EGT Manifold temp vs Filtered EGT temp

[theclutch]

Can anyone tell me the difference between EGT Manifold temp readout vs the Filtered EGT temp? I'm trying to figure out which would be a better EGT readout especially if I track the car every so often.

 

[Joe_Mama]

Better read out for what? One is the pre cat temp the other is the post cat temp.

 

[theclutch]

Better read out for what? One is the pre cat temp the other is the post cat temp.

Doh! That explains it... thanks! I didn't catch that "filtered EGT" meant "catalytic converter filtered". I thought it was some sort of other electronic trickery/adjustment that VW was doing.

So having said that, when people talk about measuring "EGT temps" whether it's for track or tuning or both, which EGT temp reading do people usually refer to? Before or after the cat?

Thanks in advance!

 

[Joe_Mama]

I would think the pre cat temp would be the one to quote if you're looking for exhaust temps right from the engine. So the manifold egt

 

[theclutch]

During the limited time that I've been watching it, there appears to be up to a 250F difference between the two. Seems like an awfully large drop in temp compared between before and after the cat converter. I suppose that if these two numbers get close to each other when the car is fully warmed up, it means that my cat is dying.