Why are headers/race pipes bad for a Stillen Supercharger SC ?
#16
06-08-2007, 02:39 PM
Originally Posted by helldorado
A lot of it comes from that they're using a roots blower. With a CSC, lysolm or turbo, the air that comes from the turbine outlet is already compressed. With a roots blower, it just comes out faster, but still at atmosphere pressure. They don't compress the air within the unit, like the others do. The compression takes place between the blower and intake valves, in your intake manifold.
On a 4 stroke cycle, when the piston is dropping down the cylinder and the intake valve opens, a vacuum is created in the cylinder. Because of the overlap portion of the cam duration, the exhaust valve is still open. An appropriate level of back pressure allows the incoming air/fuel mixture to completely fill the cylinder. Too much back pressure, keeps exhaust gases in the cylinder, not enough draws the air/fuel mixture out through the exhaust valve.
So on a boosted application, since the intake manifold is no longer at atmospheric pressure, the pressure there is pretty much always higher than the pressure in the exhaust, so during the overlap phase, some of the air/fuel mixture is pushed out the exhaust valve. With a turbo or csc, the air that is added is already pressurized so its easier for the entire intake manifold to retain that air pressure level as air is rushing out the exhaust manifold. With the roots blower, it has to repressurize the entire intake manifold by pushing more ambient air into the chamber.
Since a roots blower is positive displacement, it pushes a fixed amount of air per revolution. So when the intake manifold pressure drops, there is only so much the unit can do to raise it back up and add extra air to the mix. This is extremely tough for the unit at higher rpms, why the Stillen doesn't generate huge peak whp. But at lower rpms, its much easier since the valves stay open longer. Why it generates such great low end torque.
Its not as much that you need a lot of backpressure for the unit to operate. Its that you need the right amount to keep the pressurized air/fuel mix from going straight out the exhaust valve and keeping it in the cylinder for maximum power. And the right amount is pretty much at stock backpressure levels.
On a 4 stroke cycle, when the piston is dropping down the cylinder and the intake valve opens, a vacuum is created in the cylinder. Because of the overlap portion of the cam duration, the exhaust valve is still open. An appropriate level of back pressure allows the incoming air/fuel mixture to completely fill the cylinder. Too much back pressure, keeps exhaust gases in the cylinder, not enough draws the air/fuel mixture out through the exhaust valve.
So on a boosted application, since the intake manifold is no longer at atmospheric pressure, the pressure there is pretty much always higher than the pressure in the exhaust, so during the overlap phase, some of the air/fuel mixture is pushed out the exhaust valve. With a turbo or csc, the air that is added is already pressurized so its easier for the entire intake manifold to retain that air pressure level as air is rushing out the exhaust manifold. With the roots blower, it has to repressurize the entire intake manifold by pushing more ambient air into the chamber.
Since a roots blower is positive displacement, it pushes a fixed amount of air per revolution. So when the intake manifold pressure drops, there is only so much the unit can do to raise it back up and add extra air to the mix. This is extremely tough for the unit at higher rpms, why the Stillen doesn't generate huge peak whp. But at lower rpms, its much easier since the valves stay open longer. Why it generates such great low end torque.
Its not as much that you need a lot of backpressure for the unit to operate. Its that you need the right amount to keep the pressurized air/fuel mix from going straight out the exhaust valve and keeping it in the cylinder for maximum power. And the right amount is pretty much at stock backpressure levels.
#17
06-09-2007, 06:38 AM
#18
06-09-2007, 11:45 PM
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Hey guys. Just got myself an 04 coupe 5at. Been reading up alot about the car, don't know to much about cars. The only way to learn is to read and do it yourself. I've figured doing a bunch of little mods seems pretty pointless because I wont get to much hp out of them, especially for the amount of money it costs. So i was gonna go with the stillen sc kit that i seen on there website for $3800 roughly. My buddy from work is pretty heavy into cars and has owned a mustang for a long time and was telling me that this kit doesnt come with a intercooler, which is true, but u can get this other part which hooks up and sprays wiper fluid/water into I guess the intake to cool the engine down and u gain about 80 hp to replace the intercooler. Just wondering if this is true, and if its worth the money to buy the stillen supercharger.
#19
06-10-2007, 12:09 AM
Originally Posted by nickvvv
Hey guys. Just got myself an 04 coupe 5at. Been reading up alot about the car, don't know to much about cars. The only way to learn is to read and do it yourself. I've figured doing a bunch of little mods seems pretty pointless because I wont get to much hp out of them, especially for the amount of money it costs. So i was gonna go with the stillen sc kit that i seen on there website for $3800 roughly. My buddy from work is pretty heavy into cars and has owned a mustang for a long time and was telling me that this kit doesnt come with a intercooler, which is true, but u can get this other part which hooks up and sprays wiper fluid/water into I guess the intake to cool the engine down and u gain about 80 hp to replace the intercooler. Just wondering if this is true, and if its worth the money to buy the stillen supercharger.
Stage 2 stillen SCs and up come with an intercooler setup. It is not $3800 but rather $5340 for the stage 2 kit and the prices increase as the staging increases. (3 and 4 are also available if I'm not mistaken)
Don't forget that with the stillen supercharger you'll have to modify your hood or purchase their hood so that it will fit.
finally, start your own damn thread
jk, you'll probably get better responses once youve used the search button on the forum. there's a lot of threads about the stillen SC.g'luck
secondly the stillen SC kit is NOT $3800.
#20
06-10-2007, 06:32 AM
Originally Posted by nickvvv
Hey guys. Just got myself an 04 coupe 5at. Been reading up alot about the car, don't know to much about cars. The only way to learn is to read and do it yourself. I've figured doing a bunch of little mods seems pretty pointless because I wont get to much hp out of them, especially for the amount of money it costs. So i was gonna go with the stillen sc kit that i seen on there website for $3800 roughly. My buddy from work is pretty heavy into cars and has owned a mustang for a long time and was telling me that this kit doesnt come with a intercooler, which is true, but u can get this other part which hooks up and sprays wiper fluid/water into I guess the intake to cool the engine down and u gain about 80 hp to replace the intercooler. Just wondering if this is true, and if its worth the money to buy the stillen supercharger.
Haha, Your buddy is more than likely referring to a methanol/water mist system like the one offered by Snow Performance which uses the cars existing windshield washer fluid reservoir for the kit. It is a good idea, but works better WITH the intercooler. The Stillen kit is a great kit for what it is, just as long as you don't beat your head against a wall trying to make too much more power than it is wanting to give you out of the box. I would recommend the Stillen Stage 2-4, depending on your budget. Great kits, just not alot you can do about/with that kits Eaton E62 unit, that is the SC kits weak link, if there is one (especially since Stillen got the bugs worked out of the belt/pulley issues)
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