"Normal" EGT's?

[klaw]

Does anyone have EGT pyrometers in their FI 3V? Is it better to install them in a primary and get a more accurate reading on one cylinder or at the collector and get and average albeit further down the exhaust? What EGT's do you see at idle, cruise, and WOT?

I'm trying to track down a "problem" where my headers start to glow under cruise on the dyno. My tuner doesn't believe it's a problem with the tune and thought it was a physical cam timing issue. I've torn the engine covers off and confirmed that the cam timing is fine. The datalogs for the cruise look fine (apparently) but the session was aborted due to the header glow and the tune therefore is still far from optimized.

I'm planning on installing pyros in the collectors on each side to see what the actual temps are.

The basics are: 298 stroker at 9.1:1, stage III heads, stageII blower grind cams, Whipple HO at 15psi (Steeda 10-rib drive), 60#/hr injectors, Whipple monoblade TB, Kooks headers w/ catted X.

Any EGT data would be greatly appreciated.

 

[ASRoff]

EGT depends on where you put the probe. the further out you put it the colder it gets. with that said, you need to place the probes and then collect data to see what the engine likes. If the car runs best at 1200* but detonates at 1250* you know what your window is. no two engines are alike due to builds and probe placement. only after "studying" your data can you determine what your EGT should look like.

most exhaust headers glow during cruise. if its at idle then either the timing is wrong or your A/F is screwed up.

 

[Wes]

Agreed on the EGT position determining what you see. There is no set # that you shoot for. Your valves will be rated at a certain temp before they start to soften.

While tuning I use EGT probes as often as I can -- taken with data from a *accurate* wideband you can great a great feel for how an engine is performing and how each cylinder is receiving fuel.

If using multiple probes you want them situated identically - usually 1.5"-2" or so off the head.

Most headers can exhibit some glowing (thinner material than manifolds) at cruise/WOT. Turbos especially with the backpressure. As a general rule if you have detonation the EGT will go down (heat is being dissipated to the head/block before the exhaust valve opens).

Wes

 

[klaw]

Thanks guys - pyros will go in this weekend and then I'm going to get this thing on the road. Will report back what sort of numbers I see.