As I mentioned in my previous post, Matt Steedle is a hell of a good transmission guy.
So after reviewing my gear ratios which I brought with me when delivering the 091, he gave me a slow head shake and said, "I'll build whatever you want: you're the one who's paying. I'll just say that based on what you described wanting, this gear ratio won't give you that."
I was stunned. After all of the work I'd put into the gear selection (dropping to a .70 for 4th gear, which would give me 65mph at 2700rpm, the same as the donor Impreza the engine came from) hearing that it was a bad selection was kind of demoralizing. So I asked and Matt replied, "The .70 will work on the flat. The moment you come to a hill, you're going to find yourself back in 3rd gear, and based on your 3rd gear choice, you're going to be spinning the engine like a dynamo. You're trying to stretch things out to artificially get the numbers to match the Impreza. I know they weigh the same, but the Bus had an enormous amount of wind resistance by comparison and your gearing doesn't take that into account."
I finally saw what he was getting at. My EJ22 NA Impreza engine makes 145HP, about twice what the original Type4 engine did on its better days. But without gear ratios (both individual gears, as well as the big Ring & Pinion) that produce a similar final drive ratio (which includes the diameter of the tires!) there was never going to be a smooth set of gearing for the 091. Not only that, Weddle Racing is the only USA source making gears for the 091, and those gears are meant either for racing, or for Sand buggies which make heavy use of the 091 because it is very robust. As a result, while you get a variety of Weddle gears, they are expensive and meant for the sudden, heavy loads of drag strip or sand, not for consistent, long hauling. They're good; they're just meant for a different application.
So what do I have now? Well, a stock 1977 Bus with an 091 manual (which may have a different transmission or gearing than your Bus has!) is geared like so from the factory:
1st: 3.78:1 / 2nd: 2.06:1 / 3rd: 1.26:1 / 4th: .82:1 // 4.57:1 Ring & Pinion. // 185r14C tires (special tires, but have a diameter of 25.7)
Using Richard Atwell's formula, I'll fill in my correct variables (if you want KPH, change 336 to 210):
MPH = RPM * TIRE DIAMETER / GEAR RATIO / Ring&Pinion / 336
65MPH = 3300 x 25.7 / .82 / 4.57 / 336
Lovely! Only one problem: While 65 MPH may be John Law approved, driving a reputedly slow vehicle in 2017 at 65mph is bound to attract the kind of attention you don't want. So with the engine and transmission package going back in as stock, I've got to get a better final drive.
At Matt's suggestion, I returned to bigger tires: 27x85R14C (orLT). These are only made by a few manufacturers but are popular for VW offroaders. I had run this size of tire in 1992 when I lived in Oregon and Washington and ran them (BF Goodrich) on my 1971 Deluxe Bus. So I have some experience with them: great off road, but noisy with poor traction in the rain on the highway. (After 6000 miles of highway on them, I felt like I knew what they could and couldn't do safely.)
Today the tires of choice in that size are the General Grabber AT2, which has all of the benefits and hazards of the classic BFG I ran 25 years ago. But at Colin Kellogg's (Itinerant Aircooled) suggestion, I've decided to use the same tire that he uses on all of his buses for 80% onroad / 20% offroad: The Maxxis 751 Bravo. The Man did Death Valley in them and the rest of the country to boot. Because Colin has been good enough to share his experience, I'll have a decently mannered road tire (and the spare, which will be in regular rotation) and be able to meet my target of 65MPH @ 3300 (good for flatland and passes without downshifting) and 75MPH @ 3700 for when the traffic around me gets pushy. Viva la Itinerant Aircooled! Viva la Matt Steedle! Viva la Comunidad!
