Discuss all things tuning in this section. News, products, problems and results.
first, I would like to thank you guys for the great tunning courses that you provide.
I had completed all the basic courses and the Reflashing course also, but now I want to know the concept of fuel economy tuning and exhaust pops on low load tuning, and how we can do it.
thank you :)
Hi Alaa and thanks for the kind words!
As far as fuel economy goes, if you're reflashing a stock engine then there's often a limit to what you can achieve since they will typically run in closed loop under idle and cruise targeting 14.7:1. You can often find a small improvement in fuel economy by tuning for about 15.0-15.2:1. You also want to make sure that your ignition timing in the cruise areas is optimised to MBT and if you have cam control you also want the cam angles optimised.
Exhaust pops on overrun requires the over run fuel cut off to be disabled so that fuel is injected when the throttle is closed. Once you've done this you'll need to retard the timing and richen the mixture to get the effect you want.
As always andre a great straight to the point explanation, thanks for the fast reply
They are normally set up a little leaner than stoic'. There is something called 'lean best power' which is the term used when the maximum power per unit of fuel is obtained. It's usually in the high 15's, low 16's, but does vary* so worth testing.
As Andre said, on part throttle there is less charge in the cylinder, so the flame front burns slower and allows more initial timing for best torque/power.
*Stratified and direct injection will use a richer mixture close to the spark plug, for easy ignition, and a much leaner mixture in the rest of the cylinder for economy. Leam mixtures being harder to ignite, especially with variations in fuel distribution, so wider 'plug gaps and/or higher voltage ignitions may be required.