Cholmes

Can someone tell me what the differance is between the 5.9 HO and the regular 5.9? I know HO came in the six speed only but what makes it an HO? I am not looking for HP and torque differances but rather what is done to the engine to bring it to HO specs.

rebal

235 hp 460tq verses 245 hp505 tq HOs have a higher comp ratio, SO has the potential to make more HP a

luke03cr

the difference was different programing in the engine computor

AggieJustin

There is also a difference in the VP44. The HO VP44 uses smaller plungers running higher pressure, which is why people swap to the SO VP44 for more fuel flow in heavily fueled applications.

Dr. Evil

Your answer is here:

http://www.dodgeram.org/tech/dsl/Facts/01ISBspecs.html

What's new in the ETH engine:

- Electronic Controls: New ECM calibration and fueling algorithms.
- Fuel Pump: Increased fuel flow in the Bosch VP44 injection pump.
- Injectors: Designed to provide increased fuel flow.
ETH injectors (3946306) flow 600cc at 100bars for 30 seconds
ETC injectors (3944828) flow 640cc at the same test.
- Turbocharger: Revised wastegate setting for 26psi at the turbocharger outlet.
- Manifold boost specification is 43.5 inches Hg / 21 psi
Head: Valve seat inserts for added durability.
- Pistons: New pistons with higher 17:1 compression ratio.
- Flywheel: New flywheel with 330 mm diameter clutch (vs. std. 310 mm).
- ISB Design Improvements and Features - from 1998 Mastertech
FWIW: Reports from owners indicate that ETC engines are more responsive than ETH engines are to the major fueling boxes.

KATOOM

If your plan is to try and make your SO into an HO then dont bother. Not only is there a lot of differences which would be costly and very involved to change but there's nothing wrong with the SO and as already mentioned, the SO motor is more desired amongst people after HP because the SO is more capable of making more HP than the SO and the SO will also make power with lower EGT's.

Cholmes

I wasn't actually thinking of changing it, I was just curious of what the manufacturer did to make it different, seems like allot of trouble especially as all they really had to do is make a better air intake and exhaust system as well as a bit of programing.

Dr. Evil

Its all about $$ man....they can charge more for an HO because consumers are suckers.

Cholmes

You know, you probably don't know how right you actually are!

rebal

I bought mine for the 6spd + the HO is just as easy to mod Im not looking for 1000hp 335/800 pulls my 17,000 5er up any hill just fine the 6spd was the selling point for me.

Dr. Evil

yes, you have a point there.

supr

The tow rating was higher too. With 4.10 gears, it tows heavy fivers very well.
Mine is rated about 14,750, pretty good for 2002.

KATOOM

When the HO was first introduced, it was more about marketing than actual performance over the SO. Dont forget that the first NV5600 came with a smaller input shaft and other specifications which were upgraded in 2001. So if you have a pre-2001 NV5600 then you have the weaker of the two. With respect to ratings, all the SO manuals, HO's, and 1 tons came with the same drivetrain and axles so therefor were the same trucks. The only variables to possibly affect GVWR between them was the NV4500 and the NV5600. Both trannys have their pro's and con's too so that may be more the deciding factor instead of HO or SO.

Cholmes

Mine is a 02 6 speed quad cab 2500

dodgeguy71

I have to disagree with the same axle remark. The 2500 with the manual came with a Dana 80 hybrid which is a Dana 80 center section with Dana 70 spindles and bearings. The one tons had the true Dana 80's. Where the 2500 auto's had the Dana 70's.