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-   -   Planning a tranny swap. (http://www.fuelly.com/forums/f12/planning-a-tranny-swap-4262.html)

northboundtrain 04-12-2007 11:28 AM

Planning a tranny swap.
 
I have the 020 AWY tranny in my Jetta. Fifth gear has a 0.894 ratio, and the R&P is 3.941. This gives a 3.523 overall ratio. With 22" tires that means I'm doing 3,770 rpm at 70 mph, which is way too high for this engine. In fifth gear, the sweet spot seems to be about 50 mph, which is about 2,700 rpm.

If I take a tranny out of an 8 valve gasser of the same vintage (A2), then I'll have a 0.745 fifth and a 3.667 R&P, with an overall ratio of 2.732 This means that at 2,700 rpm I'll be able to cruise at about 65 mph.

I'm planning on going to the junk yard the next free day I have. I'll probably get the tranny rebuilt, so it will be a little while before I have it installed, but I'll report back when I do.

BeeUU 04-13-2007 06:37 AM

Quote:

Originally Posted by northboundtrain (Post 47329)
I have the 020 AWY tranny in my Jetta. Fifth gear has a 0.894 ratio, and the R&P is 3.941. This gives a 3.523 overall ratio. With 22" tires that means I'm doing 3,770 rpm at 70 mph, which is way too high for this engine. In fifth gear, the sweet spot seems to be about 50 mph, which is about 2,700 rpm.

If I take a tranny out of an 8 valve gasser of the same vintage (A2), then I'll have a 0.745 fifth and a 3.667 R&P, with an overall ratio of 2.732 This means that at 2,700 rpm I'll be able to cruise at about 65 mph.

I'm planning on going to the junk yard the next free day I have. I'll probably get the tranny rebuilt, so it will be a little while before I have it installed, but I'll report back when I do.

Have a look at http://www.techtonicstuning.com/trannyratios.asp, I think this will help you find a good transmission.

northboundtrain 04-13-2007 07:14 PM

Yup, the 1.8L 8v trannys are what I want.

trebuchet03 04-13-2007 07:36 PM

Have you considered doing a 5th gear swap? rather than swap a whole tranny?


http://www.driversfound.com/scirocco...earconversion/
http://forums.vwvortex.com/zerothread?id=2246118

If I had the money, I'd be swapping my Jetta's 5th with a TDI 5th :)

You'll have to do some research as far as part numbers (I've seen kits around) and dates and such to make sure it can be done (cost effectively) to you're year. I know my 02a can be converted (as low as .68xx) without even pulling the tranny out of the car :thumbup:

omgwtfbyobbq 04-13-2007 09:28 PM

020's are so cheap, it's better overall to just get an entirely new tranny and sell the old one. Especially considering northboundtrain would probably get more for the AWY than the new taller geared trans would cost. To the OP, just make sure the gearing isn't too tall. I have a GP w/ 13" tires, and imo a few hundred rpm more would be a nice trade off for some more power on the highway. With the ratio you listed, you'll drop ~300rpm below where I'm at right now, provided my calcs/assumptions are correct. I think something in between would be better. No need to spend too much time in 4th if we don't have to imo. :thumbup:

lovemysan 04-14-2007 12:37 PM

Quote:

Originally Posted by BeeUU (Post 47399)
Have a look at http://www.techtonicstuning.com/trannyratios.asp, I think this will help you find a good transmission.

Beeuu

Would the 5th gear swap guide I sent you apply to this transmission it seemed fairly painless.

BeeUU 04-24-2007 09:48 AM

Quote:

Originally Posted by lovemysan (Post 47530)
Beeuu

Would the 5th gear swap guide I sent you apply to this transmission it seemed fairly painless.

Yep, I did not mention it because I had the impression that northbound was looking for the entire unit.

But northbound have a look at this link for a 5th gear swap if you are interested: http://www.rpi.edu/~carabd/gearswap.pdf

Thanks to lovemysan for that valuable link!! :cool:

northboundtrain 04-28-2007 06:05 AM

I'm planning to swap the entire tranny for several reasons: first, I need a taller ring and pinion gear. Second, my tranny is leaking and needs the seals replaced, Third, I'd like to have a more equal spread of the gears rather than close ratio 1st through 4th and then a big step up to a taller overdrive.


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