13:1 pistons 2.0L
08-01-2002, 01:28 AM
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Vehicle: 2008 Toyota Prius 2006 Suzuki SV650S
New pistions (to raise the CR), I wouldn't reccomend trying milling the deck enough to raise the CR that high.
A re-mapped ECU (not available) to deal with the higher compression....so that leaves your only option a Haltec or similar ecu replacement device.
If you were going to try a 13:1 CR motor, you should have serious head/combustion chamber work done first. You wouldn't believe the carbon build up that happens. I've got 2 motors ripped apart in my garage. One with 5000 miles (XD/Beta2 motor) and one with 40000 miles on it (J2/Beta1 motor) They both have horrible carbon deposits on the pistions, and on the roof of the combustion chamber. There are too many rough surfaces and sharp edges to collect carbon build up in the stock setup to allow 13:1 CR to last for long without serious detonation problems.
[ August 01, 2002, 08:31 AM: Message edited by: Random ]
A re-mapped ECU (not available) to deal with the higher compression....so that leaves your only option a Haltec or similar ecu replacement device.
If you were going to try a 13:1 CR motor, you should have serious head/combustion chamber work done first. You wouldn't believe the carbon build up that happens. I've got 2 motors ripped apart in my garage. One with 5000 miles (XD/Beta2 motor) and one with 40000 miles on it (J2/Beta1 motor) They both have horrible carbon deposits on the pistions, and on the roof of the combustion chamber. There are too many rough surfaces and sharp edges to collect carbon build up in the stock setup to allow 13:1 CR to last for long without serious detonation problems.
[ August 01, 2002, 08:31 AM: Message edited by: Random ]
08-01-2002, 01:40 AM
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Along with that, the BETA probably wouldn't get a lot of use out of 13:1 pistons. The problem is actually in the combustion chamber shape in the BETA cylinder head... It's a prime candidate for boosted application, but the trough shape does no good for normal aspiration. That, and the 90-degree bend in the exhaust port is horrendous as well.
But, I'd agree with Random on all the basic points. Standalone engine management, massive headwork, and you WILL need to have a different set of cams built for that thing. Also, since a 13:1 piston would require a very large dome on the piston crown, you will need to double- and triple-check to make sure the valves have proper clearance.
Last thing you want is to spend $800 to have those pistons prototyped, try starting the car and ramming all 16 valves into the faces of your four brand new pistons. I bet the pistons would live, but the valves wouldn't frown
But, I'd agree with Random on all the basic points. Standalone engine management, massive headwork, and you WILL need to have a different set of cams built for that thing. Also, since a 13:1 piston would require a very large dome on the piston crown, you will need to double- and triple-check to make sure the valves have proper clearance.
Last thing you want is to spend $800 to have those pistons prototyped, try starting the car and ramming all 16 valves into the faces of your four brand new pistons. I bet the pistons would live, but the valves wouldn't frown
08-01-2002, 01:50 AM
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If these are indeed a "production" part, they may have calculated the valve reliefs in the crown correctly... Therefore, the valve-ramming issue may not actually BE an issue. Eh... Hopefully... 
Still, these motors just really do suck at normally aspirated power. The money you'd spend on making 200WHP N/A would equate to about 350WHP turbocharged.
You know which one I'd vote for
[edit - I suck at typing wink ]
[ August 01, 2002, 08:51 AM: Message edited by: Red ]
Still, these motors just really do suck at normally aspirated power. The money you'd spend on making 200WHP N/A would equate to about 350WHP turbocharged.
You know which one I'd vote for
[edit - I suck at typing wink ]
[ August 01, 2002, 08:51 AM: Message edited by: Red ]