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  1. #1
    oldskoolmc's Avatar
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    Higher compression pistons

    Has anyone installed a set of pistons to up the base compression? Results? Anyone try the 10.5:1?


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    Quote Originally Posted by oldskoolmc View Post
    Has anyone installed a set of pistons to up the base compression? Results? Anyone try the 10.5:1?

    dont know why you would want to raise the compression, more compression brings detonation when you raise boost and play with the engine like these guys do. The compression is low because its supercharged/turbocharged and is force fed air to make up for lower compression, without supercharger/turbo the engine would be a dog.


    Higher compression+Heat= detonation

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    oldskoolmc's Avatar
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    Quote Originally Posted by RickWhite View Post
    dont know why you would want to raise the compression, more compression brings detonation when you raise boost and play with the engine like these guys do. The compression is low because its supercharged/turbocharged and is force fed air to make up for lower compression, without supercharger/turbo the engine would be a dog.


    Higher compression+Heat= detonation
    Adding boost adds compression.

    Compression is compression. So adding more boost via a wheel or pistons doesn't really make a difference in my eyes.

    This is from procharger: " Assuming an engine with a compression ratio of around 9:1 running pump gas,if a supercharger gives your engine 14.7 psi of boost (another atmosphere) that will essentially double the output of your engine, everything else being equal"

    So with that being said, How about keeping boost levels down and adding higher compression pistons instead of a monster psi wheel. I'm just wondering if anyone has tried that approach.

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    I like that idea,but from a tuning stand point, I think its easer to tune with lower compression, and higher boost pressure, they will be changing to turbo kits soon, I had a honda turbo, higher boost was better and had "less" lag effect, detonation was combatted by fuel and a massive intercooler, higher compression would bring more chance for detonation. My honda turbo R12X was 8:5:1. Its personal prefrence tho in tuning,

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    Kristian Keppel Waterholics's Avatar
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    I think some have went with some high compression pistons almost N/A pistons but with stock sc wheel or less. But I don't think this makes sense because it just leads to more problems like having to build your engine and having to run race gas and what not.

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    I thought key was the amount for air flowing through the engine.....more air=more power, so if you lowered boost I would think power would go down as well cause less air th engine is takin in, I may be wrong but its personal prefrence, oppinion

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    Quote Originally Posted by Waterholics View Post
    I think some have went with some high compression pistons almost N/A pistons but with stock sc wheel or less. But I don't think this makes sense because it just leads to more problems like having to build your engine and having to run race gas and what not.
    you would have to run massive racefuel with 10:5:1 compression running 10-15psi of boost, and the intercooler would have to be massive as well and the amount of fuel you would have to feed woud be massive as well, very hard on Head gasket and valve springs.

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    oldskoolmc's Avatar
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    I can see the wheel swap being the norm because of ease of install. I've done many piston swaps and isn't that big of a deal for myself. Just trying to see if anyone else has done it and how it worked out. I personally would keep the boost levels down if I went this route.

    Look at it this way, the VXR has 11.0:1 compression and I read on this forum that someone is building a turbo kit for it. Do you think the plan is to run a 8psi turbo or make a race fuel only kit?

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    Addicted Member 5001craig's Avatar
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    Ross went with slightly higher compression pistons and discusses them in his build thread.


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    abracadabra's Avatar
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    Quote Originally Posted by oldskoolmc View Post
    I can see the wheel swap being the norm because of ease of install. I've done many piston swaps and isn't that big of a deal for myself. Just trying to see if anyone else has done it and how it worked out. I personally would keep the boost levels down if I went this route.

    Look at it this way, the VXR has 11.0:1 compression and I read on this forum that someone is building a turbo kit for it. Do you think the plan is to run a 8psi turbo or make a race fuel only kit?

    No, in the case of the Riva turbo kit you will have the ability of setting different boost levels. For a stock VXR application they will probably boost somewhere around 6 to 8 psi and maybe even less. If you go back six years Riva had a supercharger system made for the FX HO and it only boosted 4 to 5 Psi. That put the motor from 160 HP to 210 HP and that was a tiny motor only 1000 CC. That particular motor had 11.9:1 compression ratio, Julio...

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