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Thread: LHU in place of an LNF - Quick question on Map sensor

  1. #1
    Tuner in Training
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    LHU in place of an LNF - Quick question on Map sensor

    Hello!

    I am swapping in an LHU in place of my blown out LNF and since the motor is so clean, I wanted to use the LHU intake and exhaust. So my question, is the Map sensor on the LHU the same 2bar as the LNF? I can't swap them (tried, different size hole in manifold), do I have to swap the intake or will it run fine?

    I bought the motor used with 36K miles, and it was complete with intake, exhaust, turbo, throttle body, and belt with all the accessories. If you don't think I should just use the whole engine, please let me know.

    Thank you!
    1997 Wrangler - LQ4 6.0 and 4L60e NP231C/J
    2009 Saab 9-7X with a 6.0 swapped in, 4L65E from a 2009 Suburban, 2005 trailblazer selectable transfercase, and 3.42's from trailblazer as well
    2015 Sierra 2500 Duramax with a fuel sucking emissions system
    2009 G8 GT (wifes car)

  2. #2
    Tuner in Training
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    Dec 2012
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    Not sure if this response is too late but I am in the same boat. my lhu will be at my house tomorrow and my broke lnf is already out of my cobalt. I know the exhaust manifolds are different and the turbo sits about 1" higher in the LHU. so, I plan to use my lnf exhaust manifold. also, I looked up injector part numbers on a gm parts website and they list LHU injectors to be the bigger Opel units with the E85 compatible seals. the LNF injectors flow 120# and the Opel's are 135#. compression in an LHU is 9.3 and the LNF compression is 9.2 yet the pistons are the same part number. the connecting rod numbers for 08-09 LNF engines are different from 2010 LNF and LDK/LHU engines. there's also a pump on the exhaust cam for a brake booster that needs to be removed and replaced with a block off plate. or buy the tube assembly to connect the pump to the brake booster.
    02 ws6-nitrous,intake
    99 gsx,880 injectors,eboost 2,lc-1,evo9 fuel pump,hard pipes,self tuned,17psi
    09 cobalt ss- LHU swap w/LHU manifolds & injectors,intercooler & pipes,3" dp,K&N intake,3 bars,hp tuned-ish
    02 softail-se204 cams,intake,VH exhaust,carb rejet

  3. #3
    Potential Tuner
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    May 2007
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    Easiest is going to be swapping the intake and exhaust manifolds. Otherwise as Flash said, your exhaust manifold puts the turbo higher. The intake sensor is obviously not the same part number, I'm not sure if the connector even fits.

    When I did my LDK swap I purchased just the motor from ZZP and reused my manifolds.

  4. #4
    Tuner in Training
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    Dec 2012
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    I used the lhu exhaust manifold and intake. the map sensor hole on the lhu intake manifold is smaller so a smaller o-ring needs to be used than what was supplied with my 3 bar sensors. also, the bolt hole for the map sensor is closer to the map hole so I had to modify my 3 bar map sensor so it would bolt on.
    02 ws6-nitrous,intake
    99 gsx,880 injectors,eboost 2,lc-1,evo9 fuel pump,hard pipes,self tuned,17psi
    09 cobalt ss- LHU swap w/LHU manifolds & injectors,intercooler & pipes,3" dp,K&N intake,3 bars,hp tuned-ish
    02 softail-se204 cams,intake,VH exhaust,carb rejet

  5. #5
    Senior Tuner cobaltssoverbooster's Avatar
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    Dec 2008
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    Nevada
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    4,452
    the lhu came with a new set of pressure sensor which is why your seeing a difference.
    the an20 still used the cobalt sensor kit which is why the manifolds didnt need to be swapped.
    2000 Ford Mustang - Top Sportsman