Million dollar mod
12-23-2006, 08:45 PM
#1
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Anyone else ever sat down and thought about the benefits of more gears?
I work in the diesel truck trade. Alot of you might not realize that trucks have plenty of gears. This is because the diesel powerband is a narrow 1200 rpm to 1900 rpm (estimated generically in the transport industry).
The transmission has 5 forward gears (low, 1, 2, 3, 4). Internally, it has a ratio splitter on another shaft assembly that is actuated pneumatically to engage, at which point, the truck has another 5 forward gears, all at higher speed ratios than the previous five. Which altogether is 10 speeds.
Some are equipped with a split differential, another pneumatically actuated rear end that has two ratios. This means the truck has 20 speeds (low is hardly considered a speed since the reduction is so slow, so they are just called 18 speeds).
Recently for a special heavy haul application, we took an 18 speed highway truck and added another splitter box between the transmission and split diffs for extra reduction. Bringing our truck to a whopping 36 speeds. WOT in low gear, low diff range, and low splitter range yielded a speed no faster than a man could walk. Of course, the amount of torque it was producing just to get going, it would pull just about anything with that kind of reduction. The more I looked into it, the more I noticed the other companies in extreme heavy haul actually neccessitate use of splitter boxes, split differentials, and 18 speed transmissions. The technology in heavy haul driveline alone is staggering (see Premay - Transport Architects). Few pictures in there of extreme heavy haul.
Remeber, the diesel powerband is very low, and they are designed for hauling weight. This techonology can be applied to race cars. I've read about this over and over and seldom do I see it make it's way to racing.
Many have had the pleasure of driving a 6 speed sports car over a 5 speed. Some have been around for the days of the 4 speed. What's the difference? Well the more gears you have, the more your car "hangs out" in the powerband.
Imagine 7, 8, or 9 speeds? Imagine your peak horsepower and torque band being applied to your wheels more often? Imagine losing that laggy area of your shift (although some of you don't really recognise it with high horsepower).
What if applying maximum power to the wheels was your neccessity?
Just food for thought I guess.. I recommend anyone who can get their feet wet in driveline technology just to jump right in. Some of the creations out there are just as technologically advanced as the motor that turns the input shaft.
I work in the diesel truck trade. Alot of you might not realize that trucks have plenty of gears. This is because the diesel powerband is a narrow 1200 rpm to 1900 rpm (estimated generically in the transport industry).
The transmission has 5 forward gears (low, 1, 2, 3, 4). Internally, it has a ratio splitter on another shaft assembly that is actuated pneumatically to engage, at which point, the truck has another 5 forward gears, all at higher speed ratios than the previous five. Which altogether is 10 speeds.
Some are equipped with a split differential, another pneumatically actuated rear end that has two ratios. This means the truck has 20 speeds (low is hardly considered a speed since the reduction is so slow, so they are just called 18 speeds).
Recently for a special heavy haul application, we took an 18 speed highway truck and added another splitter box between the transmission and split diffs for extra reduction. Bringing our truck to a whopping 36 speeds. WOT in low gear, low diff range, and low splitter range yielded a speed no faster than a man could walk. Of course, the amount of torque it was producing just to get going, it would pull just about anything with that kind of reduction. The more I looked into it, the more I noticed the other companies in extreme heavy haul actually neccessitate use of splitter boxes, split differentials, and 18 speed transmissions. The technology in heavy haul driveline alone is staggering (see Premay - Transport Architects). Few pictures in there of extreme heavy haul.
Remeber, the diesel powerband is very low, and they are designed for hauling weight. This techonology can be applied to race cars. I've read about this over and over and seldom do I see it make it's way to racing.
Many have had the pleasure of driving a 6 speed sports car over a 5 speed. Some have been around for the days of the 4 speed. What's the difference? Well the more gears you have, the more your car "hangs out" in the powerband.
Imagine 7, 8, or 9 speeds? Imagine your peak horsepower and torque band being applied to your wheels more often? Imagine losing that laggy area of your shift (although some of you don't really recognise it with high horsepower).
What if applying maximum power to the wheels was your neccessity?
Just food for thought I guess.. I recommend anyone who can get their feet wet in driveline technology just to jump right in. Some of the creations out there are just as technologically advanced as the motor that turns the input shaft.
12-24-2006, 02:17 PM
#3
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Join Date: Jun 2004
Posts: 524
1200 to 1900 isn't all that narrow, in comparison. Multiply by five and you have 6000 to 9500, wider than many performance rotary powerbands.
Regardless, more, closer gears is nice to have, but more gears also means a transmission that is either larger, heavier, and with more rotational inertia, or weaker. Or both. Plus, with an H-gate, reasearch has shown that beyond seven gears, it can be easy to get lost in the gate.
Peugeot concentrated on giving their WRC engines a wider powerband so that they could run a four speed transmission instead of a six speed. Bear in mind that they have electronically aided sequential transmissions, so "getting lost" is not a problem. They must have seen some significant advantage in having fewer gears to go that route.
Regardless, more, closer gears is nice to have, but more gears also means a transmission that is either larger, heavier, and with more rotational inertia, or weaker. Or both. Plus, with an H-gate, reasearch has shown that beyond seven gears, it can be easy to get lost in the gate.
Peugeot concentrated on giving their WRC engines a wider powerband so that they could run a four speed transmission instead of a six speed. Bear in mind that they have electronically aided sequential transmissions, so "getting lost" is not a problem. They must have seen some significant advantage in having fewer gears to go that route.
12-24-2006, 04:16 PM
#4
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Location: Ireland
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I definitely agree with what you're saying - I just got an old golf gti which has the closest ratio box I've ever seen in a car - top speed is probably around 120mph bouncing off the limiter, but the other thing it does is it means you don't have to rev out of the powerband to land in it again! It makes the car an absolute joy to drive (apart from motorways maybe 
).
12-25-2006, 06:13 PM
#6
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Well, I'm not entirely sure about how to go about a little project like this or where to begin really.
Just wanted to stimulate some minds..
The trucks still use H-gates, but there is an air switch for the pneumatic actuation of the splitter. Air switch on the shifter itself. The beauty part is it is done on the fly. It's all in knowing how to drive it. For example, picture your 5 speed ****. Replace 1,2,3,4,5,R, with: R,Low,1-5,2-6,3-7,4-8. Lets row through all the way up to 8th. 1 accelerate to top revs, shift to 2 accelerate, shift 3 accelerate, shift 4 acc-flipswitch-elerate, sh*click*ift 5 accelerate, shift 6 accelerate, shift 7 accelerate, shift 8 accelerate. The pneumatics are part engaged during 4th gear with no damage to anything. The second you pull it out of 4th, the split fully engages long before you even go to stick your shifter from 4 back in to "would-be-1-but-now-is-5"
All you have to do is at some point during your acceleration motion in 4th is flip the pneumatic switch, and you have nothing else to worry about. You can clearly see what gear range you are in by the position of the switch. Sure you could get lost, but truckers are doing this across north america every day. I'm sure any one of us could figure it out.
Notice the lever where your index and middle finger would be? It's a simple up down switch.
Of course it has since been gone over again, and they have another range splitter (on most trucks generally) at your thumb position. So those models have one at your finger and one at your thumb.
It really doesn't take too long to get to know how to work the range splitters. I learned flawlessly just driving them in and out of the shop. Of course I was using a low diff range so shifting to 5th was still yeilding a small MPH.
Just wanted to stimulate some minds..
The trucks still use H-gates, but there is an air switch for the pneumatic actuation of the splitter. Air switch on the shifter itself. The beauty part is it is done on the fly. It's all in knowing how to drive it. For example, picture your 5 speed ****. Replace 1,2,3,4,5,R, with: R,Low,1-5,2-6,3-7,4-8. Lets row through all the way up to 8th. 1 accelerate to top revs, shift to 2 accelerate, shift 3 accelerate, shift 4 acc-flipswitch-elerate, sh*click*ift 5 accelerate, shift 6 accelerate, shift 7 accelerate, shift 8 accelerate. The pneumatics are part engaged during 4th gear with no damage to anything. The second you pull it out of 4th, the split fully engages long before you even go to stick your shifter from 4 back in to "would-be-1-but-now-is-5"
All you have to do is at some point during your acceleration motion in 4th is flip the pneumatic switch, and you have nothing else to worry about. You can clearly see what gear range you are in by the position of the switch. Sure you could get lost, but truckers are doing this across north america every day. I'm sure any one of us could figure it out.
Notice the lever where your index and middle finger would be? It's a simple up down switch.
Of course it has since been gone over again, and they have another range splitter (on most trucks generally) at your thumb position. So those models have one at your finger and one at your thumb.
It really doesn't take too long to get to know how to work the range splitters. I learned flawlessly just driving them in and out of the shop. Of course I was using a low diff range so shifting to 5th was still yeilding a small MPH.
12-26-2006, 07:47 AM
#7
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Location: Ireland
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You're thinking of doing this on a car? I'd love to see it! I can't think of how you'd retro fit something like that to a car gearbox - you'd have to have a kind of seperate reduction gearbox somewhere along the line?
A problem you get with some bike engines for kitcars is that the output rotates far too fast to use with a standard ratio diff - so what I've seen done once or twice is they fit a car gearbox backwards in between the bike's gearbox and the propshaft! Not really a solution if you ask me, not sure that a gearbox would like being run backwards and that's a lot of extra pointless weight - but the idea of having ~30 gears is cool - would make setting the car up for different circuits pretty easy!
Heretic - no vw motorsport box, it's still a daily driver - but at the same time I'd be surprised if 5th wasn't pretty close to 1.00
A problem you get with some bike engines for kitcars is that the output rotates far too fast to use with a standard ratio diff - so what I've seen done once or twice is they fit a car gearbox backwards in between the bike's gearbox and the propshaft! Not really a solution if you ask me, not sure that a gearbox would like being run backwards and that's a lot of extra pointless weight - but the idea of having ~30 gears is cool - would make setting the car up for different circuits pretty easy!
Heretic - no vw motorsport box, it's still a daily driver - but at the same time I'd be surprised if 5th wasn't pretty close to 1.00
12-26-2006, 10:25 AM
#8
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Well not 30 gears.. Just utilizing some of the driveline technology for a little more versatility on a road car.
I was thinking more of a small splitter box with a 1:1 ratio and a smaller ratio, and being able to shift between splits on the fly.
Considering most of our cars have independent rear suspension, calculating driveline angles is way easier if you were to incorperate a splitter between the trans and diff.
I was thinking along the lines of having a simulated split differential with the box. And being able to change on the fly could prodouce something like rowing 1-5, shifting the split back to 1:1 from low range and reusing 4th and 5th gears again. Of course the math comes into play as to finding out which gears are virtually doubled with the split. 4-Low and 3-High might be pretty close to the same ratio with the splitter box massaging the output speed.
That or just using low range 1-5 in city/short courses (depending on your application) and 1:1 range 1-5 during highway/broad courses, maybe using a 3.9 final drive diff rather than my stock 4.1.
A simple two gear splitter box that can handle the output power of a 13B has potential to be pretty compact.
I was thinking more of a small splitter box with a 1:1 ratio and a smaller ratio, and being able to shift between splits on the fly.
Considering most of our cars have independent rear suspension, calculating driveline angles is way easier if you were to incorperate a splitter between the trans and diff.
I was thinking along the lines of having a simulated split differential with the box. And being able to change on the fly could prodouce something like rowing 1-5, shifting the split back to 1:1 from low range and reusing 4th and 5th gears again. Of course the math comes into play as to finding out which gears are virtually doubled with the split. 4-Low and 3-High might be pretty close to the same ratio with the splitter box massaging the output speed.
That or just using low range 1-5 in city/short courses (depending on your application) and 1:1 range 1-5 during highway/broad courses, maybe using a 3.9 final drive diff rather than my stock 4.1.
A simple two gear splitter box that can handle the output power of a 13B has potential to be pretty compact.
12-26-2006, 11:01 AM
#9
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Why not dabble more in advancing the CVT? Of course that probably wouldn't be good for hauling loads, but for a sports car, it could have great benefits. Engineer the engine to operate best at a single rpm, and let the CVT do the ratio-choosing.
12-26-2006, 11:51 AM
#10
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Originally Posted by ColinRX7' post='850243' date='Dec 25 2006, 04:13 PM
Well, I'm not entirely sure about how to go about a little project like this or where to begin really.
Just wanted to stimulate some minds..
Just go to Quaife and buy their range-change gearbox. Available with steel or aluminum maincase, synchromesh or dog ring.
http://www.quaife.co.uk/Ford-Rocket-Comple...-alloy-maincase
If you don't mind a PDF, you can see the ratios and a better image
http://www.quaifeamerica.com/downloads/14-26.pdf here on page number 15.
Picture a nice racing 4-speed, with a gear-splitter activated by rotating the shift **** 90 degrees.