3.91 in A6 auto scale correct?

I found auto scale can be wrong or I'm missing something.
Why in stock file current gear ratio is different than calculated?
let's say 2004 corvette, I belive there is 3.42 installed, stock values:

Mile 31*027
rev-trans 12.6836
ratio 3.42
trans rev 2446

calculator says
current: 26 and 3.42
calculated 26 and 3.15

When I enter new as current, so 26 and 3.42, then he rescales speed and
rev-trans 11.6953
trans rev 2652

When I enter new as calculated so 26 and 3.15 then nothing is changed in tune except ratio that is changed to 3.15.

If I type similar data in Bluecat software, I get speeds close to 3.15 and they are similar to this from factory tune.

Could be that in tune factory speeds are not adjusted? Or they don't need to be adjusted because if only ratio is changed he calculates it self?

Looks like your working on an A4. The calculated 3.15 is correct, as the A4 either had a 2.73 or a 3.15 gear ratio. I don't know why GM set it up that way.

Russ Kemp

Thanks for answer.
I didn't want to create separate thread for this, so asked here.

Then looks gear ratio field is informational only and not used by PCM.

Quote:

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Originally Posted by Russ K

The auto scale is correct. 3.45/3.91=.8849x113=99.99

Russ Kemp

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Russ,
Im just curious for a learning moment, what's the number 113 used for in your equation?

Quote:

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Originally Posted by Phil'sC5Vette

Russ,
Im just curious for a learning moment, what's the number 113 used for in your equation?

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113 was the OP's 4-5 shift MPH with the 3.45 gears.

Russ Kemp

Maggie TVS1900 going on this spring. Gonna see how long I can handle the 3.91's with the boost, but I've had some suspension work since I last checked in.

BMR Super Pro cradle kit
BMR trailing arms
BMR adjustable toe rods
BC coilovers
New 285/35/19's out back for the street and same Hoosiers for the track

Everyone is telling me I'm crazy but I yet to find anyone chime in with their experience with tuning this setup.

I'm going to a whole new shop this spring to have the tune completely started over from scratch and will update this thread then.

Help! Top speed...shift denied 5th -> 6th!

I installed GM 3.91 gears kit on my 2010 Camaro L99 A6 (6L80) and I recalibrated my tune with hp tuners with the gire/tyre wizard.
Stock tyre 27,79 (no change)
gear ratio 3.27 -> 3.91
--------------------------
multiplier = 0,836

I try top speed (German autobahn) but I cannot shift 5th->6th (DIC shift denied) and the car comes to rev limiter 5900 rpm (approximately 228 km/h = 141 mph).

which tables should i pay attention to?

attached my tune.