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Thread: L99 Magnuson Heartbeat S/C Kit Advice

  1. #1
    Advanced Tuner 96gt4.6's Avatar
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    L99 Magnuson Heartbeat S/C Kit Advice

    So i'm working on tuning a '15 Camaro L99 A6 car with a Magnuson Heartbeat S/C kit. The supplied Maggie tune seems SUPER soft, hardly any timing with not even a hint of KR on any pull. Shift points are entirely stock at 5900, no changes to the trans section over stock at all.

    I was able to determine that I could add about 5 degree timing safely, which pulled up the power nicely.

    I want to move the shift points up a couple hundred RPM, but not sure if that's a good idea on the L99 with the DOD springs and already having 6psi of boost acting on the valve heads, worried about valve float/damage there.

    Trans wise, any ideas on how much HP the A6 can handle? I would love to go in and set it up to have a little bite on the shifts like I do my N/A guys, but worried perhaps it's being pushed as-is. This kit is rated at 600 hp engine (obviously best case scenario at sea level), by the numbers it's making around 560-80ish at my location.

    Seems to run pretty solid, but looking for any advice on boost tuning with the L99/A6 setup this car has.

    Thanks!
    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw

  2. #2
    Advanced Tuner Lakegoat's Avatar
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    The tunes from Magnuson have to be 50 state legal. And--a lot of guys do their own install and then go out and beat on the car without checking anything in the tune. If the tune was set up close to max power, those guys would blow up their engines and then call Magnuson wanting a new engine installed for free. If you have a 6L80, it will hold a bunch of power if it is tuned correctly. Just don't turn off all of the torque protection if you want it to live. If that 15 Camaro is a DI engine, it can take a few more degrees of timing than a non DI motor. My non DI max timing at boost is 18 degrees. I know of a few guys that run 22--23 degrees in a DI/blower setup. It takes good gas though.
    2005 GTO, TrickFlow 225, Magnuson 2300, 4L80, 4 link 8.8
    2013 Silverado 5.3, 6L80

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    Advanced Tuner 96gt4.6's Avatar
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    Thank You. I'm very close then as I have it taking 18 degrees with no KR at this point on 91 pump, with having to start pulling 1-2 degrees above 100 degrees post blower IAT. 2015 still uses the non DI 6.2L, and this kit really seems to push the stock fuel pump to the brink. Looks like they up the maximum fuel pump DC to 100% from 90%. The car runs a static fuel pressure of 55, and by the shift point it's a good 5-8psi down. The ZL1 of this era has a different fuel pump, and most say the stock SS pump will support 520ish crank on boost applications, which I certainly believe. I'm willing to bet the actual AFR is getting in the 12:1 range above 4k looking at the data.

    It's a good kit, love the potential this setup has for sure. Would be nice to see a larger intercooler reservoir as well, the IAT's hold solid from a dig until about 3rd gear, then by the end of the 1/4 I have about a 15 degree temp rise, you can really see when the system starts to get heat saturated during a pull. However, it fully recovers immediately after with little to no soak that I can see.

    Thank you for the advice on the trans section, it shifts great and has full TM and stock settings, i'll leave that be. Happy to see i'm right in the realm of where I should be, and I really appreciate the advice!
    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw

  4. #4
    Advanced Tuner Lakegoat's Avatar
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    Are you saying you are tuning your blower engine with no wideband? The fuel pressure needs to be steady also. What is your injector duty?
    2005 GTO, TrickFlow 225, Magnuson 2300, 4L80, 4 link 8.8
    2013 Silverado 5.3, 6L80

  5. #5
    Advanced Tuner 96gt4.6's Avatar
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    Quote Originally Posted by Lakegoat View Post
    Are you saying you are tuning your blower engine with no wideband? The fuel pressure needs to be steady also. What is your injector duty?
    Correct. No changes made to the fueling section (supplied tune). Magnuson increased the timing on their 2nd revision (they use HP Tuners RTD Tool) by 2 degrees right out of the gate. I ended out 2 degrees above that, rest of the tune is as-supplied.

    I agree on the fuel PSI, should hold 55 the entire time, however it is my belief that the stock fuel pump is being pushed too far straight away as even with the supplied Magnuson tune the fuel PSI will not hold in the upper R's.

    The Lingenfelter kit (same magnuson kit) even states they change out the pump, the Whipple kit comes with a Zl1 pump. Nothing against this kit, it works, but I think it's pushing the stock pump too far. It appears to me there is an attempt to compensate for this shortcoming in the upper R's by commanding a richer and richer AFR (to compensate for lower fuel pressure = command richer lambda and injector DC). It's in the 9:1 range (supplied Maggie tune) by 5900. In the tune, that's not cat protection either as the max cat protection lambda is well above that afr.

    On 4.5-5.5 psi I am seeing at this altitude, that's not really playing with fire enough to hurt anything as long as it's in the mid/high 11's AFR and conservative timing and not doing 1/2 mile or longer pulls. However, any mods even such as a K&N filter would probably up the boost just enough to really push the thing into areas I would be uncomfortable with fueling wise.

    Again, it's a good kit, I love it compared to some I have installed and the power is great for what it is, but I think adding just a pump booster into the mix would make it a perfect kit right out of the gate and give some headroom for light mods such as headers/exhaust.
    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw

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    Advanced Tuner 96gt4.6's Avatar
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    Quote Originally Posted by Lakegoat View Post
    Are you saying you are tuning your blower engine with no wideband? The fuel pressure needs to be steady also. What is your injector duty?
    So my suspicions were correct. Installed my wideband, the AFR was pretty solid in the mid 11's. All they are doing is following the fuel pressure decline with richer targeted lambda. It works, in my opinion it's not correct, but works. Fuel pressure starts at 57 and is at 38psi by 5900 RPM.

    I then added a set of longtubes, K&N Filter and a JMS Fuel Max pump booster.

    Locked the AFR in at 11.8 through the range. Fuel pressure is solid at 53-55 psi through the run with the JMS box set to 1/2 it's available range (around 2V increase). Lost about 1lb of boost, so obviously the cats and factory mid pipe were are restriction.

    Car runs pretty solid. Getting about 20 degrees timing on 91 pump in 90 degree ambient. The next issue will be the heat rise post blower, the intercooler tank is super tiny and by the start of 3rd gear the IAT really starts to take off vs holding solid from the hit until that point, you can see when the intercooler reserve starts to run out. A nice 1 gallon or so tank would be very beneficial I think. All in all, the kit is pretty solid and the fit/finish is awesome. Not even pushing the blower at all......which I like.

    Would love to pulley down and run 6-8 psi, but i'm fearful of the stock L99's weak springs and possible valve float. The next addition should be a nice cam/spring/pushrod combo to really start to utilize this setup.
    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw

  7. #7
    Advanced Tuner Lakegoat's Avatar
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    You are not going to affect the springs with 8psi.
    2005 GTO, TrickFlow 225, Magnuson 2300, 4L80, 4 link 8.8
    2013 Silverado 5.3, 6L80

  8. #8
    Advanced Tuner 96gt4.6's Avatar
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    Quote Originally Posted by Lakegoat View Post
    You are not going to affect the springs with 8psi.
    Interesting, thank you for that! Honestly I have never confirmed that, just always assumed the L99 cars were pretty weak spring wise and didn't want to risk anything. I think moving up to 8 or 9 psi would be a great improvement if the rest of the powertrain can take it safely.
    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw