Supercharging a motor, what mods should be done
11-07-2001, 12:32 AM
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Supercharging a motor, what mods should be done
How much boost can a stock 350 handle, and a 350 mildly worked with a cam and some head work? and what horsepower gain should be expected?
11-07-2001, 04:34 PM
#2
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Should be able to handle 6 to 10lbs of boost.
The important thing is to avoid detonation
at all cost. This is best done with modest compression raio 9:1 or less, Hi-octane pump gas 93 or 94 or better. Sufficant fuel delivery, Correct air/fuel (just slightly rich) mixtures while under boost and correct timing, and a good cooling system Slightly cooler heatrange spark plugs help too. Look for around 100 to 120 additional horsepower.
A water injection system will allow more boost and or less timing retard for the same octane fuel.
The important thing is to avoid detonation
at all cost. This is best done with modest compression raio 9:1 or less, Hi-octane pump gas 93 or 94 or better. Sufficant fuel delivery, Correct air/fuel (just slightly rich) mixtures while under boost and correct timing, and a good cooling system Slightly cooler heatrange spark plugs help too. Look for around 100 to 120 additional horsepower.
A water injection system will allow more boost and or less timing retard for the same octane fuel.
11-08-2001, 11:05 AM
#4
Supreme Member
When water evaporates it absorbs heat.
A lot of it. If water is injected at high pressure after the supercharger, it will vaporize/evaporate and absorb some or all of the extra heat of compression from the supercharger. It is heat not pressure that causes detonation. The water will also buffet or moderate the combustion prosess by the fact that it doesn't burn and reduces peek tempetures in the combustion chamber. While at the same time adding to the average pressure by expansion when it converts to steam. So by using water injection it allows more boost and or compression ratio for the same octane of fuel for more power. The amount of water must be carefully controlled or power will be reduced. Too much water equals too much cooling. and slows the combustion down too much for maximum output. The more water that vaporizes in the intake track the better it will work so less water will be required overall. Thats why it is best spray injected at high pressure.There are many internet sites that can help you understand why and how it works. Do a search...
[This message has been edited by F-BIRD'88 (edited November 08, 2001).]
A lot of it. If water is injected at high pressure after the supercharger, it will vaporize/evaporate and absorb some or all of the extra heat of compression from the supercharger. It is heat not pressure that causes detonation. The water will also buffet or moderate the combustion prosess by the fact that it doesn't burn and reduces peek tempetures in the combustion chamber. While at the same time adding to the average pressure by expansion when it converts to steam. So by using water injection it allows more boost and or compression ratio for the same octane of fuel for more power. The amount of water must be carefully controlled or power will be reduced. Too much water equals too much cooling. and slows the combustion down too much for maximum output. The more water that vaporizes in the intake track the better it will work so less water will be required overall. Thats why it is best spray injected at high pressure.There are many internet sites that can help you understand why and how it works. Do a search...
[This message has been edited by F-BIRD'88 (edited November 08, 2001).]
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