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Need help with 5.8 Gt500 motor and 4.0 whipple. Only making 630rwhp.

Discussion in 'SVT Shelby GT500' started by gtmustang00, Jun 29, 2019.

  1. gtmustang00

    gtmustang00 Active Member Established Member

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    Friend of mine has a Foxbody with a 5.8 gt500 motor and a 4.0 whipple. Tuned by Lund Racing. Had shop do the conversion for and they did pulls on dyno with brand new crate motor. Best reading they could get due to tires breaking loose was 650rwhp on a "Safe" break in tune. Drove it for a bit and noticed smoking every once in awhile. Dropped it back off and car was down on power. Local engine builder took motor apart and had a blown headgasket. While it was out the rods and pistons were swapped for forged parts and cams degreed. Meth was also added for safety measure. Put motor back in and engine builder wanted 1000 miles driven before car was put on dyno. Drove the car 1000 miles then put on dyno and car is making 630rwhp. 22lbs of boost. Knock sensor is going nuts and intake temps are around 160°. Using a stock 2013 gt500 heat exchanger.

    Shop wants to try and fix the knock sensor or tame it down, use a larger pulley to get boost down to 17-18 lbs, and switch heat exchanger to a larger one.

    Shouldn't this motor make way more power than it is? Car is on pump gas with a few gallons of race gas added for extra measure. Would you back the boost down or leave it and use race gas or 93 with Torco?boo IMG950782.jpg
     
  2. 2011 gtcs

    2011 gtcs GT500 poster Established Member

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    I'm assuming it has a full return style fuel system, maybe I missed it but what fuel is he using? 4.0L whipple at 22psi should be making some steam. How hot is the weather were you are? 160 IAT2s is not good at all, the hottest my IAT2Ss get with my Gen3 TVS is 130 and that's if I'm beating on it. Did you say it has a stock 13 GT500 intercooler system? Also anything vibrating around the engine will make the knock sensors go crazy.
     
  3. devilish64

    devilish64 Member Established Member

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    Only time ive seen 160 iat2 was when my intercooler pump took a shit.... something to check maybe?
     
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  4. Stangra

    Stangra Member Established Member

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    160°? Dinner's ready!!!
     
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  5. RBB

    RBB Well-Known Member Established Member

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    IAT2s are way too high, check that IC pump. Make sure the KS isn’t being set off by some sort of vibration, exhaust rubbing, etc. Also, I would not try to mix a couple gallons of race fuel in with pump 93 and just crank up the boost. Use an octane booster or go strictly with a better quality fuel. What fuel are you mixing?

    Do you have access to the datalogs? What is the max load value during the pull?
     
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  6. boduke0220

    boduke0220 Well-Known Member Established Member

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    Knock sensor going crazy and high IAT's.. need to get those issues sorted out. Computer is trying to save the motor. Check to see if the exhaust is hitting anything to cause false Knock..

    Also does Lund know about the meth? They generally wont tune for it and can make the car go pig rich if they don't know about it. also 22psi on 93 is a lot lol
     
  7. sleek98

    sleek98 Well-Known Member Established Member

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    KS is likely pulling 1-2* of timing, 160* IAT2 another 5-8* of timing. If your losing 5-10 degrees of timing that could easily be a few hundred HP.
     
  8. gtmustang00

    gtmustang00 Active Member Established Member

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    What heat exchanger would you go with assuming it will fit the notch? I put a Gords heat exchanger in my 03 Cobra. What are the gt500 guys using? What about the Killer Chiller system? Stock heat exchanger system that I know of.

    Lund should know about the Meth. Shop is remote tuning with Lund. Shop has a mustang dyno.
     
  9. RBB

    RBB Well-Known Member Established Member

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    VMP Triple pass with fans, or the C&R unit with fans.
     
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  10. gtmustang00

    gtmustang00 Active Member Established Member

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  11. Weather Man

    Weather Man Persistance Is A Bitch Premium Member Established Member

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    Find another shop, pump gas and a 4.0 whipple and IAT way out. A 1,000 miles before tuning? Any competent shop could break that motor in easy on the dyno and then tune. I see another blown motor coming fast. Get that motor on the corn now. I am amazed LUND would provide a tune with all the issues and fuel used.
     
  12. Zemedici

    Zemedici Well-Known Member Established Member

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    what am I reading...
     
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  13. gtmustang00

    gtmustang00 Active Member Established Member

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    Lund tuned the motor originally....car was smoking on decel. Dropped back off, took motor out. Engine shop said motor blew a headgasket. Fixed it and upgraded rods/pistons while in there. Said to put 1000 miles on it before putting on dyno and going WOT. Finally put on dyno and here we are. I don't seem to confident in Lund at this point. Motor was originally a brand new crate motor with 0 miles.
     
  14. fullboogie

    fullboogie Well-Known Member Established Member

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    Ya think?

    I hope you get it ironed out. Sucks terribly to have spent that kind of money for the troubles you are going through.
     
  15. RBB

    RBB Well-Known Member Established Member

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    I wouldn’t point the finger at Lund here. The motor had a blown head gasket, problem #1. Apparently that was fixed.

    Now you’ve got very high IAT2s, which would indicate a problem with your IC pump. In addition to that you’re trying to run 22psi from a 4 liter blower with pump gas, which IMO, is way overboard for the octane. Not surprising the knock sensor was going crazy.

    I’m surprised LR would even tune that combo for you with that fuel. They didn’t mention that wasn’t a good idea?
     
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  16. StrayBullitt

    StrayBullitt Well-Known Member Established Member

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    NS..

    LOL @ You guys are trying to run 22psi on Chocolate Milk and you wanna blame Lund
     
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  17. HillbillyHotRod

    HillbillyHotRod Hooligan rabble rouser Established Member

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    Don’t know all the circumstances but if the tuner knew what he had he would either write a tune to suit or tell him what he needs to make it tunable. Can’t see a reputable tuner, Lund, VMP, Bj doing that.
     
  18. RBB

    RBB Well-Known Member Established Member

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    I find it incredibly hard to believe they would agree to tune that unless you didn’t fully disclose all details of the setup. All my experience with LR is exactly the opposite, they’re fairly conservative and this is anything but. This combo on pump 93 is just flat out wreckless.

    I don’t think we’re getting the full story, just doesn’t add up.
     
  19. biminiLX

    biminiLX never stock Established Member

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    Nothing adding up.
    Also the 5.8 block with a blown head gasket may not just accept new rods and pistons.
    I’d get this car to a very well respected shop and try to save it.
    That’s some great hardware if you give it the right fuel and cooling.
    -J
     
  20. gtmustang00

    gtmustang00 Active Member Established Member

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    Shop has installed a Afco heat exchanger with fans and a cobra jet intercooler pump. Will be going back on dyno. Car has race gas in it now.

    Will update when that happens.
     
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