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Info om motorskillnader mellan GT1, GT2 och GT3

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  • Info om motorskillnader mellan GT1, GT2 och GT3

    Ville bara lägga in lite nyttig info om motorskillnaderna mellan de olika GT modellerna från brittiska Punto gurun James Hans:


    GT1 - 136hp = 127.54 lbs/ft * ( 5600rpm / 5252rpm )

    GT2 - 133hp = 124.37 lbs/ft * ( 5600rpm / 5252rpm )

    GT3 - 130hp = 121.9 lbs/ft * ( 5600rpm / 5252rpm )

    From the above calculations given the same turbo, injectors boost and fueling one would expect that the GT1 was the car to run the higher compression and have less lag. This is not the case. The engine remained the same but the compression was reduced by adding material to the head (gt3) and removing material on the pistons (gt2).

    As said before the compression was raised in two ways. Firstly there are differences between the GT1 and GT3 heads. The GT1 head had 1.8 x 80.5 mm of material added as a layer to its head.
    And also 1mm removed from the surface of the piston. This made it 7.8:1. The GT3 had a completely smooth head surface with only the valve recesses and the extra 1mm added to the piston.

    This enabled it run 9:1 This is also the reason why you will always see more big power PuntoGT1s than GT3s. When tuners lower compression they normally go into the 7s. Here the GT1 already started at 7.8:1 which made it a good basis for using a bigger turbo and with correct fueling.

    GT3s are limited with what you can do to them because running 9:1: although they are torquey and quite quick they go pop much sooner than a GT1 running the same boost. So if your going to seriously modify a GT (185+hp) LOWER THE COMPRESSION by either getting a GT1 head or just get forged pistons.

    Mvh
    Marco
    Fiat Coupe 16VT 302hk / Abarth 595 Competizione 180hk
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