I was talking to one of my buddy's who was a dirt track guy back in the day and we got to talking about sneaky ways to make power on a "stock" looking engine and he said that if he car has a smog pump it can be reworked to make it into a poor mans supercharger he said something like 3-5 psi is possible... Has anyone ever heard this to me it dose not seem viable.
I have done this, very small increase, not near 3 to 5 psi, more like 1 or 2 psi. Look at the size of the pump.
Smog pumps were used on small displacement engines (50cc or so) to set records at Bonneville in the appropriate bike class. No way a smog pump is going to pump 3-5# on a V8. Not even if it was a 221" SBF. Take a look at the physical size of superchargers that can pump 3-5# on a typical small block. NASCAR and some drag racers use an improved, race quality smog pump as part of a crankcase evacuation system.
As for me........I try and get my wife's tail any chance I can. As far as wives' tales though, this is a new one one me.
Actually, I have this done on my 65 merc M-100. The 351W was out of a '92 F-150 and had all the gov. mandated crap on it. I replaced the fuel injection with a Eddy carb & intake and re-routed the pump intake to in front of the radiator with its own filter. I plugged the holes in the back of the heads and have the Pump pushing air directly into the carb and air cleaner. I have no idea what the psi is, but I get @ 20MPG with 2 engines and trannies in the back (@1500 lbs) The pump does not push enough air to run the engine by itself however. It seems to only allow the engine to "free breath". (doesn't have to 'suck' as hard) And this way it pushes cool air from in front of the truck into the engine, instead of the hot engine compartment air. I guess this is really called a Ram Air system?!!??
Hey, whatever. I guess it's true: ignorance is bliss! You do sacrifice a bit of HP to run the pump true, but the introduction of cold forced air into the engine has been proven to get better MPG and Hp. Using the stock smog pump is just another avenue for the engine to get what it needs.
I saw a smaller bike with a smog pump running in the supercharged class at Bonneville one year. He removed the tube between the pump and his intake and picked up seven mph. And if you pump much air with that thing it won't be cool air.
Note that if it's merely blowing into the aircleaner or otherwise just throwing air in the general direction of the carb, it is essentially doing nothing. To build pressure would require a sealed connection--and since the thing is WAY to small to supply a significant engine, it would then function essentially as a CHOKE. To supercharge, you gotta stuff in more air than just atmospheric pressure can and force it into the intake side. Making a whirring sound near the carb does not actually count as supercharging...
They work well as a vaccum pump. We started using them on motors such as 327's with no "real" options for crankcase evacuation (for example, Offy valve covers with no holes, and an Edelbrock manifold without the fill tube in the front.) but still had the old road draft hole. we would plumb that to a smog pump, and actually pull a vaccum into the motor. Not long after, we discovered they had to have p.c. seals on the intake and exhaust valves, otherwise, at Idle, You could pull enough vaccum to keep the valves from lubricating properly. aside from that mess, You have never seen a cleaner engine. 0 leaks.
You will pick up many more horsepowers by plugging the vaccuum side into the valve cover. We use these on drag cars alot, course they arent the cheap ugly ones.
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