Considering JPS Coupe. Seeking Guidance.

ALB posted:

Rusty- 3.44x3.11 is hugely long, and for anything but flat ground will be a pain at idle speeds (and just above). If you compare final drive numbers (r&p x 1st gear)- stock VW 1600 (3.88x3.78) is 14.6,(which, I agree, is short for a bigger engine'd car when performance off the line isn't a priority) where (as far as I've found) most 356 final drives in 1st gear were in the 14.1- 13.7 range (there is 1 combo - 4.375x2.90, that gives a 12.6 final drive, but as far as I've read it was more for just getting the car moving for road racing). 3.44 x 3.11= 10.69; as I said before, that's long!

The 3.44 r&p/3.78 1st combo, which a lot of guys like in a Speedster, gives a 13.0 final drive, and at 900rpm (idle or just off) you're already doing 5-6 mph. Stock 1st-4th gear spacing with the 3.44 gives great highway speeds! (don't ask me for help with the tickets) and is really close to what was in the Spyder (without the expense of the custom mainshaft/gear set). Going with the 3.88/3.11 gives a 12.0 final drive, and a member here (Trevor?) says it's perfect. Any longer and parking lots and hilly areas (where do you live?) will be hard on the clutch.  Remember, a Spyder is a much lighter car (25? 30%?) than a Speedster, and what feels right in the Spyder won't necessarily translate straight across into a Speedster. What are you trying to achieve with this?

Don't get me wrong; if you're sure that's what you want to do, then great. Just be sure. Al

I've got a 3.10/3.44 first. I wouldn't call it hugely long, but it's the limit I'd go to.

This is the issue with a 4 speed-- you have to give up something. Everything I'm going to throw out there is for guys with 2+L motors. Iv'e got amost no experience with smaller ones, and I'm not sure what works there. Also, I'm assuming a guy wants to use his car as a GT-- driving to places, seeing stuff. If he wants to be the baddest bruiser on the boulivard, I'd think he would just buy a Mustang and be done with it.

A VW Type 1 wants to rev, but nobody wants to hear their engine screaming down the highway at 4K+ RPM to keep up with traffic. This necessitates a final-drive in the .89-.82 range with a 3.88, or a .93-.89 with a 3.44. I suppose an argument could be made for a .77 with a 4.11, but that's a silly way to go for a variety of reasons.

This is the issue with a 4 speed-- you have to give up something.

1.  Cruising Ratio: This is what everybody notices first off, and wishes to correct. The easiest way to get this done is to put a smaller ring and pinion in. 3.88s are reasonably priced and everywhere, 3.44s are more expensive. As the ring gear gets smaller, it gets stronger as well.
2. "Digger" 1st Gear: Stock, the 1st gear seems to be sized for getting a fully loaded sedan with 4 people inside started going up a mountain with a 1200 cc lawn-mower engine hitting on 3. A smaller R/P makes 1st longer, but even with a 3.44 it seems excessive... unless you want to be a stoplight hero. Everybody would like to be a stoplight hero, because there are no shortages of idiots at stoplights. And indeed, 99% of the VW enthusiast aftermarket is oriented towards this, as very few of them are using their cars for anything besides catching a small-block Camaro off-guard. Those guys are going with the most ridiculous gearsets imaginable for the way most of us use our cars.
3. Reasonable Gear Spacing: It's possible to get a nice, snappy 1st and a long cruising final drive. However, with only 3 steps from first to fourth, those steps start to get wide-- really, really wide-- and it never seems like the car is in a usable gear.

Torque...  Allowing wide ratio gear combinations for decades

I had a '73 mustang with a wide ratio AOD and 3.89 gears... it was the best of both worlds!   A really aggressive first gear, and overdrive that kept RPMs around 2,700 at freeway speeds.

My SAS Cab has a Subaru '09 Legacy GT transmission with a 3.9 final drive.   The transmission has:

1st 3.166,   2nd 1.882,   3rd 1.296,   4th 0.972 and 5th 0.738

1st gear is pretty aggressive... Really nimble, yet decent cruising speed RPMs

"If it's available in June it'll be worth the wait."

Rusty- Missed a word in my last post. And even if it takes longer, I'd still wait. What about throwing the engine back into the car (so you're driving it during prime summer season) until the parts are in?

"I'd probably ignore the well-intended advice, and just drive it and develop your own opinions regarding what needs done (or not). You'll know soon enough what you'd like to change (and you will develop a long list before you know what's happening)."

Chris- I agree with what Stan said above- if you like the car enough to buy it, drive it and decide what you want to change as you go. That's what winter is for- spending money on your car!

"This is the issue with a 4 speed-- you have to give up something."

More wise words, Stan; you really hit the nail on the head so often! And you're right- what works with 2 liters and larger doesn't always work so well with smaller engines. In a Speedster, even with less inherent torque you don't have to keep the granny first gear, but I think going really long would be awkward and hard to drive. It wouldn't be so bad out in the flatlands, but your car with a 1600, for example, in someplace like San Francisco, would be really hard on clutches (and almost impossible in certain places). Vancouver is somewhat like that, a lot of up and down (although maybe not quite as bad as San Fran). Driving your 1st/r&p combo around here with a half pint powerplant would be challenging, to say the least!

You don't have the leeway to increase highway cruising speeds, either. A larger engine can loaf along on the idle circuits (staying relatively cool) at higher speeds and slightly slower rpm's while with a smaller engine your foot is now in the gas pedal far enough to be in the main jet(s) making the necessary power, but also creating waaay more heat. This is why when VW went from the 4.125 to the longer 3.88 ring & pinion, the less aerodynamic beetle got the slightly shorter .93 4th while the slippier Ghia was able to keep the .89 (and higher highway speeds).

I know you get all this, Stan (and you too Rusty, and some others), but hopefully it will make sense to a few more people...Al

PS- It's not too late, Stan; call Berg and put that fancy mainshaft to good use. I even have the "perfect" gearstack worked out for you. You can put it away for now and after the house is built it'll be your first winter project in the new garage. You know you want to...

I just talked to Greg. 3.11 1st, 1.86 2nd, 1.21 3rd, .89 4th with a 3.44 r&p. He said we could wait on the mainshaft and that may be here as early as next week.

I wish all of these posts were in a transaxle thread. This is all really really good information. I think there are a lot of folks on here that have not had the opportunity to experience these cars with a longer gear set.

Stan hit it right with this comment - "Digger 1st Gear: Stock, the 1st gear seems to be sized for getting a fully loaded sedan with 4 people inside started going up a mountain with a 1200 cc lawn-mower engine hitting on 3." .... now that is funny!

Moreover, after extending 1st you can extend 2nd and 3rd as well to make for a very nice cruising experience. This setup is not for the stoplight to stoplight street brawler that is foaming at the mouth!

Thank you guys for your input. Perhaps Theron can put this in a Modified Transaxle thread for safe keeping and I will update once I get my car back.

Chris, edit your topic name and change it to Transaxle options or something. This is good for me too Thank you all!!

OK guys I migrated this transaxle portion of this topic to a new topic titled Transaxle Gearing options under Technical General so we can continue it there.  Thanks!!