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Re: Negative Supercharging

From: Hank Dozier
Remote Name:
Date: June 01, 2003


Attached below is a reply I posted for a similar type of "natural power enhancement". Although the basic physics are there, believe me, it is WAY more complicated than these guys are putting out (from 25 plus years in the business). ********************** Bending Physics...... From: Hank Dozier Email: Remote Name: Date: March 01, 2003 Comments I have seen this stuff before. Some of the things this guy is doing are directionally correct, and other is is on the other side of that fine line I draw that places it in the camp of "junk science". Of the stuff this guy is stating, here is what DOES work. For years, racers have placed an insert in the entrance of the headers at the exhaust face that reduces the cross-sectional area of the exhaust port slightly, with the immediate downstream section being larger. This produces a "reversion block" on the exhaust flow (kinda like a diode) and causes the flow to only go in one direction, which "pulls" on the port. This increases the scavange effect of the header. Couple this with mathematically designed exhaust pipe lengths, and a "H" pipe crossover for additional tuning/scavanging bank-to-bank, and you get this guys basic "neagative supercharging" phenomena. Now, you can also play with th intake tract and camshaft design to assist this effect by removing induction restriction (can we say "pumping losses" here), and this could magnify the effect somewhat, although this is an independent effect on engine performance enhancement, as we all know. Then we can through in friction reduction (roller cams, roller rockers, lightweight parts and low=pressure oiling, etc) to get more power (remember, we are looking at IMEP to BMEP ratio here). Finally, good old large pipe low restrictive exhausts will help. No magic, and has been proven time and time again. His other claims are dubious at best.


Last changed: July 19, 2018