what is the 400 redline and how does the ECU handle max revs

[twobone]

I think I hit the rev cut off rather abruptly.

What is redline and how does the ECU deal with it? Is it fuel cut or ignition cut?

[Sardonicus]

twobone said:

I think I hit the rev cut off rather abruptly.

What is redline and how does the ECU deal with it? Is it fuel cut or ignition cut?

Fuel cut only, it differs be it 4.0 or 4.0 HC (lumpy cam) model from memory its around 6250 for the HC but its all over before that ceiling

[HiAsAKite]

twobone said:

I think I hit the rev cut off rather abruptly.

Yup...that feels about right...!

[davep]

twobone said:

I think I hit the rev cut off rather abruptly.

What is redline and how does the ECU deal with it? Is it fuel cut or ignition cut?

Here's the theory: The ECU has a maximum RPM limit value (set in the respective fuel map data section), for the majority of TVR tunes this is 5800 RPM for the 4 litre and 6188 RPM for the 450/500 variants. Using the spark period an engine RPM value is calculated, immediately this value gets close to the maximum (there is safety margin of 75 or 100 RPM) a throttle position sensor derived value is checked more frequently and adjusted downwards if needed. If after this adjustment the throttle position value continues to remain high it is sent towards zero and the injector pulse width adjusted accordingly for cut off.