Gov. Spring Max RPM's

[Smoker]

I would like to hear some numbers. How high have some of you revved the B5. 9? Dave Mitchell turns about 5000(give or take 100 RPM's), but he has also had his motor balanced.

 

[ramman]

4000 comes easy and fast.

 

[Smoker]

I've hit about 4400 so far when truck pulling. What part of KY are you from?

 

[HoleshotHolset]

What about the complete torsional harmonic destruction that is supposed to occur at 4100rpm?





All I need to do is have my rotating assembly balanced (did Cummins not do this from the get-go??) and I can crank 'er right up to the 5600rpm that it's supposedly rated to??

VERY curious, as I'd love to see at least 3500rpm... . if I can get more, I'll take it!



Matt

 

[SLang]

HoleshotHolset, 34-3500 RPM is easy. Past that the valve springs will need to be replaced.



Cummins did balance your assembly. But the engines are OEM manufactured for 3000 RPM max. So to keep cost down they use a larger spec. for balancing. 5000 RPM will take much tighter tolerances. OEM's only go as far as they have to and still make requirements. That business.

 

[Smoker]

factory balance

I've been told by a Dodge mechanic that is very knowledgable about the 5. 9 that the motor is balanced from the factory at 3800 rpm. He said that you can turn about 4500 rpm's with the factory balancing.

 

[HoleshotHolset]

With upgraded valve springs and a governor spring kit I can see 3500rpm with no issues. That's what I like to hear.

OEM's love to save money... . that's why there are 'christmas tree fasteners' holding on our door panels. Who thought this was a good idea... ??!!

I am VERY glad I bought a Cummins, though.



Matt

 

[sewman]

Stock springs are good to 3200

 

[SLang]

I put my gov. springs in this weekend. Loved them. I can rev clear through 3400 RPM with power. I still shift at 2700-2800 RPM but if I want it it's there.



Piers told me I could run to 34-3500 RPM without valve springs. He put 3200 RPM in his instruction for obvious liability reasons. The only catch I can see is to make sure the lifters/valves are adjusted correctly.

 

[Forrest]

Don't know. When SOTN & I test drove, I took it to 3200. Since then, I've been there a few times, but never pushed it. SOTN said to gain full advantage by advancing the timing. Still haven't done it. Haven't found anyone I'd trust.

 

[HoleshotHolset]

I'd love to have my timing advanced too... ... someday I hope to be able to do it myself. The increased cylinder pressures associated with advanced timing is a subject I'd like to see discussed... . I don't wanna go popping a headgasket...



Matt