A4 question

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Jan 23, 2004 | 05:35 PM

CORTVET

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From: Putting a 50¢ sticker of the U.S. Flag on a $50,000 import does not make one a patriot.

A4 question

With an A4 and 3.42's, what gear would be closer to 1:1? 3rd or 4th?

Thanks,

AZC5

Jan 23, 2004 | 05:49 PM

OldSStroker

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Re: A4 question (AZC5)

In a 4L60, 3rd is always 1:1. Rear gear has nothing to do with the transmission.

1st = 3.06
2nd = 1.63
3rd = 1.00
4th = 0.70

If what you are asking is total final drive ratio:

With 2.73 rear, 3rd is 2.73 and 4th is 1.91
With 3.15 rear, 3rd is 3.15 and 4th is 2.21
With 3.42 rear, 3rd is 3.42 and 4th is 2.39
With 3.73 rear, 3rd is 3.73 and 4th is 2.61 which is close to 3rd with a 2.73.

[Modified by OldSStroker, 11:16 PM 1/23/2004]

Jan 23, 2004 | 05:51 PM

tomdcarguy

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Re: A4 question (AZC5)

3rd gear is 1:1 in all A4s... no matter what rear you have.

Jan 23, 2004 | 06:00 PM

CORTVET

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From: Putting a 50¢ sticker of the U.S. Flag on a $50,000 import does not make one a patriot.

Re: A4 question (OldSStroker)

Yes, I was looking for final ratios. Thank you. Ever since my switch from 2.73's to 3.42's my dyno readings are screwy. I was wondering if dynoing it at 4th would show a more accurate reading.

Thanks for the help,

AZC5

Jan 23, 2004 | 06:15 PM

OldSStroker

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Re: A4 question (AZC5)

Quote:

With more gear your car accelerates faster so there are more inertia losses, and you might see a little less power on a chassis dyno. If you could lock it in 4th and pull from about 2500 you might see good results, but you can't. It probably drops to 4200-4400 after the 3-4 shift (depending on converter). That's aboiut 130 mph with 3.42's isn't it? If you finish the pull in 4th you'll be over 180. Your dyno guy might not like that. Make sure your tires are pumped up well. I've seen 200 on a chassis dyno and it's not easy on the tires.

It would be nice to see about 6-7 seconds for the engine to pull from 4000 to 6000. That would be about 300 rpm per second, which is a popular engine dyno acceleration. I'll bet the Dynojet is quicker than that in 3rd.