Running in an unmapped engine
Discussion
What would be the best way to run in an unmapped engine? Say you just rebuilt an engine, new rings, bearings etc, but you swapped cams or turbocharged it so at the same time you've gone for a standalone ECU.....
I've read about hard running in procedures which makes sense to me, but if it's not mapped properly you surely can't run it hard? So you map it first, but surely this takes some gentle running too, getting it perfect throughout the revs, but by the the time it's mapped well enough to run it hard would it then not be too late for the rings to bed in nicely?
I've read about hard running in procedures which makes sense to me, but if it's not mapped properly you surely can't run it hard? So you map it first, but surely this takes some gentle running too, getting it perfect throughout the revs, but by the the time it's mapped well enough to run it hard would it then not be too late for the rings to bed in nicely?
The "trick" is not to spend too long phaffing around before you get some load onto the engine!
To this end, stick in some nice "warm" plugs to start with, which will make getting the inital starting and cold start cal working a lot easier
Then just do as little mapping as you can to get to the point where it will start and idle relatively reliably (no point going to a rolling road etc and having problems / wasting time just with starting)
Don't get too carried away, turn off any trick stuff like lambda control/ idle control/ ALS etc etc.
1st job is to ensure your "Load determination" is stable and repeatable (TPS or MAP based etc) and that you engine speed and position sensing is working without sync errors.
2nd job is to calibrate the ignition offset with a timing light, to make sure that when the ems says "TDC" it really is firing at tdc.
These basic checks should really take no longer than perhaps a total of 30mins running, trying to avoid too much "cold" running.
Then, get the car to a set of rollers, or test facility where you can start to load the engine a bit. Once you have mapped up to say 3000rpm and 50% throttle, it is probably worth spending approx 20-30mins just running the warm engine through a few speed and load sweeps to bed it in a bit (checking for the usually leaks /funny noises etc
On my car, i have a nice hydraulic handbrake and large rear discs, so i could do a bit on running on the sill stands just aginst the brakes for a few mins to start getting a feel for the fuelling curve at low throttle settings.
It's not really worth spending too much time on ignition settings until you can get some load onto the engine, so just set starting to 5deg, and everywhere else to 20deg, avoiding large steps, especially just on the idle operating point etc
Remember to swap back to the proper grade spark plugs however before doing any high load work!!!
To this end, stick in some nice "warm" plugs to start with, which will make getting the inital starting and cold start cal working a lot easier
Then just do as little mapping as you can to get to the point where it will start and idle relatively reliably (no point going to a rolling road etc and having problems / wasting time just with starting)
Don't get too carried away, turn off any trick stuff like lambda control/ idle control/ ALS etc etc.
1st job is to ensure your "Load determination" is stable and repeatable (TPS or MAP based etc) and that you engine speed and position sensing is working without sync errors.
2nd job is to calibrate the ignition offset with a timing light, to make sure that when the ems says "TDC" it really is firing at tdc.
These basic checks should really take no longer than perhaps a total of 30mins running, trying to avoid too much "cold" running.
Then, get the car to a set of rollers, or test facility where you can start to load the engine a bit. Once you have mapped up to say 3000rpm and 50% throttle, it is probably worth spending approx 20-30mins just running the warm engine through a few speed and load sweeps to bed it in a bit (checking for the usually leaks /funny noises etc
On my car, i have a nice hydraulic handbrake and large rear discs, so i could do a bit on running on the sill stands just aginst the brakes for a few mins to start getting a feel for the fuelling curve at low throttle settings.
It's not really worth spending too much time on ignition settings until you can get some load onto the engine, so just set starting to 5deg, and everywhere else to 20deg, avoiding large steps, especially just on the idle operating point etc
Remember to swap back to the proper grade spark plugs however before doing any high load work!!!
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