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Author Topic: Do higher tire pressures help mpg? Back to Topics
iaqxf

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Ohio

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Message Posted: May 19, 2011 6:29:26 AM


.............................................

tires at 10psi = 3.7% increase in consumption

tires at 30psi = 1.2% increase in consumption

Control, 35psi (manufacturer recomendation)

tires at 40psi = 6.2% decrease in consumption

tires at 60psi = 7.6% decrease in consumption

From Mythbusters test....


[Edited by: iaqxf at 5/19/2011 6:31:29 AM EST]
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dontuknowOH
Champion Author Ohio

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Message Posted: Mar 7, 2014 11:36:41 AM

I agree with HotRod10 You need right air pressure in the tires for good mileage not just air. putting in just air is low inflated. use the pressure gauge device. Balloons accept lots of air because they stretch/stretch/stretch, tires are much different, the correct pressure instead of volume is the clue for load support/safety/wear DIYing my modern tires for better fuel mileage. LOL
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HotRod10
Champion Author Wyoming

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Message Posted: Mar 7, 2014 10:44:48 AM

"Follow manufacturer specs on the tire wall"

The specs on the tire are maximums for safe usage of the tire, not recommendations for what to use for any particular vehicle. The same tire usually fits many different vehicles with varying load conditions. I have similar sized tires on a van and a pickup; the recommended pressure on the door panel of the van is 38 psi, but it's 26 psi for the pickup. The max on the sidewall is 44psi for both. I run about 30psi for the pickup (unless I'm loading it near it's max payload, when I'll push it up to about 38) and about 40psi for the van. The van has a much heavier curb weight and requires higher pressure for the tires to be the right shape under the load they normally carry.
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jimmy544
Champion Author Boston

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Message Posted: Mar 7, 2014 10:04:19 AM

The ride can be very harsh at excessive tire pressure and tire wear gets concentrated in the middle of the tread.
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Vin63
Champion Author San Bernardino

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Message Posted: Mar 7, 2014 9:46:39 AM

Yes, at the expense of faster/uneven tire wear.
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jay93LA
Champion Author New Orleans

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Message Posted: Mar 7, 2014 9:42:06 AM

yes
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WES03
Champion Author Maryland

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Message Posted: Mar 7, 2014 9:06:22 AM

Generally speaking, yes.
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chrisisawesome1
Sophomore Author Texas

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Message Posted: Mar 6, 2014 11:08:52 PM

The correct psi depends on the tire. Higher or lower decreases economy and increases tire wear. Follow manufacturer specs on the tire wall
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goldmonk
Sophomore Author Toronto

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Message Posted: Mar 4, 2014 8:28:50 PM

mine keeps at 30 psi
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skaboss79
Sophomore Author New Mexico

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Message Posted: Mar 4, 2014 11:39:04 AM

how long does it usually take for tires to deflate?
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Houckster
Champion Author Atlanta

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Message Posted: Mar 4, 2014 10:38:59 AM

FLORIDAMAN writes: I always keep my tires near the max air pressure on the sidewall which makes the mpg's better, tires last longer, car handles better. Just rides a little rougher. It's a better trade off.
_____
That's my experience. If I run over a dime, I can tell you if it was heads or tails.
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Floridaman2013
Champion Author Atlanta

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Message Posted: Mar 4, 2014 10:06:00 AM

I always keep my tires near the max air pressure on the sidewall which makes the mpg's better, tires last longer, car handles better. Just rides a little rougher. It's a better trade off.
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HotRod10
Champion Author Wyoming

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Message Posted: Mar 4, 2014 9:55:23 AM

"Also, don't forget about warranty issues."

I've read the warranty exclusions for my tires. For the warranty to be valid, the pressure needs to be maintained at or above the vehicle's recommended pressure (on the door tag) and below the maximum design pressure on the sidewall.
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twt
Champion Author Virginia Beach

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Message Posted: Mar 4, 2014 7:51:54 AM

Keep your tires inflated at the recommended factory specs.
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hoopitup2000
All-Star Author Virginia

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Message Posted: Mar 4, 2014 7:04:53 AM

Yes, it will improve fuel economy, especially if one knows how to coast effectively.

Many people I know have to ALWAYS be pressing on either the gas or brake & NEVER allow the car to coast. These people will benefit little from higher tire pressures.
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BobFang
All-Star Author Cincinnati

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Message Posted: Mar 4, 2014 6:13:19 AM

It helps but the higher pressures should be used in moderation.
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Houckster
Champion Author Atlanta

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Message Posted: Mar 4, 2014 1:09:09 AM

DIESELPOWER2014 writes: It is true if they are inflated really tight. As the tire expands it becomes round instead of flat. That's why your tires wear out on the inside and outside of the tread surface when under inflated.
__________
By "inflated really tight" I am guessing that you mean inflated beyond the Max PSI on the tire sidewall. No one here is recommending that. Short of the Max PSI though, there will be no increased tire wear. You're 40 years behind the times. We are not using bias-ply tires anymore. Modern radial tires have belts to prevent tire squirm and expansion that will cause excessive wear in the vented of the tread. I've always run higher pressures than recommended by the OEM. I've got 50K+ on these tires and they'll be good for another 30K more.

As for wear on the edges of the tire of tire when underinflated. Any tire will wear excessively on the edges if it doesn't have enough air to maintain its proper shape under load.

[Edited by: Houckster at 3/4/2014 1:15:01 AM EST]
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stonejd
Champion Author Illinois

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Message Posted: Mar 4, 2014 1:06:37 AM

a little bit
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dieselpower2014
Veteran Author Atlanta

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Message Posted: Mar 4, 2014 12:35:04 AM

It is true if they are inflated really tight. As the tire expands it becomes round instead of flat. That's why your tires wear out on the inside and outside of the tread surface when under inflated.
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hoopitup2000
All-Star Author Virginia

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Message Posted: Mar 3, 2014 10:39:59 PM

"but also wear the center of your tires"

Absolutely not true!! Not sure where you heard this, but it is wrong
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Kruilty
Sophomore Author Washington

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Message Posted: Mar 3, 2014 9:25:00 PM

Also, don't forget about warranty issues. If for any reason you try to replace tires for issues and they have a clause in there for air pressure. You best bet is to strengthen the positive and negative wiring for your electrical and ignitions. Go to any audio store and ask for the "big 3" upgrade. It'll give you another 1.5mpg.
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HotRod10
Champion Author Wyoming

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Message Posted: Mar 3, 2014 8:00:10 PM

And there goes another ignorant person who apparently can't even read the last post. Guess you need to repost it again Houckster.
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70plus
Rookie Author San Diego

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Message Posted: Mar 3, 2014 7:16:55 PM

It will improve mileage, but also wear the center of your tires at an increased rate. So cost of tires verses a slight increase in MPG.
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Houckster
Champion Author Atlanta

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Message Posted: Mar 3, 2014 9:28:03 AM

DIESELPOWER2014 writes: It will improve milage. But it will also wear the center of the tire out.

LUVMYRV writes: save a minimal amount on fuel but premature wear of tires and a $1000 tab to replace them....Does that make any sense?
_____
Canada and the US completed conversion to radial tires over 40 years ago yet these warnings continually crop up. Bias-ply tire had this problem, radial tires don't.

[Edited by: Houckster at 3/3/2014 9:30:34 AM EST]
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55Russ
Veteran Author Cleveland

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Message Posted: Mar 3, 2014 12:44:16 AM

Yes but you don't want to over inflate
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HotRod10
Champion Author Wyoming

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Message Posted: Mar 2, 2014 7:39:35 PM

"When you over inflate, you lose traction."

That's only true when you're braking or turning hard enough to take rubber off of the tires. The total friction between the tire and the road is equal to the total force multiplied by the coefficient of friction. Only if the tire patch becomes small enough that you exceed the shear strength of the rubber, does it separate and leave the surface layer of your tires on the road (skid marks). Until then, the traction is the same regardless of the contact area.

In hard braking or turning the weight shifts and the tire or tires with the most weight on them will deform more under the extra load. So, even if you were to inflate the tires to the point where under normal load only the center of the tire is touching (which would be VERY overinflated), under hard braking or turning, it would deform to have the full contact area.

[Edited by: HotRod10 at 3/2/2014 7:41:47 PM EST]
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luvmyrv
Veteran Author Winnipeg

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Message Posted: Mar 2, 2014 7:28:58 PM

save a minimal amount on fuel but premature wear of tires and a $1000 tab to replace them....Does that make any sense?
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SmoknFord
Champion Author British Columbia

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Message Posted: Mar 2, 2014 3:27:52 AM

Yes, to a certain point.
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dieselpower2014
Veteran Author Atlanta

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Message Posted: Mar 2, 2014 1:02:33 AM

It will improve milage. But it will also wear the center of the tire out.
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X_Rider
Rookie Author Georgia

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Message Posted: Feb 28, 2014 8:52:28 AM

I run 2 lbs under MAX inflation listed on tire. It DOES increase gas mileage. I do not have a firm % but about 2-3 mpg. I drive 800 miles a week so it adds up.
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Houckster
Champion Author Atlanta

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Message Posted: Feb 27, 2014 4:49:12 PM

VIN63 writes: It can, but at the expense of faster wear on your tires…so, compare the cost of new tires to the amount of fuel savings then make your decision.
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Not true. Forty years ago when most of us still had bias-ply tires, this was a real problem but modern tires have belts to keep the tire from distorting. I run my tires at 10-12 PSI above the OEM recommendation. I have 50K on them and I'll get another 30K out of them at least. It's tire flexing that causes tread wear and weakens the tire fibers.
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Vin63
Champion Author San Bernardino

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Message Posted: Feb 27, 2014 9:51:27 AM

It can, but at the expense of faster wear on your tires…so, compare the cost of new tires to the amount of fuel savings then make your decision.
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Houckster
Champion Author Atlanta

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Message Posted: Jan 28, 2014 12:38:57 PM

BLUEENVOY writes: The manufacturer gives you the right inflation level for your ride on the door frame(unless it's Ford making up for a poor suspension).
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There is no one right inflation level for a vehicle. The OEMs usually supply a PSI level for their cars that should be regarded as the minimum safe tire pressure while providing the maximum comfort level.

Adding, say, 4-6 PSI to the front tires and 2-4 PSI to the rear tires will improve mileage and handling at a minimal cost to comfort while also increasing tire life. This is especially important for new car tires because the OEMs buy their tires partially based on rolling resistance to improve their CAFE rating. Replacement tires don't have as good performance as the OEM tires because they have a higher coefficient of friction.

[Edited by: Houckster at 1/28/2014 12:38:22 PM EST]
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bluenvoy
Champion Author Nashville

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Message Posted: Jan 27, 2014 10:00:28 AM

The manufacturer gives you the right inflation level for your ride on the door frame(unless it's Ford making up for a poor suspension).
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ricebike
Champion Author New Jersey

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Message Posted: Jan 27, 2014 8:52:42 AM

key words, don't exceed the tire's sidewall rating

"I also believe it is best to have a slightly higher PSI than OEM recommendations in the front tires since they handle more weight."

agree & it's less wear on the sides of the treads of the front tires due to turning

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dassfg
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Message Posted: Jan 27, 2014 8:09:50 AM

Absolutely
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flguy71
Veteran Author Orlando

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Message Posted: Jan 27, 2014 7:41:32 AM

anywhere between recommended tire pressure and max tire pressure will help save fuel and be safe
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51stovi
All-Star Author Nashville

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Message Posted: Jan 27, 2014 7:36:39 AM

Interesting reading all the debate.
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Houckster
Champion Author Atlanta

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Message Posted: Jan 24, 2014 4:01:19 PM

THIRSTYV8SUV writes: yea not sure what's up with mythbusters on the higher PSI. my assumption was always that higher PSI resulted in better MPG due to less resistance (less surface contact)
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I didn't see the Mythbusters show but you are correct. As long as the pressure in the tire remains at or below the max PSI rating on the sidewall, the tire should roll more easily with higher pressures because the tire doesn't deform or flex as much thereby reducing friction.

As for losing traction, higher pressures do reduce the size of the tire patch but if one is using a higher PSI to save fuel, it is likely that the person will also be driving more slowly making the reduced traction a nonissue. In my own personal experience, the loss is inconsequential. I've been running my tires as 44/40 as opposed to the OEM recommendation of 30/30. I've had no problems with these pressures and it looks like I'll get about 80K out of the tires.

Of course no one needs to run that much over the OEM specs. The vast majority of improvement will be realized at 4-6 PSI over the OEM spec. I also believe it is best to have a higher PSI in the front tires since they handle more weight.

[Edited by: Houckster at 1/24/2014 4:02:21 PM EST]
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twt
Champion Author Virginia Beach

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Message Posted: Jan 23, 2014 5:46:30 AM

When you over inflate, you lose traction.
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thirstyV8suv
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Message Posted: Jan 22, 2014 7:43:52 PM

yea not sure what's up with mythbusters on the higher PSI. my assumption was always that higher PSI resulted in better MPG due to less resistance (less surface contact)
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The_Waysiders
All-Star Author Georgia

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Message Posted: Jan 20, 2014 6:58:45 PM

Dangerous to overinflate.
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marlboroman311
Rookie Author California

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Message Posted: Jan 20, 2014 3:34:14 PM

of course they do. Less rolling resistance.
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dassfg
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Message Posted: Jan 20, 2014 2:51:57 PM

Absolutely -- keep them aired up
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ricebike
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Message Posted: Jan 20, 2014 1:29:10 AM

i usually add a few psi at the front, because they take more wear-n-tear at the shoulders of the tires (due to turning)
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atdes
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Message Posted: Jan 19, 2014 11:40:41 PM

yes, but decrease in tire life, handling and rougher ride. May also shorten life of suspension system and alignment
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herbiepopnecker
Champion Author British Columbia

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Message Posted: Jan 19, 2014 10:39:28 PM

200 psi. Every inch in increased tire diameter saves a fortune!
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poetdog73
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Message Posted: Jan 19, 2014 3:45:08 PM

I stay with the 35psi (4cyl so my mpg is ok
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Psusennes
Rookie Author Indiana

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Message Posted: Jan 19, 2014 2:57:08 PM

I've tried higher pressures. It does increase mileage somewhat. But over extended time, tire wear in center of tread occurs.
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GLM4205
Champion Author Toledo

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Message Posted: Jan 19, 2014 2:31:01 PM

So what happens to the manufacturer's tire pressure???
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traffic cop
Champion Author Boston

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Message Posted: Jan 14, 2014 1:11:03 PM

It's important to note that the major advantage, according to iaqxf's OP (now 10 years ago!) was 6.2% at 5 psi over OEM. Adding 20 psi over that produced only .6%. Talk about the Law of Diminishing Returns!

I run 4-5 psi over OEM. My main reason is that Toyota's (2009 Sienna) TPMS tends to give me false positives. A few extra pounds gives me more time before the idiot light comes on and I have to check it.

And yes, I know, Houckster, I should be manually checking pressure anyway. So many things to attend to. Any report (other thread) on Ethanol Defense?
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