Official: What are your real world MPG Numbers

[dvn]

I am quite impressed so far, and the MPG is actually making me want the Trifecta tune more than the increase in power!

Don't expect better mpg with the tune unless you have a LOT of self control. I don't.

 

[mitdr774]

DId a quick run tonight to check a few things. Going to have to redo the run with the stock 15" wheels and tires though. I suspect the 17s hurt my numbers big time.

201.7 Miles (90% highway)
5.54 gallons
36.4 MPG

SLP cat back
DDM/Solo second cat delete
upper grill blocked ( was to help with a coolant temp issue I was having earlier)
17" LTZ wheels
225/45/17 Falken Ziex 512 tires
Trifecta tune (no log and update yet)

This was done at 60 MPH
outside air temps ranged from 32-43
IAT ranged from 39-45

Not pleased with the number. I wonder just how much the 17s and wider rubber are hurting the numbers.

 

[GeneralZod]

Not pleased with the number. I wonder just how much the 17s and wider rubber are hurting the numbers.

It does make a differnce, a big one.

Those temps don't help. Try it when over 45 and it can jump 2 mpg.

Also, a short test like that is not a good indicator.

 

[mitdr774]

I used the same pump and filling technique for the past 20 some fill ups. its good enough to be close.

 

[GeneralZod]

I may have missed a joke there, but I was talking about the fuel rates the engine uses at those temps, and the other factors associated with it.


Nice to see another OCD pump freak.

 

[mitdr774]

Imay repeat with the 15s to get a better idea of the loss associated with the 17s. They are heavier and have more rubber on the ground, but is it that much of a loss?? Winter blend blows.

The gas station employees know what pump I use.

 

[GeneralZod]

I mapped out the mpg with the temps around here somewhere. I think it was this thread. When you drive under 35F the mpg takes a dump.

 

[mitdr774]

I know it drops off quick, but I still think the 17s hurt more than I would like them to.

 

[GeneralZod]

I know it drops off quick, but I still think the 17s hurt more than I would like them to.

Oh yeah, they do...

 

[mitdr774]

Maybe the Z24 16s will be better when I get new rubber for them and adapters. Once the car is lower (for improved aerodynamics and better economy of course ) I will measure to see if the wheels and tires will clear before ordering adapters.

From what I recall the 95-99 Z wheels are about 17#. Debating using a 205/55 or looking for a 195/60.

 

[GeneralZod]

The 195s are the way to go... They just won't have the look you want. That is why they make LRR tires for larger rims. I find most LRR tires to be unsafe. My Jetta had them OEM. When I changed tires I when with the Primacy greenline. They are hybrids. Great tire, no spin outs in a dusting of snow. No loss of traction in rain. More surprisingly, there was no loss in mpg.

Just some things to think about. Engineering is all about pros and cons, or innovating to deflect the costs. You might have to find the right rim with the right tire.

Personally, I am waiting for some Eco rims to be sold for a decent price.

 

[mitdr774]

I have at least 3 sets of Z24 wheels (95-99 and 00-02 style) and a set of aftermarket Discount special 15s in 5x100 to choose from. I dont think I will loose to much by running the 205/55 tires, but they currenty have 225/50/16 Falken Azenis 615 tires mounted on them. 195/60/16 is proving to be hard to find for a reasonable price compared to 205/55/16.

I was going to try and get Eco wheels, but they rarely pop up and they go for a premium still. The 16" wheels will also offer a slightly softer ride. That will be nice on long trips.

 

[Natesriv]

If only

I'm still averaging 30-31 mpg... but I love pushing the reset while on the highway at steady state:

Kansas City is ringed by I-435. I plan on doing that highway loop and hypermiling it to see if 40+ can be done (by me)...

 

[Turbo Lover]

Yeah for highway mileage the diameter of the tire is just as important as overall wheel weight. But in the city there is no doubt that a smaller, lighter wheel is going to be more fuel efficient. This is one reason I didn't find the LTZ all that desirable. The wheels they put on that car would lower the MPG, and the Hankooks put on the base are adequate for DD use IMHO.

 

[joe truck driver]

gas coming back

last fill up 39.9 ACTUAL. high point of 51.6 on gauge after 30 miles on expressway. start up next day lose 7 by end of side street and down to 45 on expressway leg 2. by 4th leg, down to 42 and up to 43 at fill up at finish leg 6(39.9 actually).

heard tune bypass will void warranty but new air intake will not. any truth to this?? :blankface:

 

[mitdr774]

Yeah for highway mileage the diameter of the tire is just as important as overall wheel weight. But in the city there is no doubt that a smaller, lighter wheel is going to be more fuel efficient. This is one reason I didn't find the LTZ all that desirable. The wheels they put on that car would lower the MPG, and the Hankooks put on the base are adequate for DD use IMHO.

The tire sizes I am looking at are very close in diameter. I knew that economy would be lower with the 17s compared to the stock 15s and 195/65/15 tires. The 17s just look so much better than the 15s and I do like to corner quick. For my track visit to see the patheticlly slow 17 second pass I will probably use the 15s. My next night time economy test should show the difference between the wheel/tire combinations. I will have to do it soon to keep the temperature factor down to a minimum.

 

[GeneralZod]

The tire sizes I am looking at are very close in diameter. I knew that economy would be lower with the 17s compared to the stock 15s and 195/65/15 tires. The 17s just look so much better than the 15s and I do like to corner quick. For my track visit to see the patheticlly slow 17 second pass I will probably use the 15s. My next night time economy test should show the difference between the wheel/tire combinations. I will have to do it soon to keep the temperature factor down to a minimum.

The 205/55/16 will offer the most benefits and most options. Don't forget the option of using a steel wheel with a solid hubcap. They make for good daily driving and use the rims for the track.

 

[mitdr774]

I wish my 14" wheels would clear the front brakes. Factory wheel that weighs 13 pounds.

Cost wise 205 would be a fair bit cheaper. the 195 just seems to be a bastard size and not many options.

 

[Turbo Lover]

This car sucks, I want a refund

 

[firstorbit84]

Don't rev it