winger Posted July 14, 2014 Share Posted July 14, 2014 E7 or EM7, what's the difference, or is there any? I'm looking at a few. 2001 with an em7 w/275hp a 2000 e7 w/350hp and some 1994's w/300 hp. And how easy is it to bump up the hp on these engines? Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/ Share on other sites More sharing options...
Superdog Posted July 14, 2014 Share Posted July 14, 2014 The EM7 is a low rpm "Maxidyne" engine..Depending on the engine,pump,injectors,turbo,computer reprogramming can bump hp.Just takes $$$$$$. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-252841 Share on other sites More sharing options...
winger Posted July 14, 2014 Author Share Posted July 14, 2014 The EM7 is a low rpm "Maxidyne" engine..Depending on the engine,pump,injectors,turbo,computer reprogramming can bump hp.Just takes $$$$$$.What do you mean when you say "low rpm"? Do these engines not rev to 2100? Will I have an issue with an em7 running down the highway at 60-70mph? Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-252853 Share on other sites More sharing options...
Superdog Posted July 14, 2014 Share Posted July 14, 2014 they are designed to only turn 1700 Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-252856 Share on other sites More sharing options...
j_martell Posted July 15, 2014 Share Posted July 15, 2014 they are designed to only turn 1700 ....and the power starts earlier...around 1000rpm I believe. Quote Lack of planning on your part does not constitute an emergency on my part.... Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-252945 Share on other sites More sharing options...
farmer52 Posted July 15, 2014 Share Posted July 15, 2014 EM7 peak torque @ 1020 rpmE7 peak torque @ 1200-1250 rpm Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-252962 Share on other sites More sharing options...
winger Posted July 16, 2014 Author Share Posted July 16, 2014 But the e7 is governed at 2100 rpm right? Is it possible to raise the governor on the em7? Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-253061 Share on other sites More sharing options...
farmer52 Posted July 16, 2014 Share Posted July 16, 2014 E7-250 = 1950 rpm, E7-300 = 1700 and 1900, E7-350 & E7-400 = 1800EM7s were rated at 1750 rpmBased on my engine experience, I would suspect more than a governor change. I agree with Superdog....lots of parts to change.My MH is an EM7-300 with T2050 transmission and 5.02 ratio. I can run all day at 65-70 mph (GCW is 65,000#). 1 Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-253075 Share on other sites More sharing options...
farmer52 Posted July 16, 2014 Share Posted July 16, 2014 What do you mean when you say "low rpm"? Do these engines not rev to 2100? Will I have an issue with an em7 running down the highway at 60-70mph?Highway speed is based on engine speed, transmission final ratio, rear axle ratio, and tire size. I think the important question is...what is the gross weight? That will determine your horsepower requirement. Either of these engines (E7 or EM7), if geared correctly, is capable of running 70 mph. Quote Ken PRR Country and Charter member of the "Mack Pack" Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-253076 Share on other sites More sharing options...
winger Posted July 17, 2014 Author Share Posted July 17, 2014 My gross weight on the drill rig is 66,000 lbs. Speed limits on our highways around here are 90kmh (55mph) but I would like to stay at 100kmh (62 mph). The only real requirement for the HP is the many hills around. The current engine/tranny set up is a Cummins v903 W/13 over, so its running about 265hp and under 900 lb/ft of torque. Does fine on the flat and slight grades at 55mph but you need to tape up the headlights so it can't see the bigger hills coming. This is actually better than the cat 3208 N/A that was in it before tho. Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-253138 Share on other sites More sharing options...
bts-4120 Posted July 18, 2014 Share Posted July 18, 2014 300 maxidyne or 350 will be a big improvement over a 903 with no turbo 903 with turbo would be a different animal Quote Link to comment https://www.bigmacktrucks.com/topic/36349-e7-or-em7/#findComment-253203 Share on other sites More sharing options...
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