Transaxle gearing Qs

We have many discussions on the particulars of engine performance, 1776 vs 2110, T1 vs T4, yada. All of them are interesting and I learn something most times a post is made.

But, I seldom see any discussion on the merits or downsides of different gearing, or even transaxle set-ups. So to educate myself and maybe get some discussion going I am throwing out a few Qs. Weigh in and educate me.

1. For a nice all around driver, doing 150 mile jogs and much in town driving, what would be a good set up based on the standard VW transaxle. For hyptohetical purposes let's say the engine is anywhere from 90 to 130 HP? I have a standard set up with a 3:88 R/P. What gearing would enhance this in 3rd and 4th? Is a stock German clutch adequate?

2. Same Q as above but the engine is now 140+ HP. Clutch? Gearing?

3. Same as Qs 1 & 2 except primary driving is stoplight and canyon carving.

4. Same as Qs 1 & 2 except you want to drive 70-75 crosscountry with an adequate oil cooling system already installed.

5. The Gene Berg 5spd kit? Pros and Cons? Cost? Mods?

6. 901-5spd? How much, pros, cons, mods?

7. Best all around clutch for a driver that occasionally gets a minor thrashing through the gears at a stoplight to stoplight setting?

8. Discuss possible gearing set-ups on the VW 4spd, 1st, 2s, 3d, 4th... also, a 3:44 vs a 3:88.

That's it/

Jim OKC

(Message Edited 12/5/2002 11:03:25 AM)

Jim,

Here is a good resource I found concerning Type 1 transmissions when I went through upgrading my engine and transmission:

www.tunacan.net/t4/tech/trans.shtml#t1

This deals with T4's but is applicable to higher HP Type 1's as well, There are a good few paragraphs discussing ratios and modifications of the Type 1 transmission to handle added power.

The author also discusses a lot of the other questions you have like the Gene Berg 5 speed conversion, etc.

Me... I have a 4.12 R/P from Der Transaxle with welded 3rd and 4th gears on a 2176 T1 generating approximately 145-150hp. I can turn 13's in the 1/4 mile and still cruise comfortably on the highway... 65mph somewhere around 3000-3500rpm.

Hope that helps.

Jim:
You have asked an interesting question. However, I do not think it can be answered, at least not in a simple form.

Let us select a horsepower level of 125; a level that should allow decent performance for an average Speedster. Driver A has a 94mm X 82mm 2276cc Type 1 engine with good low speed torque and a moderate RPM rating for maximum power. Driver B has a screaming engine of stock 1600cc (actually 1585cc) size. The 1600cc engine has no low speed torque and 125HP at extremely elevated RPM. The two engines have entirely different gearing requirements for both intermediate gears and final drive.

If that is not bad enough, let's throw in a 105mm X 80mm 2771cc Type IV engine with 125HP at a very lazy RPM and enough torque to move an 18 wheel truck.

IMHO the question you ask is way too broad and way too complicated for anything short of a PhD thesis.

Thanks Colton, I'm looking up that page as soon as I finish this post.

Alan, Ok, for specifics. Let's say I'm running 100-105 HP on a built 1776cc now, but am hoping fortune smiles soon and I put in a 2007-2110cc in the 130hp range. Driving is primarily easy cruising in metro settings, with an occasional thrasher run through the gears for grins. But, but, I would like to be able to use 4th (or 5th?) for freeway crusing, maybe Interstate runs of 150-200 miles between cool downs. Not high speed, just 65-75 mph at a non-bruising RPM.

Now, my Qs would be? R/P? 4;12, 3:88, 3:44? Welded 3rd 4th?, What gears for 1-4, especially 4th! Clutch? Gene Bergs 5spd kit... yada. Also axles, etc.

Thanks for joining in. I guess I just see this as a place for me to learn. We talk about the limitations of T1s on handling heat and high sustained RPMs.... but seldom discuss positive (if any) effects of gearing on this situation. I am fairly new to the air-cooled scene, having a Speedster Replica (VS) for 18 months. I went in uneducated, but now I'm merely dangerous. I know cars in general and have been involved in street rodding for too many years. So, to a rank aircooled amateur like me, it just seems logical that there has to be a pretty decent set up for my application. Trouble is, I don't want to fork out too much coin in the learning process... i.e.; get it right when I go about replacing some items in the drivetrain and also be ready to upgrade the engine to a mid-ranger of 130hp in the 2-2.1L range.. Colton's article will help... hope you can too!

Jim

(Message Edited 12/5/2002 12:48:03 PM)

Yet another factor is how tall your rear tires are.

Jim, I would imagine your future engine builder will offer suggestions, or contact one of the better Vw performance transmissions shops. The Tuna site has good info, though as Colton mentioned its focus is the T4 & its characteristics. Over at STF some of the guys talk about having a taller than stock fourth gear, a faux overdrive for those that want to hit the open road.

Jim,

As I'm sure you know, there is no single right answer for the myriad of driver types that comprise the VW/Speedster cars out there. My suggestion is that you decide how important freeway driving, or driving at freeway speeds, is to you. Then drive that speed, 65, 70, or whatever, for a test. See what your rpm's are. If they are within proper spec's, i.e., around 3,000, you know that your top gear is the proper gear ratio.

The rest you can reverse engineer. If you are satisfied with your tire size and R&P, then it's merely a question of splitting the remaining gears to your liking. I have read on the CLF forum (but can't personally attest) that Berg will set 1st through 5th at a variety of ratios, depending on driver preference.

Obviously, this is the Reader's Digest version. Changing R&P and tire size will change the equation, but the big picture remains the same. It's part science, part art, since most of us use our Speedsters for a multiplicity of tasks: pleasure driving, commuting, the occassional adolescent reversion, etc.

The above doesn't even mention the appropriate bulletproofing of any stock tranny to accept 140+ HP. Personally, I run stock VW gearing, with a 3:88 rear end, welded 3rd and 4th, with SuperDiff. The downside is that at freeway speeds of 75-80, I turn 3,800 rpm, a little higher than I would like. The upside is that I now live on Kauai, where the maximum speed limit is 50 mph. If there was one perfect setup, we'd all have it. BTW, I enjoy your posts. Regards, Jim

I did the homework on gear ratios, etc., and built these specs into my car (Porsche 901 5-speed with 195/65x15" tires):

ring/pinion 4.4286 to 1 (transaxle P/N 902/02 1282133, speeds are with 25.5" tires); format is gear, ratio, overall ratio, and approximate mph/1000RPM:

1st, 3.091, 13.689, 5.37 mph
2nd, 1.889, 8.366, 9.00 mph
3rd, 1.318, 5.837, 12.67 mph
4th, 1.040, 4.606, 16.17 mph
5th, 0.793, 3.499, 21.33 mph

The fifth gear gives 70 mph at 3,250 RPM.

(Message Edited 12/6/2002 2:20:54 PM)