1965 Posted October 16, 2015 Share Posted October 16, 2015 Just got a 2012 CHU613 with the 505C engine; was wondering what should the pyrometer read during a good hard pull; at 1700 rpms truck shows the best boost around 32psi; pyrometer got to 800 degrees; does that seem right?I had a 09 model & didn't have it long & it seemed to pull real good; it was 425E engine; the 425E seemed to pull good down to around 1200 rpms & pulled to around 1700; this 505c seems like it doesn't like to get lower than 1400 & pulls little higher on the top side; but did notice the boost pressure falling off after around 1700Question is does this seem about right? Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/ Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 (edited) If its running right, it should pull better down low. I have a 16 505c+ and it's peak torque is 1050 to 1400 rpm, I believe is what the literature said. It is usually around that 800 degree mark on a grade. The only thing you are doing at 1700 with these newer engines is making noise and wasting fuel. I understand mine is a + and has the same torque in all gears, but even without the +, I'm fairly certain the curve stays the same. Edited October 16, 2015 by wiserfrombud Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307643 Share on other sites More sharing options...
1965 Posted October 16, 2015 Author Share Posted October 16, 2015 When you are going through the gears where do you shift at? I have been turning it to 1700 to shift; but if you are in cruising speed & or have cruise set it seems to not like it below 1400; it's dead feeling at 1050 to 1200; it really doesn't feel like it's got 80 more hp than my 425 had; but if the boost is at right numbers & pyrometer is right number might just be me; haven't run it but 3 days & have loaded it pretty heavy. Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307666 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 I usually shift around 1300. It's tough to tell how a truck is running just off of the boost gauge. With the variable geometry turbo's, the boost constantly fluctuates based on ambient temp, elevation, and state of the emissions system at any given time. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307671 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 (edited) What is the torque rating on that motor? It's rated at 1860 like mine right? In my experience horsepower is just kind of a byproduct of torque. Hp doesn't matter nearly as much in how the truck pulls as torque. Edited October 16, 2015 by wiserfrombud Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307672 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 And for what it's worth, I am almost always 80 000 lbs gross running the I15 corridor from California to the Canadian border. Lots of good pulls on that route. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307673 Share on other sites More sharing options...
1965 Posted October 16, 2015 Author Share Posted October 16, 2015 Well I'll try something different; been hauling some grain at 87000 lbs gross; in little hwy but mostly city traffic; not running today but I don't think it will pull at that low; it want pull that low in the low side gears; I've never watched boost gauge never had truck with one; I watched it to post this because most of the time that's the firist questioned asked; don't watch tach either but did watch it when it didn't feel like it was pulling like I thought it should; it want pull it empty that low of rpm; does pretty good when it's up between 14 & 1700; just curious if it should do more; the older trucks that did have fuel turned up would run more heat in the exhaust & I realize we're talking whole different ballgame with the no smoke set up just wanted to make sure it was getting the fuel it should be gettingThanks for your information Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307688 Share on other sites More sharing options...
Lavernm Posted October 16, 2015 Share Posted October 16, 2015 1965, you may still have the original 505c programming. Have a dealer check the program. We have two '13 CHU 613's that were 445c's when we got them with 1660 torque. The early 505's had the same torque rating. The 505 + rating didn't come out till sometime in '14. When we bumped them to the 505c+ they were like a new truck. Cost about 1800 to bump them. The dealer we had do it, thought that ours were to old to get the + rating but we got it somehow. Don't know if it will go back to a '12 model or not. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307701 Share on other sites More sharing options...
bts-4120 Posted October 16, 2015 Share Posted October 16, 2015 bet he's got a 505e Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307723 Share on other sites More sharing options...
1965 Posted October 16, 2015 Author Share Posted October 16, 2015 If he is me; no it's got C on it; also says it when Mack has laptop plugged in; had all that done when I bought it because the vehicle details sheet they pulled up when bought it from dealer said it was 500M but valve cover said 505C and I had verified & also saw another Mack dealer hook-up lap top on another deal; I saw it say 505CWished it was an E Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307739 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 Ol well what is the truck spec'd out to do? 87,000 lbs is a pretty good load. What rears are in it? When you say it doesn't pull very food down low. Compared to what? Are you unhappy with it because you can't accelerate with traffic from a light? To me an underpowered truck is when you are pulling a hill, and it will not pull a grade in anything higher then 3rd gear. If I takes you a while to get rolling, or you have to grab a few gears in the grades, so what? Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307742 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 Oh I see you were comparing it to your 09. I can't see that 12 being every bit as strong as your 09 and then some provided you are comparing apples to apples. Same spec, load, terrain etc.... if the 09 had 411 rears, and this new one has 36 rears, that will be a noticeable difference for sure. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307746 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 Btw the E is the economy designation I believe....if you aren't happy with the C, you certainly would not wish you had an E. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307747 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 Btw the E is the economy designation I believe....if you aren't happy with the C, you certainly would not wish you had an E. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307748 Share on other sites More sharing options...
1965 Posted October 16, 2015 Author Share Posted October 16, 2015 It's got 394 rears; l don't expect it to be a race truck; as I said it doesn't seem to pull as good as the 09 425E did down to the 1200 to 1050 RPMS; it seems good up at the 1400 & higher; not complaining just want to know if it is right or not; Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307751 Share on other sites More sharing options...
wiserfrombud Posted October 16, 2015 Share Posted October 16, 2015 394's!? Wow. That's geared pretty low. On what size rubber, and what transmission? Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307753 Share on other sites More sharing options...
1965 Posted October 17, 2015 Author Share Posted October 17, 2015 24.5 & T318LR maxi-torque Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307755 Share on other sites More sharing options...
wiserfrombud Posted October 17, 2015 Share Posted October 17, 2015 Hmph. It's on big rubber but still.....I am surprised you find that thing to be such a slug. 800 degrees sounds like it's getting all kinds of fuel to me. Maybe try getting the + update as suggested earlier?? I'm not sure what else to think about that. Mine I am very happy with the performance out of mine for a 13 litre! Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307761 Share on other sites More sharing options...
1965 Posted October 17, 2015 Author Share Posted October 17, 2015 I'm fine with it; not going to spend that money; I'm used to one pulling down at lower rpm; I think it feels strong as long as you keep it above the 1400 mark; It does good on cruise control; but when it gets to 1400 it starts falling quick; you keep it above 1400 it feels good & strong; just curious had anyone else's pulled this wayActs kinda like the accelerator pedal is out of adjustment or something when starting off; like a dead spot;or slow response; I know the turbo has to adjust and all that electronic stuff keep it from smoking; but seems like something isn't in sink with everything; taking off from stop try to just ease it up & it gets up to bout that 1400 range & it acts like it wants to take off; it's been hard to get use too; since I'm more familiar with the older ones; & like I said didn't notice it with the 09 with the 425E;it was 13spd; I don't split the low side but if I don't rev it to 1700 between the low gears it's flat; falls on its face til 1400 then like a rocket Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307764 Share on other sites More sharing options...
wiserfrombud Posted October 17, 2015 Share Posted October 17, 2015 How many miles are on it? Has the turbo ever been replaced? If so I wonder if it was calibrated improperly? Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307769 Share on other sites More sharing options...
wiserfrombud Posted October 17, 2015 Share Posted October 17, 2015 Something does sound out of whack now with that explanation, because mine certainly does not behave like that. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307770 Share on other sites More sharing options...
1965 Posted October 17, 2015 Author Share Posted October 17, 2015 How many miles are on it? Has the turbo ever been replaced? If so I wonder if it was calibrated improperly?It's got 206000 on it; doesn't look like it's been off; I found out where the truck was bought new & checked for and on all work that had been done before I bought it; all updates done; made them pull dpf off & have cleaned & got pictures they sent me; my Mack dealer is hard to deal with about stuff like this; wonder if it's a way to check all the calibrations on it Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307771 Share on other sites More sharing options...
wiserfrombud Posted October 17, 2015 Share Posted October 17, 2015 Hmmmmmm. How is the DEF usage? Did you have them clean the DPF just for good measure before you bought it or was there a soot load/frequent regen issue? Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307775 Share on other sites More sharing options...
wiserfrombud Posted October 17, 2015 Share Posted October 17, 2015 If the turbo is original and it's never been off, there is no reason for it to be out of calibration. How long ago did you purchase the truck? It was bought from the dealer you are speaking of? I think if it were ME, I would pull a full service oil sample from a lab. Not bench top bs. If your turbo is out of whack, you should be seeing elevated soot levels. Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307776 Share on other sites More sharing options...
wiserfrombud Posted October 17, 2015 Share Posted October 17, 2015 If none of this helps, maybe try posting some of this in the engine forums?? I have only owned my Mack for 5 months. I am not a certified tech or anything, but this is now my 3rd emission truck as well, so this isn't my first rodeo either. My last truck was a 10 kw 660 with an ISX. I had a fair number of issues with that motor so I am just brain storming with you. Both motors use that pos Holset VGT turbo. It's great when it's new. They don't last, they aren't cheap to replace, and have fun finding a shop that truly knows how to set it up properly! Quote Link to comment https://www.bigmacktrucks.com/topic/42214-mp8-505c/#findComment-307778 Share on other sites More sharing options...
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