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Discussion Starter #1
I am curious to know if anyone has done some egt testing on a stock engine. I am curious to know as this number could be used for a benchmark for setting a high limit for egts when installing a performance enhancer. The other reason is that I am hearing egt numbers that far exceed what I would have thought acceptable for an aluminum alloy cylinder head and also compared to numbers from other engines. A rule of thumb is usually about 1250°F for a sustained max egt reading, and I have seen reports of up to 1400°F on stock vehicles (I think) and some reports of the hot-rodders roofing the thermocouple at 1800°F
I would expect that if guys with stock trucks pulling heavy loads are approaching 1400°, this rule of thumb doesn't apply to the DMAX.





Any comments?
 

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I put my guages on before I installed any chips. I saw peak (full throttle blasts) EGTs at around 1000 to 1100. I also saw my EGTs across the board (in all operating ranges) go down about 100 to 150 degrees when I cut out the factory muffler and spliced a flow-thru Magnaflow muffler into the factory pipes. The addition of an Edge Juice made it real easy to get some rapidly escalating EGTs that required backing out of the throttle to prevent exceeding 1200 -1300 degrees - especially if pulling any kind of load.
 

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I had the same thoughts as you but got impatient waiting on mods. I plan on doing this when it warms up around here though. I am still on the fence whether I want to keep this 4" exhaust system on or not due to the noise (some people like it, others don't). My plan is to put the stock exhaust back on and make 1 tow without the Juice to see what my EGT's are. Like I said in another thread, I wish there was a quieter way to obtain 100-200 degree drop in temp. Of course I haven't seen this temp yet as I haven't towed with this 4" setup yet, I still want to compare the 4" exhaust tow with the stock exhaust tow. sigh...never satisfied I guess....


Bob
 

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I installed my guages before my exhaust, and I benchmarked by EGT's in the full stock configuration. As Tom notes, full throttle, level road I'd see up to 1,100. Full throttle, pulling a 7,000 trailer up a long moderate grade, I'd see 1,400, which surprised me. After installing my 4" exhaust, this dropped to 1,200, full throttle unloaded dropped to 1,000.


Running Hot Juice 4.61, level 2 (+75 hp?) WOT 7,000 lb trailer up the same grade with the exhaust I can hit 1,300. Its still climing at this point but I'm backing out 'cause of the imprudent speeds achieved....
 

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Pulling 20,000 of backhoe stock it was hard for me to exceed 1200 stock, at around 300 ft above sea level and temps not in excess of 90f. The aluminum cyl head isn't an issue I don't think as the cooling passages won't allow the cyl temp to be anywhere near as high as exh. temps. Aluminum is chosen in high perf. engines cyl heads primarily because it has superior heat transfer properties over cast iron. Weight loss is a benifit, but I don't think it's the biggest reason. The pistons will I think be the first to fail from high egt's. They are oil cooled and transfer heat to the cyl wall as well of course, that along with their thermal mass will allow them to withstand temps well in excess of their melting point for short periods of time. Sort of like holding your hand over a hot stove. The hotter the stove, the shorter time it takes to become painful. In other words there will be no set egt that is the max as it would be a function of time as well as temp. So while the hot-rodders may spike well in excess of 1800 say three or four times in a eleven or twelve sec. run, you may not be able to get anywhere near that temp towing before melting the piston domes. In short I guess I'm saying that any testing done would result in a chart where temp and time were both relevant and therefore wouldn't be of much good for us guy's that drive more than a 1/4 mile at a time or at least our driving would be too varied for any absolute # to be useful other than by knowing that whatever a stock engine can hit should be safe for an unlimited amount of time.


On edit: for sustained egt's we can't forget the turbo as well.Edited by: a64pilot
 

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Discussion Starter #6
Another question I have, is the difference from Bank to Bank. I have seen from J. Kennedy's web site, a significant restriction on the driver's side exhaust manifold. I was curious if there was more of an effect on this bank with respect to power adders and egt's
 

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aljolleyjr said:
Which side is correct to install the temp. sensor, intake or exhaust for an egt guage?

I assume your talking about the turbo? If so one is no more correct than the other really, it depends on what your trying to do. The vast majority of thermocouples I believe are mounted in the exh manifold,exhaust gas intake side of the turbo.
 

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Is there that much difference in temp. from the intake side to the exhaust side? It would be simpler ( I think) to mount the sensor on the exhaust side because you wouldn't have to worry about the shaveings from drilling and tapping going into your turbo.
 
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