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Instead of using an A/F meter, why not buy a digital EGT. Tune for the ideal temp. Price 150.00 and up. Was on a chassis dyno about a month ago and A/F showed high 12's low 13's. Yesterday I used a EGT and found I'm running way lean...
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Jack,
Where can I find charts or info correlating A/F ratio to EGT? I would think an A/F analyzer would be a more direct and accurate method of measurement. I am interested in hearing you make the case for Egt tuning. My mind is open on this subject. Steve:) |
EGT is the way to go.
Get your's from Exhaust Gas Technologies, in Anaheim, CA. |
Fixit,
can you post the chart or info correlating EGT to A/F ratio? Or a chart of desirable EGT targets through load ranges? Thanks, Steve :) |
Steve,
Haven't been able to find direct crrelation charts. Optimal way to tune using EGT is first set up engine on engine dyno with EGT and get the temp for max power, you then keep engine in tune to that temp. Carb engines usually make best power in the 1350-1400 range at WOT....higher temps means you're lean and lower temps mean rich. Should have around 600-700 at idle and around 1100-1200 cruisin. Just started using one yesterday to tune car...but now Frances is putting a damper on my testing for a couple of days. |
Jack,
Where in the exhaust stream did you place the probe? is it measuring one cyl or after the merge? Steve |
I've got it on a long runner and about an inch from the head flange. You drill a 3/16 hole in the header then stick the probe in the hole and it has a radiator like clamp. Then run the probe line through the firewall and I've got the digital read out sitting on the hump. You can unplug it and take it out at any time and just put a sheet metal screw in the hole.
Here's a link to some EGT gauges. http://www.biondoracing.com/DataRecorders.shtml |
Here is a coated piston, ceramic coated on the dome to help preventy against piston damage from detonation and/or lean-high temp conditions. The skirt is coated with a dry film lubricant to help reduce friction. How much it makes a difference, I don't know, but I think it was about an extra $50 to have all the pistons coated
[IMG]http://www.clubcobra.com/photopost/d...piston-med.jpg [/IMG] |
Jack,
Thanks for that info. I have some research to do.:) Steve |
Anthony,
I remember meeting you at one of the Spring Flings. You have an interesting photo gallery. Are all those cool parts yours? Back to the subject, I'm not sure the coating would have helped my friend. The detonation seems to have started where the head of the piston meets the top ring. Today we more or less confirmed the prevailing theory of detonation. As I cleaned the combustion chamber that bore the brunt of the failure, I found erosion along where the head gasket seals the combustion chamber.... Just above the area on the piston that was effected. We removed the valves, cleaned them, then did a dye check for contact with the seats. They survived just fine. I will try to get a picture of the head damage. Luckily, it is minor. Steve |
Here is the head damage: Sorry about it being blurry. Pound a shot of Tequila and squint a little. :)
Steve http://www.clubcobra.com/photopost/d...g_9826-med.jpg |
Gee, I hate to throw gas on an open flame, but did you say this was a LoneStar car?
Did they provide the engine? You may want to search for troubles with engines and LoneStar. |
Lone Star is in the clear. They had nothing to do with the engine. He seems pretty happy with the car.
Steve |
Steve,
Here's a link to an EGT gauge in a Mustang. The video is 10 megs long. The EGT gauge is the rectangular gauge in the middle. Watch the temps as he runs the 1/4 and crosses at a little over 1400 degrees. This is exactly the temp you're looking for. The video is the 4th from the bottom and click the link in the right column. http://www.fasttrackperformance.com/...omerrides.html |
Steve, yes, I remember meeting you at the first fling, the only one that I attended.
Yes, all those parts are mine. Ive been thinking about a project down the road for my car. I would like to go with fuel injection, which fuel injection system I will use, I don't know at this time. Maybe next winter I will work on it. The coated pistons help with detonation by eliminating hot spots on the piston, which set off detonation. The coated pistons also help to some degree with heat transfer to the piston, to help with too-lean conditions resulting in too high combustion temps. For the extra $50, I figured it couldn't hurt. And, it may have paid for itself already, as I ran the car last year's R&G in a too lean condition on the road race and drag course, and I think my engine is still OK. I may check a leak down test to be sure, but the engine isn't smoking or doing anything weird. I also saw a test in one of the mags I get about a wide band A:F meter that works really good. I had my exhaust system made from the beginning with O2 sensor ports in the collectors, for this purpose, especially if I end up going with fuel injection. |
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