Threshold for Pain: How much can your diesel take?

[ShinerBock]

Recently Diesel World Mag made a few articles about how much each diesel can handle, but never ended up posting the Cummins numbers. Drivingline, an autoblog owned by Nitto, just finished up a similar series of how much each diesel has been known to handle and what their weak link is. This time, they posted all of the diesels.

***Please note: These power numbers are for engine only assuming all supporting mods(i.e. driveline, trans, fuel delivery) are capable of handling these power numbers. So yes, a stock trans will blow long before you hit these numbers.

What is also interesting, and contrary to what many here believe, is how well a diesel engine will hold up to high power numbers with proper tuning. With the advent of common rail and electronically controlled injectors, many novice tuners added too much fuel and timing down low causing too high of cylinder pressures which is very hard on engine internals. This caused many horror stories and many internet myths. Cutting back on fuel and timing at low rpms and increasing it as the rpms rise is much better for your engines internals as the articles state. And of course these are all rear wheel numbers which are generally about 15% less than crank numbers.

THRESHOLD FOR PAIN: POWER STROKE EDITION

7.3L Forged Rods (94.5-00)
Threshold for Pain: 600 HP (1,100-1,200 LB-FT)
Weak point: Rods

7.3L Powdered Metal Rods (01-03)
Threshold for Pain: 450 HP (850-900 LB-FT)
Weak Point: Rods

6.0L (03-07)
Threshold for Pain: 800 HP (1,300-1,400 LB-FT)
Weak Point: Rods

6.4L (07-10)
Threshold for Pain: 900+ HP (1,500-1,700 LB-FT)
Weak Point: Pistons

6.7L (11-Present)
Threshold for Pain: 700 HP (1,300-1,500 LB-FT)
Weak Point: Rods


THRESHOLD FOR PAIN: DURAMAX EDITION

LB7 (01-04)
Threshold for Pain: 550 to 600 HP (1,100-1,200 LB-FT)
Weak Point: Rods

LLY (04.5-05.5)
Threshold for Pain: 550 to 600 HP (1,100-1,200 LB-FT)
Weak Point: Rods

LBZ (06-07)
Threshold for Pain: 650 HP (1,200-1,300 LB-FT)
Weak Point: Pistons

LMM (07.5-10)
Threshold for Pain: 650 HP (1,200-1,300 LB-FT)
Weak Point: Pistons

LML (11-16)
Threshold for Pain: 700 HP (1,200-1,300 LB-FT)
Weak Point: Rods

L5P (17-Present)
Threshold for Pain: Not yet known since no one has been able to crack the ECU yet


THRESHOLD FOR PAIN: CUMMINS EDITION

5.9L Mechanical (89-02)
Threshold for Pain: 800 HP (1,400 to 1,600 lb-ft)
Weak Point: Rod Bolts
Threshold for Pain (Race Applications): 1,400 to 1,500 hp due to running at higher rpm's

5.9L Common Rail-6.7L (03-Present)
Threshold for Pain: 900 HP (1,800 lb-ft)
Weak Point: Rods

[FishOnOne]

ShinerBock wrote:
Sounds like a douche bag neighbor. I see all sort of douche bags like this driving all sorts of vehicles.

Trust me he's not... He's just doing what he loves to do with the added friendly jesture.

[ShinerBock]

Sounds like a douche bag neighbor. I see all sort of douche bags like this driving all sorts of vehicles.

[FishOnOne]

Lessmore wrote:

FishOnOne wrote:

Lessmore wrote:
Interesting piece. Not surprising though, every mechanical device has a destructo limit. I must add, that I don't for the life of me know why some guys just have to soup up their engines to the point of quick and eventual no return, given that diesel engines in modern HD pickups offer tremendous power in their stock form.

I can understand that those in the racing industry...would extend their engines as far or farther then they can handle...it's racing and that's a factor in winning...after all that's the bizness they're in.

But for some guy driving around in a street truck...I do not know why.

In 1970 you could order a Chevelle with a basic 350 4blr carb or you could order a Chevelle SS with a LS6 454. I owned the later and it was a pure joy to drive. It's what floats your boat.... And mine was HP with good looks to top it off. :B

You could order a '70 Chevelle with a straight six too. That 4 barrel 350 with 300 hp moved out nicely. A buddy back then had a '70 Chevelle SS454 with the LS6..450 hp, 4 speed Muncie. I got the occasional ride in it...twice I think...both times in bumper to bumper traffic...he never got it out of first...dang it !! 😞

A year or so before...I had a '67 Camaro coupe, RS, red line tires, Muncie, 327 V8, rally wheels, Marina Blue...still think it was a very sharp looking car.

It was a jewel of a car...

Another story there's a older gentlemen(estimated upper 60's) that lives in my neighborhood that has a tuned ram 6.7 and he gets a thrill passing me on the some of the local roads and waiving at me while I can't do a thing. I get a laugh every time I see this guy coming cause I know what's going to happen.

[1stgenfarmboy]

It's a really quick old truck at 6,200 lbs, locked in 4x4 with a 18 lb boosted launch. 0-50 on the street it is hard to outrun, as alot of mustang and camaro guys have found out, when they hear the turbo starting to spool they loose there mind and stomp the gas and roast the tires as I drive away, it would be close if they could get off the line.

It's not funny to them when a dually 4x4 grandpa truck outruns them, but it is to me.

[ShinerBock]

1stgenfarmboy wrote:
I have a hybrid 60/16 GDS, 3 inch stainless cooler tubz, 7.3 power stroke intercooler, huge John Deere combine air filter, and I removed the grid heaters, timing is to the head, dynomite diesel stage 4 injectors, dynomite diesel fuel pin, carter 4160 fuel pump, 4 inch exhaust, 3,200 governor springs, the VE injection pump is near maxed out, big fuel lines, and a tuned AFC, I have smoke at low boost but it cleans up nice at 42 psi, EGT's are 1,300* pre turbo on a max wide open throttle run.

Nice! Makes me miss my old 12-valve. Yours is a little more bombed then mine was. There is a 95 2500 reg cab standard with 200k for $8,500 not far from me. I have been debating on picking it up as my next project.

The good thing about these modern VG turbos is that, along with he exhaust brake, they spool quick enough so that the air catches up with the fuel being injected a lot quicker limiting the smoke, but the down side is that they are not as reliable as the old turbos.

[TakingThe5th]

1stgenfarmboy wrote:
I have a hybrid 60/16 GDS, 3 inch stainless cooler tubz, 7.3 power stroke intercooler, huge John Deere combine air filter, and I removed the grid heaters, timing is to the head, dynomite diesel stage 4 injectors, dynomite diesel fuel pin, carter 4160 fuel pump, 4 inch exhaust, 3,200 governor springs, the VE injection pump is near maxed out, big fuel lines, and a tuned AFC, I have smoke at low boost but it cleans up nice at 42 psi, EGT's are 1,300* pre turbo on a max wide open throttle run.

Wow! Just think how well it will run when you start doing some mods :):W

All I have is a modified vacuum cleaner that can suck up broken rods, engine block pieces and other large debris. I hate to litter.

[1stgenfarmboy]

I have a hybrid 60/16 GDS, 3 inch stainless cooler tubz, 7.3 power stroke intercooler, huge John Deere combine air filter, and I removed the grid heaters, timing is to the head, dynomite diesel stage 4 injectors, dynomite diesel fuel pin, carter 4160 fuel pump, 4 inch exhaust, 3,200 governor springs, the VE injection pump is near maxed out, big fuel lines, and a tuned AFC, I have smoke at low boost but it cleans up nice at 42 psi, EGT's are 1,300* pre turbo on a max wide open throttle run.

[ShinerBock]

1stgenfarmboy wrote:

BTW, do you have a stock Holset or an aftermarket on that 12 valve?

[RobertRyan]

1stgenfarmboy wrote:
If you want to make clean usable HP/TQ it takes both more fuel and air, add lots of fuel without adding air and it will be smokey.

Agreed

[ShinerBock]

1stgenfarmboy wrote:
If you want to make clean usable HP/TQ it takes both more fuel and air, add lots of fuel without adding air and it will be smokey.

This is true if you do not have enough air for the amount of fuel being injected just like things will go south real quick in a gas engine if you do not have enough fuel for the amount of air being added.

[1stgenfarmboy]

If you want to make clean usable HP/TQ it takes both more fuel and air, add lots of fuel without adding air and it will be smokey.

[ShinerBock]

RCMAN46 wrote:
A diesel is regulated by fuel, not air'

Not totally true as if it were a turbo charger would not be needed.

Both gas and diesel if you want more power increase the air flow much more difficult than adding more fuel which is very easy.

A turbocharger is not needed on a diesel. A diesel just benefits from a turbocharger since it allows it to utilize more air to burn the fuel better thus making it more efficient and powerful. There have been (and still are in some applications) many diesels that do not use turbos. The Ford 6.9L and GM 6.2L are just a few examples.

[RCMAN46]

A diesel is regulated by fuel, not air'

Not totally true as if it were a turbo charger would not be needed.

Both gas and diesel if you want more power increase the air flow much more difficult than adding more fuel which is very easy.

[ShinerBock]

RobertRyan wrote:

Fair point. If you want a long life do not veer from the factory tune.

This is not always the case. Contrary to what many believe, modern engines are not tuned for longevity as the primary concern. They are tuned to meet emissions above all else even at the expense of engine longevity. After all, you can't sell an engine or vehicle if it doesn't meet emissions first.

Take the EGR and DPF's on many diesels. The EGR creates excess oil contamination and the DPF regen creates fuel dilution harming the longevity of the engine just to meet emissions. You also have the factor that many US diesels are also tuned to handle higher altitudes as well, and you can add power when you aren't in such conditions. Basically you are adjusting the truck's power level to how you are currently using it instead of the "vanilla" tune made to meet emissions and for many different duty cycles.

Same with my old Ecoboost F150. Although still in safe parameters, my laptop recorded considerably more knock on the factory 330 rwhp tune (since the timing was programmed to meet emissions) than I did on my 390 rhwp custom tune. Same thing with my friends direct injected GM 5.3L on his custom tune. Basically what the tuner did was remove all the programming that was made to meet emissions, which was actually doing more harm to the engine, and thus increased power.

Although I do find it funny that if the factory adds 40 hp or 100 lb-ft just through computer programming year over year then that is fine, but if an aftermarket tuner does the same then everyone looses their mind.