QuestionHi Dan, I'm installing a data logger on my stock racing engine, its a SBC 305 which has apprx. 270hp. What exhaust gas temp should I be seeing and what advice can you give me to lower or raise the egt's.
Thanks
Bruce
AnswerHi Bruce!
EGT is controlled by ignition timing advance (use about 34 degrees 'all in' for starters) and your fuel mixture.
Aluminum starts to melt around 1350 Deg. F. But in my race cars I try for about 1400 topped out in high gear. Anything more is flirting with the motor meanies.
To alter your EGTs, you will probably have to put an electronic rheostat in line with your cylinder head temperature sender. This will allow you to alter your fuel mixture somewhat. You can't make your test runs at a drag strip , cuz you aren't running at full revs long enough to get accurate readings.
On a circle track, run about 5 laps hot, and read the guages at the end of the longest straight. Do this BEFORE coming to the turn in point though (!) If it's a road racer, read at the end of the longest straight, also after about 5 hot laps.
You can look at your plugs too, if you see tiny flecks of black on them, richen it up a tad, if they're still there after another run, back the timing off a notch. (a notch is about 2 Deg. ) Also , the color of the internal insulator should be VERY light coffee/crream color, if they're poure white , you're too lean, or timing is too far advanced or both. Never change more than one thing at a time. EVER !
Note, the little black flecks are bits of aluminum from your piston crowns- - - don't think you can get away with this for any length of time.
If you will go to <www.summitracing.com > find their tech line, and call them , you may be able to get some better info from someone who works with FI engines regularly. Their tech guys are REAL good .
Hope this is a help!
Dan Liddy
Sarasota, Florida
