Taller 5th gear, where to get one

[Rabbit on Roids]

personally, i like the high ring&pinion with the low trans gears. but then again, i like shifting.

[Doakster]

Well fellas, I got another option.

Thanks to Ilikevwdiesel (Scott), i just talked to another local trans builder. Turns out he might have a AGS trans which i could have rebuilt, or I he's going to try and find a .71 fifth gear.

So these are my most logical options:

1. Swap my AVX out for an AGS, the way the builder described it was the car over all will be a little more sluggish, but I'll get a little lower RPM as a whole. And with the few build ups that i plan on doing to the motor it would be a pretty nice set up. I just ordered a 2.5 downpipe and exhaust from techtonics so that is going on when the trans goes back in. Rebuilt Giles injectors are going in and eventually a Giles IP.

2. Rebuild my AVX and install a .71 5th gear. There will be a noticeable jump between 4th and 5th on this one he said. I'll still do the same engine mods with this set up though. I'm actually leaning toward this set up because once the mods get done, i would think i should be able to pull through any bigger jump from 4th/5th with the added power.

Thoughts about either trans set up with the mods i'm going to do?

[Quantum TD]

If the costs are the same, I'd go with the AGS with a .71 5th.

[8v-of-fury]

Find a 4K or an AWY, then get a .71 5th and BOOM amazing trans.. You'll be able to keep the engine in the power band all through out the 4 in town gears (1st 2nd 3rd and 4th) and be able to keep the revs done, whilst near the torque band for highway economy and passing ability!

Assuming a tire size of 185/65/14 and the 3.94 Final drive with the .71 5th gear, you will be able to turn 2400 rpm's at 60 mph on the highway. Doing the limit and good economy however it will still make good power all the way up to 3500, which will put you near 87mph

You would have awesome power in town, and amazing cruising ability! I have the 4K in my Gasser right now with a tach, and i can turn 2300 in 4th in town doing 60 kph or roughly 36 mph. HOWEVER there will be a HUGE jump from fourth (1.13) to fifth (0.71) which isn't really a big deal.. means you just gotta take fourth to about 3500 rpm's or about 55mph. And then not shove it back down in to fourth on the highway EVER lol Really simple if you ask me.. It will make the diesel feel sporty in town for sure.

It's what I am going to do when I get my N/a in my car, put a .71 in my 4K

[8v-of-fury]

Yes the AGS with a .71 5th will be optimal.. it will be slow as all hell on an N/a you will feel like you are driving a RIG! lol

[overdrivegear]

Another questions for you fellas.

The AVX (ECO) has the following gears.

3.455/1.944/1.286/.909/.745  Final Drive 4.250


The AGS has the following gears.

3.455/1.944/1.286/.909/.745  Final Drive 3.941

So the only difference between the two is the final drive which will essentially still lower rpm over all but will have the same gearing between each gear, correct?

If you're interested, I have an ACH out of an 85 Jetta NA and an AGS out of an 86 Jetta NA.  And in my 85 Westy Golf I'm running an ACH-hybrid with the 0.71 fifth from an FF rabbit.  That gearing puts me at 2500 RPM at a *GPS confirmed* 60 MPH.  I also have a buddy with a NA using a 9A-hybrid (3.67 R&P coupled with 0.71 fifth).  Both work out great for interstate cruising and very manageable even without a turbo.  I've been getting 52 mpg on the interstate!

I can sell you one of these transmissions for $125.  I highly highly recommend getting rid of your AVX with that R&P and selling it to an auto-crosser.  I'm sure they'd love to have it.

[Rabbit on Roids]

125 bucks is a damn good deal for a tranny! especially with a .71 already installed.

[overdrivegear]

Sorry, I wasn't clear...I'm not parting with my modded ACH tranny.  I have two extra ones: stock AGS and stock ACH.  $125 for either.

[Doakster]

Thanks for all the input fellas, I'm actually dropping the trans off to the rebuilder tomorrow, I talked to him today and he has an AGS available, but his suggestion was to .89 fifth gear in it so that it wasn't such a dog in fifth gear, really though that would go against what I'm trying to do with getting lower RPM in 5th. Plus i don't really want to mess with adapting the reverse switch although i'm sure it isn't too hard.

I actually do like how peppy the AVX is, just not the high rpm of the 5th gear. He also said that the used .71 fifth gears that he has are for a smaller shaft size and won't fit on the AVX shafts.

So i'm at a cross roads. And i think ultimately I am going to stick with the AVX, if i can't do the .71 5th gear now than I may end up doing while the trans is back in the car if I can ever find one.

I even called Brian at brokevw, he doesn't have a .71 available right now.

I'm gonna talk it over with the builder tomorrow again when i see him.

[ilikevwdiesel]

dude...you're going at this from the wrong angle. Do you know why VW put a 4.25 to 1 ring and pinion in the ECOdiesel Jetta? Because the engines are DOGS! If you increase the power output of the engine you won't have to mess around with building a transmission you can just use an as is AGS, ACH, 4S, or AOP trans with a 3.94 to 1 ring and pinion. If you get a bigger engine like an AAZ, you can use a Mk3 gasser trans with a 3.67 to 1 ring and pinion and turn even less RPM on the highway. Now on the other hand, if you are going to race keep the AVX trans and put a 9A gearset in it. If you want to run better, increase the power and decrease the RPM drop between shifts. Go to scirocco.org/gears and compare the gearsets on the various boxes.

[Doakster]

dude...you're going at this from the wrong angle. Do you know why VW put a 4.25 to 1 ring and pinion in the ECOdiesel Jetta? Because the engines are DOGS! If you increase the power output of the engine you won't have to mess around with building a transmission you can just use an as is AGS, ACH, 4S, or AOP trans with a 3.94 to 1 ring and pinion. If you get a bigger engine like an AAZ, you can use a Mk3 gasser trans with a 3.67 to 1 ring and pinion and turn even less RPM on the highway. Now on the other hand, if you are going to race keep the AVX trans and put a 9A gearset in it. If you want to run better, increase the power and decrease the RPM drop between shifts. Go to scirocco.org/gears and compare the gearsets on the various boxes.

I know most of you guys are shying me away from the AVX rebuild. I realize they had to put a shorter ring and pinion to compensate for the lack of power of the eco, but I also like the way the trans shift because most of the gears are closer.

I'm not going to go crazy on power with this motor, or swap a bigger motor in the car, I'm simply going to add an exhaust, built pump and maybe an intake.

I was surprised when George suggested to put a .89 fifth in the AGS if he rebuilt the AGS for me, because that really wouldn't gain me much in fifth. What ever trans i get, regardless of he condition, it's going to get rebuilt with a peloquin. I'm not going to have the trans out and not get it done while i can. Call me crazy for not doing it cheaply, but that's what i want.

I'm going to talk it over with George tomorrow and see if we can finalize something.  Bottom line is that even though it isn't critical that this car gets back on the road, I want it back on the road in a few weeks and if I end up keeping the AVX and maybe doing a .71 5th in the future then i can live with that. 

I did do the calculators and you're right, the 3.94 will drop the rpm more than putting a .71 in the AVX, the 3.94(.75 fifth) drops it about 220rpm @ 65mph, while the 4.25 w/.71 fifth only drops it about 160rpm @ 65mph, in comparison to the original 4.25(.75) AVX setup.

And actually Georges suggestion of the AGS with a .89 fifth comes out to be 274 rpm higher than the original AVX set up, so that's not going to work.

So how about this idea, have George swap a 3.94 final in my AVX, then i would have the same exact set up as an AGS and i wouldn't have to alter my reverse switch. I would be a little more doggy of course but all the more reason for me to put an LDA pump on it.

[ilikevwdiesel]

dude...you're going at this from the wrong angle. Do you know why VW put a 4.25 to 1 ring and pinion in the ECOdiesel Jetta? Because the engines are DOGS! If you increase the power output of the engine you won't have to mess around with building a transmission you can just use an as is AGS, ACH, 4S, or AOP trans with a 3.94 to 1 ring and pinion. If you get a bigger engine like an AAZ, you can use a Mk3 gasser trans with a 3.67 to 1 ring and pinion and turn even less RPM on the highway. Now on the other hand, if you are going to race keep the AVX trans and put a 9A gearset in it. If you want to run better, increase the power and decrease the RPM drop between shifts. Go to scirocco.org/gears and compare the gearsets on the various boxes.

I know most of you guys are shying me away from the AVX rebuild. I realize they had to put a shorter ring and pinion to compensate for the lack of power of the eco, but I also like the way the trans shift because most of the gears are closer.

I'm not going to go crazy on power with this motor, or swap a bigger motor in the car, I'm simply going to add an exhaust, built pump and maybe an intake.

I was surprised when George suggested to put a .89 fifth in the AGS if he rebuilt the AGS for me, because that really wouldn't gain me much in fifth. What ever trans i get, regardless of he condition, it's going to get rebuilt with a peloquin. I'm not going to have the trans out and not get it done while i can. Call me crazy for not doing it cheaply, but that's what i want.

I'm going to talk it over with George tomorrow and see if we can finalize something.  Bottom line is that even though it isn't critical that this car gets back on the road, I want it back on the road in a few weeks and if I end up keeping the AVX and maybe doing a .71 5th in the future then i can live with that. 

I did do the calculators and you're right, the 3.94 will drop the rpm more than putting a .71 in the AVX, the 3.94(.75 fifth) drops it about 220rpm @ 65mph, while the 4.25 w/.71 fifth only drops it about 160rpm @ 65mph, in comparison to the original 4.25(.75) AVX setup.

And actually Georges suggestion of the AGS with a .89 fifth comes out to be 274 rpm higher than the original AVX set up, so that's not going to work.

So how about this idea, have George swap a 3.94 final in my AVX, then i would have the same exact set up as an AGS and i wouldn't have to alter my reverse switch. I would be a little more doggy of course but all the more reason for me to put an LDA pump on it.

that's a good idea, then you'd have a ***in trans and all you'd have to do is get a good pump and a straight exhaust and you'd run a lot smoother. sell the AVX ring and pinion on the vortex for big bux to a racer.

[Doakster]

that's a good idea, then you'd have a ***in trans and all you'd have to do is get a good pump and a straight exhaust and you'd run a lot smoother. sell the AVX ring and pinion on the vortex for big bux to a racer.

Yup i think it all just came together, mostly thanks to you guys and your suggestions, gonna talk it over with George tomorrow, and persuade him to do so, hopefully he has a 3.94 final.

So what can i sell a 4.25 for?

[VelocityConservation]

Doakster,

I think you are on the right track.  Although I think I would go with the 3.89 R&P instead of the 3.94.  Not much difference in final but every little bit of RPM you can take out of cruising speed goes right to longevity.

Plus a 5th gear swap can be done "in the car".

I did mine on "out of the car" but it was not that difficult with "BrokeVW's" instructions.

VelocityConservation

[Doakster]

I should have all my parts this week, so next hopefully next Saturday I'll be watch/helping the guys who's rebuilding my trans. Going to go with the 3.94 final and .71 fifth gear later on if needed.