So many people talking about making an ETA rev higher, and putting in lower gears trying to make more "power", the fact is no body seems to know how to use what they have, to make what they have work better for them, and why torque is more important than HP.
ETA motors put out great torque, so USE IT. Putting in a lower gear differential doesn't help an ETA build power, it's an old school method that works by turning RPMs into torque. That is what the transmission and differential does, it turns the motors low torque and high RPMs into putting more torque at a lower RPM into the wheels. Loosely translated it means if you have lots of lower gearing you are going nowhere fast with tons of torque. Think of riding a mountain bike, starting off in first gear, you'll peddle like crazy (building loads of torque at the wheel) but you are not going fast or covering any real distance. However you needed less leg torque, just RPMs. Put the bike into a higher number gear and you need loads of leg torque to start off but now you can go faster. You need to find the gearing that makes the most of the available power (leg torque) and trading that to obtain most distance traveled with the most wheel torque.
This same principle applies to cars too. Since lower gears will up the torque it will also drop the useable torque RPM range. (staying in each gear less and shifting more) You must gear your car correctly for the rpm range to make the most of the torque your motor is building with the greatest amount of distance with out going out of your torque's RPM window.
What to do?
Now you should be thinking "So putting lower gears into an ETA (or any high torque, low rpm motor) is shooting myself in the foot, ok, so how do I build more low end torque? A large turbo?" No, a smaller turbo, another misconception. Turbos are, simply put, a torque multiplier. Larger turbos require great amounts of exhaust (aka RPMs) to spool up. Something the ETA doesn’t do well and is out of the ETA's useable torque range. (what good is it adding torque in the higher RPM range when there is no torque to add to?) The answer: Install a smaller quicker spooling turbo to increase the low end torque you already have.
With the quicker spooling turbo you "boosted" your torque in the motors torque rpm window (power band) Now lets jump back to the bike metaphor, this means with the turbo you have pumped up your legs (more "leg torque") and now you can use the upper gears to start off moving faster using "leg torque" getting the most out of gearing and still putting that power to the ground. Now since you have more power in the lower RPM range you also spread out your power band because you are moving faster at a lower leg RPM. In the car it means you can use that higher geared differential to turn your motor's higher torque into more wheel torque at lower RPMs, aka: More power and speed.
This principle is why that screaming 10,000 rpm, huge turbo powered honda seems to have so much "power" In reality it doesn't, the turbo is dumping torque into the upper RPMs just so it can trade it off for lots of wheel torque. It's also why you see so many dead hondas (and other high RPM cars) too... They are asking the motor to spin faster which is very violent and detrimental to a engine with so many moving parts. The wankel rotary motor is perfect for high RPMs (less moving parts) but that is another story....
Now I hope some of you get this and understand why torque is more important than HP. And also explain why a 180hp 460 ft/lbs of torque huge diesel powered truck can actually move very fast. Also why lower gears makes cruising on the highway going 60 mph @ 3500 RPMs very stupid because your motor is just spinning it's legs and going "nowhere fast".
ETA motors put out great torque, so USE IT. Putting in a lower gear differential doesn't help an ETA build power, it's an old school method that works by turning RPMs into torque. That is what the transmission and differential does, it turns the motors low torque and high RPMs into putting more torque at a lower RPM into the wheels. Loosely translated it means if you have lots of lower gearing you are going nowhere fast with tons of torque. Think of riding a mountain bike, starting off in first gear, you'll peddle like crazy (building loads of torque at the wheel) but you are not going fast or covering any real distance. However you needed less leg torque, just RPMs. Put the bike into a higher number gear and you need loads of leg torque to start off but now you can go faster. You need to find the gearing that makes the most of the available power (leg torque) and trading that to obtain most distance traveled with the most wheel torque.
This same principle applies to cars too. Since lower gears will up the torque it will also drop the useable torque RPM range. (staying in each gear less and shifting more) You must gear your car correctly for the rpm range to make the most of the torque your motor is building with the greatest amount of distance with out going out of your torque's RPM window.
What to do?
Now you should be thinking "So putting lower gears into an ETA (or any high torque, low rpm motor) is shooting myself in the foot, ok, so how do I build more low end torque? A large turbo?" No, a smaller turbo, another misconception. Turbos are, simply put, a torque multiplier. Larger turbos require great amounts of exhaust (aka RPMs) to spool up. Something the ETA doesn’t do well and is out of the ETA's useable torque range. (what good is it adding torque in the higher RPM range when there is no torque to add to?) The answer: Install a smaller quicker spooling turbo to increase the low end torque you already have.
With the quicker spooling turbo you "boosted" your torque in the motors torque rpm window (power band) Now lets jump back to the bike metaphor, this means with the turbo you have pumped up your legs (more "leg torque") and now you can use the upper gears to start off moving faster using "leg torque" getting the most out of gearing and still putting that power to the ground. Now since you have more power in the lower RPM range you also spread out your power band because you are moving faster at a lower leg RPM. In the car it means you can use that higher geared differential to turn your motor's higher torque into more wheel torque at lower RPMs, aka: More power and speed.
This principle is why that screaming 10,000 rpm, huge turbo powered honda seems to have so much "power" In reality it doesn't, the turbo is dumping torque into the upper RPMs just so it can trade it off for lots of wheel torque. It's also why you see so many dead hondas (and other high RPM cars) too... They are asking the motor to spin faster which is very violent and detrimental to a engine with so many moving parts. The wankel rotary motor is perfect for high RPMs (less moving parts) but that is another story....
Now I hope some of you get this and understand why torque is more important than HP. And also explain why a 180hp 460 ft/lbs of torque huge diesel powered truck can actually move very fast. Also why lower gears makes cruising on the highway going 60 mph @ 3500 RPMs very stupid because your motor is just spinning it's legs and going "nowhere fast".