MoTeC Global Forum

Hi ,

I am wondering on how far fuel temperature can make tolerance on ignition timing to go a bit aggressive
Let’s assume we cool it down from 40c to 5c
A pump gas 98 octane

Hi Victor,

Which ECU are you using?

From experience, cooling the fuel without a matching change in the default Fuel Temperature set in the ECU, will make the engine run rich, and a change from 40° to 5° will move the Lambda from around 1.00 to 0.85 at idle without any other changes. Having a Fuel Temperature sensor in an M1 will compensate for this.

When it comes to Ignition control, there will be an effect, but not as much. There are a lot of variables in play when it comes to Ignition advance, so whilst having more charge cooling can assist, having a denser mix in the combustion chamber can increase the dynamic compression ratio and increase to possibility of an abnormal ignition event occurring.

Stephen Dean wrote:Hi Victor,

Which ECU are you using?

From experience, cooling the fuel without a matching change in the default Fuel Temperature set in the ECU, will make the engine run rich, and a change from 40° to 5° will move the Lambda from around 1.00 to 0.85 at idle without any other changes. Having a Fuel Temperature sensor in an M1 will compensate for this.

When it comes to Ignition control, there will be an effect, but not as much. There are a lot of variables in play when it comes to Ignition advance, so whilst having more charge cooling can assist, having a denser mix in the combustion chamber can increase the dynamic compression ratio and increase to possibility of an abnormal ignition event occurring.

Hi Stephen,
Thanks for your fast reply
I am using M150 and fuel temp is connected but as i am limited on the competition on pump gas 98 i am looking for every single space to make power as i will be knock limited so , if cooling fuel temp will rise the knock limit this would help to add another 2-3 psi of boost
,
I would be appreciated also someone look for everything that can help
- fuel temp
- air charge temp

Also i am considering the oil nozzle spray underneath the piston( factory design )if this can cool down piston and keep pushing power on “pump gas “

Thanks

Keeping the inlet air temp as low as possible will also assist, as will the oil squirters.