Reply from Bison.
"BDC had some good posts there. The actual temp reading means little comparing one engine to another. Dropping the inlet temp on a given engine if you keep the a/f ratio in check will usually show more power. The location of the sensor may show a difference but the temperature of the alky injected, the amount and the air inlet temp and pressure prior to injection is what will determine where you really are. The hotter the alky injected the better you are. The IAT (in the back of the intake on both cars)in an application like mine where i have the ecu adding timing if the inlet air temp drops below 65* can have a direct effect on power but otherwise it means little except comparing day to day or modification to modification on the same engine. Injecting hot alky as close to the cylinder as possible is the way the alky will have the greatest impact at reducing the temperature in the cylinder regardless of what is posted. If you look at its latent heat of vaporization you will see that alky is really good as a liquid intercooler. It has a relatively low boiling point and it removes a bunch of heat when it boils and is consumed as a fuel rather than a inert substance like water or hydrogen peroxide that have a lot of potential as an intercooler once they boil but are inert and will slow down the engine when injected. If the injected alky is too far from the cylinder it will boil earlier and remove the heat where it boils only to start and re-gain some of that heat back as the air travels through the intake system. I have noticed on dyno testing that there becomes a point where more injected alky will not drop the air inlet temp any further as far as the reading on the IAT shows. This is because the extra alky injected does not boil in the intake and enters the cylinder as a liquid where it likely quickly boils as the compression stroke is completed Usually this seems to occur at 5-10* below ambient temps when the ambient temps are in the 60's to 80's. There may need to be more alky injected though there is no accurate gauge as to how much so i just overspray and pull fuel out of my tables to get the a/f where i want it. If you want it in the back of intake you can use a stubby drill on an angle grinder and drill it without removing it. Just stuff rags in the runners and vacuum the chips out. Tapping is easily done with a 8 point socket on a 3/8 NPT tap."
This is a very interesting analysis and helps me understand how alky works.
Thanks, Brian.
Phil Engle
"BDC had some good posts there. The actual temp reading means little comparing one engine to another. Dropping the inlet temp on a given engine if you keep the a/f ratio in check will usually show more power. The location of the sensor may show a difference but the temperature of the alky injected, the amount and the air inlet temp and pressure prior to injection is what will determine where you really are. The hotter the alky injected the better you are. The IAT (in the back of the intake on both cars)in an application like mine where i have the ecu adding timing if the inlet air temp drops below 65* can have a direct effect on power but otherwise it means little except comparing day to day or modification to modification on the same engine. Injecting hot alky as close to the cylinder as possible is the way the alky will have the greatest impact at reducing the temperature in the cylinder regardless of what is posted. If you look at its latent heat of vaporization you will see that alky is really good as a liquid intercooler. It has a relatively low boiling point and it removes a bunch of heat when it boils and is consumed as a fuel rather than a inert substance like water or hydrogen peroxide that have a lot of potential as an intercooler once they boil but are inert and will slow down the engine when injected. If the injected alky is too far from the cylinder it will boil earlier and remove the heat where it boils only to start and re-gain some of that heat back as the air travels through the intake system. I have noticed on dyno testing that there becomes a point where more injected alky will not drop the air inlet temp any further as far as the reading on the IAT shows. This is because the extra alky injected does not boil in the intake and enters the cylinder as a liquid where it likely quickly boils as the compression stroke is completed Usually this seems to occur at 5-10* below ambient temps when the ambient temps are in the 60's to 80's. There may need to be more alky injected though there is no accurate gauge as to how much so i just overspray and pull fuel out of my tables to get the a/f where i want it. If you want it in the back of intake you can use a stubby drill on an angle grinder and drill it without removing it. Just stuff rags in the runners and vacuum the chips out. Tapping is easily done with a 8 point socket on a 3/8 NPT tap."
This is a very interesting analysis and helps me understand how alky works.
Thanks, Brian.
Phil Engle
