Not sure what to do.

Rotarydave · 02-07-2009, 12:40 AM

they now make an adapter to be able to use the 5 inch on anything,

on the flywheel i think he can get away with the alum one on an rx7 the heavy ones like the rx4 or a repu different story

I kind of agree on the porting issue but disagree also, there is room to improve the flow mostly on the exhaust side though, the exhaust needs to be monster ports with a like system. The intake side just pay attention to overlap don't increase it.

I can't prove it but I think additional overlap slows the engine i believe it does this either by loosing boost while trying to "backflow" into the exhaust there by engine braking the motor, or because exhaust gasses are being "recycled" or "retained" into the new cycle thereby causing an artificial inflation of boost with exhaust gases that will not increase power.

The only way to test this would be to measure the volume of air taken in vs the volume of exhaust gases over a period of time say 2-5 minutes and look for an appreciable difference this should also be measured at various rpm as well to compare that as well. and then as a control I would pull the s/c off that engine and check it in NA confirguration this would establish a base reference point.

02-07-2009, 12:40 AM	#11
Rotarydave Rotary Nut Case Join Date: Jan 2009 Location: Cibolo, TX Posts: 273 Rep Power: 17	they now make an adapter to be able to use the 5 inch on anything, on the flywheel i think he can get away with the alum one on an rx7 the heavy ones like the rx4 or a repu different story I kind of agree on the porting issue but disagree also, there is room to improve the flow mostly on the exhaust side though, the exhaust needs to be monster ports with a like system. The intake side just pay attention to overlap don't increase it. I can't prove it but I think additional overlap slows the engine i believe it does this either by loosing boost while trying to "backflow" into the exhaust there by engine braking the motor, or because exhaust gasses are being "recycled" or "retained" into the new cycle thereby causing an artificial inflation of boost with exhaust gases that will not increase power. The only way to test this would be to measure the volume of air taken in vs the volume of exhaust gases over a period of time say 2-5 minutes and look for an appreciable difference this should also be measured at various rpm as well to compare that as well. and then as a control I would pull the s/c off that engine and check it in NA confirguration this would establish a base reference point.