11 replies to this topic

[Tornado99]

What is a reasonable rev limit/redline to set on my newly fitted Smiths tacho on my 1275 c.c. Mini?

I have it presently at 6500 rpm.

Also are there any electronic ignitions on these car that have rev limiter functions?

[InnoCooperExport]

123Ignition Tune is an electronic Dizzy that you can programme by Bluetooth or USB (depending on the version) and you can set a rev limit in that which works by advance spark stealing apparently. 

[timmy850]

There’s lots of choice in units that purely limit the rpm. It would interrupt the signal between distributor and coil when you reach the set figure

Eg
https://www.murraymo...NRoCLu4QAvD_BwE

[MiniMadRacer]

The REV limit should be set based on the build, so what CAM you have head, etc etc...and of course what crank and rods and how you balanced it all up...many people rev an engine well beyond the useful power bands of the equipment they have installed

[Tornado99]

The REV limit should be set based on the build, so what CAM you have head, etc etc...and of course what crank and rods and how you balanced it all up...many people rev an engine well beyond the useful power bands of the equipment they have installed

Well I don't have specs for my engine other than a 1275 running a HS4 single carb. I presume it is stock cam and nothing special going on internally. Seems to pull well up to 5k but I have not gone much higher to see what lies beyond that!

[Ethel]

Standard MG Metro peaked at 6000rpm. That's the top of the tree as they came from the factory really.

[cal844]

My 998 gets revved to 6000rpm (Nippon Seiki guage red line ) regularly, it might even rev higher on a downshift as i listen to the engine more than looking at the guage

[Zach P-D]

Have my omex set to soft cut at 7250
Fully built 1310 by the way.

[nev100]

Apart from a Dyno how can it be calculated??

Appreciate its probably tricky....

[Cooperman]

I was told many years ago by a very successful engine builder that the rev limit should be considered as 500 rpm above the point at which max bhp is developed with a bit extra for a full race engine like 10% above max bhp revs.

That has always seemed to work and, typically, an MG Metro cam gives max power at 5700 rpm and 6200 rpm is good for the red line.

I have a car with a 286 cam and that gives max power at 6400 rpm. I have set my red line at 7000 rpm.

[Ethel]

Apart from a Dyno how can it be calculated??

Appreciate its probably tricky....

 

Take the direct approach & use your smart phone as an accelerometer. The question you're really asking is which gear will give you the most acceleration at a specific road speed.

 

Do a flat out run in one gear, then the other & see at what speed the acceleration plots cross. Convert that speed in to rpm for the  shorter gear.

 

 

Though, if you're looking for a true red line you'd have to thrash it until something breaks 

[Spider]

While not fitted with a Tacho, the 'Red Line' for the (original 60's) Cooper S was 6500.

These same engines were fitted to our locally produced Clubman GT (different car to the 1275 GT), which were fitted with a Tacho, and that was where they had the red Line set on them. I think the early 1275 GT also had the same or similar Tacho, but later dropped that to a 6000 Red Line.

 

In the case of the standard Cooper S Engine, they'd run out of breath around the 6300 - 6500 mark, so not point going any further.