3.55 limited slip mpg??

V6/AT/3.55, 525 miles, 50% hwy/50% city, 100% Sport mode = *gasp* 17 mpg. That's GT mileage!

I am hoping this goes up after break-in. Or, I could cut back on the Sport mode...Nahhh...

icarumba said:

V6/AT/3.55, 525 miles, 50% hwy/50% city, 100% Sport mode = *gasp* 17 mpg. That's GT mileage!

I am hoping this goes up after break-in. Or, I could cut back on the Sport mode...Nahhh...

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Sport mode locks out 6th so it is either cut back on the sport mode or accept GT milage! lol

zackmd1 said:

Sport mode locks out 6th so it is either cut back on the sport mode or accept GT milage! lol

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I thought that might be the case, so I tried slipping into it into D at cruising speed at 70 mph on the interstate, but the RPMs didn't drop. I'll have to explore this further. WOO HOO! Another reason to take a drive!!!

icarumba said:

I thought that might be the case, so I tried slipping into it into D at cruising speed at 70 mph on the interstate, but the RPMs didn't drop. I'll have to explore this further. WOO HOO! Another reason to take a drive!!!

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Try driving in regular D mode to get the eco 6th when cruising gear as Zack said. Out of curiosity, approximately what RPM do you see at 70 mph?

Reaper said:

Try driving in regular D mode to get the eco 6th when cruising gear as Zack said. Out of curiosity, approximately what RPM do you see at 70 mph?

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I will try that, thanks. I believe it was around 2200, but I'll need to verify

I get 17 with 3.15s...granted that's all "city" with the lovely hills of the Texas hill country...and a heavy foot lol when I do get on the highway it bounces between 28-32 depending on which direction I'm going on the hills lol


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Reaper said:

Try driving in regular D mode to get the eco 6th when cruising gear as Zack said. Out of curiosity, approximately what RPM do you see at 70 mph?

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I had a chance to do this tonight.

V6/AT/3.55:

6th gear, Drive mode @ 70 mph = 2200 rpm
6th gear, Sport mode @ 70 mph = 2200 rpm
6th gear, Drive mode @ 65 mph = 2000 rpm
6th gear, Sport mode @ 65 mph = 2000 rpm

There was no difference between Sport mode and Drive mode at either 65 or 70 mph. At both speeds, I went from D to S and then S to D; the tach needle didn't move a hair.

In both D and S modes, and at both speeds, I flipped the right paddle, and got a flashing "6" to indicate I was already in 6th gear.
In both D and S modes, and at both speeds, I flipped the left paddle, got a "5", and the rpms went up.
In Sport mode, at both speeds, in 5th gear, I flipped the right paddle, a "6" appeared, and the rpms dropped.

3.55 mpg

On road trips I avg 30-32 I'm pretty much bone stock I only have flowmaster 40 series and x pipe I only run 5-20w Royal purple with k&n oil filter with k&n drop in air filter. I drive 150-200 miles a day. I've avg over entire 77000 miles 23.4mpg that's every hard acceleration and donuts so I really can't complain about mpg from this car it's great for gas for what it can do. I've only had it since Oct 28th 2015

I'm Manual as well

just think of the fun we could have if the EPA went bye bye one can only hope

markbento said:

just think of the fun we could have if the EPA went bye bye one can only hope

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I dunno, I kind of enjoy clean air and water....

I've got a V6 manual with 3.15 gears and am considering 3.55s. Based on what I read here it doesn't seem like too much of a hit to mileage. My driving is about 50/50 between town and highway.

Can someone with a manual and 3.55s tell me what their RPM is at 70? With my setup its about 1,800 rpms. Any idea what sort of difference in mileage, on average, between the 3.15 and 3.55 gears?

https://1drv.ms/x/s!AkFoSc-wigxciEFcr0_3xlqVmW1j

The above link is a spread sheet that is an rpm calculator rear end