 'dump the carbon filter' bandwagon also but the .pdf posted by 2k3T4R also mentions that the intake runners are adjustable through the "ACIS". Maybe the ACIS takes into account the restriction of the carbon filter and adjusts the intake track length to compensate....

Maybe that's why there isn't a performance increase after the carbon filter is removed. Maybe it throws off the intake track tuning.

Of course there's nothing like personal real world testing to proove it out. Remove the filter in a way that it can be reinstalled. If fuel economy drops or stays the same, then put it back in.

Regular is $2.99 in Austin. I'm willing to try it.

Dave
 
I'm ready to jump on the 'dump the carbon filter' bandwagon also but the .pdf posted by 2k3T4R also mentions that the intake runners are adjustable through the "ACIS". Maybe the ACIS takes into account the restriction of the carbon filter and adjusts the intake track length to compensate....

Maybe that's why there isn't a performance increase after the carbon filter is removed. Maybe it throws off the intake track tuning.

Of course there's nothing like personal real world testing to proove it out. Remove the filter in a way that it can be reinstalled. If fuel economy drops or stays the same, then put it back in.
Dave
 
The carbon filter is to adsorb vapors in the manifold when the engine is off. It is not restrictive. Even if it was it would affect max power (low air charge density due to pressure drop) but not your MPG.

In other words, a pressure drop across the throttle butterfly will be significantly higher than a pressure drop across the air filter with less than WOT operating point. So a higher intake restriction would appear like a more closed throttle butterfly.

You can remove it with no consequence if you like. It does not affect tail pipe emissions.
 
In to see others who have MPG increases from trying this...not that I don't believe the thread starter but for me to tinker with my new toy it's gonna require more than a week or two on one truck...

Great job on thinking outside the box and being willing to try new things...hopefully a few more people stronger than I will give it a shot and back up your results (toy'd with my Supra too much...wife would kill me if I mess with this for no good reason :) )
 
The only official results we have are Gadget claiming no results in dyno testing, but he never posted the results nor was he too descriptive. Who wants to go out and test before and after?
 
An interesting project would be use a manometer and measure the pressure differential across the the carbon filter by its self then again using a new pleated filter minus the carbon filter to compare the difference. Also measuring the total differential with both filters installed.This would determine whether or not the carbon filter causes a restriction in air flow.
 
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