Boost drop from ported head.

The difference between stock and the PDR head was pretty minimal. Nothing bad against PDR, it's a mild port job and only on the exhaust side. There was about a 50 degree difference with the head and another 50 degrees with the old pdr cam. 100 deg total seemed pretty good at the time. I lost about 200 deg's(actually more like 300 on top) with the first set of twins. I sent my truck up to PDR(paid my son to take it up) for it's first good tuning. With the twins and a set of Jammer 2's it made just over 500hp and would hit 1300deg if you mashed it long enough. Hard to believe it see's almost double that now with only a slight increase in egts and 1.5mpg less. Was actually more fun to drive around then too. All bottom end.LOL
 
the newer the head better it flows stock , so pdr might not have the newest info thats what i found when i ported my head . prd is not what it once was,
 
We went from a stock head to a fully milled Indy P&P head with plenum and individual runners and lost almost 30 PSI. I also had to go back to smaller water injection nozzles as it was to cold. Made a hell of a difference in our application.

BBD
 
BigBadDodge said:
We went from a stock head to a fully milled Indy P&P head with plenum and individual runners and lost almost 30 PSI. I also had to go back to smaller water injection nozzles as it was to cold. Made a hell of a difference in our application.

BBD
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Dang. 30 psi. Makes me want to spend more on the head work.
 
but does the fact that he's running over 150 psi to begin with factor into that equation?
 
Might mean the difference of putting 4 big ass ratchet straps around the entire motor to keep the head on ;). i dont think it would be 30 psi in rons case but would def. be significant and well worth it
 
I'm quite sure that his higher starting point has everything to do with the 30psi reduction. I'm at about 1/2 that so 10-15 is more realistic . But it's still a big deal and worth a bit of extra coin.
 
indeed ive seen alot of great posts/info here. Ron i think your more advanced in the diesel world than me but this head sounds like a winner! The more boost loss=More air flow correct? the head is where the restrictions lie. i would put the $$$ into that for sure in your case!
 
The more boost you start with the more realized boost drop will be. less boost means more CFM, when all things are the same as before. the engine needs CFM, boost means very little to a engine. Cutting corners on a cylinder head.....bad idea. the head is the life line to the rest of the engine.
 
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DIESEL_POWER said:
The more boost you start with the more realized boost drop will be. less boost means more CFM, when all things are the same as before. the engine needs CFM, boost means very little to a engine. Cutting corners on a cylinder head.....bad idea. the head is the life line to the rest of the engine.
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Exactly! The more psi you were running the bigger the drop you would see. On my truck I was only running about 65 psi and after I did the ported head and the manifold it was down in the mid to low 50's. Where a person that was running 80-90 psi may see a drop as much as 20 to 25 psi.
When I made my first manifold the main reason was to free up the air in the two end cylinders there is and awful restriction there. I had burnt the pistons on both ends twice and figured I had to do something different.
 
I changed absolutely nothing but the head on my truck and saw at least a 10 lb. reduction. I bought a zz fab intake and ported it myself using advice from greg at zz, and had a modern multi angle valve job done while the machine shop had it to machine the gasket surface for the intake. I had a 64 mm garett bb turbo that would make 50 lbs easily and I would lift because of stock head bolts. After the head, I could hold it all day and just barely see 40 lbs. and the egt's would actually stabilize at about 1200, before they would continue to climb past 1400...I would certainly spend as much as the budget allows on the cylinder head, it works!
 
Joesixpack said:
I'm almost positive I suggested the stock pistons a while back.......;) With the billet rods you should be good to go.
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I was told that the stock piston p-pump combo was really smokey. That's why I've been looking at other options. Unfortunately Cummins pistons are the only ones with the steel inserts for the top rings and I have heard that they will not hold up on a daily driver without the steel insert. Too bad they don't make a 6.7 piston with the HO bowl. My 5.9 drives nice and has worked well.
 
I can see that, the stock 12V bowls are very high swirl design that will make up for poorer atomization, don't have direct experience with it, but it makes sense. Still think that piston is your best option however, stock compression, no more nozzle than you need.

You`ll want the steel ring lands if you want any time out of them.
 
Porting/polishing

Ihad my head Extrude Honed. All the runners are extremely slick all the way through. You can reach through the intake side and as far as you can go either way it is slick,... feels like it is teflon. My result is as many on here have said,... in the 10-15psi range. On EGTs it may hit 1400 for a milisecond shifting from 3rd into od and then it drops back and stays at 1250ish. With my Bill Fletcher cam the truck pulls on top end unbelievably. I also had the head 3-angled when the seats were replaced (they have to be pulled following the Extrude Honing. I also had those freakin' soft plugs pulled and had threaded plugs installed.
 
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