BigJohn89 Posted June 20, 2017 Share Posted June 20, 2017 I know the difference between the ai and ac motors but I'm trying to figure out the difference between the ami and ai motors any help would very thankful Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/ Share on other sites More sharing options...
Mackpro Posted June 20, 2017 Share Posted June 20, 2017 Same motor. The AMI's were Maxidyne and the AI was Econodyne. Different programimg for HP/torque curves. The AMI's seem to made their HP at a littler higher RPM's . At last thats what I can tell by the charts. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-372839 Share on other sites More sharing options...
Mack Technician Posted June 21, 2017 Share Posted June 21, 2017 AMI is the group of Three Maxidyne engines that all have a 60% torque rise. Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-372956 Share on other sites More sharing options...
Mack Technician Posted June 21, 2017 Share Posted June 21, 2017 Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-372957 Share on other sites More sharing options...
Bigjohn4300 Posted July 14, 2017 Share Posted July 14, 2017 Ok, thanks! Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-374840 Share on other sites More sharing options...
Rod72 Posted September 20, 2019 Share Posted September 20, 2019 Which is best, given the choice? Looking at two trucks now. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-432469 Share on other sites More sharing options...
Mack Technician Posted September 20, 2019 Share Posted September 20, 2019 (edited) 1 hour ago, Rod72 said: Which is best, given the choice? Looking at two trucks now. Thanks What are you using the truck for.... straight truck, tractor, dump? How much are you hauling? The difference is when the fuel is delivered to the cylinder and how much. If you deliver fuel slightly later in the power stroke you lose HP (ability to accelerate more quickly) but gain torque (ability to maintain speed). Pay attention to the torque rise column on the chart I entered.... AI- delivers lots of power in a tight RPM range. Delivers good torque in a tight RPM range. When you hit a hill speed begins to drop and torque rises 27% to try to maintain your pull. So you lose speed faster and have to shift, but overall you have more tow power. AMI- delivers less HP than AI(varies). Delivers less torque than AI (varies).....BUT, as you begin to lose speed up a hill the torque rises 60% as your RPMs drop. So AMI works harder to maintain your hill climb as speed and RPM begin to drop. Your buddy with the AI made it over the hill faster, with a larger payload, but burned more fuel and had to shift 5 times. Edited September 20, 2019 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-432471 Share on other sites More sharing options...
Rod72 Posted September 20, 2019 Share Posted September 20, 2019 Thank you very much! Good post for sure. Looking at 4 roll off trucks. 04 c12, 14 isx15, 05 mack ami 335 and 06 Mack AI 350 which has a new reman. I want to lean towards the Macks. All real nice but every one has it’s demons. Was gonna buy the isx15 which is a 14 model with only 200k till i started reading on that engines problems today then i came back to these macks which have the cam that dirties the crankcase and gets bad mileage. Not much other choice unless i just buy an mp7 or 8??? What is your thoughts? Read a lot of your posts!! Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-432487 Share on other sites More sharing options...
Mack Technician Posted September 20, 2019 Share Posted September 20, 2019 (edited) 5 hours ago, Rod72 said: Thank you very much! Good post for sure. Looking at 4 roll off trucks. 04 c12, 14 isx15, 05 mack ami 335 and 06 Mack AI 350 which has a new reman. I want to lean towards the Macks. All real nice but every one has it’s demons. Was gonna buy the isx15 which is a 14 model with only 200k till i started reading on that engines problems today then i came back to these macks which have the cam that dirties the crankcase and gets bad mileage. Not much other choice unless i just buy an mp7 or 8??? What is your thoughts? Read a lot of your posts!! Depends on what you want. I’d take an AI over interim 4 or final tier 4 engine any day. MP series has some short comings that are impossible to remedy. AI has short comings that are more simple to remedy. We run a fleet of tier 3 AI engines at work. They do great for reliability. If you have good fleet service support, and a knowledgeable mechanic, get a final 4 MP engine. If you want easier reliability and the ability to diagnose and fix stuff yourself get an AI and convert out the exhaust recirc. I’ve noticed the resale value of the Mack AI vintage hasn’t seemed to drop despite a shady reputation. I’ve talked to fleet owners who don’t like MP, but appreciate the extra MPG enough to keep buying them. I have a buddy who loves his MP8 so long as the warranty has him covered. His brother wanted to buy his truck once warranty was up and he refused to sell it to him as an act of mercy. Edited September 20, 2019 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-432488 Share on other sites More sharing options...
Rod72 Posted September 20, 2019 Share Posted September 20, 2019 Ok i am following you. You speak of the AI but you are talking about AI/AMI (either)? So to make a wonderful long lasting engine a cam swap and possible exhaust manifold and and trash the muffler?? Again it has 400k but it was a clean fleet maintained lumber truck till now. Your thoughts? Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-432518 Share on other sites More sharing options...
Mack Technician Posted September 20, 2019 Share Posted September 20, 2019 PM me. Quote Link to comment https://www.bigmacktrucks.com/topic/50235-difference-between-ami-and-ai-motors/#findComment-432522 Share on other sites More sharing options...
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