Rebuild an SO as an HO?

[Parshal]

Just a thought since I know it's a long, long way away. In the future, when it's time to rebuild my SO, I wonder how easy/more expensive it will be to make it an HO. I assume in the next few years it could be reflashed as an HO and the exhaust manifold should be easy enough to replace. But the pistons and j-jets are interesting.



By the way, it would cost around $4k to replace the NV4500 with the NV5600. That includes the new transmission and all replacement pieces. A fairly expensive proposition!

 

[Swayse]

The exhaust manifold is different?



I was parked next to my nephew's HO 48RE and both were idling, his sounded different and was a bit quieter. His had more of that diesel sound than mine did. I wonder if they have higher compression than the SO.

 

[PCline]

No reason

I don't see a reason to rebuild your SO into an HO. You can bomb it to something waaaay beyond an HO.



Also, after reading the latest issue of the TDR I'm convinced the J-jets and ported pistons are for emissions reasons, not power/longevity reasons. Cooler cylinder temperatures are part of the emissions goal. I know Cummins claims it adds to the longevity of the engine but I think that's marketing talking and not Engineering.



The yet-to-be-released fueling boxes that will modify timing and injector duration will more than compensate for the HO's ECM.

 

[Parshal]

Re: No reason

I know I can get power beyond what the HO offers (probably already have it with the EZ). With the HO, though, you're starting out with more power before you add the modification boxes so you'll end up with more in the end. If the j-jets and ported pistons were for emissions purposes wouldn't both the SO and HO have them?



Of course, this is my thinking on how I can compensate for not getting the HO to begin with!

 

[PCline]

you're starting out with more power before you add the modification boxes so you'll end up with more in the end

This is not entirely true. The power creating difference between the HO and SO is the duration of the injection event (and maybe a little bit of timing and fuel pressure I don't know). There's only so much time to efficiently inject the fuel. Once you hit that duration limit, it doesn't matter what you started with. An HO will just get to that limit sooner than an SO.



Some of the fueling box manufacturers have already stated that some box levels are for the SO only (to make up for the lower starting point of the SO). I already know what you thinking... you'll use those levels for the HO, but my guess is that you'll just create more smoke and only minimally more power.



I'll probably get blasted by someone saying the different box settings for the SO and HO are based on the turbo limit and not the duration limit. That's true. But the fact still remains, that all other things being equal (turbo, injectors, exhaust, etc. ) the SO can be made to make as much power as the HO.



Also, J-jets don't make power. The HO has them because it's programmed with more power (fuel) but still has to meet the same emissions requirements as the SO. Therefore the cylinder temperatures need to be better controlled.



Just my . 02... blast away!

 

[Parshal]

Originally posted by PCline

Some of the fueling box manufacturers have already stated that some box levels are for the SO only (to make up for the lower starting point of the SO).

Which boxes do that? I haven't seen those.

 

[PCline]

Parshal... I've spent the last 30 minutes trying to find where I read about the different settings for an SO. For the life of me I can't find it. I thought it was in Issue 39 of the TDR but I just read through that and couldn't find it.



At this point I think I have to back-up and say that maybe I got injectors and turbos mixed up with boxes (DD states that Stage 2's are only recommended for the SO because the HO may develop too high EGT's with stock turbo).



I could swear I read that at least one of the boxes had settings specific to the SO. Has anyone else run across that information? If so, where?

 

[Parshal]

I think the answer to this is yes but aren't the turbos the same on SO and HO?



I have an EZ and they are the same for the SO and HO.

 

[DragRacer]

Turbos are the same SO vs. HO.



Parshal,



How do you like the EZ on your SO?



DragRacer

 

[Parshal]

It's very nice. I just keep wondering how much I'd like it if I started with an HO!

 

[DragRacer]

Parshal,



Have you had the opportunity to dyno your SO before and after the EZ?



Thanks,



DragRacer

 

[Parshal]

Not yet. I haven't had a chance to get down to the dyno yet. I hope to in the next few weeks, though.

 

[Elite1]

The HO has higher compression pistons and a larger flywheel, along with the other differences mentioned.

 

[DieselpowerDude]

All I have read is that the pistons have additional oiling, possibly for cooling. Have not read anything of the HO having a higher compression ratio. Where did you get the info?







95 for sale, 03 on order!Oo.

 

[MCummings]

Originally posted by Elite1

The HO has higher compression pistons and a larger flywheel, along with the other differences mentioned.

This info is correct for 2nd Gen 24V ISB, NOT for 3rd Gen 24V ISBe.

 

[Elite1]

Originally posted by DieselpowerDude

All I have read is that the pistons have additional oiling, possibly for cooling. Have not read anything of the HO having a higher compression ratio. Where did you get the info?







95 for sale, 03 on order!Oo.

Read and click on 22 thru 25, from this link... http://216.239.53.104/search?q=cach...nce/faq/index.cfm+cummins+h.o.&hl=en&ie=UTF-8

 

[Parshal]

#25 appears to be for the HO prior to '03 since it's mentions 245 HP and 505 ft/lbs of torque.

 

[DieselpowerDude]

The Cummins FAQ clearly states that the HO power on the 03 engine is made in software only. That would mean that on the SO including the CA version the same power can be bombed ultimately making the 2 engines the same, right? Oo.











95 For Sale, 03 on orderOo.

 

[Elite1]

Originally posted by DieselpowerDude

The Cummins FAQ clearly states that the HO power on the 03 engine is made in software only. That would mean that on the SO including the CA version the same power can be bombed ultimately making the 2 engines the same, right? Oo.











95 For Sale, 03 on orderOo. [/QUO



I wouldn't say "clearly"... this is from the Cummins FAQ:



"What is the difference in the HO engine versus the Standard Output engine?





What did we do to make the HO engine 305 horsepower and 555 lb-ft torque? First we beefed up components such as the pistons to handle this power level. We use gallery-cooled pistons which receive an oil spray to for cooler temperature and longer life. Then we modified software to create the greater horsepower and torque, while staying within all engine and driveline parameters. "



It doesn't say the SO also has the same beefed up pistons...

 

[Elite1]

Originally posted by DieselpowerDude

The Cummins FAQ clearly states that the HO power on the 03 engine is made in software only. That would mean that on the SO including the CA version the same power can be bombed ultimately making the 2 engines the same, right? Oo.











95 For Sale, 03 on orderOo.

Cummins also states differences in the HO vs. the SO, in the year 2000' when the HO first came out... Where does it clearly say the SO in 2003' is the same as the HO except for computer software?



My question is, does the 2003' SO have the same pistons as the HO?, does it have the same fuel pump components? Does it have the same injectors?, does it have the same valve seats?, does it have the same fly wheel???



This from the Cummins site, FAQ: What is the High Output Cummins Engine? What changes were made to the HO engine?





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.