Advancing ignition increases or lowers EGTs?

[tristanlee85]

I've been wondering this as of recently mainly because the more I advance my ignition, the better my plugs look. My theory would be that increasing the spark angle would lower readings of EGTs since the fuel is being burned more complete and transferring heat to the piston rather than the exhaust ports.

 

For instance, my original spark advance on my car was 17* @ 9psi. I now have it up to 24* with a bit more noticable power and cleaner plugs. My guess is that at a lower ignition advance, since all of the fuel isn't burning completely, it's collecting in the manifold and generating heat that way where as a more advanced spark will transfer the heat to the piston instead of the exhaust port.

 

I've only come up with this idea based on how some use anti-lag to spool large turbo. For example, if I set my timing to -5* across the board, I can get my turbo to spool at ~80% throttle @ 1800 - 2000 rpms and no engine load and make about 4psi, but all the raw fuel is really heating up the turbine.

 

So, is the higher advance making the EGTs read lower since the heat is going right to the piston rather than the exhaust port since it's burned "more complete"?

[Farkas]

Uhm.. be careful

 

I'm not going to answer your question because I'm sure there are plenty of other people with better advice than me, but I highly suggest getting a wideband meter.

[Dave1647545494]

yes the piston runs hotter on more advance

 

advance the timing enough and you'll burn a hole right through it

 

be carefull

[Total Sign]

No idea on a saturn, but blown big blocks will have cooler EGT's at 34* than at 32*

[mrblunt]

Advancing timing will lower egt's. Retarding timing will raise them. My egt's at WOT are in the 1600 range. I plan on adding a degree or two to lower them a bit. My af's are good so i'm not super worried but I'd like them to be a touch lower. If you don't have forged internals i'd watch how high they are getting.

 

You using the MS to advance the timing?

[tristanlee85]

Yes, I'm using the MS for fuel and spark. I have the AEM wideband so I know my AFR. At WOT of 5psi or above I'm at 12:1 and it goes down to 11.5:1.

 

I don't have an EGT to monitor which is why I was wondering. I just noticed on my last engine where the stock ECU was controlling timing, my plugs had a good bit of aluminum speckales on them which is why one of the pistons was melted. I didn't have a way to monitor the timing being pulled by the stock ECU, but you could definately feel it. I'm guessing it pulled it back to 5* - 10* on anything above atmospheric pressure.

[AJ]

maybe you should look into getting a EGT gauge hooked up. there only about $100 and could save you in the long run. last thing you want to be doing is replacing yet another engine if you don't have to.

[tristanlee85]

It's stock. If it goes it goes. I've got the forged one to put in some day.