MPG, how to improve? (1 Viewer)

[1meancruiser]

They are the ones I am talking about. Aren't the sensors on top of the cats?

Search for my exhaust thread as the pics show the cats with the extended sensors

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Edit: sent from my desktop
https://forum.ih8mud.com/100-series-cruisers/304721-new-exhaust-pics.html

and post #2 you see the sensors.

I've checked a few times now and to my surprise there are no sensors whatsoever after the cat's. only one on each side directly after the exhaust manifold...

is it possible they deleted the 2nd set of 02 sensors on the 2006 vvt-i engine?

 

[mechanixhorseman]

I got bored enough and did the math to see how much more efficient the actual fuel economy is than the ECU's perceived fuel economy after upgrading from stock 31.3" tires to 33" tires.

If you were to correct your speedo/trip to account for the increased diameter of the larger tires you would yield about .6 MPG better. They aren't REAL or ACTUAL gains in MPG but at least you can feel .6 MPG better about yourselves if you've beefed up your tires.

I still only get 11.6 MPG in the city, which I guess is better than the 11 I thought I was getting. We'll see how much new headers and front O2 sensors helps when I install them next weekend.

 

[TheFuzz]

I know i mentioned this already on my other thread, but just to reiterate the point...after doing my spark plugs and making sure that loose intake tube was locked down tight (thus eliminating the air leak at the throttle body), my mixed mpgs jumped way up to 15.4 on the last tank. Vacuum leaks apparently have a profound affect on mpg.

 

[mister bean]

I got bored enough and did the math to see how much more efficient the actual fuel economy is than the ECU's perceived fuel economy after upgrading from stock 31.3" tires to 33" tires.

If you were to correct your speedo/trip to account for the increased diameter of the larger tires you would yield about .6 MPG better. They aren't REAL or ACTUAL gains in MPG but at least you can feel .6 MPG better about yourselves if you've beefed up your tires.

I still only get 11.6 MPG in the city, which I guess is better than the 11 I thought I was getting. We'll see how much new headers and front O2 sensors helps when I install them next weekend.

It should be a percentage, not an absolute value. This can be calculated using tire sizes, but it would be better to use something like a GPS to find the actual difference, calculate the adjustment percentage and then use that number to adjust in the future.

 

[mechanixhorseman]

I used fixed variables and my current fuel economy in order to find an actual number. All you really need to know is that the circumference of a 33" diameter tire is 6% bigger than a 31.3" tire (stock, and what the trip assumes you have) It's only a coincidence that for my application the MPG "gain" is .6 MPG better than what the trip would tell me it is. It is initially broken down into a percentage, but then that percentage can be used to find an exact-ish number. For example when my trip says I've driven 250 miles, I've actually driven 265. A GPS would, in fact be a great way to tell actual fuel economy. I think slee sells some sort of speedo correction device for those who are bothered by the inaccuracy after upgrading tire sizes.


It's pretty trivial really, but I had a few minutes to burn. YRMV.

 

[TheFuzz]

I use the same method - I take the tripmeter reading, multiply it by a fixed percentage to get the total miles driven for that tank (I use 5.1%, as a 285-75-16 is only 32.83", or 5.12% larger than stock), and then use that number to calculate MPG based on miles traveled vs gallons used to fill the tank.

I think that it's important to note that while we can use use whatever percentage we want to correct for tire size, none of us are hypermilers here. I use the figures just so I know what "normal" is for my truck. If I see a significant reduction in mileage, then I know something is up. Took me a while to track down the problem, but I knew that 11.5-12.1 mpg was way below the norm considering how I drive.

 

[TwiceWithHair]

275 65 18 (32.1") and everytime I cruise past a radar for school zones or slow corners or construction zones, It calls my speed exactly as my speedometer sees it. I can only assume the odometer is synced up with the speedo. I'm pretty sure my cruiser is getting the milage she claims. Which isn't much. Unless the radars are off...

 

[mechanixhorseman]

275 65 18 (32.1") and everytime I cruise past a radar for school zones or slow corners or construction zones, It calls my speed exactly as my speedometer sees it. I can only assume the odometer is synced up with the speedo. I'm pretty sure my cruiser is getting the milage she claims. Which isn't much. Unless the radars are off...

I don't really trust the factory speedo on just about any vehicle I have had. I have a BMW with the stock wheel sizes and my speedo usual says I'm going about 3mph faster than what I actually am. Sometimes I wonder if this is intentional by the factory for any number of reasons.

I really can't imagine any way that the ECU/trip would be able to adapt to a larger tire size without some sort of GPS built in (which only some cruisers have).

 

[gtfour43]

I don't really trust the factory speedo on just about any vehicle I have had. I have a BMW with the stock wheel sizes and my speedo usual says I'm going about 3mph faster than what I actually am. Sometimes I wonder if this is intentional by the factory for any number of reasons.

I really can't imagine any way that the ECU/trip would be able to adapt to a larger tire size without some sort of GPS built in (which only some cruisers have).

Same here on my LS400. Shows about 5 mph fast at 60 mph. Confirmed with my ultragage and speed traps.

 

[moooooooo]

The Scangauge II allows you to enter a percentage correction for things like this. On mine with its 265x75x16 when the GPS says I'm doing 100km/h the Scangauge and speedo says 98.
Given I can get a speeding ticket for doing 103 in a 100 zone (I kid you not!) thie GPS and Scangauge correction ability is important.

 

[watchknut]

Took the first road trip this weekend, given it was a short one, but got around 15mpg overall and up to 16mpg at one point.

 

[G-Cat]

This looks promising...the adaptability to any car without modification is it's genius.

Student hybrid car project could bring millions to Tennessee university | Fox News

 

[consalvochris]

16 mpg with 285's, no roof rack, 1.5 OME lift (if it matters) fresh alignment/oil change/MAF & TB cleaned/new spark plugs, Mobil 1 synthetic fluids recently changed in front and rear diff, transfer case and a trans drain-refill. This was with a mix of highway driving 70-75 mph and half city driving. Pretty happy with it right now, I was getting 12mpg consistently before all this. Oh yeah and 93 octane

 

[SanDiegoCruiser]

16 mpg with 285's, no roof rack, 1.5 OME lift (if it matters) fresh alignment/oil change/MAF & TB cleaned/new spark plugs, Mobil 1 synthetic fluids recently changed in front and rear diff, transfer case and a trans drain-refill. This was with a mix of highway driving 70-75 mph and half city driving. Pretty happy with it right now, I was getting 12mpg consistently before all this. Oh yeah and 93 octane

That's impressive. I averaged 19 mpg 100% highway going 65mph on hwy 40 on the way the Mojave Desert last weekend. Same config as you but with a Slee Rear and Sliders.

 

[RobRed]

That's impressive. I averaged 19 mpg 100% highway going 65mph on hwy 40 on the way the Mojave Desert last weekend. Same config as you but with a Slee Rear and Sliders.

Unless you disco'd the front drive shaft and hyper miled there is no way you got 19 mpg... allright, alternatively downhill in a hurricane... maybe.

 

[SanDiegoCruiser]

It was slightly downhill...

 

[white_lx]

16 mpg with 285's, no roof rack, 1.5 OME lift (if it matters) fresh alignment/oil change/MAF & TB cleaned/new spark plugs, Mobil 1 synthetic fluids recently changed in front and rear diff, transfer case and a trans drain-refill.

That is a pretty amazing increase. What do you think was the biggest factor? How old were the spark plugs?

Thanks

 

[mcgaskins]

FWIW I've put 3 tanks in since I've owned my LC, and my first tank was 14.8, second was 15.2 (with about 20 miles of off road, and the last was 14.1. I'd say I'm 60% city, 40% highway. I just took off the Yakima MegaWarrior 2 days ago, so I'm betting on a slight increase in mpg. I put 285s hours after I bought the LC, so I don't have a baseline as to before. I did however correct using a GPS and it looks to be off by about 4.5% from stock.

 

[RobRed]

How are you calculating these mpg numbers?

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[consalvochris]

That is a pretty amazing increase. What do you think was the biggest factor? How old were the spark plugs?

Thanks

Cleaning the throttle body and removing the roof rack were probably the biggest factors for me. I'm not sure how old the spark plugs were, I just changed them so I know now that they are good. I calculate my mpg's by filling up the tank, resetting the odometer and then the next time I fill up, I divide how many miles I drove by the exact amount of fuel it took to fill back up. Since I have 285's, I add 5 more miles for every 60 miles driven (so a 240 mile trip is actually 260 miles with the larger tires). I've noticed when I'm driving 60 mph and there is a speed clock on the highway, it reads 65. Probably not the best way to calculate my mpg's, but I think it's close enough.