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View Full Version : Pyrometer/ LM-1 Wideband Tuning...Must read!!!!! - By Super Steve

11-02-2019, 07:45 PM
Okay folks,

I did some integrated tuning with the SS map clamp in conjunction with the Innovate LM-1 and thus far these 2 tuning devices are the best on the market for the tuner crowd. I highly recommend this to folks with moderate mods.

Yesterday, I decided to up the boost and so I tuned my map clamp and FPR to get the right F/A for 25lbs of boost.

1st off, our cars (http://www.srtforums.com/forums/showthread.php?t=56652&highlight=pyrometer#) run stoechimetric at 14.7:1 pretty much at all cruise modes at and before full throttle. There is some fluctuation in the F/A at part throttle runs i.e 13.5:1 to 14.7:1, but either way the F/A never drops down in the rich zone unless you are at WOT which is how the PCM is designed. It's for emission purposed for this design. The design of our motors and the programming of our PCMs are designed to run this way and doesn't hurt the engines durability in any way.

So I decided to monitor the Pyrometer temp readings in cruise mode. At very low cruise speeds, the operating temps are between 900 to 1100 degrees. At moderate cruise speeds, the temps were 1100 to 1350 degrees. At higher cruise speeds of 90 to 100 mph the temps were 1200-1400 all while remaining in the 14.7:1 stoechimetric F/A table. None of these cruise modes were at WOT. Of course these temps had me concerned but my F/A was operating normally. The ops temps would drop sharply once the throttle was released.

Then it was time to do some WOT runs. 1st I did a WOT run from a 50mph roll at 15lbs of boost. I normally run 9.8:1 at this boost level which is fine. So the ops temp was at 1300 degrees and when I went WOT to redline the temps dropped to 1150. Perfect. This allowed me the comfortability knowing that I'm getting the fuel I need for safe engine (http://www.srtforums.com/forums/showthread.php?t=56652&highlight=pyrometer#) operations.

Next it was time to up the boost to 25lbs. I had previousily tuned my map to 4.6v to ensure I get the fuel I need and I upped the FPR to 55lbs at idle. Now it was time to see the temps. I was up to the same 50mph speed, and Bamm!!!!!!!! going from 15 lbs to 25lbs of boost was unbelievable. Fricken G-Forces. Anyway I went to redline in second and third and the ops temps dropped from 1400 to 1250 and the F/A, recorded 12.2:1. Both were perfect. For those of you that don't know, the engineer Ethen advised me that 1700 degrees is the limit before melt down of the pistons. So my eduacted guess is if you get close to 1600 degrees take the foot off the gas.

In review, 14.7:1 in all cruise modes is normal operating F/A is with Ops temps between 900 to 1400 degrees.

In WOT modes it seems that 1200 to 1250 degrees revieled sufficient F/A. which was data recorded and revieled by my LM-1. Anything past 1300 degrees at WOT reviels the engine running in the lean zone. Anything below 1200 degrees indicate running in the rich zone.

So there you have it. Pyrometeric temp readings for perfect F/A at WOT is in the 1200 to 1250 degree. This is my observation for my mods and by no means is it set in stone. These numbers were the result of 2 great tuning tools (http://www.srtforums.com/forums/showthread.php?t=56652&highlight=pyrometer#) and is recommended for those of you getting serious with your SRT.

Hope you will enjoy this info.