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Gearing: how tall is too tall?
by
overdrivegear
on 22 Dec, 2009 13:14
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I'm currently running an AGS (3.94) 3.45 1.94 1.29 0.91 0.71 transmission with the modified 0.71 fifth gear in my 1.6 NA (CR). I currently get 50 MPG (standard) and have well enough torque to pull most hills. A buddy of mine has a 9A trans (3.67) 3.45 2.12 1.44 1.13 0.71 with a 0.71 fifth in his 1.6 NA Jetta designed for super interstate cruising although the fuel economy is not improved over my gearing.
My question is what do most of your turbo fans have for gearing and are there many other NA fans out there that have totally sacrificed all of their torque for lower RPMs?
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#1
by
moTthediesel
on 22 Dec, 2009 14:47
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Well, I don't know how relevant it will be to your situation, but I just had Rancho build a new trany for my Turbo Tub. The stock gasser gears that were in the old Porsche box were way too short for the built 1.6 TD engine that we have in the car now. With that box 70 mph required 3600, now that same speed will need only about 2300. After much deliberation, we went with 3.78/2.06/1.21/0.7 with a 3.44 r&p. That may seem pretty tall, but this car only weighs 2000# and is very aerodynamic. We'll see how it works when it comes back out of the shop in the spring.
Here's the gear chart, the black lines are the original ratios, the yellow is what we have now --
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#2
by
Doakster
on 22 Dec, 2009 15:17
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I myself have an the original AVX trans in my ECO, but the R&P is swapped out to a 3.94, so the gear is the following:
3.45 1.94 1.29 0.91 0.75 w/3.94 R&P (which is the same gearing as an AGS)
I just swapped in a Giles IP, and the car now pulls fairly strong in all gears, in my opinion before the IP swap in stock ECO form and stock AVX gearing (4.25 R&P) the car was a dog, after the 3.94 R&P swap the car was even more of a dog, but picked up great power after the Giles pump went in.
Personally I like the gearing and power it has now, and the only other thing I might do is swap in a .71 fifth gear.
I would never consider going to a 3.67 R&P, because i think that would be too much a jump and make the car feel like it's in stock ECO form again.
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#3
by
rabbitman
on 22 Dec, 2009 15:24
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I have a FN with 3.89 R&P and a .71 5th. 70mph is 3000rpm, I wouldn't mind a bit higher 5th but head winds and slight hills would require down shifting.
Seems like much a much faster R&P would really kill 1st gear, for what I do I'd like an even lower 1st......
1.6na
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#4
by
maxfax
on 22 Dec, 2009 15:33
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I've been though several trannies now on my N/A Bunny
I started with a 4A 3.45 1.75 1.6 .70 and a 3.94 Final.. It was horrid on mountains.. IT was either lug it in 3rd or scream it in 2nd...
Then I swapped in an FF 3.45 1.94 1.29 .97 .76 and a 3.89 Final.. Much better having that extra gear, and the milage didn;t really change noticably..
After the FF exploded I went with an ACH 3.45 1.94 1.37 1.03 .75 and a 3.94 final... Perfection! For my particular drive which is mostly 2 lane and a mountain it's prefect. I rarely have to downshift, I can pull the mountain in high gear and maintain 45mph.. My mpg's actually increased with this.. I suspect because I'm not screaming the crap out of it in a lower gear all the time...
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#5
by
burn_your_money
on 22 Dec, 2009 17:50
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My 91 Golf has seen it's share of trannys and engines.
It started out with a bagged out 1.6 NA with a Giles pump
I had a AWY (basically the same as the 4k)
3.45 1.94 1.44 1.13 0.89 final 3.94
This transmission was fantastic around town but as soon as I got on the highway it was screaming for mercy.
Then I swapped in an AGS
3.45 1.94 1.29 0.91 0.75 final 3.94
This one was ok. Around town felt a little slow and the revs still felt like they could be lower on the highway
The AGS blew up on me so I swapped in a 1.9 NA with a Giles pump and a ACN gearbox
3.45 1.94 1.37 1.03 0.75 final 3.67
Acceleration is good, but I still find 5th too short. I've thought about dropping in a 0.71 but I don't think that is going to happen.
I do plan on swapping in a CTN which is an 02A gearbox.
3.778 2.118 1.360 0.971 0.756 Final 3.157
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#6
by
overdrivegear
on 23 Dec, 2009 05:54
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...After the FF exploded I went with an ACH 3.45 1.94 1.37 1.03 .75 and a 3.94 final... Perfection! For my particular drive which is mostly 2 lane and a mountain it's prefect. I rarely have to downshift, I can pull the mountain in high gear and maintain 45mph.. My mpg's actually increased with this.. I suspect because I'm not screaming the crap out of it in a lower gear all the time...
I have an ACH which came stock in my 85 Westy Golf and gears 1-3 are pretty good for acceleration but I've found that the jump from 4th at 1.03 to fifth (0.71 in my case) is not good for pulling mountains. I go across the Appalachian mountains frequently and it just seems like you need something in between. That's why I'm going to an AGS with the 0.91 4th and the same 3.94 R&P as the ACH.
My ideal gearing would be a CHD or a DFP although my old 81 Rabbit had an FF (3.89), 3.45,1.94,1.29 ,0.91,0.71 and it was really nice. Especially for a very light car.
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#7
by
VelocityConservation
on 23 Dec, 2009 07:02
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I started out with a AWY tranny.
3.45, 1.94, 1.44, 1.13, .89, final 3.94. Great around town, but with today's highway speed limits it was a screaming nightmare. I basically quit using the car if I had any real highway in the trip. Fortunately my daily commute was all back roads.
I then had a FF built into a MK2 case.
3.45, 1.94, 1.29, .91, .80 final 3.89. This was better on highways and delivered better mileage on my standard commute than the AWY, but still not good enough on the highways. (note: yes I know that the FF should have had a .76 or .71 5th to begin with but the at the time the price was right).
Most recently I put a .71 5th in to my FF. Love the highway RPM's. This is a very good compromise. It's single downfall is the HUGE jump from 4th to 5th.
If I build another tranny for it I will build something along the lines of an AGS with the .71 5th added.
AGS = 3.45, 1.94, 1.29, .91, .75, final 3.67.
I have a 1.6TD with a k24 putting out 13-15psi. and a custom downpipe so I am making more power than stock.
Good luck,
VelocityConservation
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#8
by
overdrivegear
on 23 Dec, 2009 08:20
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If I build another tranny for it I will build something along the lines of an AGS with the .71 5th added.
AGS = 3.45, 1.94, 1.29, .91, .75, final 3.67.
I've actually thought about swapping my 3.94:1 final drive to a 3.67:1. How big of a deal is that? Clearly you have to totally take a transmission apart, but as far as making the parts work, is it all plug n play?
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#9
by
VelocityConservation
on 23 Dec, 2009 08:53
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OverdriveGear,
Let me clarify. I paid a reputable rebuilder to put the FF internals into my A2 case.
Then I personally, using BrokeVW's guidance, installed the .71 5th gear. The 5th gear is located in its own housing (VW took their 4spd and added a 5th).
Although I had great success installing the 5th gear and have built close to a dozen different motors I think I would still pay for an experienced and reputable transmission rebuilder to tackle anything inside the main case.
With that said, as far as I can tell with 020 transmissions it is plug-n-play. The best resource I have found on this is
www.brokevw.com.
Good luck,
VelocityConservation
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#10
by
Rabbit on Roids
on 23 Dec, 2009 09:52
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i had a GC 4 speed first. that was retarded. 83 mph on the governor up hill, down hill, whatever.
then i swapped in an AUG out of a 92 jetta. its really nice for accel and cruisin around town, but it screams at 70.
then i swapped in a 9A, pretty much the same trans, but with a different 2nd gear. reverse exploded.
now im rollin with a AGS 5 speed out of an econo box 86 jetta. 3.67 r&p with a .75 fifth. im pretty happy for now. dont want to sacrifice too much acceleration, still wanna rip when i need to. it turns about 2300 at 60 if i remember right. the old 9A and AUG both turned 3k at 60mph. i think this tranny will be just fine for me, until i explode it or shear off all the rivets.
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#11
by
Doakster
on 23 Dec, 2009 15:31
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OverdriveGear,
Let me clarify. I paid a reputable rebuilder to put the FF internals into my A2 case.
Then I personally, using BrokeVW's guidance, installed the .71 5th gear. The 5th gear is located in its own housing (VW took their 4spd and added a 5th).
Although I had great success installing the 5th gear and have built close to a dozen different motors I think I would still pay for an experienced and reputable transmission rebuilder to tackle anything inside the main case.
With that said, as far as I can tell with 020 transmissions it is plug-n-play. The best resource I have found on this is www.brokevw.com.
Good luck,
VelocityConservation
I would agree with this, I went to a small time guy that has been building VW race engines and trans for 25 plus years, i got to help/watch him rebuild the trans. Only cost me $350 which included a used 3.94 R&P. I still would probably take it to him again if I need work.
The R&Ps are plug and play, but you will need to get an ARP diff bolt kit (can be found a variety of places), the R&P is held on to the differential with rivets when installed from VW, you have to grind off the rivets and use the bolt kit when installing a R&P.