[WrxToBeamerGuy]

So I've been noticing this for a while and I'd like some clarity. Why is it that my tune and my tuning tables don't match up?

In the image you can see that I have a load of approx. 170 and RPM of approx. 6500 which corresponds to about 11.75 deg of timing yet my timing sits at 7 deg instead.

Coolant Temp is 91C and IAT is 53C which corresponds to approximately 0.34 in the timing correction table but I am unsure how that table plays into the base ignition timing table.

[Glemm1970]

IAT +20-35C . +53C Not good.

[weehe126]

It's summer, so when it's 90-100F out 53C is expected.

I'm guessing there are probably other tables being referenced to lower timing more. Throttle position and valvetronic lift should also play a role in timing along with possibly calculated EGT.

[franksidebike]

Hallo
is that dot in the wrong place in the timing correction table?
0.34=3,4°?
Frank

[IMS-340C]

No, the table is a factor not degrees.

Originally Posted by franksidebike

Hallo
is that dot in the wrong place in the timing correction table?
0.34=3,4°?
Frank

[WrxToBeamerGuy]

Originally Posted by weehe126

It's summer, so when it's 90-100F out 53C is expected.

I'm guessing there are probably other tables being referenced to lower timing more. Throttle position and valvetronic lift should also play a role in timing along with possibly calculated EGT.

Yes it was 100F outside lol

I wish I had a flowchart to see what tables are referenced in what order.

[IMS-340C]

I think the DME is multiplying timing request in the tune by (1 minus the correction factor)

11.5 X (1-0.34) = 7

[WrxToBeamerGuy]

Originally Posted by IMS-340C

I think the DME is multiplying timing request in the tune by (1 minus the correction factor)

11.5 X (1-0.34) = 7

Yeah I thought that too! But I was unsure.

Then it makes me wonder if I could lower the limits slightly and monitor for knock.

[IMS-340C]

I got the same result, my timing request 18 degrees at IAT 40C log was 14 degrees.

Originally Posted by WrxToBeamerGuy

Yeah I thought that too! But I was unsure.

[WrxToBeamerGuy]

Originally Posted by IMS-340C

I got the same result, my timing request 18 degrees at IAT 40C log was 14 degrees.

Do the same math and see if your theory is correct

Timing Requested - ( 1 - Timing Requested * Correction Factor)

[IMS-340C]

You mean T - ( 1 - ( T x Factor )) ?

I am wondering what does coolant temp has to do with timing.

Originally Posted by WrxToBeamerGuy

Do the same math and see if your theory is correct

Timing Requested - ( 1 - Timing Requested * Correction Factor)

[WrxToBeamerGuy]

Originally Posted by IMS-340C

You mean T - ( 1 - ( T x Factor )) ?

I am wondering what does coolant temp has to do with timing.

Yes, we both wrote the same equation.

I also don't understand why coolant has a scale and corrections kick in lower than our operating temperature. We should not exceed 112.778C or 235F as that is when the thermostat opens.

IMO these values in the thicker line should be zero.

[WrxToBeamerGuy]

Actually here is a log I took when I went out racing on a very hot day on E55 my IATs are insane but im not sure the timing pull matches with our theory

https://www.bootmod3.net/log?id=62d2...90c60265a43b80

[IMS-340C]

It doesn't, unless your tuner tweaked the temp correction table ?

Originally Posted by WrxToBeamerGuy

Actually here is a log I took when I went out racing on a very hot day on E55 my IATs are insane but im not sure the timing pull matches with our theory

https://www.bootmod3.net/log?id=62d2...90c60265a43b80

[WrxToBeamerGuy]

Originally Posted by IMS-340C

It doesn't, unless your tuner tweaked the temp correction table ?

That's a valid point lol

[IMS-340C]

Easier: T - ( T x Factor )

Originally Posted by WrxToBeamerGuy

Do the same math and see if your theory is correct

Timing Requested - ( 1 - Timing Requested * Correction Factor)

[OldDudesBimmer]

What type of fuel/octane are you running? If using 91 octane and in high temps, it could it be changing over to lower octane timing tables when it senses too much knock (i.e. the retard/timing corrections you see in the log). It's hard to know what is actually in your tank unless you are testing it. I didn't look at logs, but in the data point you shared for review you had a 0.8 correction on one cylinder. If your logs are peppered with corrections, especially larger ones (0.8 and higher), then it wouldn't surprise me if it jumped to using the lower octane timing map. Do you have those handy to look at? Someone also mentioned EGT's, that is also a good thought to log and check.

When I was tuning my 300 whp Golf using 93 octane, on a hot day, the only way I could achieve timing targets and clean logs without lots of corrections was to use E20-25 (or lower the boost a tad until they corrected). The added ethanol did wonders to keep cylinder\EGT temps lower, and ultimately avoid the annoying timing corrections.

[blacksapphire440i]

Originally Posted by OldDudesBimmer

What type of fuel/octane are you running? If using 91 octane and in high temps, it could it be changing over to lower octane timing tables when it senses too much knock (i.e. the retard/timing corrections you see in the log). It's hard to know what is actually in your tank unless you are testing it. I didn't look at logs, but in the data point you shared for review you had a 0.8 correction on one cylinder. If your logs are peppered with corrections, especially larger ones (0.8 and higher), then it wouldn't surprise me if it jumped to using the lower octane timing map. Do you have those handy to look at? Someone also mentioned EGT's, that is also a good thought to log and check.

When I was tuning my 300 whp Golf using 93 octane, on a hot day, the only way I could achieve timing targets and clean logs without lots of corrections was to use E20-25 (or lower the boost a tad until they corrected). The added ethanol did wonders to keep cylinder\EGT temps lower, and ultimately avoid the annoying timing corrections.

[IMS-340C]

We are discussing correction for temps which are not visible in the logs.

Also he has almost no correction for fuel so there's no issue with fuel, 0.8 in one cylinder is not significant.

Originally Posted by OldDudesBimmer

What type of fuel/octane are you running? If using 91 octane and in high temps, it could it be changing over to lower octane timing tables when it senses too much knock (i.e. the retard/timing corrections you see in the log). It's hard to know what is actually in your tank unless you are testing it. I didn't look at logs, but in the data point you shared for review you had a 0.8 correction on one cylinder. If your logs are peppered with corrections, especially larger ones (0.8 and higher), then it wouldn't surprise me if it jumped to using the lower octane timing map. Do you have those handy to look at? Someone also mentioned EGT's, that is also a good thought to log and check.

When I was tuning my 300 whp Golf using 93 octane, on a hot day, the only way I could achieve timing targets and clean logs without lots of corrections was to use E20-25 (or lower the boost a tad until they corrected). The added ethanol did wonders to keep cylinder\EGT temps lower, and ultimately avoid the annoying timing corrections.