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The car was stock. It seemed to be well kept other than blown struts and shocks. A Marine had it before me. When it mists or frosts you can see where the Marine logo was on the rear window. It pretty neat!
Haha.
That's pretty cool.... A "ghost" sticker! :)

Was just curious if maybe the car had a set of rear gears installed by a previous owner. It doesn't sound like it though.
The mystery continues....
 

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Discussion Starter #23
The car was stock. It seemed to be well kept other than blown struts and shocks. A Marine had it before me. When it mists or frosts you can see where the Marine logo was on the rear window. It pretty neat!
Haha.
That's pretty cool.... A "ghost" sticker!


Was just curious if maybe the car had a set of rear gears installed by a previous owner. It doesn't sound like it though.
The mystery continues....
How can I confirm what rear gears I have? I know how you can easily check with a manual but I don’t know how to with an automatic. People say the stock gears are weak but there are times when I punch it to pass someone that it feels REALLY fast!
 

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How can I confirm what rear gears I have? I know how you can easily check with a manual but I don’t know how to with an automatic. People say the stock gears are weak but there are times when I punch it to pass someone that it feels REALLY fast!
1. Jack the rear wheels off the ground.
2. Place a piece of tape on one of the tires, and another piece on the drive shaft so that you can see it while spinning the wheel.
3. Spin the wheel exactly one complete revolution while counting the number of revolutions of the drive shaft.

Be as accurate as possible.
If the drive shaft turns 3.5 times, the rear gear ratio is 3.55. If the drive shaft turns 3.75 times, the gear ratio is 3.73, and so on.

If the gear has been changed from stock, it would require that the tune reflects that change so that the speedometer will be accurate.
So, if you are the one that purchased the tune and tuner, and the ratio was changed from stock, you would have had to enter the correct gear ratio information into the tune, or your speedometer would be registering a higher than actual speed.
 

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Discussion Starter #26
How can I confirm what rear gears I have? I know how you can easily check with a manual but I don’t know how to with an automatic. People say the stock gears are weak but there are times when I punch it to pass someone that it feels REALLY fast!
1. Jack the rear wheels off the ground.
2. Place a piece of tape on one of the tires, and another piece on the drive shaft so that you can see it while spinning the wheel.
3. Spin the wheel exactly one complete revolution while counting the number of revolutions of the drive shaft.

Be as accurate as possible.
If the drive shaft turns 3.5 times, the rear gear ratio is 3.55. If the drive shaft turns 3.75 times, the gear ratio is 3.73, and so on.

If the gear has been changed from stock, it would require that the tune reflects that change so that the speedometer will be accurate.
So, if you are the one that purchased the tune and tuner, and the ratio was changed from stock, you would have had to enter the correct gear ratio information into the tune, or your speedometer would be registering a higher than actual speed.
Awesome thanks! Maybe my speedometer is off because I had 4 different people tailgate me today! OneBMW pulled up so close I could barely see the top of his windshield.
 

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I have a 2013 V6 coupe with numerous performance related mods (3.73 rear gears, Borla Stinger S axle back exhaust, BBK ceramic short tuned headers, ...) and have seen roughly the same 24 MPG on typical highway driving in Colorado - hills of various elevation change, windy curves, mixed in with pretty level straights. One item not discussed in this thread unless I missed something was fuel octane. I normally run 87 octane because I am cheap (actually my wife is cheap), do you who run premium 91 or better seen a large enough increase in MPG to justify the increase in price. Also, how does extreme altitude changes (like 5280 feet in Denver to around 10,000 feet in mountain passes) due to air density have on MPG?
Not cheap.... Frugal! :lol:
Actually, smart.
You don't need to use high octane fuel in naturally aspirated engines when they are being used at relatively high altitudes (5000+ ft). The engine management system will not allow the engine to perform well enough to be able to take advantage of the higher octane fuel. I.E. the computer will not advance the timing enough in the thinner air to necessitate the use of the slower burning high octane fuel. The only exception to this would be if the engine was tuned in Denver to specifically run on high octane.
With an engine that uses forced induction of some sort, it is a different story.... The engine doesn't know that it is at a high altitude breathing in thin air, due to it being compressed into the engine. So they can still take advantage of using higher octane fuel.
A couple of decades ago, before the proliferation of so many factory produced boosted engines, a person probably had to hunt around a bit, in the higher altitude places, in order to find premium gasoline, if they needed it for some reason.
Under normal driving conditions, it is my opinion that there would be absolutely no advantage to using higher octane fuel in regard to fuel efficiency. And, as I alluded to earlier, there is less energy in higher octane fuel, which could actually cause a slight loss of fuel economy, in many cases.
Mountain driving is mountain driving. With modern engine management systems, I don't think that you would see a huge difference in fuel economy whether at 1000 ft, or 10,000 ft.
 

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Awesome thanks! Maybe my speedometer is off because I had 4 different people tailgate me today! OneBMW pulled up so close I could barely see the top of his windshield.
No problem!

Please be safe while underneath your car. Chalk the front wheel, use jack stands, an old piece of lumber, a big rock.... anything that you have around to keep the car off of you in the event of a jack failure.

Keep us posted!
:thumb:
 

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Discussion Starter #31
Awesome thanks! Maybe my speedometer is off because I had 4 different people tailgate me today! OneBMW pulled up so close I could barely see the top of his windshield.
No problem!

Please be safe while underneath your car. Chalk the front wheel, use jack stands, an old piece of lumber, a big rock.... anything that you have around to keep the car off of you in the event of a jack failure.

Keep us posted!
Oh, I’ll definitely be careful! I’d rather over do safety than under do it.

I need to engage the parking brake, right? (Runs and hides while waiting on responses lol)
 

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Parking brake off. Transmission in neutral.
Those wheels will be off of the ground anyway, so you will need to block a front wheel.

I usually like to err on the side of safety, as well. After I get the vehicle onto jack stands, I will purposely shake it and see if I can knock it off the stands....If it's going to happen, better then, than when I'm underneath it!
 

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Discussion Starter #33
Their stock 2.73

I took it to a friends shop and he allowed me to put it up on a lift and check.
 

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My 14 manual gets up to 32 on pretty flat freeway going 65 MPH. On the city roads, 15-17 MPH.
I believe I have 2:73s in the back and all I have done to my car is muffler delete, air aid tube, and K&N drop in filter. I use cruise control on the freeway and it's about 35 miles one way trip. I change my oil every 5k miles or less and I run full synthetic oil and I use premium gas 91 octane.

---------- Post added at 10:03 AM ---------- Previous post was at 10:03 AM ----------

My 14 manual gets up to 32 on pretty flat freeway going 65 MPH. On the city roads, 15-17 MPH.
I believe I have 2:73s in the back and all I have done to my car is muffler delete, air aid tube, and K&N drop in filter. I use cruise control on the freeway and it's about 35 miles one way trip. I change my oil every 5k miles or less and I run full synthetic oil and I use premium gas 91 octane.
 

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My car with 2.73's would get 30 to 31 on I 40 (flat and straight), going 70 to 75 when it was stock. It has dropped to 26 - 28 with 2 73's, but with redone lowered suspension, shorty headers , MPT 93 octane performance tune, BBK, Air-raid, aluminum drive shaft, flowmaster 2's. I did all this before swapping the gears to force myself to do it before saving the best mod for last.
 

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I averaged around 26 MPG over 24,800 miles in my 2014, 3.7, MT82 with 2.73's and a Steeda CAI and 93 octane tune.

The picture shows 239.5 gallons of fuel used and 16,285.4 miles (the 1 gets cut off on the display) with an average of 26.2 MPG. The car was driven about 30/70% city/highway. Also taken to the drag strip a few times and had occasional trips to Mexico. Was not driven for MPG, just normal driving. Pretty impressive really.

 

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Discussion Starter #37
I averaged around 26 MPG over 24,800 miles in my 2014, 3.7, MT82 with 2.73's and a Steeda CAI and 93 octane tune.

The picture shows 239.5 gallons of fuel used and 16,285.4 miles (the 1 gets cut off on the display) with an average of 26.2 MPG. The car was driven about 30/70% city/highway. Also taken to the drag strip a few times and had occasional trips to Mexico. Was not driven for MPG, just normal driving. Pretty impressive really.

Wow, that’s nice! I think I fixed mine with changing the spark plugs. It feels better now and gets better gas mileage. I bet Mexico was fun!!😜
 
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