2012 a4 6spd manual vs 8spd tiptronic, 0-60

[AndyLien79]

Hello all,
the A4 specifications on www.audiusa.com shows that the 2012 A4 as follow:

Manual Tiptronic® Multitronic®

0-60 MPH 6.5 sec. 6.3 sec. 7.2 sec.

How is the 8 speed tiptronic faster? Is it a misprint? just curious :)

[gdawg'05a4]

The new 8 speed tiptronic changes gears very quickly, quicker than previous iterations of the 6 speed tip. Gear changes take 0.2 seconds (per ZF) and match DSG shift times per Audiusa.com for the S Tronic gearbox. Though I miss my 6-speed manual, the new auto gearboxes have gotten much better.

http://www.zf.com/corporate/en/produ...enjoyment.html

[AndyLien79]

Really? Interesting, I purchased a 2011 with the new 8 speed tiptronic and I thought it stated a 0-60 time of 6.6 seconds vs. the 6.4 with manual.
I wonder if they misprinted last year? haha

The new 8 speed tiptronic changes gears very quickly, quicker than previous iterations of the 6 speed tip. Gear changes take 0.2 seconds (per ZF) and match DSG shift times per Audiusa.com for the S Tronic gearbox. Though I miss my 6-speed manual, the new auto gearboxes have gotten much better.

http://www.zf.com/corporate/en/produ...enjoyment.html

[Stubek]

Check the gear ratios of the 8 speed. 1st gear is bigger than the 1st gear on the manual, then it shifts much quicker to second gear which is almost as big as the manual first gear

Man Tip
1 3.778 4.714
2 2.050 3.143
3 1.321 2.106
4 0.970 1.667
5 0.811 1.285
6 0.692 1.000
7 xxxx 0.839

[BMWBig6]

I still don't completely understand what Audi did with the 8-speed transmission, because I had a 2011 loaner for 2 days and it did NOT behave like I expected.

In my 2009 with 6-speed auto, I am turning 2500-2600 RPMs at 80 MPH. So if the first 6 cogs of the new 8-speed are identical to the 6 speed auto unit, then I should still be turning 2500-2600 RPM at 80 MPH when manually holding 6th gear. But that's not what I observed! It was around 3000 RPM. So was there also a corresponding change to the final drive ratio in cars with 8-speeds? Or is the transmission software showing its hand here?

For the record, I was turning around 2000 RPMs at 80 MPH with the 8-speed.

[gdawg'05a4]

Gear 6-speed 8-speed
1st 4.171 4.714
2nd 2.34 3.143
3rd 1.521 2.106
4th 1.143 1.667
5th 0.867 1.285
6th 0.691 1.000
7th ****** 0.8xx
8th ****** 0.6xx

Final 3.403 2.848

It's not identical to the 6-speed 6HP gearbox.

[B8_Jim]

Check the gear ratios of the 8 speed. 1st gear is bigger than the 1st gear on the manual, then it shifts much quicker to second gear which is almost as big as the manual first gear

Man Tip
1 3.778 4.714
2 2.050 3.143

That's only half the story - what is the final drive? You need the product of gear*final drive to compare. Plus I wouldn't trust these numbers (from audiusa.com/a4-sedan/detailed-specifications) farther than you can throw a tip equipped A4 - they only list 7 gears for the tip (is this S-tronic which we can't get in the US in the A4?) - but the final drive is listed as 2.848 which would mean 60 mph would require 3rd gear vs 2nd gear in the 6mt.

Other numbers I've seen show the new 8 speed using the same ratios as the 6 speed up until 6th and just adding 2 additional higher overdrive gears - but BMWBig6's info above seems to indicate that didn't happen...

So - bottom line - I wouldn't trust the #'s posted on Audiusa - from my experience they are often inaccurate.

[gdawg'05a4]

That's only half the story - what is the final drive? You need the product of gear*final drive to compare. Plus I wouldn't trust these numbers (from audiusa.com/a4-sedan/detailed-specifications) farther than you can throw a tip equipped A4 - they only list 7 gears for the tip (is this S-tronic which we can't get in the US in the A4?) - but the final drive is listed as 2.848 which would mean 60 mph would require 3rd gear vs 2nd gear in the 6mt.

Other numbers I've seen show the new 8 speed using the same ratios as the 6 speed up until 6th and just adding 2 additional higher overdrive gears - but BMWBig6's info above seems to indicate that didn't happen...

So - bottom line - I wouldn't trust the #'s posted on Audiusa - from my experience they are often inaccurate.

The gear ratios I posted, gears 1-6 are from Audiusa.com which matches ZF's PDF I have on the 8-speed 8HP gearbox. 7th is 0.8xx and 8th is 0.6xx.

http://www.1point8turbo.com/8HP/8HP.pdf (right-click Save As)

[B8_Jim]

The gear ratios I posted, gears 1-6 are from Audiusa.com which matches ZF's PDF I have on the 8-speed 8HP gearbox. 7th is 0.8xx and 8th is 0.6xx.

Sorry - I didn't see your #'s. I started my response, got distracted, and didn't finish until after you posted.

So for the numbers that matter - gear times final drive ratio - the 6MT has about a 4% gearing advantage in 1st, 18% disadvantage in 2nd (3rd is 23% disadvantage). The new tip has to shift to 3rd to get to 60 - but that 18% advantage in 2nd, quick shifts, and perhaps a brake torque launch could be 0.2 sec advantage. (?)