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1.6 td engine - Modify 020 ACN trans for lower rpm highway cruising?
by
punkvideo81
on 28 Jun, 2012 12:26
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Has anyone taken their 1.6 turbo diesel's ACN (or other) trans and modded the 5th gear for lower rpm highway cruising? .71 is okay, but I want to cruise the highway at 75-80mph without the engine @3500rpm. What does it entail to swap in a better 5th gear? Anyone done it? I think giulianot on here had a .65 in his, and I've tried to IM him about it to no avail. Your help is appreciated. Thanks!
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#1
by
R.O.R-2.0
on 28 Jun, 2012 12:35
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Has anyone taken their 1.6 turbo diesel's ACN (or other) trans and modded the 5th gear for lower rpm highway cruising? .71 is okay, but I want to cruise the highway at 75-80mph without the engine @3500rpm. What does it entail to swap in a better 5th gear? Anyone done it? I think giulianot on here had a .65 in his, and I've tried to IM him about it to no avail. Your help is appreciated. Thanks!
.71 is the HIGHEST 5th gear that you can get your hands on cheaply.. there are a couple other REALLY RARE higher geared 5th gears, but they are SUPER RARE, and usually cost as much for the gear set, as you would pay for a trans that is tougher with better ratios..
TDI trannies have like 3.16 r&p, and .62? 5th gears..
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#2
by
punkvideo81
on 28 Jun, 2012 12:50
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I also have a spare FN trans. So, where would I begin to look to find the gearset, and what do you think it might run me?
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#3
by
CrazyAndy
on 28 Jun, 2012 20:14
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Has anyone taken their 1.6 turbo diesel's ACN (or other) trans and modded the 5th gear for lower rpm highway cruising? .71 is okay, but I want to cruise the highway at 75-80mph without the engine @3500rpm. What does it entail to swap in a better 5th gear? Anyone done it? I think giulianot on here had a .65 in his, and I've tried to IM him about it to no avail. Your help is appreciated. Thanks!
.71 is the HIGHEST 5th gear that you can get your hands on cheaply.. there are a couple other REALLY RARE higher geared 5th gears, but they are SUPER RARE, and usually cost as much for the gear set, as you would pay for a trans that is tougher with better ratios..
TDI trannies have like 3.16 r&p, and .62? 5th gears..
The trans you're talking about is the CTN/CHU trans from B3/B4 TDI/VR6 Passats. It has a R&P of 3.157 and a 0.756 5th gear, which equal 2392 RPMs @70mph when assuming stock 185/65/14 wheels on a mk2. However, it's a 02A cable shift/ hydro clutch trans, and while rod shift and cable clutch options and conversions are out there it's a bit of money. You can run the shift cable box, but be prepared to do some cutting to your firewall to get the cables in. You also don't come across a CTN or CHU every day.
Back to the 020, a 0.71 5th in a ACN nets you about 2612RPMs @70 assuming above tire sizes. Your stock 5th in a ACN is 0.75, which is 2759RPMs w/ same speed and tire size. That's 147 RPMs of differenece, not much noticability. Any other super rare high 5ths are be worth more than the trans you're putting them in, as R.O.R. said. That's if you CAN find them . . . .
punkvideo's FN will do 2769RPMs under the same numbers; that's a hair MORE than your stock ratio combo. Not to knock his offer, but It won't net you any noticeable difference.
ADHD version (sorry for the excessive info drop): You're only inches away from the 020's cruising cear 'ceiling'. If you want to install a 0.71 in your ACD, that would be the best option, but you're looking at a small RPM difference. Any lower that that, then look to the 02A trans, which is pricey to acquire, but doable in a Mk2 given the correct parts.
Sorry if my post sounds discouraging, but I'm just trying to lay the info out in a factual manner. In the end, it's your car and your transmission. If you wanna just put a 0.71 in, hunt down a hens-tooth low 020 5th, or go 02A swap crazy, be sure it's the choice you'll think YOU will enjoy. So enjoy your car and happy gearing!
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#4
by
theman53
on 28 Jun, 2012 20:27
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I do not know how interchangable stuff is from 020, 02a, and 02j...They make a .685 gear for my 02j TDI trans, maybe something like that could be adapted to fit an 020?
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#5
by
bbob203
on 28 Jun, 2012 20:30
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I do not know how interchangable stuff is from 020, 02a, and 02j...They make a .685 gear for my 02j TDI trans, maybe something like that could be adapted to fit an 020?
what about these amish folks you know?
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#6
by
CrazyAndy
on 28 Jun, 2012 21:19
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I do not know how interchangable stuff is from 020, 02a, and 02j...They make a .685 gear for my 02j TDI trans, maybe something like that could be adapted to fit an 020?
what about these amish folks you know?
Didn't know that even amish folks know VW stuff.
And no you can't change 02a/02j stuff into 020. The splines and shaft diameters are different, as is the 5th gear synchro assembly. Also the bolts are secures a little differently. Basically EVERYTHING is different.
Gonna get me a 0.681 5th myself; that way I can cruise at around 2700 @ 70 mph with the shorter wheel/tire combo I want in the future. Tried finding good used 0.717 but no dice; too rare for anyone to either have at regular intervals or have a reasonable asking price.
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#7
by
punkvideo81
on 28 Jun, 2012 23:15
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Thanks for all the info! Just to set the record straight, the car is an 81 rabbit pickup, not a mk2. Maybe I will pop out the ACN currently bolted to the '91 1.6td and throw in the spare FN I have. I was hoping that maybe someone out there had (or made) a smaller 5th gear that I could simply buy and have installed. Too bad. I do a lot of highway driving in my pickup, and just wanted to have a better 5th gear for quieter and more fuel efficient cruising at 75+mph. If anyone out there has this elusive .65 for an 020, get in touch. Thanks.
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#8
by
theman53
on 29 Jun, 2012 04:47
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The only thing you could do then is buy that high dollar ring and pinion that GEE BEE did. That and the .71 fifth would get you lower rpm.
I did a 3.42 with / .71 ff final
Dont ask what I paid for the 3.42 new set....
Later...
GB
^ that is what he posted in the other section here.
Also, the amish machine shop guys around here can and will make you anything if you have the money. Most machine shops, and they as well, want multiple piece lots of stuff to do. But these guys will make you one piece and charge a fair ammount, not something super inflated. If I had a 5th set and wanted them to make me another, the one guy would do it. I have no idea how much it would cost, but I know if I needed 1 set, he would do it. Then the real money would come in the heat treat and then taking it to the cryo lady, as they are not the amish and don't do well with one piece.
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#9
by
flowmastergfunk
on 29 Jun, 2012 08:46
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I bought a spare 0.71 set off ebay last year to replace my busted acn. Come to find out, the pinion shaft was stripped and the old gear was welded on. Now I have that AND a 0.71 FF but still don't have anything to put in my project! I am hoping to find a decent ACN or something of the like this weekend at the junkyard. I thought that the third, fourth and fifth from my FF would go well with a 3.67 but that 3.42 final drive sounds heavenly!
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#10
by
punkvideo81
on 29 Jun, 2012 15:45
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Thanks for all the info. I guess I'll track down Gee Bee and see what he has to say.
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#11
by
CrazyAndy
on 29 Jun, 2012 15:53
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I guess when you think about it the lower RB is the best solution; none of the gears will feel too spaced otu with it, and you'll be able to go faster and cruise at lower RPM's. The big downside is that you'll have to split the case and pull it all apart to get to the gears onto the new pinion shaft and the new ring on the diff. Don't forget the hardened diff bolt upgrade. Oh, and Brokevw.com has great disassembly pics!
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#12
by
punkvideo81
on 29 Jun, 2012 16:22
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Thanks, I checked out brokevw (lots of good info there!) and also found that Gee Bee got his trans from
http://vwtransaxles.com/, so I will look into it and see what I can afford to do.
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#13
by
theman53
on 29 Jun, 2012 16:33
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If it is a trans at or pre 84-85 ish the rivots are OK, this comes from Brokevw not me. What I would do is leave the FF rivots alone if you are going to do one do the later trans OR contact brokevw for a spare carrier that has them drilled and removed already. He has a bunch of parts usually and is willing to sell them to help fellows like us out.
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#14
by
CrazyAndy
on 29 Jun, 2012 17:48
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Yeah I agree w/ theman on that 100%, pick up a good diff middle, put the ring on it and put it in the ACN. Bam, 0.71 5th and gear ratios that work together well instead of something like 4+E. Don't be afraid to ask broke, he's an agreeable dude from what I hear.