Why 12-valve makes more power than 24-valve?

[Joe G.]

The biggest reason they switched was because of EPA requirements getting tougher. The P7100 pump is just too smoggy for the later requirements.

 

[TxDieselKid]

yep, the EPA is to blame here, getting rid of the P7100, and adding more valves cleans up the soot some.



Andrew

 

[Rob Thomas]

and adding more valves cleans up the soot

Gee, I hope they (EPA) don't see my truck!



Yea, I'm gonna' get a turbo (or deux), still doin' reserch, I know it's gonna' take $$$$ to get 550Hp, but I got time,I've only been doin' this BOMBIN' fer about 2 months now I'm drained ,gotta' replentish my wallet. So I'll ask questions now,'till I can spend more money... ... ... ... ... ... ... ... ... ... ... . I'm not very patient



Later, Rob

 

[Don M]

Rob,



Ill stir the pot a little and say that nobody has gotten 550HP from a 24 valve yet on number 2 alone.

I have never seen a single dyno sheet to prove it. 500 plus has happened and DD got to 546 as stated earlier. Other than that... . notta. Work with a person who has the knowledge to get you there. An organization that can do it. There are too many fellas trying all kinds of things and end up disappointed when the truck does not get the good numbers they thought it would or felt in the seat of their pants.

The 24 valve has its limitations and some more reasearch needs to be done. If you have the cash, the time and work with a trusted organization you will get there. Next year should bring some very good upgrades to the market to smash more records of HP.



Don~

 

[Rob Thomas]

Ill stir the pot a little and say that nobody has gotten 550HP from a 24 valve yet on number 2 alone.

Don,



I just need another 150 ish HP, thats not too much to ask, is it? ROFLMAO



Time and Money huh, 2 things I'm short on.



As far as an organization, what better one than this one!



Later, Rob

 

[Don M]

Its funny how that first 200HP seems to come pretty easily, but that last 150 is pretty expensive in time and money.

Hours of working and experimentation has gotten others close to the 550 mark. I realise it is just a number, but it is a big one when you actually have to go get it and then show you have it at events.



Don~

 

[LarryB]

RE: reason Cummins went to 24V



Please remember that meeting clean air requirements does not automatically mean more efficient. In fact the opposite can be true. Also perceived clean air can be very different from actual clean air. When politics are involved, all logic is excluded.



Also, I believe most Cummins industrial/marine engines are still 12v.

 

[Don M]

Larry, you are right the diamond B is still a 12 valve and the 24 valve has yet to be marinized. Prolly never will be either.



Don~

 

[TxDieselKid]

Would you want to put that fragile little VP44 in an application where it has to deal with salty air all the time? I KNOW I wouldn't.



Andrew

 

[Vaughn MacKenzie]

Head porting flow

Stephan, when I talked to Piers he gave me these numbers for flow improvement:



Stage 1

Intake 9%

Exhaust 15%



Stage 2

Intake 13%

Exhaust 24%



Stage 3 (bigger valves)

I didn't write it down 'cause it cost too much

But it was roughly:

Intake 19%

Exhaust 30%

(don't quote me on these)



Vaughn

 

[Rob Thomas]

Well to me those #'s seem like it would be well worth the effort to get the port job. Just another thing on my need-to-do list, this list is gettin' long, I need another pad of paper.



Thanks Vaughn



Later,Rob

 

[Don M]

Air is going to flow only as good as its smallest restriction. If your valve is big and your ports are small you have accomplished little.

As port size increases... velocity decreases in most cases. Porting the cylinder head is a great idea for EGT reduction. No HP gains are made, yet. Maybe with more R&D we can get some power.

Air + Fuel = Power, right? Well if one considers that that getting air out is part of the equation they will be on their way to more power. Not by flow alone, but other things that help you along.

Lets say you have a big set of valves and good runner size to flow the air with and for a turbo you have a baby HX35. What have you gained? Notta. Because air can only flow as good as the smallest restriction and it could very well be your lame turbo or turbine wheel. Camshaft design can kill ya too. Big honkin lift numbers do little to make HP in our RPM range.



Don~

 

[Rob Thomas]

Don,



Lower EGT's are always a good thing, being with my stock turbo mine are through the roof, which is the next thing that will be replaced. As far as a cam goes,yer right I'd rather have some duration, let some of that fuel in there.



Later, Rob

 

[Don M]

Originally posted by RAMTHIS1

Don,



Lower EGT's are always a good thing, being with my stock turbo mine are through the roof, which is the next thing that will be replaced. As far as a cam goes,yer right I'd rather have some duration, let some of that fuel in there.



Later, Rob

Rob,



The fuel is injected, not flowed in by the intake valve or the camshaft like a gas pig. The idea is to have the air flow in and back out with a port job.



Don~

 

[Rob Thomas]

Oh duh, to many fumes today



So a longer duration will flow more air, right?



Rob

 

[Don M]

Originally posted by RAMTHIS1

Oh duh, to many fumes today



So a longer duration will flow more air, right?



Rob

yeah, but can hurt compression.



Don~

 

[Vaughn MacKenzie]

I think besides increasing your EGT ceiling, a well-flowed head could help reduce spoolup time. I haven't seen any discussion on this but it would seem if the air can flow in & out of the engine easier and with more inherent volume, it would improve turbo performance. Of course with a flowed head, ATS & everything you probably don't want to cork it off with an HX35.



Vaughn

 

[Rob Thomas]

Well, if I had the time this would be a good time to do the head work cosidering that mine is hangin' from the engine hoist right now. Yep, the head gasket took a dump this morning,I posted a thread about it, oh well another day in the life... ...



Later, Rob

 

[TxDieselKid]

Just think what could have happen if you did have 550hp.



Andrew

 

[MCummings]

Originally posted by TxDieselKid

Just think what could have happen if you did have 550hp.



Andrew]

Ohh,, I like that number,,,,



Muncie shoud get interesting. Should I take a headgasket?



Merrick Cummings