How much Boost is safe on a stock engine.
#74
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Best way to boost a stock engine is ducting the eyeball vents to the intake manifold.
You get instant electric boost.
You need to duct all 4 eyeball vents, otherwise you WILL get a boost leak.
Just turn the blower **** up all the way to 4 if you want to pass that Ferrari on a mountain road.
You get instant electric boost.
You need to duct all 4 eyeball vents, otherwise you WILL get a boost leak.
Just turn the blower **** up all the way to 4 if you want to pass that Ferrari on a mountain road.
#79
It's about the volume of the engine at BDC and volume of the engine at TDC. Pressure is not in the equation of compression ratio.
Only volume.
Of course pressure effects how much mass of air there will be at a given volume and temperature, however again the compression ratio is unaffected, it simply compresses more or less mass of air, but still at the same ratio.
So if you have 1 litre engine, it will compress that 1 litre volume down to 0.1 litre of volume.
This comes with an increase in pressure due to the compression.
This doesn't care about the base pressure when the piston is at bottom dead center.
I.e.
You have 1 Litre at atmosphere (14.7 PSI).
You compress it and now you have the same mass of air compressed into a 0.1 Litre volume, this will increase pressure.
If you are turbo you might have 1 Litre at atmosphere + 5PSI so you have 1 Litre at 19.7 PSI.
You compress it and now have the original mass of air (1 Litre at 19.7 PSI at whatever temp your intake air temp is) compressed to the volume of 0.1L, this will cause an increase in pressure.
The compression ratio of the engine is still the same. It is still 10:1, it is just compressing a larger mass of air into the same volume.
Also note, that this is assuming perfect cylinder filling, i.e. the cylinder is completely fill of air at the mentioned pressure, however even when it isn't this doesn't effect the math, just the individual values of mass air being compressed.