On the Hunt for MORE H.P!! Why??

[Joey Mack]

I keep seeing post's about wanting More H.P.  ok... but they want it out of  an E-6 or E-7..  400+ H.P. I don't have a million miles or many different skill sets for the different loads to pull.  But I did drive many slow and deliberate Macks, with E-6 2 and 4 valves, and E-7's for a construction company..  I can understanding wanting more power at times, but I also believe the truck needs to match the job it is doing.  I can tell you , the '79 R-model I drove was a Hoss.  It was a long frame, fixed 5th wheel, 1070B 12spd, 4.42 rears,  yeah it had power steering,,  that's it!  I have been pulled over by ''The Man''  a few times, weighing 118,000 -122,000..  of course got tickets, but looking back,, that truck hauled the loads..  My guess is that 25 years later,   doing the same work at 70 MPH is what they are after..  I was running roads in Maine from the pit's to the job site's..  I am NOT a long time driver, but I remember how those trucks got it done..  I guess I am looking for opinions..  Because to me.... If you need big power.....  Buy It!!  you aint gonna get it out of these Mack engine's, but if you keep them tuned and lubed, you will get million mile reliability, just have to do it below 70 MPH...    OK guys, now it's time for my beating on this..   Jojo

P.S. ...  I drove ALL of thier  Macks, and one of the best pullers was a '97 with an E-7 400/18 spd. All Mack..  

[JoeH]

My 95 E7-350 is a bit of a dog; it's a great truck, but some more umph would be nice on some hills. At 25 tons or 36 doesn't really change how fast you are moving by the time you hit the top of the hill. Which is a bit sad, you'd think the truck would move noticeably better with 22,000 less lbs on board.  But, it is a 12 liter engine, nearly 30 years old. 

2023 Cummins 6.7 is boasting 370hp and 850 ft lbs.  That's a lot of power from a little motor. Not far off of our old trucks.  New trucks with a load on also drive like cars, which TBH is really kinda scary. I had an a$$hole hotrodding and tailgating another truck coming the opposite direction towards me the other week; he was halfway out in my lane chasing the truck in front of him coming around a bend; I didn't see him til the first truck got even with my  front bumper. he got out of my way about 4 feet before he hit me. I put myself as far over as I could in my lane without wiping out the trees and ditch and locked up a couple tires to buy the inches that a$$hole needed to get back in line.

[Joey Mack]

I am glad you made it out safely..  I dont like driving new trucks.. they are too comfy and I dont want to feel like im in my wifes Avalanche,  I will get lazy and forget its a Big truck...  I drove a few m-Drives and found myself driving way too fast..  Jojo

[JoeH]

The 2023 Ford Powerstroke High Output is an outrageous 500hp and 1200 ft lbs of torque, compared to the Cummins H.O. at 420/1075. 

Both of these are a measly 6.7 liters.

[Joey Mack]

our city trucks are F-350's.. 6.7's..  all with loaded service bodies.. they scoot right along.  10 spd. transmissions, plenty of gears.. 

[JoeH]

Our 2003 MR688 is an automatic. I love it. There's no going too fast in that truck, being a heavy spec cabover every bump in the road hurts.

[Freightrain]

My 2000 F350 PSD, 6 spd, 4.10 gear would run up Fancy Gap with my trailer at 65 mph just barely holding the throttle in 6th gear.  That 7.3 was only 235 hp.  I would wonder if my 237 Mack would do the same today?   I know the ol 673 would surely not do it.  I'm only at 28K lbs GCW.

I've more then once wished my 237 had just a "bit" more power on some hills.  It's no slouch on flat land, but start out on a grade and it just creeps along.  I'm just glad I found the 237 a few years back.   Of course a 300 would really make me smile!

[The Rubber Duck 006]

I drove a 1997 Mack CH613 Gold bulldog with the Elite interior for the owner operator. I think the Mack Motor had 400hp. Pulled 34,000lbs plus 12,000lbs at 70mph no problem 

[Geoff Weeks]

Power is something that will never be satisfied. I'm old enough to remember trucks pulling Snowshoe or other eastern hills at 25 mph, That was the norm, and "O/O hot dogs" may blow by you at 30-35 mph. Today you'll be a hazard pulling the same weight at the same speed.  The 670 +/- CID of the Mack was quite impressive for what it was, and put up against Cummins and Cat's of larger displacement.

 I was called on to work a train de-rail by a company I used to work for. (I was my own carrier at the time) and when I found out where and where we were to move the damaged cars, I got my Fleetstar with a 6-71 and left my 9670 at home. The other O/Op's were laughing when I showed up, but soon their tune changed when the found out we had to go down the access beside the track. I quickly offered to drag the stretch trailers in, turn them around and stretch them out, if I got the 1st load out. There was one old (brought out of retirement) company driver there also. The O/Ops said "you may be 1st out, but you'll be last in"! The old guy said quietly, "We used to move super loads with a 6-71".  Yeah, I was 1st out and 1st delivered, but everybody heard me coming! I have a Dart oilfield truck from the early 50's. I had a 200 hp 2 valve  6-71. It had a 66,000 GVW (most road tractors have 52,000) and hauled much more as a CGVW.

 That said, you can not climb Butte grade in low gear at 5-7 mph like I did back in the day,, with O/D O/W loads, you'll get hit a dozen times before you reach the top. I used to almost get hit coming down that grade with the jake on full at the recommended 25 MPH.

 Drivers both "professional and John Q Public" are not paying attention, and anything that causes them to look up or god forbid, disengage   C/C might get you shot at or hit.

 When I retired, my trucks had around 425-440 hp and were deep into the "Fleet" hp ratings of the day. I moved the same freight, and got it where it needed to go in a timely fashion. I did it the old way, by keeping the left door closed. I ran most times around 65 mph. Tires and fuel went much further, brakes lasted and I had time to react when stupidity happened in the front window.

[Geoff Weeks]

Wind resistance and wind direction can have more effect than weight. When I pulled 48K+ re-bar loads, my mileage was closed to what I would get with an empty trailer. Sure it pulled the grades slower but it also rolled along on the down hill side much further without needing throttle, was less effected by wind gusts etc.

Because wind resistance goes to the square of speed, a little increase in speed makes a big difference in power required to move at that speed, and of course fuel to to get that power.

[D-Day]

47 minutes ago, The Rubber Duck 006 said:

I drove a 1997 Mack CH613 Gold bulldog with the Elite interior for the owner operator. I think the Mack Motor had 400hp. Pulled 34,000lbs plus 12,000lbs at 70mph no problem 

 

32 minutes ago, Geoff Weeks said:

Wind resistance and wind direction can have more effect than weight. When I pulled 48K+ re-bar loads, my mileage was closed to what I would get with an empty trailer. Sure it pulled the grades slower but it also rolled along on the down hill side much further without needing throttle, was less effected by wind gusts etc.

Because wind resistance goes to the square of speed, a little increase in speed makes a big difference in power required to move at that speed, and of course fuel to to get that power.

Thanks for the truck driver point of view on these things some of us who have never driven do not know these interesting things about trucking if you work on the sidelines its hard to imagine how it all works as a mechanic its not always easy to figure out the drivers point of view

[BOBWhite]

Washboarded dirt roads and spring ride are most of what I've dealt with so more horsepower just wastes more fuel. Since all I've used a big rig for is hauling around equipment and grain I can't say I've ever even gotten up to over 65. 

I'd like to see one of those 6.7 or 6.6 high output motors in something like a tractor and keep a load on it for 14 hours or so.

[mrsmackpaul]

1 hour ago, BOBWhite said:

I'd like to see one of those 6.7 or 6.6 high output motors in something like a tractor and keep a load on it for 14 hours or so.

Absolutely correct

The old 320 coolpower can be on full load for a million miles and not skip a beat, I dunno about these high HP little motors 

All that been said, my old bucket of bolts is factory built and rated by Mack on the plate 115 ton or 253,000 pound in yanky talk

And it will pull that all day long up hill and down 

People's expectations are pretty much up a lot further today than they were 40 years ago

These od trucks will get you there but not at break neck speed

There is no substitute for sitting in the seat driving the truck 

 

Paul

[Licensed to kill]

I like power. IMO a vehicle is like a knife. You are less likely to cut yourself with a sharp knife because it takes less effort which give you more control of it. More power allows you to have more control, particularly in mishap avoidance. Of course, in the wrong hands and/or used improperly, both a sharp knife and a powerful vehicle can be a menace. My Pete came with a 475HP C-15 which is sufficient for what I do as I am relatively light weight, my max weight being around 42MT (92,000 LBS). Nonetheless I had it flashed to 680HP. I would like more but any more and fuel economy starts to suffer. For the record, I don't drive fast. That is not why I increased the power. I keep to 100KMH (62MPH) even when the speed limit is 110KPH because tires are designed to run at 60MPH max and if you exceed that, they wear exponentially AND increased speed requires more braking. Added weight increases braking distance in a linear fashion (double weight, double braking distance), increase SPEED and you increase braking distance by a factor or 2 (double speed QUADRUPLE braking distance). BTW, IMO, service brakes are for emergencies, engine brakes are for slowing/stopping. While I am not OTR and don't put on anywhere NEAR the miles of the highway guys, in the 18 years that I have been driving trucks, I have yet to wear out a set of brakes and I doubt I ever will but I only have less than 500,000KM on my 2005 Pete (300,000 miles) and still have original brakes and they are in very good shape yet. All "small potatoes" compared to the guy that flashed my ECM. HE is a power junkie. He ran a '98 Pete (IIRC) with a C-16 that puts 1500HP to the ground on the dyno and always wants more. That was back in '09 when I had mine done, don't know what he runs now. 

[coop661]

Far as I can tell from reading here and other forums, the E7 350, 400, and 427 are the same motor, just with different turbo, injectors, and camshaft. So turning a 350 up to 400 or 427 doesn't sound like it's asking too much of the drivetrain.

[Joey Mack]

Yes sir,  I'm mostly commenting on trying to make Big Power, from Small Mack engines, like the E-6.  That is why I say, just buy a bigger engine..  I like reading these responses...  Be Safe Drivers... Jojo

[doubleclutchinweasel]

My '17 Ram 3500 had the 950 ft-lb version of the 6.7L Cummins.  Plenty of power for pulling anything I'll ever hook to it.

But, it does NOT have to move 80K+.  It does NOT have to move that 80K+ for 600+ miles every day.  It does NOT have to stop that 80K+ a dozen times an hour.

I've had this discussion with some of the die-hard Ram guys a dozen times.  It's not all about power, it's about longevity.  I love my 6.7, bit even the old 250 horse 673 I drove would outlast it in a heavy truck!

Jo-Jo, this is an interesting discussion.  Like everybody, I seem to always want MORE POWER (argh, argh, argh).  But, I also remember all too well the 180 horse Thermodynes slooooowly dragging those heavy weights up the hills.  The 237 and 250 motors were noticeably better.  A 300 or 350 was incredible.  The 400 HP stuff just seemed like showing off!  I guess it is just progress that newer stuff is stouter.  I guess the comfort levels of the newer stuff are supposed to reduce driver fatigue.  But, to me, a truck is SUPPOSED to be a little bit rough.  But, that's probably just because that's how they were "back then".  I'm sure my back would appreciate the improvements in the newer stuff.

In any engine, turning up the power can reduce longevity.  Everything in life is a bit of a trade-off.  But, there is also usually an optimum point...where the lines cross.  I mean, straining the guts out of a weaker engine can shorten its longevity, too.  Just like putting too much power on it can.  I guess, if we knew what that magic number was, we could just tune everything to that point and get the best compromise of power and longevity.

Then we would go buy lottery tickets, because we would apparently have gifted insight into the netherworld!

I am going to keep reading this one because EVERYBODY'S opinion on this is valid.  They vary by experience and requirement.

[JoeH]

Fact is, Mack missed out on the Big Power market when they didn't move forward on their "Big Six" prototype sitting at the museum.  Their E9 V8 is the only real Big Power option, but all I've heard is parts are hard to get and they suffer in the longevity department. Whether that's just scarcity and age or design flaws, I couldn't say.  I have heard that V engines' main flaw is that they have to run 2 connecting rods on each crankshaft offset.

[JoeH]

If you take the power to displacement ratio of the e7-460 at 12 liters and apply it to the Big Six at 14.5 liters then you wind up around 555hp. Decent, but unknown upward potential.

[Geoff Weeks]

I remember when we were told that we'd all be driving small displacement engines with lots of gears, Cat pushed the 3306 and Cummins the L-10, but they were coupled to 9 or 10 spds and were slow. Top power was around 300 for either, or about what the E-6 was at that time.

Don't get me wrong, these smaller displacement engine today have impressive power for their size, but at the time they came out it was poor. Turning up one of these old small displacement mechanical engine is a courting disaster. Once the electronic's and stronger pistons and rods come in, they did produce a lot of power.

 Big power has always been available to those willing to pay. 12V-71, K-19 and the Mack V-8, but there was a huge price to pay for the privilege of being the big engine on the road. It came up front in purchase price and continually in fuel and maintenance. I have never been a fan of V engines, and have never owned one in a truck.

 Most engines will take 10% over what the factory rated them for without too much trouble, once you start trying to push over that, it can really take its toll.

 Some look at today's electronic engines of about the same displacement and say 'if they can get that out of the same displacement, why can't I with my older engine of the same size?". But that fails to understand HOW mfg got to where they are and the changes needed to get there. Not only are the mechanical pieces stronger, seal better and take heat better, the electronics which allow injection timing to be idealized for the condition also allow it to not over-stress at low speed but still take more when it can. Mechanical, you don't get that ability. you have to make compromises.

 The Detroit 60 series was the 1st to show what electronics and smaller displacement could do, in terms of hp. just as the Maxidyne showed what a broad torque curve could do decades earlier.

Edited October 18, 2023 by Geoff Weeks

[fjh]

 My perception of it is! Its the racing mentality that comes out in most every teenager and some never let it go!  The  Spirit of  Competition !   Pride! Specially when you believe in something ! Face it the only Power most of us will ever experience is that that we can  buy, build  or create our selves ! We can pretend to vote for it but it is only an illusion and rarely  turns out the way we perceive it!😪 

[Geoff Weeks]

2 hours ago, JoeH said:

2 hours ago, JoeH said:

If you take the power to displacement ratio of the e7-460 at 12 liters and apply it to the Big Six at 14.5 liters then you wind up around 555hp. Decent, but unknown upward potential.

Fact is, Mack missed out on the Big Power market when they didn't move forward on their "Big Six" prototype sitting at the museum.  Their E9 V8 is the only real Big Power option, but all I've heard is parts are hard to get and they suffer in the longevity department. Whether that's just scarcity and age or design flaws, I couldn't say.  I have heard that V engines' main flaw is that they have to run 2 connecting rods on each crankshaft offset.

Big power and the costs:

Mack V-8's aren't as common because they cost a premium, same as the K-19 and the 3408. Parts are harder to come by because fewer were made to begin with.  The K-19 is still made or was recently (Q19) but not used in road trucks, the 3408, V8 Cummins and the like were dropped as they didn't have  large sales to continue there development. The V Detroit 2 strokes were around until the end of the 2 stroke.

The Mack V8 was well respected, but its higher costs didn't make sense in the days of 55 MPH, but the time that went away we were on the cusp of the electronics and the same power from smaller displacement 6's.

 When the Big V's ruled the high hp truck market, the other driveline components weren't generally as strong as what came later, that left broken trans and rears if pushed too hard. It wasn't until the 80's that those components were beefy enough to take the higher output. Yes, Mack had their big rears, as did other mfg, but they weren't highway geared, for high speed and high torque.

 Remember the  SQHD (sure quitter's) ?

[67RModel]

I think Mack engineers knew what they were doing when they designed their engines. There is a reason they have the reputation they do in terms of longevity and fuel economy. If there was a benefit of 500+ HP E7 then one would have been available from the factory.  When the E6 and E7s were new a12 liter engine was best suited for the vocational market and linehaul markets where you were hauling legal weights or less, which was Mack's bread and butter. When you send away to the Mack museum for all the literature and documents for a specific truck you will see that each chassis was designed for a specific use case and a maximum speed at a specified grade and GVW as requested by the customer/dealership. From there Mack engineering would select (or recommend) the appropriate engine and gearing to meet those requirements. I think a lot of people asking for more HP out of 300 or 350 Mack engine have other things working against them or are trying to use the truck in a way it wasn't originally specified for.

A 6.7 Cummins rated at 350 HP? 😂. The B10 Life for that engine is 250,000 miles. I seriously doubt a 6.7 Cummins under the hood of Mack CH tractor would make one complete trip across the country at 80,000 pounds GVW all else being equal. The power density of the light duty diesels way too high for the type of longevity class 8 engines are expected to get.

I think most people (probably everyone) drive entirely too fast. 10-15 over the posted speed limit is basically the new limit. Modern vehicles have got to be so powerful, quite, and smooth that its so easy to unconsciously pick up speed. Modern brakes and suspensions make the extra speed very easy to handle. I think a lot of that carries over to trucking. Guys want to be able to effortlessly fly up big hills and keep up with 4 wheelers. 

[Licensed to kill]

5 hours ago, doubleclutchinweasel said:

  I guess the comfort levels of the newer stuff are supposed to reduce driver fatigue.  But, to me, a truck is SUPPOSED to be a little bit rough.  But, that's probably just because that's how they were "back then".  I'm sure my back would appreciate the improvements in the newer stuff.

Agreed, back when a trucker was a TRUCKER, no PS, no AC, no air ride, no power, twin sticks double clutching every gear. My dad started hauling logs on the west coast in the mid 60's, this truck, IIRC had a 275 cummins, 5&4 but then got a "big power" transplant...... a 315 cummins. He had to have his hip replaced I think in the early 2000's and the surgeon looked at the X-rays and said "Truck driver eh?". Dad said "yes, how did you know that?", doctor, "the way your left hip is wore out is common among ling time drivers that double clutch every gear. I remember dad saying once he thought he would count his shifts on a trip, stopped counting at 200 and IIRC he was still on the way IN. More power reduces that number considerably, especially when driving west coast logging roads.

[Geoff Weeks]

The biggest improvement to ride quality was the elimination of B-B length laws. My back-up tractor was spring and if loaded correctly road as good as the other two. Belly load it and it would beat you to death, split or uniform load the deck and it road fine.

 Even my Fleetstar with walking beam would ride well loaded, but with the short wheelbase and light tractor, would launch you empty over the bumps. It only have an old Viking T bar seat.

 One thing that has not changed much over the years is unsprung weight. That is where the "rough ride" of a truck can not be eliminated.