29 replies to this topic

[Cooperman]

You guys must drive very gently if you don't go over 5000 rpm. When 'enjoying' a Mini on twisty roads and using the performance of even a mildly tuned engine, it is quite normal to use up to 6000 rpm in 2nd and 3rd. For example, an MG Metro cam doesn't max until 5700 rpm.
An 1100 engine is fine up to 6000 rpm through the gears. I had a Mini with an MG1100 engine and it would cruise at 5300 rpm on its 10" wheels and 3.76:1 final drive and it was used daily on a 30-mile commute.

[Hegnirst]

You guys must drive very gently if you don't go over 5000 rpm. When 'enjoying' a Mini on twisty roads and using the performance of even a mildly tuned engine, it is quite normal to use up to 6000 rpm in 2nd and 3rd. For example, an MG Metro cam doesn't max until 5700 rpm.
An 1100 engine is fine up to 6000 rpm through the gears. I had a Mini with an MG1100 engine and it would cruise at 5300 rpm on its 10" wheels and 3.76:1 final drive and it was used daily on a 30-mile commute.

cruise at 5300rpm? that doesnt sound right

[dklawson]

Regardless of how you drive your car....

Repeating what I tried to convey earlier,
1) This tach runs on 24V, not 12V
2) This tach is for positive earth, not negative earth
3) This tach uses a separate pulse generator to count crankshaft revolutions

It may look just like what you want but it will take a lot of work to make it function in a car.

[Hegnirst]

Regardless of how you drive your car....

Repeating what I tried to convey earlier,
1) This tach runs on 24V, not 12V
2) This tach is for positive earth, not negative earth
3) This tach uses a separate pulse generator to count crankshaft revolutions

It may look just like what you want but it will take a lot of work to make it function in a car.

as i said, i bought rubbish (the complete wrong thing) XD
you know a hell of a lot. How come you know so much!
every topic i read about technical stuff, your input is just zapping on the mind ahah!

[dklawson]

It's because I am an irritable old person.

I like to share what I know so people don't repeat my mistakes.

[cooperrodeo]

The linearity of rev counters at the end of their range tends to be poor. So, if a 5000rpm meter is reading correctly at about 4000rpm then the engine could be doing the best part of 5500rpm when reading 5000rpm.

It's not that difficult to build a circuit to drive the meter, though admittedly you do need some knowledge of electronics.

[Hegnirst]

It's because I am an irritable old person.

I like to share what I know so people don't repeat my mistakes.

aha! i think your awesome fella! aha

[Carlos W]

Hopefully you'll sell it and make enough money to buy one suited to your needs (or at least get your money back)

[dklawson]

The linearity of rev counters at the end of their range tends to be poor. So, if a 5000rpm meter is reading correctly at about 4000rpm then the engine could be doing the best part of 5500rpm when reading 5000rpm.

It's not that difficult to build a circuit to drive the meter, though admittedly you do need some knowledge of electronics.

Very true. A number of people have taken on the task of making a modern driver for the Smiths electrical movement. Many are based on variations of the 555 timer chip. Another option if you want to tinker with this is to build a circuit based on the LM2907 family of chips. I breadboarded a couple of test circuits using this chip after reading the product datasheet and what others ( a Mr. King in OZ or NZ comes to mind) had done to develop their own board. I did get my breadboard circuit to work but it required the addition of two other sub-circuits for the power supply and an amplifier. I never bothered making a prototype to fit into a gauge. The parts are still on my bench waiting for the day when I work up energy to tinker with it again. The biggest problem with making a new circuit to operate the Smiths movement is that the Smiths meter requires a fair amount of current to move the needle.

[Cooperman]

You guys must drive very gently if you don't go over 5000 rpm. When 'enjoying' a Mini on twisty roads and using the performance of even a mildly tuned engine, it is quite normal to use up to 6000 rpm in 2nd and 3rd. For example, an MG Metro cam doesn't max until 5700 rpm.
An 1100 engine is fine up to 6000 rpm through the gears. I had a Mini with an MG1100 engine and it would cruise at 5300 rpm on its 10" wheels and 3.76:1 final drive and it was used daily on a 30-mile commute.

cruise at 5300rpm? that doesnt sound right

The 998 Cooper had a 3.76 diff and gave about 14.7 mph per 1000 rpm in top gear. So at a max speed of about 88 mph it was pulling 6000 rpm and at an 80 mph cruise it was pulling around 5500 rpm in top (all day long on a motorway). The original Cooper 'S' with the 1071 engine had exactly the same gearing.
Minis do rev and I believe the standard later 998 cam gave max power at about 5200 rpm. With my standard Innocenti Cooper 1300 I am happy to use 6000 rpm in the gears and cruise at 5000 rpm which is almost exactly 80 mph in top with its 3.44:1 final drive ratio.
Most people I know who have fitted a tachometer to a Mini have done so because they are enthusiastic drivers and the most popular tacho is the Smiths 0 - 8000 unit. On the 970 Cooper 'S' my son had he fitted a 0 - 10000 rpm tacho as it pulled round to around 8500 rpm. The 970 'S' - all revs and no go!

[Hegnirst]

You guys must drive very gently if you don't go over 5000 rpm. When 'enjoying' a Mini on twisty roads and using the performance of even a mildly tuned engine, it is quite normal to use up to 6000 rpm in 2nd and 3rd. For example, an MG Metro cam doesn't max until 5700 rpm.
An 1100 engine is fine up to 6000 rpm through the gears. I had a Mini with an MG1100 engine and it would cruise at 5300 rpm on its 10" wheels and 3.76:1 final drive and it was used daily on a 30-mile commute.

cruise at 5300rpm? that doesnt sound right

The 998 Cooper had a 3.76 diff and gave about 14.7 mph per 1000 rpm in top gear. So at a max speed of about 88 mph it was pulling 6000 rpm and at an 80 mph cruise it was pulling around 5500 rpm in top (all day long on a motorway). The original Cooper 'S' with the 1071 engine had exactly the same gearing.
Minis do rev and I believe the standard later 998 cam gave max power at about 5200 rpm. With my standard Innocenti Cooper 1300 I am happy to use 6000 rpm in the gears and cruise at 5000 rpm which is almost exactly 80 mph in top with its 3.44:1 final drive ratio.
Most people I know who have fitted a tachometer to a Mini have done so because they are enthusiastic drivers and the most popular tacho is the Smiths 0 - 8000 unit. On the 970 Cooper 'S' my son had he fitted a 0 - 10000 rpm tacho as it pulled round to around 8500 rpm. The 970 'S' - all revs and no go!

i stand corrected then aha

[Cooperman]

You guys must drive very gently if you don't go over 5000 rpm. When 'enjoying' a Mini on twisty roads and using the performance of even a mildly tuned engine, it is quite normal to use up to 6000 rpm in 2nd and 3rd. For example, an MG Metro cam doesn't max until 5700 rpm.
An 1100 engine is fine up to 6000 rpm through the gears. I had a Mini with an MG1100 engine and it would cruise at 5300 rpm on its 10" wheels and 3.76:1 final drive and it was used daily on a 30-mile commute.

cruise at 5300rpm? that doesnt sound right

The 998 Cooper had a 3.76 diff and gave about 14.7 mph per 1000 rpm in top gear. So at a max speed of about 88 mph it was pulling 6000 rpm and at an 80 mph cruise it was pulling around 5500 rpm in top (all day long on a motorway). The original Cooper 'S' with the 1071 engine had exactly the same gearing.
Minis do rev and I believe the standard later 998 cam gave max power at about 5200 rpm. With my standard Innocenti Cooper 1300 I am happy to use 6000 rpm in the gears and cruise at 5000 rpm which is almost exactly 80 mph in top with its 3.44:1 final drive ratio.
Most people I know who have fitted a tachometer to a Mini have done so because they are enthusiastic drivers and the most popular tacho is the Smiths 0 - 8000 unit. On the 970 Cooper 'S' my son had he fitted a 0 - 10000 rpm tacho as it pulled round to around 8500 rpm. The 970 'S' - all revs and no go!

i stand corrected then aha

"Give it some stick!"

[stevede]

The linearity of rev counters at the end of their range tends to be poor. So, if a 5000rpm meter is reading correctly at about 4000rpm then the engine could be doing the best part of 5500rpm when reading 5000rpm.

It's not that difficult to build a circuit to drive the meter, though admittedly you do need some knowledge of electronics.

Very true. A number of people have taken on the task of making a modern driver for the Smiths electrical movement. Many are based on variations of the 555 timer chip. Another option if you want to tinker with this is to build a circuit based on the LM2907 family of chips. I breadboarded a couple of test circuits using this chip after reading the product datasheet and what others ( a Mr. King in OZ or NZ comes to mind) had done to develop their own board. I did get my breadboard circuit to work but it required the addition of two other sub-circuits for the power supply and an amplifier. I never bothered making a prototype to fit into a gauge. The parts are still on my bench waiting for the day when I work up energy to tinker with it again. The biggest problem with making a new circuit to operate the Smiths movement is that the Smiths meter requires a fair amount of current to move the needle.

Or, you could do what I did when I bought the wrong one! (Idea inspired by DK Lawson)

http://www.theminifo...x...5702&st=495

You'll need to scroll down the page a bit

Regards

Steve

[Hegnirst]

You guys must drive very gently if you don't go over 5000 rpm. When 'enjoying' a Mini on twisty roads and using the performance of even a mildly tuned engine, it is quite normal to use up to 6000 rpm in 2nd and 3rd. For example, an MG Metro cam doesn't max until 5700 rpm.
An 1100 engine is fine up to 6000 rpm through the gears. I had a Mini with an MG1100 engine and it would cruise at 5300 rpm on its 10" wheels and 3.76:1 final drive and it was used daily on a 30-mile commute.

cruise at 5300rpm? that doesnt sound right

The 998 Cooper had a 3.76 diff and gave about 14.7 mph per 1000 rpm in top gear. So at a max speed of about 88 mph it was pulling 6000 rpm and at an 80 mph cruise it was pulling around 5500 rpm in top (all day long on a motorway). The original Cooper 'S' with the 1071 engine had exactly the same gearing.
Minis do rev and I believe the standard later 998 cam gave max power at about 5200 rpm. With my standard Innocenti Cooper 1300 I am happy to use 6000 rpm in the gears and cruise at 5000 rpm which is almost exactly 80 mph in top with its 3.44:1 final drive ratio.
Most people I know who have fitted a tachometer to a Mini have done so because they are enthusiastic drivers and the most popular tacho is the Smiths 0 - 8000 unit. On the 970 Cooper 'S' my son had he fitted a 0 - 10000 rpm tacho as it pulled round to around 8500 rpm. The 970 'S' - all revs and no go!

i stand corrected then aha

"Give it some stick!"

i do, 4000 for me is around 85-90

[dklawson]

Thanks for the nod Steve. Your work on the tach conversion is spectacular. Absolutely great work... and doesn't it make you feel good too?