96 Gt Pi Head Swap - Help!

Discussion in 'SN95 4.6L Mustang Tech' started by GOAT44, Apr 23, 2014.


  1. GOAT44

    GOAT44 New Member

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    I have a 96 GT vert 5sp with 53,000 miles on it. I am looking into doing a PI Head/intake/and comp cam 262 swap and have some questions. The car is a weekend warrior so I am looking to make it faster and more fun to drive.

    The car has run great since I owned for last 10 years. Normal maintenance stuff but no major repairs/problems. I drive the vehicle less than 1,000 miles a summer.

    Here is a list of current performance mods to the car:
    CAI
    TB/upper intake
    short throw shifter
    LT headers
    Stock Mid
    Flowmaster catback
    3.73 gears

    I have done some research and have gone through many posts. I will use a Bama SCT custom tune afterwards and run 93 Octane

    My questions are if I complete PI swap, how is durability afterwards?

    Since I am performing the swap, do I need to upgrade fuel system? rails? Injectors ect.. What about Iginition at all?

    Any other ancellary items I need to upgrade as well?
    #1
  2. wmburns

    wmburns SN Certified Technician

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    Since adding PI heads to a Non-PI bottom end reduces the PTV clearance, I would DOUBLE check the combo with Comp cams.

    Because of the the reduced PTV clearance, it's much more important to accurately degree the installation.

    Be sure to take pictures of the timing chains during the installation.
    #2
  3. GOAT44

    GOAT44 New Member

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    The research I have done and everything I have read to date indicates that any stage 1 cam will work. The 262 is mild which is what I am going for but better than stock PI cams. If someone knows anything different, please let me know

    Anything in the fuel or ignition department that should be upgraded while doing the swap?

    I will be inspecting timing chains, gears etc to make sure they are in decent shape when its torn down.
    #3
  4. sneaky98gt

    sneaky98gt Mustang Master

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    Does it actually? I know the placement of the valve in the PI head allows for less ICL advance than the NPI head does, but that would only come into play when running PI cams in NPI heads, no? The valve makes contact with the piston outside of the dish, so the different dish shapes shouldn't affect PTV clearance, right?

    You will almost certainly be able to install them straight up and have no problems, but you really need to degree them in and check the PTV. When I bought my cams, the ICL was retarded 6 degrees from what it was supposed to be (it was 114 vs. advertised 108), so I had to advance them 6 degrees to take full advantage of the cams. In my case, with the cams retarded that much, if I would have just installed them straight up (i.e. not degreed them in), I would have just lost some amount of power. Albeit, at 6 degrees, it probably would have been a significant amount. However, if you get a set that are off that much in the other direction (i.e. advanced 6 degrees), your valves will be having an unpleasant meeting with Mr. Piston. And that will not be fun to fix.
    #4
  5. sneaky98gt

    sneaky98gt Mustang Master

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    Oh, and to your other questions. That will make for a very strong running setup assuming it's all done right. Should make close to 300 rwhp and run in the 12s with good tires and aggressive driving. You won't be making enough power to worry about breaking anything other than maybe the clutch if you really abuse it. Stock fuel system and ignition system will be fine at that point, although the injectors will be getting close to maxed out. If you can, an offroad mid-pipe will pick up a little power (10-15 hp) and a lot of sound.

    Also, be careful with Bama. They already like to put too much spark advance in their tunes, and with your high compression (from running PI heads on the NPI pistons), you don't need any extra timing at all. I'd pretty seriously contemplate an actual custom tune on a dyno with the cams. Low end torque, idle quality, and driveability can be a bit tricky with cams.
    #5
  6. COramprat

    COramprat Drone Driver Mod Dude

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    I had Comp 262's in my old 96. Added a PI intake and I would up with 240RWHP...much better than the 177 I started with.
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  7. GOAT44

    GOAT44 New Member

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    If I decide to add the O/R mid pipe, I can use a tuner to clear the CEL codes so I can still pass NYS inspection?
    #7
  8. sneaky98gt

    sneaky98gt Mustang Master

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    Was that with PI or NPI heads? Seems awfully low if with PI heads.

    Clear the codes? Yes. Still pass inspection? I doubt it; mostly depends on what type of inspection they do (OBD2 or just visual). But depending on how mechanically inclined you are, it's pretty easy to swap the mid-pipe back and forth to stock in order to pass inspection. I can easily swap mine in less than an hour from wheels up to wheels down.
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  9. GOAT44

    GOAT44 New Member

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    NYS inspection is OBD2. Would MIL eliminators allow me to pass?
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  10. sneaky98gt

    sneaky98gt Mustang Master

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    Maybe. The MIL eliminators keep the sensors from sending an error code from the start (vs. a tuner that just ignores the code). So they should, in theory.

    Still wouldn't be able to pass visual inspection, if you have that.
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  11. COramprat

    COramprat Drone Driver Mod Dude

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    NPI...I was doing it on a budget. I may have had another 10HP in the tune but the tuner kept it pretty tame.
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  12. GOAT44

    GOAT44 New Member

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    Thank you for all the help! One last question...

    Has anyone had any experience with Modular Head Shop (Nick @ MHS)? Degreeing the cams might be a little above my ability and this shop's name comes up a lot on here with their ability to degree cams. What would be needed for this shop to degree my cams? Would I have to send the heads,cams ect or just cams? Apologize if questions are redundant but just learning.
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  13. COramprat

    COramprat Drone Driver Mod Dude

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    The cams are degreed once they are installed. If you are doing 262's you should be OK. I didn't degree mine and didn't have any issues.
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  14. sneaky98gt

    sneaky98gt Mustang Master

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    They need the cams and your cam gears, or you can pay extra to get another set from him if you want to keep your car running in the mean time. Regardless, the cams and cam gears have to stay matched up in order to be accurate.

    He has a test motor setup that supposedly closely resembles most production motors (like in your car) with the full bottom end, heads, valves, springs, lifters, etc. except the cams. He takes the cams and gears you send him, and installs them straight up, which is the dot-to-dot method with the chains. Then he'll go through all the motions with a degree wheel, dial indicator, etc. all that jazz to find out where the actual intake centerline is located. You take the difference between that number and the recommended intake centerline, and that's your offset. For example, your 262s have a recommended ICL of 109 degrees; let's say he checks them and finds them to actually be 113 degrees when installed straight up on a particular set of cam gears. So to install them on the correct ICL, you as the end user need to advance them 4 degrees to get from 113 to 109. Make sense? Because cam gears and cams can vary individually, this number may be different on each bank.

    You do this with the Trickflow adjustable crank gears. They're pretty darn easy to use, and used to be fairly cheap (~$40). Not sure what they are now.

    I don't know this for fact, so I'm assuming this: Nick is very knowledgeable about these things, and he may recommend something different than what the cam manufacturer recommends (since he's degreeing someone else's cams, and not his own). I know I've read before on forums where he's found that some aftermarket cams don't have enough PTV clearance even when installed correctly. So for example, he may know that a 109 ICL on your 262s is too tight, too loose, or just right, and make a recommendation to advance or retard them to a certain number based on his experience.

    Regardless of which way you do it, it's worthwhile to do it right and get them degreed in. As I mentioned earlier, mine were retarded 6 degrees from what they were supposed to be; if yours were retarded to a 115 ICL instead of the recommended 109, you would certainly be leaving significant power on the table. Or, on the other side, if they were advanced to 103 degrees, you'd be pulling the heads back off to fix the bent and broken valves.

    I'm not sure about now, but when I did it several years ago, it was a decent bit cheaper to pay him to do it than it was to just get the tools I needed to do it myself, not to mention all the extra time required. But that's up to you. It's actually not all that hard to do once you have the required tools, but it does take some decent time. Probably 2-4 hours per side for a newbie.

    Since this post has already turned into a novel, I'll use it to throw out my little plug for MHS. If you do much reading around online, you'll find Nick to be one of the smartest people to ever work on these mod motors, or at least one of the smartest willing to share that info with the rest of us. He absolutely knows what he's talking about, and is one of the best in the business for putting out good products without all the marketing hype. If you're not already aware, Nick sold MHS to Excessive Motorsports a year or two back. Don't let that deter you; he is still there doing head work and consulting and all that, just not the business side of things. However, Jordan (owner of Excessive) is an extremely straightforward and good guy to deal with. I bought a good number of things from them for my motor build (still ongoing), and the customer service was excellent. I had an issue where some parts I ordered hadn't come in after about a week, which was unusual since they normally ship on the same day and it gets to me within the next two. So I called up the number at about 10 p.m. on a Friday night intending to leave a message, only to be surprised by Jordan picking up the phone. He knew who I was and what I was calling about as soon as I told him my name. He explained that they were having supplier issues with the parts I had ordered, offered to switch me to a different brand of the same part (which was actually more expensive) for no charge, and had them boxed up and sent out that night. I was on the phone for less than 2 minutes and the situation was resolved.

    Bottom line: no issues when dealing with MHS or Excessive.
    #14

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