New Pistons - Query
04-04-2010, 04:33 PM
#1
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Vehicle: '99 Coupe/Tiburon F2 Evolution
just seen these on SFR Pistons and wondered whether anybody knew if they were the stock bore of a 2.0l RD1 or whether i would need a rebore
04-05-2010, 05:25 AM
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Vehicle: 2000 Hyundai Elantra
Are you running a supercharger or turbocharger? There is a vast difference in what you are running and how the engine will perform across the powerband.
04-05-2010, 06:28 AM
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If your only shooting for 14-15psi stay with the stock block and focus on good dyno tuning. If you wanna go higher get some OE Bore CP Pistons and drop them in. They are some of the best you can buy.
04-05-2010, 11:24 PM
#6
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chapp, you are missing something. Those who understand will please forgive the oversimplifications.
Most forced induction setups hit the boost above idle, and most don't even really start making power until 3-4000RPM or higher. Before that, all your new go-fast goodies are doing is causing a drag on the engine's power. If you have an 800HP turbo monster with 7:1 compression and the boost hits at 6,000RPM like an atom bomb, you will be launching at 5,000+RPM off the starting line. Why? Because your low end sucks.
Until the turbocharger starts adding power, you are running on a naturally-aspirated motor with horrible mechanical efficiency if you run low compression pistons. A high-boost motor has potential to run like a 400,000 miles clapped-out beater below a certain point in the power band, and it may not idle well, if at all.
When you consider that the stock Beta engine can handle around one bar of boost with a good tune, and that almost all of your driving around town happens with the engine well under the range when a turbo is making power for you, it is a good and oft-taken route to keep the internals stock or close to it. Not many people are willing to sacrifice that much bottom end, to get that low a compression ratio, to make that much boost, on a street driven car.
Superchargers can add power sooner and in more linear fashion than a turbo, depending on a lot of things, but low static compression is still a handicap to be overcome.
Now, if you want to start talking about a little shot of nitrous oxide to get the engine going off idle . . . wink1.gif
Most forced induction setups hit the boost above idle, and most don't even really start making power until 3-4000RPM or higher. Before that, all your new go-fast goodies are doing is causing a drag on the engine's power. If you have an 800HP turbo monster with 7:1 compression and the boost hits at 6,000RPM like an atom bomb, you will be launching at 5,000+RPM off the starting line. Why? Because your low end sucks.
Until the turbocharger starts adding power, you are running on a naturally-aspirated motor with horrible mechanical efficiency if you run low compression pistons. A high-boost motor has potential to run like a 400,000 miles clapped-out beater below a certain point in the power band, and it may not idle well, if at all.
When you consider that the stock Beta engine can handle around one bar of boost with a good tune, and that almost all of your driving around town happens with the engine well under the range when a turbo is making power for you, it is a good and oft-taken route to keep the internals stock or close to it. Not many people are willing to sacrifice that much bottom end, to get that low a compression ratio, to make that much boost, on a street driven car.
Superchargers can add power sooner and in more linear fashion than a turbo, depending on a lot of things, but low static compression is still a handicap to be overcome.
Now, if you want to start talking about a little shot of nitrous oxide to get the engine going off idle . . . wink1.gif