Attention: TDR Forum Junkies Here's the deal. I've had Geno's gauges in my truck for about three years and they've performed flawlessly. My EGT probe is installed in the elbow, after the turbo. I check it often, and rely upon it to decide when to shut the engine off -- even after short hops to run errands, etc.
I noticed, after doing the BD exhaust brake (with 60 lb. springs) installation, that the EGTs were noticeably higher during operation. I'd been enjoying level, 65 mph, EGTs in the 450 range -- now, they were 500-550. Cool-down times became extended, somewhat, too. I also noticed a very slight performance decline -- mostly in throttle response -- after the install.
A couple of months ago, I took my truck back to Everett Smith (Smith Diesel, Carlisle, KY) who's a good friend and a "Dr. Performance" installer. He did a tune up on the truck which included a throttle cable adjustment, valve adjustment, resetting the timing, etc. The difference in the truck's performance was amazing! An unanticipated "plus" was the fact that the truck ran much cooler! EGTs were back to pre-exhaust brake days; cool down periods were dramatically shortened. I could pull off the interstate, drive the last mile or two to my home, and the turbo would be at 150-200, ready to shut down. I was elated.
The last week or two, however, things have turned to crap. Performance has suffered, EGTs have begun climbing during average runs, and the cool down times have gotten longer and longer. I've checked the air filter and all pipe/hose connections between the turbo and intake. I checked the inlet side of the turbo, itself, and noticed a little bit of black (carbon?) buildup around the edges of the housing where the impeller fan is located. There's no wear on the outer edges of the fan blades, no lateral movement in the fan mounting, and it spins freely.
I am mostly annoyed by the long cool-down times, now. I can start the truck (cold), drive it around the block, and it'll take a couple of minutes to cool down to where I can shut it off. It seems, in fact, that it will cool down faster if it's been driven longer! This is weird, because the turbo's cool-down shouldn't have anything to do with the water-cooled (thermostatic) function of the rest of the power-plant. I can see where the engine, with the thermostat shut, might retain heat a little longer after a short hop, when it hadn't really had the chance to get up to operating temps -- but I don't see how the tubo's cool-down would be affected. (Okay, admit it, I've confused the crap outta you!)
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Anyway, I have a couple of theories... The main theory is that the BD Exhaust brake is, somehow, the culprit. Either it is loading up with carbon, the valve isn't returning the little "flapper" to it's normal, "in-line" position, or there is a vacuum problem somewhere that is contributing, somehow, to the problem.
My other theory is that the EGT probe, itself, is unreliable. Maybe these things become covered with carbon after a couple of years and need to be replaced?? Maybe the coating of carbon that had built up on the probe broke off, then built up again. . ?? Anybody had any similar experiences. . ?
This sitting in the driveway/parking lot for three or four minutes, waiting for the truck to cool down, is a PAIN-IN-THE-*** ! Also, the "conventional wisdom" is that EGTs are about 300 degrees hotter when the probe is located aft of the turbo. Does this mean that the truck should be allowed to cool down past the normally recommended 250 degrees? If there is a three hundred degree difference in readings (between pre and post turbo locations), then 300 degrees (after the turbo) would equate to 600 degrees before the turbo -- (I'll be explaining Einstein's relativity theory, here, next week... )
Thanks for your input!
I noticed, after doing the BD exhaust brake (with 60 lb. springs) installation, that the EGTs were noticeably higher during operation. I'd been enjoying level, 65 mph, EGTs in the 450 range -- now, they were 500-550. Cool-down times became extended, somewhat, too. I also noticed a very slight performance decline -- mostly in throttle response -- after the install.
A couple of months ago, I took my truck back to Everett Smith (Smith Diesel, Carlisle, KY) who's a good friend and a "Dr. Performance" installer. He did a tune up on the truck which included a throttle cable adjustment, valve adjustment, resetting the timing, etc. The difference in the truck's performance was amazing! An unanticipated "plus" was the fact that the truck ran much cooler! EGTs were back to pre-exhaust brake days; cool down periods were dramatically shortened. I could pull off the interstate, drive the last mile or two to my home, and the turbo would be at 150-200, ready to shut down. I was elated.
The last week or two, however, things have turned to crap. Performance has suffered, EGTs have begun climbing during average runs, and the cool down times have gotten longer and longer. I've checked the air filter and all pipe/hose connections between the turbo and intake. I checked the inlet side of the turbo, itself, and noticed a little bit of black (carbon?) buildup around the edges of the housing where the impeller fan is located. There's no wear on the outer edges of the fan blades, no lateral movement in the fan mounting, and it spins freely.
I am mostly annoyed by the long cool-down times, now. I can start the truck (cold), drive it around the block, and it'll take a couple of minutes to cool down to where I can shut it off. It seems, in fact, that it will cool down faster if it's been driven longer! This is weird, because the turbo's cool-down shouldn't have anything to do with the water-cooled (thermostatic) function of the rest of the power-plant. I can see where the engine, with the thermostat shut, might retain heat a little longer after a short hop, when it hadn't really had the chance to get up to operating temps -- but I don't see how the tubo's cool-down would be affected. (Okay, admit it, I've confused the crap outta you!)
#adAnyway, I have a couple of theories... The main theory is that the BD Exhaust brake is, somehow, the culprit. Either it is loading up with carbon, the valve isn't returning the little "flapper" to it's normal, "in-line" position, or there is a vacuum problem somewhere that is contributing, somehow, to the problem.
My other theory is that the EGT probe, itself, is unreliable. Maybe these things become covered with carbon after a couple of years and need to be replaced?? Maybe the coating of carbon that had built up on the probe broke off, then built up again. . ?? Anybody had any similar experiences. . ?
This sitting in the driveway/parking lot for three or four minutes, waiting for the truck to cool down, is a PAIN-IN-THE-*** ! Also, the "conventional wisdom" is that EGTs are about 300 degrees hotter when the probe is located aft of the turbo. Does this mean that the truck should be allowed to cool down past the normally recommended 250 degrees? If there is a three hundred degree difference in readings (between pre and post turbo locations), then 300 degrees (after the turbo) would equate to 600 degrees before the turbo -- (I'll be explaining Einstein's relativity theory, here, next week... )
Thanks for your input!
