OM606 Turbo Selection for Truck application
OM606 Turbo Selection for Truck application
If I do a WOT pull in second gear, unloaded on flat ground I can easily hit 30 PSI of boost and EGT climbs to about 1500 but only for a moment until I back off the throttle. I've even cut max fueling by about 10% in my tune. Pulling a heavy trailer is where I really have to be careful and it's different than I thought. Say I'm pulling an 8000# trailer on the highway at 65 with OD off. I may be turning 2500 RPM 10 PSI of boost 900 EGT. I see an incline and speed up to hit it with some momentum. Boost climbs to 20PSI , EGT climbs to 1100 and RPM climbs to 3000. A little way up the hill, speed and RPM starts to drop and EGT stays steady. While I'm still in third gear, I can control the throttle and add power and boost and balance the EGT right at 1250 (which is my max safe #). Th problem is IF at that moment, my transmission downshifts to second WITH THE SAME throttle position- RPM's jump to 4000 and EGT immediately spikes to above 1400 despite not adding any fuel. I have to back off the throttle to control EGT and then I loose even more speed despite being in a lower gear.
I would have thought that at the same throttle setting, being in a lower gear at higher RPM would "load" the engine less than being in a higher gear and lower RPM and thus produce lower EGT. That is NOT the case. Higher RPM seems to have a larger impact on EGT , than fueling and engine load. I've tried pulling the same hill at the same speed and the same load in both 2nd and 3rd gear. EGT is always higher in 2nd gear than in 3rd.
My truck is quite a bit heavier than yours at close to 6000 pounds. Unloaded on the highway on flat ground I'm around 700-800 degrees and 4-6 psi of boost. If I hit an incline (unloaded) boost rises to about 10 PSI and EGT climbs closer to 900-1000.
If I do a WOT pull in second gear, unloaded on flat ground I can easily hit 30 PSI of boost and EGT climbs to about 1500 but only for a moment until I back off the throttle. I've even cut max fueling by about 10% in my tune. Pulling a heavy trailer is where I really have to be careful and it's different than I thought. Say I'm pulling an 8000# trailer on the highway at 65 with OD off. I may be turning 2500 RPM 10 PSI of boost 900 EGT. I see an incline and speed up to hit it with some momentum. Boost climbs to 20PSI , EGT climbs to 1100 and RPM climbs to 3000. A little way up the hill, speed and RPM starts to drop and EGT stays steady. While I'm still in third gear, I can control the throttle and add power and boost and balance the EGT right at 1250 (which is my max safe #). Th problem is IF at that moment, my transmission downshifts to second WITH THE SAME throttle position- RPM's jump to 4000 and EGT immediately spikes to above 1400 despite not adding any fuel. I have to back off the throttle to control EGT and then I loose even more speed despite being in a lower gear.
I would have thought that at the same throttle setting, being in a lower gear at higher RPM would "load" the engine less than being in a higher gear and lower RPM and thus produce lower EGT. That is NOT the case. Higher RPM seems to have a larger impact on EGT , than fueling and engine load. I've tried pulling the same hill at the same speed and the same load in both 2nd and 3rd gear. EGT is always higher in 2nd gear than in 3rd.
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