Porting and Polishing Heads and Intake discussion.

Discussion in 'SRT Product Line General Discussion' started by 1bad4dr, Jun 3, 2008.

  1. HalV48

    HalV48 They Call Me Patron

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    That would be correct. The INDY's exhaust are hogged out to much an lose port velocity. But they where the only thing available in the beginning.
     
  2. Bone

    Bone Love maker, heart breaker

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    I offered this up on the other SRT-10 forum: We have two performance shops in town with a Porter. I can get Viper heads ported for about 1600. My guess for Hemi 6.1 heads would be 100 less. I will be doing my 6.1 heads after I put my Viper eng back together. My Viper heads were ported and polished with 3-angle race valve job. Flow numbers posted on the other forum. Porter uses a SF 600 for flow testing.

    Also put larger dual springs on the Viper heads from BPE Racing. They can put on any springs you like or buy from a vendor.

    Just offering it up, not making any money from it.
     
  3. 1bad4dr

    1bad4dr Mr. Meany

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    You SUCK... lol
     
  4. LegMaker

    LegMaker LMI - LegMakerIntakes

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    good question..... from what i have seen, trying to hand port anything is very difficult from a consistency standpoint.....

    in the case of our manifolds, i think (opinion) it is impossible to go far enough into the intake runners to really do anything significant. just my opinion!
     
  5. 1fastsedan

    1fastsedan Destroyer of Warranties

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    As someone who ported and polished his own intake manifold (with friends helping), I respectfully disagree with you. I was able to hog out a LOT of material around the ports, off the injector boss, and I was able to grind down all of the casting joints inside too. Based on my data logs, I'm getting all the air that I need. I'm hitting a 1.0 P-ratio, when a lot of guys can't get past .96.
     
  6. SharaDon

    SharaDon Supporting Vendor

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    IS the great head debate starting again. LOL

    By muscle car standards these new Hemi heads flow great. But being to nuts we all are, we always want more.
    I'll say this,, I'm partial to the 5.7 head casting. I like the port velocity it has once ported. Makes for a very responsive street head. The 6.1 head is lazy by comparison. Reshaping the 6.1 head for increased port velocity without worrying about cfm is all that you really need. You'll gain cfm as a byproduct anyway.

    We all know there is power to be had from a ported head. I think it's more from the increased velocity then CFM. Were not taking full advantage of these heads yet. So the increases (hp) from it are small.

    Lets use a 440 wedge as an example. If you gain 20 cfm in the cylinder head you'll gain 40 hp because those heads are restrictive. Unlike the hemi head. This isn't really fair because the hemi is all on it's own. But I like to use that to explain things in simple terms.

    Old school rule of thumb. A port that flows 300 cfm will support 600 HP (cfmx2 @ max lift) On a pump gas street motor
    This has been proven to many times to argue with so let's not. Pro stock is like (cfmx2.5 @ max lift)
    We're all limited by camshaft and what(we,,you) are willing to give up from a drivability stand point. Not the ability of ported heads to flow air.

    With that being said. The thing we've worked on the most is the mid lift flow # and Intake to exhaust ratio(to keep things happy)
    I couldn't care less what is happening @ .600 lift. It's past correct rocker geometry anyway.

    For you Viper guy's. You basicly have a small block magnum motor head with one extra chamber. You guy's benefit huge from porting.

    One size port does NOT fit all application. Cubic inch and forced induction play a role in the port design.
    Just look at Edelbrock and how many different heads they make for the small chevy

    My .02 cents
     
  7. Hemi31

    Hemi31 [email protected]

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    I agree.......my intake is all cleaned up and I gained 12 rwhp peak and alot more than that in the curve.
     
  8. JMatt

    JMatt Platinum Supporting Member

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    IMO (flamesuit on) ported heads for these cars is the least effective mod for the money. A simple torque converter swap will provide more set of the pants improvment and track performance than heads ever will. Next would be a simple cam swap. I'd only ever do heads if the cam was so big I needed a whole new valvetrain anyway.

    People continue to underestimate how good the stock stuff is.

    Anyone doing any kind of forced induction gets even less benefit from the heads. The intake side isn't the restriction at that point. Perhaps for BIG forced applications, porting the exhaust side has merits. Beyond that - not so much.

    Except for 426 N.A. strokers, I don't know why anyone spends money on heads until they've done a lot of other stuff first.
     
  9. SRT8U

    SRT8U Supporting Vendor

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    Nice Flamesuit JMatt!
    [​IMG]
     
  10. NetNathan

    NetNathan Not the Momma

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    Isn't it a proven 30+ HP (I might go as far as to say closer to 40) for PP heads?
    This what we were told at one time by HHP.
    Are there any members that have dyno numbers before and after heads but no cam?
     
  11. 1bad4dr

    1bad4dr Mr. Meany

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    I gained the better part of 40hp with my P&P. And yes, I have a stock spec'd cam.
     
  12. NetNathan

    NetNathan Not the Momma

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    Did you have your S/C at that time?
     
  13. HoP Racing

    HoP Racing Mad Scientist

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    Low lift cfm is the key. Intake to exhaust flow ratio's are important as well. Each cylinder head (the 5.7 and the 6.1) suffer in their own areas. With the research I did during the cylinder head shootout I tested CNC ported heads, CNC ported with a hand blending, and a full hand ported and polish. The CNC porting varies significantly, depends on who did the program and what they felt was a "good port design". Obviously they started from a hand port design first. The nice thing about the CNC is that it remains the same for all the ports and the machine does not care it does it's job. A hand port is hard to keep consistent, but....... you can make it consistent. Flow the ports measure air speed and fine tune each one to the largest, " you can always remove material but adding it is a different story". The hand ported heads we tested did very well by the way.

    Cylinder heads are just part of the deal remember they allow the air in and out that's it. The camshaft is the real deal here. If I'm not mistaken the rocker arm ratio of these motors are 1.62 with a heal. Meaning that an asymmetrical camshaft lobe is needed to keep the rocker arm ratio at a constant 1.62. Alot of power remains locked up in the camshaft and valve train. Cylinder heads imop is just the icing on the cake.


    305cc's on the intake side support 454+ cubic inches remember that. Bigger is not always better. 6.1L = 372 c.i.d.
     
  14. 1bad4dr

    1bad4dr Mr. Meany

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    yes...
     
  15. NetNathan

    NetNathan Not the Momma

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    I sort of figured that P/P heads would increase HP with a S/C.
     
  16. 1bad4dr

    1bad4dr Mr. Meany

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    :smart:
     
  17. LegMaker

    LegMaker LMI - LegMakerIntakes

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    adam - my point was not the area around the opening to the head, or the injector bosses, but much further down inside the intake runners toward the top of the manifold. having done a bit of "smoothing" of the casting remains on mine, it is very difficult to adequately get into the areas i am referring to, especially by hand, with any consistency.
     
  18. sdcarguy

    sdcarguy A bit off

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    Chris you are 100% correct. When we did adams we got in as far as we could from both sides. Having said this I still feel the best method is extrude hone. It gets everywhere. But for the little bit of work doing it by hand its worth it for the every day joe. With air tools and 2 hours you can clean it up a lot.
     
  19. diegochrysler

    diegochrysler Jose"GR8CHORIZO"Jalapeno

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    SWEET! John, when are we going to do this to my car:whistle::friends:
     
  20. sdcarguy

    sdcarguy A bit off

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    Its not that hard at all. Get a set of gaskets either stocks or the ones from bwoody and it shouldnt take more then an hour or 2 on the bench...