Are common rail trucks going to ruin diesel motorsports?

[RedPuller]

Actually the way it was explained to me was the pre-main shot is for emissions and noise control. A little diesel is easier to start a fire, then you have a fire going when the main shot hits resulting in a more complete burn. The gradual lead up to the combustion vs one big all out combustion like my 12 valve is what makes it so quiet. The post main event is for getting more torque. Part of what helps make a diesel more torque than a gasser is a slower, longer burn. By extending the burn time with an additional shot of fuel, you should get more torque.

Now my personal opinion, 3 shots I think is about right. Quiet and torquey. The 5 shots the 6.7, LMM and late 6.4/6.7 P-strokes is too much, and the 1 on the rest creates noise and slightly less torque.

That may be true but that 3rd injection event is what causes the piston crown to melt from what I have heard and read. The longer burn, as you mentioned, is what keeps the crown temp up and eventually melts it during the 3rd injection event with full load and high RPMs for a given amount of time. I know the multiple injection events are for efficency, noise and emissions on the production side of things but who wants that in a strictly race or puller truck? As a puller I want performance & reliability and could careless about the noise and emissions.
It all goes back to comparing failed 12v's vs failed CRs.......one event vs. 3 events.......not many 12v's out there melting pistons like the CRs.

Joe

 

[JOHNBOY]

That may be true but that 3rd injection event is what causes the piston crown to melt from what I have heard and read. The longer burn, as you mentioned, is what keeps the crown temp up and eventually melts it during the 3rd injection event with full load and high RPMs for a given amount of time. I know the multiple injection events are for efficency, noise and emissions on the production side of things but who wants that in a strictly race or puller truck? As a puller I want performance & reliability and could careless about the noise and emissions.
It all goes back to comparing failed 12v's vs failed CRs.......one event vs. 3 events.......not many 12v's out there melting pistons like the CRs.

Joe

Pilot injection helps a ton with noise. Post does nothing for noise. Post is to keep the charge hot for NOX emmisions purposes.

On my Dmaxs I can shut of both pilot and post injections. On my puller I only use pilot in the part thootle lower pressue areas. At full rail pressure and WOT I run just the main injection. Over a season of pulling with EGTs in the 1600 to 2000 degree range with a big single and not one piston problem. They all look fine. To melt a piston you need heat and enough time for that heat to act upon the piston. Run mutliple injection event teamed with big pulse widths you can easy have fuel burning in the cylinder for well over 90 degrees of crank rotation. That will melt pistons even at lower EGTS like 1300. Now look at my set up. At 4000 rpm I am injecting fuel less than 45 degrees of crank rotation. A cylinder fires ever 720 degrees. So in my case the piston has 675 degress of rotation to cool. While at 100 degrees of rotation you have 620. Big difference.

 

[Dockboy]

Well, I did melt mine down but, the truck was basically stock. Too much foot and not enough air.

Since then I've had 700hp+ and have raced it for over 2 years that way with no melt down issue. This on a single causing my EGT's to be very high.... easily 1600F by the 1/8th.

Being careful with programming and not holding those EGT for extended periods has had a lot to do with avoiding a melt down.

Interesting. Why would this be needed and can you provide an example please?

The only thing I can think of is right now with the crappy OEM intake, cylinder 1 and 6 are starved for consistent air, therefore you may wish to deal with that programming differently.

I think Triton is onto something with his theory of the melt downs and CR trucks. Combustion temps might be radically higher at a peak than that of a lower pressure mech. system. Reasonable rational worth consideration anyways.


C-ya

The CR piston melt downs have little, if anything to do with EGT's:bang

To melt a piston you need heat and enough time for that heat to act upon the piston. Run mutliple injection event teamed with big pulse widths you can easy have fuel burning in the cylinder for well over 90 degrees of crank rotation. That will melt pistons even at lower EGTS like 1300.

BINGO we have a winner!!

The unreliability is due to the "guessing" at the right "stack" for maximum hp. It is all related to the current "un-tunability" of the Cummins ECM. Don't worry though, as soon as custom/self tuning is available to the masses, there will be another rash of blown engines due to people stepping over the line:kick:

 

[Boostediesel]

land speed record was set with a CR. its all in the tunning. look how long it took for fuel injection to catch on. for years carbs dominated the drag racing sport. now guys with fuel injected turbo cars running 5 sec. in the 1/4. i think the CR has been moving at a rapid rate since its introduction in 03. every engine no matter what it is has its pro and cons, us CR guys have injection events and electronic's. what ruins the sport is ingonrance and stupidity. CR's have just as much of a place in diesel motorsports as 12 and 24 valves trucks do.its just going to take alot of patience and fine tunning. look at Audi and Peugot, TDI diesel engines in Le Mans! if you could go back 10 years ago and tell the road races that a diesel engine would win racers they would have laughed at you now look what is dominating the sport. its just a matter of time and the CR will we be accepted.

 

[Boostediesel]

BINGO we have a winner!!

The unreliability is due to the "guessing" at the right "stack" for maximum hp. It is all related to the current "un-tunability" of the Cummins ECM. Don't worry though, as soon as custom/self tuning is available to the masses, there will be another rash of blown engines due to people stepping over the line

i fully agree, you are right on.

 

[Idaho CTD]

The Schied rail has a 13mm pump on it Ty... I doubt that a CR system will make more power.

I would argue with that. What's it weigh? MPH and weight doesn't lie on a drag strip. If I had to guess the hp is in the 1350-1400hp range at the tire. I don't think that is out of the reach of a CR at all.

 

[jlibert]

I think they're being over timed with a incorrect ratio of fuel to air which is really helping the melt downs.

The CR system is atomizing the fuel so much at these higher psi's, it's creating a much hotter burn than the older trucks are capable of.

....yep. Even with enough air.

A lot of the "melt down" owners are new to diesel performance or are new to CR performance. If it took years to build an 800 hp truck, the owner would have years of lower HP experience to draw upon and protect the motor.

started modding in 04. Went from 400's to 500's, 600's, all the way up to 800's over the last 5 years. Still melted it down a few months ago.

The CR piston melt downs have little, if anything to do with EGT's:bang
:

Exactly. Some people have a tough time grasping this concept.



--awesome thread btw.

 

[SmokeShow]

dockboy, I wasn't talking about egt. I am talking about the hotter combustion event due to the more atomized fuel. It at least has the potential to burn hotter due to that.


Could still be wrong though.


C-ya

 

[triton]

I would argue with that. What's it weigh? MPH and weight doesn't lie on a drag strip. If I had to guess the hp is in the 1350-1400hp range at the tire. I don't think that is out of the reach of a CR at all.

Thanks Nathan... I don't know a whole lot but, think the CR doesn't really get the respect it deserves.

Tim.... don't be a hater LOL

 

[YOUNG GUNS15]

I dont think that the common rail will ruin the diesel work but the punk kids will what to blow smoke at every intersetion and burn out where in doesnt belong. it could be that since the CR is the hot new thing on the market you will hear about it more than the p pump, 12v and vp. All I can say is that the with the current problem that some people are have with common rails it as made me think the Idea of getting a Common rail and I have a VP.

i agree, one of my buddies had a CR and he beat the shiz outta it. raced him a couple times and really put the hurtin on him.

shure he drove a diesel but did he know anything outside of pushing buttons? NO!!

 

[TxDiesel007]

IMHO

the basics (IE the 12v) have been proven, and still work to this day.. All the best pullers adn high performace trucks are still P pumped... sure you cant beat the adjustability of a CR, but on the other hand you cannot beat the reliability of a 12V either... its a trade off like most other things...

will the motorsport be ruined by the CR, no.. its another branch , like the VP, P pumps, and the VE pumps are...

as stated by forrest and many others, the idiots runnin the monster smoker trucks will.....

 

[Joesixpack]

The diesel sport industry has nothing to do but thank the CR's. Just open up the latest Diesel Power and see how many of the 99 pages of 100 of advertising is aimed at the CR.

 

[Hamilton Cams]

In the last 6 years we have done probably 40 12v engines, 30 24v engines and at least 60+ cr engines. Feel the block and head on a 12v compared to a 24 v and a cr, they are super light compared to the newer castings. The piston oil cooling jets are much smaller on the 12v, larger on the 24 v and even better with the J-jets of the cr. It doesn't add up, the cr other than the valve seats should be much more durable. Even the seats would be a non issue without all of the injector failures. With VE and P-pumps the pressure is only at the injector when the cam plate or the cam sends the pulse. With cr's the pressure is there all the time waiting to get injected. One small issue with the internal metering and voila. I have seen 10 times the burned engines due to worn injectors ones due to high horsepower tunes. One other thing is that with the earlier engines the mexican hat bowl design, contained the heat and the flame much better(higher combustion temps and more Nox) whereas the spread out design of the 04.5 and later open bowl puts much more heat on the edges of the piston where they are much more likely to melt.

When the redneck blacksmokers with 370's, an hx35 and no plate pull the big trailers and overheated the engine it cracked the edge of the bowl or slightly melted it. Since this was happening nowhere close to the rings the engine lived to get beat and kicked another day. Aside from loosening the blocks .002" to give the piston room to grow we also put the injector .030" to .080" deeper in the piston and have seen much less failure as well as better piston coverage with higher timing tunes. Sorry for the book length post. Hey at least I didn't say program.

Zach

 

[Cummins Driver]

Honestly, I havent seen a common rail in a pulling application yet that even remotely wanted anything to do with any of the open class pulling trucks.

That may change in years to come, but mechanical injection is awfully hard to beat on a diesel. This is a whole different ball game than talking about gassers with EFI vs Carburetors. They have to be tuned for a perfect air/fuel ratio. With a diesel, it doesent have to be anywhere near perfect which is why overfueling will give you more power a lot of the time.

Like i said, the common rails are always getting better, but the 12 valves are also getting much better too IMO. The common rails will need something like EFI live, and probably piezo injectors or something similar to really be able to compete with the 12 valves.

And again, the reliability, and fuel mileage of an old 12 valve cant be beat. 245k miles on my engine. The head and everything else on my engine has never been touched and it sees well over 1500* everytime i run it hard. Not saying it is making big power, but it does make some EGT's and it is running 40psi and i havent touched it yet. I went to the dragstrip with it on my last tank of fuel and when i filled up I still got 18mpg. Pretty hard to beat that.

Eric

 

[RonA]

The diesel sport industry has nothing to do but thank the CR's. Just open up the latest Diesel Power and see how many of the 99 pages of 100 of advertising is aimed at the CR.

Common rails are a shops dream come true. Magazines love advertising dollars. Both understandable. But, can the average diesel racer afford the break downs? I've seen several people having second thoughts this year because of them. Is it going to become a sport that few can afford? In the end every add in every magazine is paid for by the customer buying the product. I don't care if the CR motors make 50 percent more power than my p-pump, I won't build a new motor every year. It would just take the fun out of it.

(On a side note: Excellent post Zach).

 

[2Tone12V]

IMO, it's just the opposite. CR's will end up making diesel motorsports. The older trucks are great but, they're starting to hit a wall that the CR can over come..... fueling being the main thing

Like what? I can name alot of things a common rail can't do that the others have. AND stayed together. Can't name to many things a common rail can do that a p pump can't. I like them both. But I don't have the money to melt motors down once or twice a year. Hell just for the cost of injectors you well on your way on a pretty good 12 valve.

 

[2Tone12V]

I don't know if they can flow equal amount BUT they CAN flow enough to make as much power.

Ya on a dyno. Where are they at in pulling? When you get a well put together p pumped truck, even in the 2.6. It WILL be your winner. Not a common rail. I would love to have one for a daily driver. They are like cadillacs to drive. But no thanks on melting parts and bad injectors.

 

[Timbeaux]

Thanks Nathan... I don't know a whole lot but, think the CR doesn't really get the respect it deserves.

Tim.... don't be a hater LOL

I'm not being a hater. I think you are missing the point. at Low RPM, the CR is stupid powerful. With bigass nozzles and multiple injection events, you can get ridiculous amounts of fuel in per cycle. With the badass P Pump motors, you spray in chitloads of fuel very quickly one time per cycle. The CR is no doubt tops for being able to start up easily, Idle well and make very nice power. As for a CR being capable of making the kind of power on fuel that Dan's Dragster or a mod motor does.... sure, they may be able to sustain it for a bit, but we have yet to see a CR at that level live for any length of time. Give me examples of CR's that are finishing at the top in Pro-Street, Top Dragster, Pro-stock, 3.0 or Modified with the reliability of the mechanical motors.

 

[triton]

I'm not being a hater. I think you are missing the point. at Low RPM, the CR is stupid powerful. With bigass nozzles and multiple injection events, you can get ridiculous amounts of fuel in per cycle. With the badass P Pump motors, you spray in chitloads of fuel very quickly one time per cycle. The CR is no doubt tops for being able to start up easily, Idle well and make very nice power. As for a CR being capable of making the kind of power on fuel that Dan's Dragster or a mod motor does.... sure, they may be able to sustain it for a bit, but we have yet to see a CR at that level live for any length of time. Give me examples of CR's that are finishing at the top in Pro-Street, Top Dragster, Pro-stock, 3.0 or Modified with the reliability of the mechanical motors.

I was just messing with ya Tim. You're right, we haven't seen a CR in that category... yet, and we may never see it. It's just been in the last couple of years though that Dan has put that dragster where it's at. Look how close the CR's are in even less time. It's only a matter of time.

We've not seen a CR beat anyone in pro street.... until recently. Jesse just recently opened up a few eyes as far as that goes, I'm sure there's more to come. Once someone comes along with the money Dan or Dennis has.... it just might happen.

 

[Bad-Duvall]

Ya on a dyno. Where are they at in pulling? When you get a well put together p pumped truck, even in the 2.6. It WILL be your winner. Not a common rail. I would love to have one for a daily driver. They are like cadillacs to drive. But no thanks on melting parts and bad injectors.

I take that and just as im about to come on over to the p-pump world.. You make me want to bulid another common rail to prove you wrong!