Ayoustin
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excellent info!
do you happen to know if 4G63 head builders recommend enlarging the combustion chamber diameter to fit the 86.5mm bore better?
I don't know what others recommend but I would not. You end up lowering compression and the area you open up is one of the least active areas of combustion.Originally Posted by Strm Trpr
excellent info!
do you happen to know if 4G63 head builders recommend enlarging the combustion chamber diameter to fit the 86.5mm bore better?
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excellent, thank you for the info!Originally Posted by ayoustin
I don't know what others recommend but I would not. You end up lowering compression and the area you open up is one of the least active areas of combustion.
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Quote:
excellent info!
do you happen to know if 4G63 head builders recommend enlarging the combustion chamber diameter to fit the 86.5mm bore better?
yes it’s a good idea to radius the sharp edge out to the bore size it will prevent hot spots.Originally Posted by Strm Trpr
excellent info!
do you happen to know if 4G63 head builders recommend enlarging the combustion chamber diameter to fit the 86.5mm bore better?
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Thanks man, I look forward to see how it will be.Originally Posted by 2winscroll
Looking good!
Should be one heck of a Street Beast!
Should be one heck of a Street Beast!
Hoping to stop the car and make the engine change within the end of the year
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Last year I ran through all the calcs for where the best improvements could be made and the stock intake size is fine for any engine using a bore smaller than 87mm. The exhaust would benefit slightly from a +1mm valve but it's not necessary. You'll gain WAAAY more with a good port job vs larger valves.
Originally Posted by ayoustin
Sean is correct, if you're going to run oversized valves, go with larger exhaust valves. There's math involved but it boils down to valve/bore ratios and your intake/exhaust ratio. If you run a massive valve on a small bore you're going to shoot yourself in the foot because the valves get so large that the air has a tough time getting around them to get into the cylinder.Last year I ran through all the calcs for where the best improvements could be made and the stock intake size is fine for any engine using a bore smaller than 87mm. The exhaust would benefit slightly from a +1mm valve but it's not necessary. You'll gain WAAAY more with a good port job vs larger valves.
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Thanks a lot guys for all your advices.Originally Posted by letsgetthisdone
Because that has what has been proven to be needed. For the power goal you stated, there isn't a need for any oversized valves...
Unfortunately I've been out for weeks and had no news from the mechanic.
I never put in doubt these choice, because he is 4G63 expert with tens of builds behind.
But I try to meet him tomorrow just to fix this point, because if this is proven I would follow it.
Let u know soon
LetsGetThisDone
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It's not the end of the world if he already did both. More just extra money that didn't need spent.