Trans/final drive ratios

Since this is going on and on, and since guys keep saying stuff like, "stop obsessing and drive it", I think it's fair to point out that so far-- everybody in the "it doesn't matter" camp has non-standard gearing in their cars.

The gearing was perhaps not picked by the respective gentlemen personally, but somebody gave it a lot of thought. Jake Raby did Jack's. Henry did Ray's. I never know who picks Jimbo's stuff, because he makes it sound like he's never given it any thought, but ends up with thickwall 92s, a big remote cooler, and a freeway flier (oh that my off-the-cuff choices were so tasty).

It comes harder for some of the rest of us.

There are things we discuss that don't matter. This isn't one of them.

Still going...

This topic has more miles on it than my 5 speed does.  

Sacto Mitch posted:

 Here a graph of standard VW gears (late 60s, with .89 fourth) with the two R&P's. The red bars are the 3.88, blue are 4.12. (Click on the chart to enlarge and make the numbers easier to read)

In first gear, there's not much difference, but the difference increases the higher gear you're in. The gears are 'farther apart' with the freeway flyer.

 Here's the link to the original graph, where you can read all the details and slide the cursor around to read speed in gears at any engine speed.

... and here it comes...

Mitch's graph is a perfect illustration of why this stuff really does matter.

Ideally, the ratios in a transmission are not perfectly evenly spaced. Generally, the spreads between gears would be widest between the lowest two gears and get gradually more narrow as one approaches the final drive. The stock VW ratios are almost perfectly inverted in this regard. The main-stack (first and second gears) that almost nobody replaces is ridiculous in a 4-speed, great for drag racing and plowing the back 40 but terrible for getting up to a final-drive that can be used on modern interstates.

A 5-speed fixes this. First and second gears stay the same, because nobody wants to buy a $1000 main-stack. Final drive stays the same as a freeway flier, but there is an additional step between 2nd and the final drive to keep those gaps tighter. When Bruce and Danny (two very smart guys) are talking about taller 4th gears and custom 3rds-- it's because they're interested in bringing the 2/3 and 3/4 shifts closer together. The trouble is, that even with a 3.44, a 1:1 final drive is going to have your engine spinning like a top on the freeway. Peter is duly robbed to pay Paul.

It's why the 5-er is just better for a car that's trying to do it all. That's why the 5-speed guys are the cool kids.

There are ways to get 90% of the goodness of a 5-speed with 4, but it's actually more expensive than just building the 5-speed. The first order of business is a big engine, and "big" in this case means at least a 2180, preferably a 2276 or 2332. The second order of business is a non-standard main-stack, a non-standard 4th, and a 3.88 or 3.44 RP. Somebody once told me (when I was trying to make a .82/3.88 combination work with a stock 3rd and a 200 hp fire-breather), "Son, you don't have an engine problem. You've got a gearing problem".

I didn't want to hear it after spending almost $10K on a ridiculous engine, but he was right.

Gearing matters.

DannyP posted:

 

The cheapest option for the long-legged cruiser is stock gears and a 3.44 final drive:

3.80(early) or 3.78(late) 1st, 2.06 2nd, 1.26 3rd, and either 0.89 or 0.93 4th.

Anything other than that combo is going to be more money. Like $1000 more.

I'm going to end up with a factory 3.88, Weddle custom 1-2(3.11 1st, 1.86 2nd), a 1.26 3rd and a 0.93 4th. IF I could do a fifth gear, I'd throw a 0.82 in there for interstate work. I'll also do a TBD(torque biasing differential) as I spin instead of launch.

These ratios I've chosen end up VERY close to a 3.44 with stock 1-2(but the aftermarket gears are slightly closer) and a 1.30 to 1.39 3rd and a 1.04 or 1.0 4th. Mainshaft(1-2) and corresponding idler gears and special 3-4 slider to fit that mainshaft is $1000. Plus add in the TBD which is anywhere from $800-1200.

 

 

Exactly right Stan, gearing does matter. This quote is from the 7th post down on page 1 of this lengthy thread. 

Basically, making 1st taller and 4th shorter and evening up the space in between.

I won't leave a stop quick, but once rolling, watch out. I won't be cruising at 90-100 either. But that's OK.

I've got the motor to push this, 2165 at 10.2:1 compression. 172 hp and 147 torque. The car is 1500 lbs. all-up.

Once I've got all this done, along with my own design IRS rear suspension, I'll be zipping along even better than now. Especially on the twisty and hilly roads, it should be the perfect canyon-carver that it almost is now.

I'd love to be able to do a 5 speed, but in my Spyder it's a LOT of work. Crazy amount of work.

Berg 5? Maybe, but then the cable shift linkage and nosecone(tailcone?) mount need to be redone. I've never heard of a Berg5 in a mid-engine car.

901/915? Same fabrication problems as a Berg5. Need LSD too$$$$$

Subaru trans? Convert to 2wd(RWD), get trans adapter from Subygears(staying aircooled baby!), fabricate all new motor/tranny mounts and that cable linkage again. Probably a new exhaust is in the cards with Suby transmission. Pretty much unobtanium. Add LSD to this as well.

Now maybe y'all can understand why it's not at all the easy direction in a Spyder. Which is why Bruce's car is going to take a minute for Greg to build.

As it is, I'll have to build a set of custom IRS trailing arms, two lateral links per side to make a parallelogram, a custom rear anti-sway bar, and a new and removable subframe to support and take the suspension loads. That subframe has to thread the needle of the exhaust, the trans, new CV axles, and existing stuff like the starter. Not cheap or easy, but do-able.

A 5-er is almost impossible in my car as well, Danny. Lots of Intermeccanicas have 5-speeds-- they came built for them with a different subframe.

BTW: I looked at your proposed gear set-up. I think you'll love it for mountain work.

Like everything else you've done-- perfect for the application.

Stan Galat posted:

A 5-er is almost impossible in my car as well, Danny. Lots of Intermeccanicas have 5-speeds-- they came built for them with a different subframe.

BTW: I looked at your proposed gear set-up. I think you'll love it for mountain work.

Like everything else you've done-- perfect for the application.

You car is early 2000 Stan can't remember how the cradle is made for you AC engine but the cradle might have to move back ... I guess a good go at measurements might help you decide. 

2005, and yes, the engine moves back or the frame gets really, really hacked up.

I'm not moving it back. That'd mean another new exhaust, all new surround tin, etc. It's a lot like an A-arm (or 911) front end-- I'm too far into what I've got to do it, no matter how badly I'd like to.

A VW engine in a type one beetle you can swap the tranny to a subiegears and there is no need as far as I know to push the engine back. 

I know that  IM drives the engine 1 inch or so to the front in comparison to a real speedster/roadster. 

It would be nice to know just how much further back the engine has to move in an IM frame car.  I wonder if @Anthony who did a conversion would know off hand. 

Anthony (who did the one-and-only Berg/IM conversion) outlined everything that needs done in a series of off-line correspondence. It was enough to wave me off.

Stan Galat posted:

A 5-er is almost impossible in my car as well, Danny. Lots of Intermeccanicas have 5-speeds-- they came built for them with a different subframe.

BTW: I looked at your proposed gear set-up. I think you'll love it for mountain work.

Like everything else you've done-- perfect for the application.

The berg five in a IM chassis car can be done. I did it and still used the torsion bar adjusters. If I do another one I would set up with adjustable coil overs.

IaM-Ray posted:

A VW engine in a type one beetle you can swap the tranny to a subiegears and there is no need as far as I know to push the engine back. 

I know that  IM drives the engine 1 inch or so to the front in comparison to a real speedster/roadster. 

It would be nice to know just how much further back the engine has to move in an IM frame car.  I wonder if @Anthony who did a conversion would know off hand. 

I don’t recall the exact measurement but it’s at least 1-1/2” forward. Do to the way the engine and trans are supported (similar to a 356) one would have to extend/modify the mount if considering moving the assembly towards the rear.

Great and informative posts! Actually I notice that from 1st to third there's nothing unusual in the spread between them; it's just between third and 4th. Like I said; if you're behind someone doing 40 something miles per hour on third the revs feel a little too much but if you shift to fourth at that speed you feel like you're lugging it.

Impala posted:

Great and informative posts! Actually I notice that from 1st to third there's nothing unusual in the spread between them; it's just between third and 4th. Like I said; if you're behind someone doing 40 something miles per hour on third the revs feel a little too much but if you shift to fourth at that speed you feel like you're lugging it.

That’s why the five speed makes the difference. Splitting the third and fourth gears does that and keeping your original 4th gear as fifth. The berg 5 purpose keeps you in the torque curve.  A porsche box doesn’t have ratios the do that in a stock form

Anthony posted:

The berg five in a IM chassis car can be done. I did it and still used the torsion bar adjusters. If I do another one I would set up with adjustable coil overs.

You are the man, Anthony.

Pretty much anything can be done with a large enough infusion of labor and cash (just money, if a guy is paying for labor).

I'm generally not shy about either (the cash or the labor)-- but as I said, the surgery was extensive enough to wave me off. Re-doing the rear suspension so I can have the extra gear is a bridge too far for me, and I just can's bring myself to push the engine back and redo the exhaust for the eleventy-billionth time.

When you outlined what was involved in fitting a Berg into an IM, it was the first time I envied a pan-based car. Apparently, even I have limits. 

IaM-Ray posted:

A VW engine in a type one beetle you can swap the tranny to a subiegears and there is no need as far as I know to push the engine back. 

That might be a consideration, Ray, but the Subaru 5 speed is optimal for a Subaru power-curve. I don't believe a T1 has the torque to pull the gears The transaxle has no giant aftermarket anyhow.

The beauty of the VW transaxle is that there are an abundance of gears available from a couple of different places.

Again I say, it's a lot about the engine. The more radical and race-like the engine, the narrower the power band will likely be. If your mill makes its best power at 6500 and hits peak torque at 5000 or above, you'll need those close gear ratios to keep you on the cam. 

But if you're driving a street engine that peaks at 5000 or even 6000, and makes its best torque at 3-4000 rpm, then your gear drops with a stock transaxle will not take you out of your power band. 

I'm betting that's part of the reason why Pat Downs made Anand's 2332 with Panchitos and ran it only up to 5500 on the dyno. Not only did he not want to grenade a $15,000 fan shroud, but he knows that, for this application, much better to make a torque beast that will feel strong in every gear than to try to pin the tach needle like the original 1500s did. 

Stan, we are in the same boat. A 5 speed is going to require a lot from us. 

Save your pennies, because I think we're both going to have to build another car to get the 5.

TRP posted:

Still going...

This topic has more miles on it than my 5 speed does.  

It wouldn’t if you got out and drove the damn car. 

This is fun, I think 🤔 

I've been doing a little research on this 5 speed Suby trans thing.

Subagears has an adapter for aircooled motor to Suby trans. This is really nice BUT the trans input shaft is 55mm higher, which means your engine is over 2 inches higher. Also, moves the engine 30mm further away from the trans due to thickness of the adapter.

Not gonna work in a Spyder and most probably not in a Speedster either, unless you're using a Subaru motor too. It could probably work in a Ghia or a sandrail, but that's all I see it working in.

Subagears has all sorts of cool stuff for motor/trans swaps though. Motor mounts, trans mounts, covers, 4wd to 2wd converters, TBDs, different CV flanges, you name it. Very neat stuff.

Also keep in mine which flywheel will work. I am not sure you can use the stock one and also is there a special input shaft for the Subaru trans to the VW crank?  The Subaru swap in vanagon if your using the Kennedy kit has a special flywheel that weighs a ton

Appreciate the info Anthony, but Suby 5 isn't gonna work for me.

If I ever do it, it will be a 901 or most probably a Berg5. There simply is no vertical or horizontal room to use the Subaru. I have a type1 VW engine which I'm not changing in my Spyder with an Autocraft dry sump pump. There is simply no room to be had forward due to the pump, or upward with my 911 fan shroud.

Robert M posted:

TRP posted:

Still going...

This topic has more miles on it than my 5 speed does.  

It wouldn’t if you got out and drove the damn car. 

Ok, I laughed out loud at that!

Well, we’ve passed 100 replies. Who’d a thunk?

All this has me wondering if my R&P should be 3.44 instead of 3.88 with my .89 fifth.

I only drive of freeways a few times a year, one of which is to and from Carlisle.  I run about 3500 rpm on that drive.  Is that too high for sustained operation?

Michael McKelvey posted:

All this has me wondering if my R&P should be 3.44 instead of 3.88 with my .89 fifth.

I only drive of freeways a few times a year, one of which is to and from Carlisle.  I run about 3500 rpm on that drive.  Is that too high for sustained operation?

If you did a lot of highway driving then you might have a case for it, but since you "only drive on freeways a few times a year" I wouldn't recommend it. If the engine will stay cool enough (oil temps under 210-220°F and under 350°F if head temps are monitored) then you should be able to run 3200-3500 rpm for hours on end. 3500rpm with a 3.88/.89 is 75 or 76 mph with 70 happening at just over 3200; that's fast enough to get you into trouble with the local constabulatory, is it not? Do you like the 'around town' zip the car has now? Going to a 3.44 will take a little of that away.

http://www.teammfactory.com/ca...89/0/3600/3600/1/0/2

gkgeiger posted:

Well, we’ve passed 100 replies. Who’d a thunk?

On a transaxle thread in the winter? Oh Gene, just stick around a bit.

@ALB My thinking was as you describe.  I do like the zip it has now. I have a little trouble keeping up with the PCA guys on drives although a 912 driver said he had a little trouble keeping up with me.

My oil and head temps are below what you mention

I had my 2100cc with 3:44 and it was good for long highway cruising at 70mph around 3000-3200rpm but if you do only one trip a year why change it Michael?  The city driving experience will be a bit zippier and with less 3rd and 4th year gap indicision. 

Stan Galat posted:

gkgeiger posted:

Well, we’ve passed 100 replies. Who’d a thunk?

On a transaxle thread in the winter? Oh Gene, just stick around a bit.

Wasn't the thunk the noise the tranny made?   

Evidently I have 80% of the perfect transmission. I'll make do.

Panhandle Bob posted:

Evidently I have 80% of the perfect transmission. I'll make do.

If you can, you definitely should.

Stan Galat posted:

gkgeiger posted:

Well, we’ve passed 100 replies. Who’d a thunk?

On a transaxle thread in the winter? Oh Gene, just stick around a bit.

This could go on for a few pages yet- the back and forth, trading ratios, posting graphs, with any luck degenerating into a couple of us calling each other poopieheads...you're in for a real treat! 

And @Panhandle Bob wrote- "Evidently I have 80% of the perfect transmission. I'll make do."

That last 20% is the costly part...

the bottom line is the 5 speed works.......makes a small motor feel big and a 2 liter type 1 feel like a type 4.

ALB posted:

That last 20% is the costly part...

 Oh wow-- now you've done it.

Picture a graph, gradated from 0-100%, with with the horizontal axis representing results, and the vertical axis cost. 

The line starts at 0%, and heads on a 45* angle from 0% to 75%, before sweeping upward on a parabolic curve from about 75-100%. The curve gets increasingly steep, until at about 98% (or so), it heads straight up.

This is the value curve, and it works for almost everything.

From 0%- 75% (the line on a 45* angle), results roughly match the money spent. One can see a discernible improvement in results for every dollar spent.

From 75% to 90%, every dollar buys increasingly less result. By 90%, it takes 4x (+/-) what was spent at 75% to see the same improvement. At about 95%-98% the curve is nearly vertical, so that for incrementally better results, one must spend exponentially more money. At 98%, the line is vertical-- no amount of money spent will make a substantive improvement.

80% is just about ideal, @Panhandle Bob. Pity the guy who wants it to be "perfect."

_{Ask me how I know.}

Anthony posted:

the bottom line is the 5 speed works.......makes a small motor feel big and a 2 liter type 1 feel like a type 4.

^^^What Anthony said^^^ All kidding aside, it is 1 of the best things you can do to your car. It's not cheap to do, but giving your car close ratio gears and a 5th for the highway- it is the ultimate!

Of course it is one of the best things you can do for your car.

Everyone knows that.

The problem is what Stan posted: There are diminishing marginal returns going from the 4-speed to the 5-speed versus cost/value.  So much so, that the vast majority of us simply cannot justify the greatly increased cost of buying/modifying the gearbox and modifying the pan/frame to accept it, not to mention the loooooong lead time just to get one (unless you find a decent 901 kicking around).
Believe me, I would like to go to a 5-speed, but for the amount of driving I do and the majority of the roads I take my car on, the 4-speed I have with a 3:88 rear is working quite well and I’ll stick with it.  I lost a little acceleration “kick” going from a 4:12 to the 3:88, but it’s working out very well for me, so that’s it.

Gordon Nichols posted:

 

The problem is...

We all make our own choices as to where (and how much) on these cars we spend our money, Gordon.

ALB posted:

Gordon Nichols posted:

 

The problem is...

We all make our own choices as to where (and how much) on these cars we spend our money, Gordon.

All too true...

Robert M posted:

TRP posted:

Still going...

This topic has more miles on it than my 5 speed does.  

It wouldn’t if you got out and drove the damn car. 

Too many work hours.  Too many cars to work on.  I need to sell a few of them or hire that guy Jay uses.

Ted