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Old 04-20-2012, 03:04 PM   #1
MainFrame
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Default PnP heads, or no?

My engine is getting ready to come out again (yay!) . It needs to be rehoned to see if we can get the rings to grab this time.


Anyways, if you know anything about me, every time something comes apart I can't leave well enough alone. Since the heads are going to be R&Red for free, I decided I better go ahead and have the combustion chambers worked over a little to better match the block. [ej257 block w/ej205 heads]

Then I got to thinking, would it be worth it to have the machine shop do some mild PnP work to the heads while they're there? I have 04-05 STi cams in the heads already, and +1mm Ferrea valves. I know more aggressive cams would provide better bang for buck, but I don't really want to lose low end torque and fuel economy. My understanding is that PnP work will improve power across the entire range, rather than just shifting it further to the right..
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Old 04-20-2012, 03:42 PM   #2
medamullet
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I agree. I have a brand new set of Cobb CnC heads waiting for my springs to show up right now
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Old 04-20-2012, 06:26 PM   #3
jdpsearcher
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Yes it is worth it....
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Old 04-20-2012, 07:36 PM   #4
swagwag92
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i have a pretty heavy pnp n it breathes alot better then before. good idea!
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Old 04-20-2012, 08:39 PM   #5
MainFrame
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Alright.. I wasn't sure if the cost/benefit ratio would be worth it without more aggressive cams, but I've done damn near everything else to this car, so I might as well take advantage of the opportunity while the heads are off at the machine shop.
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Old 04-21-2012, 01:59 AM   #6
jdpsearcher
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More aggresive cams will make a difference.....if you have it in the budget do it now......i good set of 272's will do wonders and they are streetable......
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Old 04-21-2012, 04:14 AM   #7
MainFrame
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Actually, Kelford 264s would probably be my choice.. maybe I should just keep feeding this thing oil like a two stroke until I can afford to do it all, of course that entails going rotated too... damnit.
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Old 04-21-2012, 07:56 AM   #8
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I guess it depends on what the cost would be to pnp the heads and what your power goals are, but i don't think it's worth it. Cams.....yes.
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Old 04-21-2012, 11:59 AM   #9
WirkZ Performance
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Ferrea +1 valves and S1's is my pick.
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Old 04-21-2012, 02:54 PM   #10
MainFrame
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I suppose my power goals would be 11.4 second full weight ETs without having to mangle my transmission off the line. I'm thinking around 430/430 on a low reading Mustang dyno. I will be running e85 (most of the time). I still haven't picked a new turbo, it's a toss up between an ATP GTX3071r, FP Red 76hta, or ATP GTX3576r. I'm leaning more and more toward the 76hta, but I would like to see some more comparable results before I spend the money on it.
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Old 04-21-2012, 03:46 PM   #11
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The plus one valves help and that's been proven likewise is a pnp but overall I have my doubts of the cost:benefit as Bertune said. Just turning up the boost or using a more efficient intercooler can get the same gains, if u aren't going for that 9 second pass, or not bathing in cash , u might want to think about it.
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Old 04-21-2012, 04:45 PM   #12
MainFrame
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That's pretty much why I'm asking for opinions. Obviously it's better to pnp than to not, and if I were going for 600whp+ it would be a no brainier. Or if money was no object.. but that's not the case. The car is a daily driver, and I'm not pushing for huge numbers or anything. I'm much more concerned with drive-ability and smooth power delivery than peak numbers.


I know more aggressive cams will provide better bang for the buck.. but if we're talking +20 peak with cams or +10 across the board with pnp, I would rather pnp.

I need to give the machine shop a call to see how much they will charge for a pnp job, that might make the decision for me right there..



Then again, I might be better off buying a beater to drive for the next two years so I can take my time and finish off this build how I really want it, pnp, new cams, rotated GTX35, reverse Cosworth intake mani, etc.
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Old 04-21-2012, 05:03 PM   #13
boost16awd
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definitely worth it id do it
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Old 07-28-2021, 06:48 PM   #14
Trapgarage
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Default 2 cents on an old thread

My experience with DIY pnp heads, tgv's, turbos, and the aluminum intake manifolds has been nothing short of amazing results. I don't have crazy expensive tools just Dremel and electric die grinder, I never get too aggressive on taking much material off just smoothing and polishing/taking away any rough surface from OEM casting has made a mind blowing difference. Been surprised everytime, I would very highly recommend. Rough surfaces produce a lot of drag and friction, things run cooler and it adds significant torque all for cheap if you take a little time. It's all about that airflow.
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Old 07-29-2021, 10:35 AM   #15
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.....
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Old 07-29-2021, 10:47 AM   #16
K3rm1tth3fr0g
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Quote:
Originally Posted by Trapgarage View Post
My experience with DIY pnp heads, tgv's, turbos, and the aluminum intake manifolds has been nothing short of amazing results. I don't have crazy expensive tools just Dremel and electric die grinder, I never get too aggressive on taking much material off just smoothing and polishing/taking away any rough surface from OEM casting has made a mind blowing difference. Been surprised everytime, I would very highly recommend. Rough surfaces produce a lot of drag and friction, things run cooler and it adds significant torque all for cheap if you take a little time. It's all about that airflow.
Check post dates friend.

You are giving advice to someone who asked 9 years ago.
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Old 07-29-2021, 12:40 PM   #17
Bariga
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Quote:
Originally Posted by bertune View Post
I guess it depends on what the cost would be to pnp the heads and what your power goals are, but i don't think it's worth it. Cams.....yes.
i agree, pocket port is all you need.
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