Jump to content

Recommended Posts

My tach stops at 2400, lower than all other trucks I’ve driven.  I usually shift around 16-1700.  I never let it get over 1900.  I’ve heard that the 460 was better suited for over the road, but it seems to do just fine in my dump.  Whats the sweet spot for pulling hills?  What’s the danger RPMs for this engine?  It’s an 01’ and is paired with an Eaton 8LL.  Thanks fellas.

Share this post


Link to post
Share on other sites

Governor is probably set at 1850, which is probably about where peak horsepower is. In general an engine will tell you where it wants to run. Sounds like you're driving it about right.

Share this post


Link to post
Share on other sites

Between 1400 and 1650 is likely where you need to be.

Share this post


Link to post
Share on other sites

I would make sure the tach is not off a few hundred rpm.

Share this post


Link to post
Share on other sites

i have a 2000 E7-427 on a 460XT tune {490hp) with a 8LL trans in a dumptruck. i shift at 1600 as well. seems right to me. 

Share this post


Link to post
Share on other sites

I frequently shift my '95 e7-350 around there too unless I'm climbing and need more, but it doesn't go above 1850-1900. 

Share this post


Link to post
Share on other sites

I have a 2000 460 that is programmed to go to 2100. In the lower gears thats what I shift at.

Share this post


Link to post
Share on other sites

Never seen a Mack that needed or wanted that many rpm’s. That sounds like driving a 2 stroke Detroit.

  • Thanks 1

Share this post


Link to post
Share on other sites
On 9/13/2019 at 6:18 PM, 1965 said:

Never seen a Mack that needed or wanted that many rpm’s. That sounds like driving a 2 stroke Detroit.

My '79 Mack endt676 wants to go to 2100, 2300 max for your shifts.

The 2400 he referenced is the standard gauge limit in most? Mack trucks. The engines never go to that (hopefully) but it's the peak reading on the gauge.

Share this post


Link to post
Share on other sites

No argument but I still stand for what I posted. 

  • Like 1

Share this post


Link to post
Share on other sites

Curve settles any arguements. You memorize that into your brain, like ECM software for your head, and drive accordingly. At your high end RPM torque/fuel economy/HP curve is diving head first right into the shallow end of the pool. EZ is driving Inside the curve’s benefits.

Edited by Mack Technician

Share this post


Link to post
Share on other sites
13 hours ago, Mack Technician said:

Curve settles any arguements. EZ is driving Inside the curve’s benefits.

This being said the tack seems a little high 200 or so in my mind so if he’s driving by it his sweet spot is not where we might think! 

Just my thought on it so add 200 to the s/s 1400 you get 1600/1850 roughly!! If the tack is off!

Share this post


Link to post
Share on other sites
On 9/13/2019 at 4:18 PM, 1965 said:

Never seen a Mack that needed or wanted that many rpm’s. That sounds like driving a 2 stroke Detroit.

Just a note !

there was an exception ! the 325 V8 was governed at 2600 ! No load in that way they were able to use a six speed trans!

Share this post


Link to post
Share on other sites
On 9/12/2019 at 6:38 PM, USMC205 said:

What’s the danger RPMs for this engine? 

I’ve seen engines come in with recorded high RPM threshold reaching over 3,100+ RPM’s and still in one piece and tuned like a piano. Same group, however, also had a gray engine, AI460, CV713, disbond the crown section of a piston on the sister machine. I didn’t get to see the threshold they reached to do it. They were tractors being pushed into downhill over-speeds by tri-axle gravel dump trailers. Hauling well over 100K+ gross so lots of engine over speed potential. IMO- Expect valve train or base engine damage anytime over 2,800-3,200 RPM would be my best guess. 

Share this post


Link to post
Share on other sites

Agree with that statement totally! Could easily start floating valves at that!

Share this post


Link to post
Share on other sites

Ouch!! 3100 rpms??

I'd chew a driver out big-time for that one!  Not just for potential damage to truck, but also for sending a freight train down a mountain to who knows who at the bottom! You ruin your engine going downhill you're F 'ed, and most likely going to kill yourself and possibly others.

Share this post


Link to post
Share on other sites

On a 2001 non - CCRS 460 ETECH. Your peak torque come on at 1200 rpm and holds till 1500 then starts slightly dropping at 1600 down to 1850 where it’s drops to nothing. Good news is , peak horsepower comes on at 1600 and holds strong till 1850 then drops like a rock. , 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...