Discussion
May be a daft question, but do the AJP8 engines have a rev limiter? I don't want to just rev it to find out.
If not, what is max revs for standard 4.5 engine?
These may seem like daft questions but every car I've had for the last 25 years has had a rev limiter so they have been "play and forget". With the Cerbera I'm too busy watching the scenery pass in a blur to look down at the rev counter.
If not, what is max revs for standard 4.5 engine?
These may seem like daft questions but every car I've had for the last 25 years has had a rev limiter so they have been "play and forget". With the Cerbera I'm too busy watching the scenery pass in a blur to look down at the rev counter.
The soft/hard cut ignition is not implemented in the Cerbera MBE 941 ECU
The 'rev limiter' is a bunch of zeroes in the fuel map.
IIRC its at 8250 so the fuel drops away from 8000
However, a few sites after the fuel is back so if you manage to rev it past 8750 it will be fully fuelled again
The 'rev limiter' is a bunch of zeroes in the fuel map.
IIRC its at 8250 so the fuel drops away from 8000
However, a few sites after the fuel is back so if you manage to rev it past 8750 it will be fully fuelled again
Nickccc said:
That's odd, mine has one for sure.
But it seems to have the soft cut, then if you push on it kills all fuel, spose it could be mapped like that, a bit less fuel then none.
I did rip the ECU with easy map and that showed a hard and soft cut, maybe the red roses are a bit different.
The ECU interpolates a value between the value at 8000 and the 0 at 8250. So the fuel trails off once the engine is beyond 8000rpm.But it seems to have the soft cut, then if you push on it kills all fuel, spose it could be mapped like that, a bit less fuel then none.
I did rip the ECU with easy map and that showed a hard and soft cut, maybe the red roses are a bit different.
Trackcar and I tried the soft and hard cut limits by changing them to 2,500 rpm but they had no effect. So I'm sure they are not implemented in the earliest software. (the version in my 98 4.2)
We didn't try it on the later versions but I doubt it was added. The V8 Cerbera ECU feature set seems to have remained fairly constant. The only addition I can think of is the oil pressure added to the Speed6 version.
The shift light is driven from a separate output that turns the buzzer and light on. The input is rpm vs speed and the 4.5 chip is set to turn on the shift light at 7000 rpm for all 15 throttle positions.
There isn't any direct relationship between the fuel map and the shift light - but they are both driven by rpm and throttle position.
There isn't any direct relationship between the fuel map and the shift light - but they are both driven by rpm and throttle position.
dempsey said:
On trackdays I rev my 2002 4.5 RR to 7500 - I don't get any MIL light, beeping or fuel cutoff.
Has your car had any work done at TCS? Joo can change the shift light map if requested.
I've not seen any standard chips that didn't have the shift light coming on at 7000 (4.5) or 6750 (4.2)
I never rev mine beyond 7250 or so out of mechanical sympathymikesr said:
dempsey said:
On trackdays I rev my 2002 4.5 RR to 7500 - I don't get any MIL light, beeping or fuel cutoff.
Has your car had any work done at TCS? Joo can change the shift light map if requested.
I've not seen any standard chips that didn't have the shift light coming on at 7000 (4.5) or 6750 (4.2)
OK. Now I'm confused (not hard to achieve). Some say they do have rev limiter albeit at quite high revs. Some say they don't.
My standard Dec 97 4.5 probably hasn't if I read things right.
With a re-map is this something that could be added/activated? Is the ecu different for a red rose
My standard Dec 97 4.5 probably hasn't if I read things right.
With a re-map is this something that could be added/activated? Is the ecu different for a red rose
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