Progress Thread The Sneaky98gt Build Thread

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by sneaky98gt, Apr 19, 2014.


  1. sneaky98gt

    sneaky98gt Mustang Master

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    Alright, this build/thread has been a LONG time in the making. Broke another piston back in December at the track. Seemed to be the result of too much cylinder pressure. Silver lining was that the car made the best pass ever on the very run it broke, at 11.90 @ 114. <<Notice how trap is a little low for my car. More on that later.

    So instead of doing a cheap rebuild, selling the car, and buying and '03 Cobra (like I SHOULD have done), I decided to have a little fun with this build, and see how far I could take the SVO blower (current record is 11.49 @ 118). To do that, here's what I'm doing on this build:

    -2012 Boss 302 rods
    -03/04 Cobra pistons
    -stock crank
    -ported heads by me
    -MHS blower cams (already been running those, but will be advancing them a couple degrees)
    -2.9" blower pulley (vs. 3.3 I have now). Should add 3-4 pounds of boost.
    -AEM 320 fuel pump to fuel all this extra power.

    On top of that, the transmission is getting a full build as well. As I mentioned earlier as per the trap speeds, it seemed like either the transmission or converter was slipping recently, so I figured with the rebuild and extra power, it'd sure be foolish not to rebuild the transmission to hold all of that. So Mr. Robert Pearson here in NC is doing a '650 rwhp build' on my transmission (same parts as in his 9 second T-bird tranny). On top of that, I've got a triple disk Circle D converter (3500-3700 stall) that just came in this past week. Will hold that power just fine.

    SO, I'm hoping to have it all running within a couple of weeks. I just came up from the garage working on it tonight. All that's left on the motor is to get the head gaskets (they're in transit) and bolt that together. Then just get it all back in the car and it'll be ready to go.

    When it's all said and done, gonna try and run 10s on this setup. I honestly don't think it'll happen, but I'm gonna try. And if it doesn't....well, I've still got the nitrous kit. :D
     
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  2. sethahoward

    sethahoward Member

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    I've been waiting on this post for a while. How bout some pics?
     
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  3. usaf_branham

    usaf_branham Member

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    nice. what are the boss rods rated at? and +1 on posting some pics.
     
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  4. SRT Handz

    SRT Handz I tripped & fell down and cut myself & got blood

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    I feel like you wouldnt break as many pistons if you had an intercooler.
     
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  5. sneaky98gt

    sneaky98gt Mustang Master

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    I haven't seen an exact number on the Boss rods, but it's up there pretty good. I unfortunately didn't get a picture of a Boss rod next to a stock 2-valve rod, but it is significantly beefier. Some people say they are stronger than the Trinity rods, and they hold 600 rwhp stock, and have been pushed to over 700 rwhp with no issues. For the money (~$20 a piece), they are a ridiculous steal for a budget build. And regardless of exactly how much they'll hold, the pistons are still the weak link, which normally start to give way around 600 rwhp.

    I'll try and post some pictures tonight. Between working 60+ hours a week, other obligations on the weekends, and working on the car any time between, it's been a struggle to post much on the boards, haha. But the only thing left on the motor build is the timing cover and valve covers. So I'm going to finish those this evening, and try to post some pics tonight.

    Nah, that has nothing to do with it. The first piston I broke a couple years ago was from a crappy tune that caused detonation when there was a problem with the meth kit.

    This one was almost certainly from too much cylinder pressure and/or timing. I datalogged the run it broke on, and the ACTs were in the 80s (it was a cool day outside). The AFR was correct and untouched throughout the day; this was the first time back to the track after my most recent retune, and I was just creeping up on the tune to see just how good I could get it to run. Started at 20 degrees of timing, crept up to 24 with noticeable gains with each addition of timing. Went to 25 degrees and only picked up a touch. I should have stopped there and backed it down a touch and been happy (lesson learned). But I went up on it one last time to 26 degrees, and that was the run it broke. Yes, you are reading that correctly: 26 degrees of timing with a non-intercooled blower on 93 octane pump gas with water/meth injection and no detonation. I'm now pretty much positive that maximum brake torque timing is around 24 degrees, and anything over that was just needlessly increasing cylinder pressure. Start spiking cylinder pressure on 2-valve pistons with those tiny ring lands at 425+ rwhp, and you will break pistons, intercooled or not.
     
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  6. sneaky98gt

    sneaky98gt Mustang Master

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    Alright, pictures, as promised.

    Broken piston: not good.

    [​IMG]


    My setup for porting the heads. Engine stand worked quite nicely for this considering all the rotating around you have to do to get to all the sides of the ports / bowls.

    [​IMG]


    And me actually doing some porting with an electric die grinder.

    [​IMG]


    A little before and after on the intake port. The biggest takeaway here is the straightened right side wall. Notice how there's a lot straighter shot at the backside of the valve after porting than the stock configuration. (And I don't know why Photobucket is flipping my pictures upside down)

    [​IMG]

    [​IMG]


    And some before and after on the exhaust bowl. It's hard to tell in the picture, but there's a big bump in the long side radius of the bowl underneath the valve guide (removed in this picture). There's no way you'd miss what I'm talking about if you had a head sitting in front of you; it is a blatantly bad flow design. Removing that bump is the majority of the gains to be had in the exhaust side.

    [​IMG]

    [​IMG]


    And all finished up after the machine shop. The only modification I did in the chamber was to lay the swirl dam back just a bit. If you look at the swirl dam up close, you'd notice the top of it is actually flat, maybe 1/8" - 3/16" wide; well, I just laid it back such that it was more of a point, rounded off of course. There's a good bit of debate on what really is the best thing to do here, but this is the most common configuration I could find through looking at other big-name manufacturer's heads.

    [​IMG]


    All of the parts laying around. I file fitted all of the rings to their perspective bores. Around .022" on the top ring and .024" on the bottom compression ring.

    [​IMG]


    Checking PTV clearance. On the last motor, the cams were installed on a 110 degree ICL, and a couple of the pistons had very faint marks where the clearance must have been very small. I got the modified intake valves from MHS (the ones with the extra part of the lip machined down) and was able to install the cams on a 108 degree ICL this time with over .050" clearance on both sides. Slightly earlier ICL should help a touch with low and mid range torque.

    [​IMG]


    Short block finished.

    [​IMG]

    Long block finished.

    [​IMG]


    And that's all the pics I've got for now. I've got a lot related to the head porting, and I'm going to do a write up sometime on how to self-port the heads. It's actually fairly easy (albeit VERY time consuming), and I'm going to point out some of the problem areas with pictures and before/afters.

    As for the motor, it is 100% assembled as of about an hour ago. As soon as I get the transmission (hoping for this weekend), it'll all be ready to drop back in the car.
     
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  7. sneaky98gt

    sneaky98gt Mustang Master

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    Car is back running now. It cranked right up as soon as I hit the key after priming the fuel pump, just like it never missed a beat. Planning on drive it some this afternoon after work.
     
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  8. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Thats always good to hear!
     
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  9. sneaky98gt

    sneaky98gt Mustang Master

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    Yessir. I was so relieved when it actually cranked up and ran.

    Drove around 50 miles this afternoon with pretty much no problems. Haven't gone over 4000 rpm yet (and probably won't for a few hundred miles), but I've been putting some load on it at lower rpm. Seems to be running just fine, making good power, too. I'm really digging the converter so far, too. I haven't put the motor all the way up on the converter yet, but I can tell it's going to be awesome.

    Only issue I've got is that the air conditioner quit working. It was working fine for the first 15 or so minutes of driving, then just randomly quit and hasn't come back on since. Guess I'll try and troubleshoot it this weekend.
     
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  10. madspeed

    madspeed Colonel Mustard Mod Dude Founding Member

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    Leak, most likely low on refridgerant
     
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  11. sneaky98gt

    sneaky98gt Mustang Master

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    That's what I'm thinking also. Gonna check and see if I got voltage on the back side of the low pressure switch.
     
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  12. usaf_branham

    usaf_branham Member

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    How is your a/f ratio doing? Any issues?
     
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  13. sneaky98gt

    sneaky98gt Mustang Master

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    Don't know, haven't gotten it into open loop operation yet. All I've been doing is high load, part throttle pulls at lower rpm. Like a 2000-4000 rpm pull in 3rd with the converter locked.

    Everything seems good on the closed loop side, though. Got about 200 miles on it with no issues thus far.
     
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  14. tannerc91gt

    tannerc91gt More durable than coconuts and twice as fast

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  15. sneaky98gt

    sneaky98gt Mustang Master

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    Car is 100% running, got over 2000 miles on it now with no problems.

    Only thing left is the tuning. I'm doing it myself now, and I'd call it 80% done. All the part throttle and idle stuff is finished. Worked on transmission shifts and torque converter lockups for a while this past week. Pretty much all that's left is WOT tuning. And assuming there's no mechanical problems (which there haven't been so far), that shouldn't take long at all. So maybe some track runs in the next couple weeks.
     
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