Forum » General Tuning Discussion » Compensation / correction for ignition timing v air temp

Compensation / correction for ignition timing v air temp

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 


Page 1
Author
1432 Views

Hi All,

I've just moved from Sydney to Adelaide and am finding the dry heat in Adelaide not agreeing with my 3S-GTE setup (W2A intercooler, forged motor, 24PSI boost).

On hot days my AIT can get up to 65-70 dec C. (I know, and I will change my intercooler setup)

However, in the interim, I have noticed in my Adaptronic, there is no settings in the corrections table for ignition timing versus temperature.

I know all engines are different - but I am looking for a a safe rule of thumb like the theoretical fuel v temp rule of take 3% fuel out per 10 deg C temp increase.

What is a good rule of thumb - take X deg C timing out for every Y deg C above Z deg C ambient temperature.

Values for X, Y, Z ??

you should take a look at the Understanding AFR course, Andre has it covered here:

www.hpacademy.com/courses/understanding-afr/air-temperature-compensation/

I don't want to post up information from one of the paid areas of the site but there is a physics based set of guide values that is all explained and a table is given

Yes. I've done that course. It explains compensation tables for fuel as temperature increases or decreases. I am after similar thing for timing.

There isn't a general rule that you can apply for timing in my own experience - What a particular engine will need is going to depend on how close it's running to knock at normal IAT (20-35 deg for example). What I mean is that some engines that aren't knock limited so to speak may need no reduction in ignition timing at all as IAT increases, or if they do it may only need minimal retard at very high IAT (above 60 deg for example).

The key really is to test and find out what your engine needs. I'll often perform multiple tests back to back on the dyno with the intercooler covered to force the IAT higher and confirm that no knock is occurring.

Hi Andre,

Thanks for getting back on this thread.

I understand what you mean. It's a hard one.

My car (St-185) has been running OK in Sydney, but in Adelaide when the temp gets over 32-33, my AIT goes up to 65-70 and I think I can hear pining. (but it may be the wastegate solenoid) I don't trust my old knock sensor, so I don't want to retard on knock - So I thought I could use the temp correction tables for timing my Adaptronic E440D.

Ie when air temp > 50-55 deg C retard 2-3 deg

I've tuned a 3S-GTE road race car (with FMIC though) for a customer, but on this one I start pulling timing above 50°C by 1 - 2 degrees depending on boost. I increase it by 1 degree every 10°C.

Usually temps never climb that high, but if he's driving in the slipstream of a car in front, I've seen them climb past 60°C from logs.

Thanks mate,

I ended up taking 1 deg out per 5 dec C above 50 - so pretty close to you..

what version of the software\firmware do you have? I know there is a correction for iat vs timing in v14 of adaptronics software under corrections tab

I'm running WARI V14 and the latest version of firwmare in my E440D

Attached Files

That's close enough to what i set,as Andre says there is not rule of thumb but i'll take out 1 deg per 10degC increase starting from 60deg.