Differences between 250hp&305hp engines

[DMuller]

I just recently bought a 03 3500 auto and was wondering what was the difference between the 250 hp( in mine ) and the 305 hp? Is it just software? Also on my ECM there is a sticker that says Authorized software update, anyone heard of that?

 

[rbattelle]

The authorized software update sticker just means the ECM has been reflashed by the dealer. Probably as part of a TSB. Perfectly normal.



As I recall there are 2 main differences between the SO and HO motors. First, there's programming. Second, the piston cooling system in the HO motor is bigger and more aggressive than in the SO motor.



I don't think it's possible to "flash" an SO and make it an HO.



Someone like Matt400 (who has a SO) might have more insight.



-Ryan

 

[DMuller]

Thanks Ryan, Im just new to TDR and finding it very informative. I used to own a 98 12v and loved it but family has grown up and needed the 4 doors. I tow a 26ft 5ver with it and am very impressed with the 03. Even fuel milage is better than the 98 and it was a 5spd. Thanks again Dan

 

[Scrappy]

Second, the piston cooling system in the HO motor is bigger and more aggressive than in the SO motor.



I don't think it's possible to "flash" an SO and make it an HO.



Someone like Matt400 (who has a SO) might have more insight.



-Ryan

the pistons in the HO have cooling passages in the bottom side of the piston and the SO does not

 

[jwilliams3]

Rail jet piston cooling is the difference (like the others said).

Although, both systems work very well. Old and new.

 

[slomodiesel]

dosn't the HO also have the cracked cap rods?

 

[Scrappy]

I think all '03 and newer have the cracked cap rods.

 

[KERMA]

Injectors are different-



555 uses 8-hole nozzles with a 143 degree spray angle (DSLA143P1058) and the 600 and newer use 5-hole nozzles at 124 degree spray angle (DSLA124P1309)



Some people suspect the 5-hole vs 8-hole nozzles for reducing the fuel economy in the newer trucks...

 

[rbattelle]

Injectors are different-



555 uses 8-hole nozzles with a 143 degree spray angle (DSLA143P1058) and the 600 and newer use 5-hole nozzles at 124 degree spray angle (DSLA124P1309)



Some people suspect the 5-hole vs 8-hole nozzles for reducing the fuel economy in the newer trucks...

That's very interesting. I wonder if the larger holes on the 5-hole nozzles are more tolerant to contaminants?



-Ryan

 

[OT-OF-HERE!!]

tolerant nozzles

That's very interesting. I wonder if the larger holes on the 5-hole nozzles are more tolerant to contaminants?



-Ryan

I would say NOT. I've seen too many on this site and DTR with white smoke and bad injectors. I had seven injectors replaced by 9k miles on my truck.

 

[bpenrod]

Injectors are different-



555 uses 8-hole nozzles with a 143 degree spray angle (DSLA143P1058) and the 600 and newer use 5-hole nozzles at 124 degree spray angle (DSLA124P1309)



Some people suspect the 5-hole vs 8-hole nozzles for reducing the fuel economy in the newer trucks...

I got lost somewhere! The 555 is an HO, what injector does the 460 use, that would be an 03 SO if I'm not mistaken!

 

[rbattelle]

I believe KERMA didn't quite understand what this thread was talking about. As far as I know the SO engine (460) uses the same injectors as the HO engine (555). His comment was interesting, but totally irrelevant to this thread.



-Ryan