differance in HO & no HO

[gjacobs]

Can anyone tell me the differance between the regular 24 valve and the H. O. 24 I know that they have higher horsepower and torque, but what makes this possible? I'm looking at a '99 that has the 6-speed does this mean that it is H. O. ?

 

[fredflinstone]

HO??

It's my understanding that the major difference's are the injector pump is slightly different internally and the pcm is different. I have also heard rumor that the injectors may be different but I have yet to pull the injectors out of my new High output so I don't know about that for sure yet. Cummins now sells a new pcm that brings the power up on the other motors to about the same leval thought if your just interested in the extra power. As for the 99 being a HO I'm not sure but I believe only the HO came with the six speed.



Seth

 

[Bob Wagner]

read all about it

http://www.dodgeram.org/support_pgs/diesel_ix.htm

 

[w-cummins]

Re: HO??

Originally posted by fredflinstone

It's my understanding that the major difference's are the injector pump is slightly different internally and the pcm is different. I have also heard rumor that the injectors may be different but I have yet to pull the injectors out of my new High output so I don't know about that for sure yet. Cummins now sells a new pcm that brings the power up on the other motors to about the same leval thought if your just interested in the extra power. As for the 99 being a HO I'm not sure but I believe only the HO came with the six speed.



Seth

Ya Mean ECM? the PCM is a Dodge part

 

[tgbol]

It may seem weird but the HO injectors are slightly smaller than the regular engine. 640 (ETC) to 600 (ETH) cc/30 seconds @100 BAR. The HO also has a higher compression ratio.

 

[rkubicki]

The following is from the Cummins website:

=====

The High Output Cummins engine is a new rating launched in January 2000 for the Dodge Ram. It produces 245hp and 505 lb. -ft torque. To create and handle the high output the rating this engine has different components:



Controls: new software instructing fuel pump to deliver more fuel.

Fuel System: VP44 fuel pump components changed to allow for increased fuel delivery.

Injectors: Changed to allow for increased fuel delivery.

Pistons: New design for higher 17:1 compression ratio-

Head: powdered metal valve seat inserts for improved Durability.

Flywheel: larger to match to larger diameter clutch for handling higher torque output.

=====



Rob

 

[TxDieselKid]

Does everybody really think it's all that from the last post? If so, how come I can go get the same ratings as an HO with the torques maxes ecm?



the part that REALLY screws up all up is that the VP44 on the HO has plungers that are 8cm, and 9cm on the NON-HO VP44's. Weird huh?



Andrew

 

[rkubicki]

Originally posted by TxDieselKid

Does everybody really think it's all that from the last post? If so, how come I can go get the same ratings as an HO with the torques maxes ecm?



the part that REALLY screws up all up is that the VP44 on the HO has plungers that are 8cm, and 9cm on the NON-HO VP44's. Weird huh?

I am guessing that the torques maxes ECM has a more radical fuel delivery map than the stock Cummins HO ECM. The higher rating of the HO engine (vs. stock non-HO) is probably due to both the higher compression ratio and a moderate increase in fuel delivery. A non-HO engine that is programmed to out-fuel a stock HO engine could make the same power, however, there is more power potential in the HO platform. Compare an HO engine and a non-HO engine both running with the torques maxes ECM and you'd probably see a difference.



As for the different pump sizes: Yes, while one pump can clearly flow more fuel than the other, their delivery rates are constantly being regulated by their ECMs... The same ECM would govern a higher-flowing pump more than a lower-flowing one to keep the delivery volumes the same. It is also possible that the pump with smaller plungers has a smaller drive gear so it is turned faster than the pump with the larger plungers - don't know about that one though.



-Rob

 

[TxDieselKid]

Originally posted by rkubicki

I am guessing that the torques maxes ECM has a more radical fuel delivery map than the stock Cummins HO ECM.

-Rob

Same ratings as the HO, and it's not says that it is for 5 speeds only. If the fueling map is the same as an HO then... ... . ?



If it smells like an HO... ... .



Andrew

 

[rkubicki]

Originally posted by TxDieselKid





Same ratings as the HO, and it's not says that it is for 5 speeds only. If the fueling map is the same as an HO then... ... . ?

You are saying that the aftermarket reprogrammed ECM and the stock Cummins HO ECM have the same fuel map?



I seriously doubt that you are going to put a stock HO ECM from Cummins on a non-HO engine and get the same power as the factory HO engine... . The differences in compression ratios and physical fuel systems (pumps/injectors) between the two engines alone would warrant different fuel maps.



Perhaps the aftermarket ECM is for 5 speeds only because it won't meet emmissions standards in an auto?



Besides, I don't think Cummins would lie about what goes into their engines:



http://www.cummins.com/na/pages/en/....cfm?uuid=00038B45-046B-1B90-BCF080C4A8F00000



-Rob

 

[TxDieselKid]

Rob,

I'm fully aware of everything that they say is in there. But it's just kinda weird how even with all that stuff, it's 505ft. lbs, and the ECM uprate is also 505ft. lbs(I have never heard of a hp number for them)



Let me share some more info with you about that list from Cummins.

Fuel System: VP44 fuel pump components changed to allow for increased fuel delivery.

Already talked about that, and you had a great thought about it. But if your trying to flow more, use smaller flowing componets?

Controls: new software instructing fuel pump to deliver more fuel.

Same thing that the ECM upgrade does.

Injectors: Changed to allow for increased fuel delivery.

The injectors on an HO do not flow as much either.

Pistons: New design for higher 17:1 compression ratio-

Ok, rasing the compression will make more power, but its 2-1 right now. They also have an extra ring from what I hear.

Head: powdered metal valve seat inserts for improved Durability.

This does nothing for power.

Flywheel: larger to match to larger diameter clutch for handling higher torque output.

Could it really not handle more without enlarging it? Anyways, yes this will transer more power, but this is to the rear wheels, we are talking about AT the flywheel.



Believe what you want to, I'm not saying one way or the other. I'm am kinda on the fence about this. I just thought it's kinda weird how you can stick it on a 5 speed, and run with the the HO.



Andrew

 

[JIM S.]

Hmmmmmm

My truck is 17. 5:1 guess they had to lower the compression so they could raise it for the HO and make it sound all wonderful



Jim

 

[TxDieselKid]

Re: Hmmmmmm

Originally posted by JIM S.

My truck is 17. 5:1 guess they had to lower the compression so they could raise it for the HO and make it sound all wonderful



Jim

You 12vers need all the help you acn get!!!



Andrew

 

[LSMITH]

The Torqus Maximus ECM is not simply an ECM with a HO ETH program. Drive them both, it is not even close. The ETH is really strong after 2000 RPM where the TM pulls hard from about 1750 on. The ETH falls on it's face at about 2850 where the TM pulls hard to 3000+. The ETH is perfectly suited to the 6 speed transmission, man it shines with the even splits!!! The TM is matched to a 5 speed with larger gaps, and has a bit wider power band to help with the larger splits. Load an ETH and an ETC/TM with 20K pounds and drag race them up a 6% grade, my money is on the ETH. I have driven both and this is my impression, the maps are totally different.





The TM is not for use on an auto because it will not handle the added power, at least that is the original reason for 5 speed only, remember these were sold by dealers for Dodge and could not void the warranty.

 

[jlccc]

Originally posted by LSMITH



[snip]

The ETH is perfectly suited to the 6 speed transmission, man it shines with the even splits!!!

LSMITH, what do you mean by "even splits"?

 

[rkubicki]

Originally posted by TxDieselKid

Rob,

I'm fully aware of everything that they say is in there. But it's just kinda weird how even with all that stuff, it's 505ft. lbs, and the ECM uprate is also 505ft. lbs(I have never heard of a hp number for them)

It just seems like you are comparing apples to oranges here, Andrew, in this case a stock engine (HO) to a modified non-HO ... .



Here is a more extreme example of my point:



I could modify my early 12-valve engine to the point that it makes power in the ballpark of a stock 24-valve - but this does not take away the fact that the new 24-valve engines are powerhouses in their own right... . To get a 12-valve to turn those kinds of numbers you would have to do some really whacked-out and expensive things and you would be seriously close, if not at, that engine's maximum potential given it's design... Now the 24-valve, on the other hand, puts out those numbers stock so I have a wide-open field of mods at my fingertips to surpass the "mega 12-valve".



Granted this is only an example... I don't want to give the impression that I have a 12-valve bias... . and I certainly would not be crazy enough to go through those kinds of mods and nuke my precious Getrag



So the point is that Cummins did a major mod for HO engine owners - they swapped pistons yielding a higher compression ratio... . A higher compression will give you more bottom end power... . Its not a huge difference but a better ground-zero starting point than the non-HOs for that reason alone... .



Yes you can deliver more fuel to your non-HO engine with an aftermarket ECM and get the same numbers as the HO (compensating for a lower compression)... but when the HO engine is reprogrammed to deliver more fuel in a similar fashion to the TM ECM you will see the HO's numbers pull away again.



I'm probably going to ruffle some feathers on this one: The smaller pump and injectors on the HO really don't make a difference when both engines are under closed-loop control from the ECM.



-Rob

 

[rkubicki]

Re: Hmmmmmm

Originally posted by JIM S.

My truck is 17. 5:1 guess they had to lower the compression so they could raise it for the HO and make it sound all wonderful



Jim

Probably had to make more clearence for the two extra valves when the piston comes up to TDC... . I like my 17. 5:1 too - you can keep the two extra valves!



... . but if someone had a 24-valve for sale cheap my number is... .



-Rob

 

[TxDieselKid]

Originally posted by rkubicki



It just seems like you are comparing apples to oranges here, Andrew, in this case a stock engine (HO) to a modified non-HO ... .



but when the HO engine is reprogrammed to deliver more fuel in a similar fashion to the TM ECM you will see the HO's numbers pull away again.



I'm probably going to ruffle some feathers on this one: The smaller pump and injectors on the HO really don't make a difference when both engines are under closed-loop control from the ECM.



-Rob

Rob,

I first posted a question on this thread. I wanted an answer from it, and had no intentions of turning it into a debate, sorry for that, I was just showing something I thought was intresting.



As far as compairing apples to oranges, how is there THAT big of a difference when the power level is so close? The different parts don't amount to a hill of beans if you ask me. Look at what is going on over in Vegas right now. The difference is none between the HO and the non-HO on the dyno when no drugs are being used. Jim Fuller(CUMMNTSTRKIN) posted a HUGE number with a non-HO, and so did the DD boys.



Now when you start talking about reprograming, are you talking about aftermarket fueling boxes? If so, it is a known fact that HO's will not respond to them as greatly as non-HO's do.



Ruffle some feathers? No way man, I'm way too friendly to take this stuff seriously.



Andrew



P. S. Are we turning into Don_M, and Sled Puller(Gene) type argueers?

 

[rkubicki]

Originally posted by TxDieselKid





Rob,

I first posted a question on this thread. I wanted an answer from it, and had no intentions of turning it into a debate, sorry for that, I was just showing something I thought was intresting.



As far as compairing apples to oranges, how is there THAT big of a difference when the power level is so close? The different parts don't amount to a hill of beans if you ask me. Look at what is going on over in Vegas right now. The difference is none between the HO and the non-HO on the dyno when no drugs are being used. Jim Fuller(CUMMNTSTRKIN) posted a HUGE number with a non-HO, and so did the DD boys.



Now when you start talking about reprograming, are you talking about aftermarket fueling boxes? If so, it is a known fact that HO's will not respond to them as greatly as non-HO's do.



Ruffle some feathers? No way man, I'm way too friendly to take this stuff seriously.



Andrew



P. S. Are we turning into Don_M, and Sled Puller(Gene) type argueers?

Not at all, Andrew, this is completely a congenial conversation in my opinion... I am not trying to argue with you or start some kind of debate... I was just a little perplexed about your early comment that there is no difference between the HO ECM and the TM non-HO ECM... . Made me think "How is that possible?"



I agree with you that most of the HO parts don't do much for the engine's overall performance (mostly for durability) but the one mod that Cummins made on their HO that is important is the raised compression... .



Bare HP/Torque numbers can be impressive if they are large, however, when the power ramps up and what the curve looks like are very important factors too. The higher compression helps with the low-end torque bringing the HO's max numbers up sooner...



Basically, from a performance point of view, an HO engine is a standard ISB with different pistons and a factory-reprogrammed ECM... . Therefore, it is interesting to hear you say that HO engines don't respond as well to reprogramming... .



I would agree that taking an aftermarket ECM programmed for a lower-compression engine in a taller geared environment would probably not be the best bet for an HO... . But what would an aftermarket ECM optimized for a 6-speed, higher compression do for the overall HO Torque/HP numbers?



Does this mean that I'd spend the extra cash and take pains to find an HO? - no way... but I would certainly have some of those pistons and a factory HO ECM on hand to reprogram for my next ISB rebuild.



-Rob

 

[LSMITH]

jpark, for the first 2 gears on the DEE (6 speed) there is about a 1000 RPM difference, then there is about 700 for each gear after that. Evenly spaced gear ratios is what I meant by even slpits.