On a forced engine I'm not sure the same applies??
As Ed Curtis says being forced creates quench ..
His words NOT mine..
We opened up some Mazda MX6 heads as above..
Had NO detonation issues up to 18 Lb..
If only the fwd gearbox was strong enough !!
Four valve motors have good exhaust evacuation..
Replacing pistons MAY not be an option ?? Price wise..
It doesn't make a differance whether its N/A or FI, the same priciples apply. Bore size seems to have the largest effect on whether or not you run into problems... The larger the bore, the more likely you'll run into problems....
Yes, people have done it and gotton away with it with out detonation acurring, but they also probably weren't making as much power as they could be either. I've personally seen a test done on two 2JZ engine ran on an engine dyno. One had the chamber ported out to achieve the desired compression and another had custom pistons made to achieve the same desired compression. Both were running everything else identically the same (boost, cam's, ect...). Both were tuned on the engine dyno (which was in a climate controlled cell). The engine with the custom pistons was able to be tuned to almost 50hp more before detonation started to accur. I clearly remember the engine with custom pistons running nearly 8deg's. less timing to achieve its MBT (Maximum best torque) throughout the power band of the engine.
Remember, the less timing that you can run and get a complete burn achieving PCP (peak cylinder pressure) in the 15 to 20 deg. ATDC the more power you will net. The earlier BTDC that you have to ignite the mixture to achieve the PCP at the correct time, the more counter productive you are in producing power. Basically, the earlier that you have to ignite it, the more parasitic losses you are obtaining...
Think about it, if you ignite the mixture at lets say 35deg's. BTDC, that is 35deg's. of crank rotation that you are fighting increasing pressure rise do to mixture burn. This is power that would otherwise be used to move the car that is now being used to overcome the pressure rise due to mixture burn. This is the whole point to fast burn technology and the squish / quench areas are a design feature of fast burn technology.
As for replacement piston not being availible due to price limitation, like the old saying say, "
power costs money.. How fast do you really want to go?" Or as I think is should say, "
Power cost money. How fast can you afford to go?"
