[VAC] Re: Vintage Puller

[Carol and Oliver Filippi]

Good Luck!   Don't sell Detroit (or Dearborn) too short.  Recognize that factory jetting and tuning are designed so the vehicle will operate at high and low altitude, high and low temperature, etc., etc.  Therefore, they lean toward a conservative compromise. [ This is why computerized port fuel injection is so good, as it can deal with a lot more variables and keep them all in balance on a millisecond (if not microsecond basis).   Most any older stock vehicle can be leaned out a little and still run fine in San Diego.  BUT, be careful when you run it under a load [like climbing the Grapevine on I 15 when it is 105 in the shade.]  The lean tuning can very easily cause burned exhaust valves. (A good excuse for water injection.) These "hot shot" tuners tend to focus on best case conditions and ignore the others.  This can get you in trouble.  All this is not to say this tuner isn't great, just don't expect a lot. Don't forget that heat engines still must obey the laws of physics and thermodynamics.  Efficiency is still  ( T2 - T1) / T2  no matter what size carburetor jets you use.   Keep us posted.   Good Luck,   Oliver Filippi     Keep us posted ----- Original Message ----- From: Bob Kiger To: Multiple recipients of VACList Sent: Thursday, June 14, 2001 8:13 AM Subject: [VAC] Re: Vintage Puller My approach is going to be to put on the exhaust and then take the puller into the carb guy with one mandate.  Do everything to fuel flow and vacuum to increase gas mileage.  He is a wiz and has already told me that he will set the carb on the margin to get a couple of miles more per gallon.  That might reduce performance a bit, but as I mentioned the truck is so hot at the low end that I could sacrifice a little performance. The numbers are staggering in terms of operating costs.  Even 1mpg is 10% increase in fuel economy.  I would not be pursuing this if I had a modern puller that was getting 20mpg or just a regular passenger car with 25+mpg.  I am still aiming for 14-15mpg and will know by next week. Thanks for all your advice. Bob At 04:54 AM 6/14/01 -0500, you wrote: Bob, ----- Original Message ----- From: Bob Kiger At 05:59 PM 6/13/01 -0500, you wrote: Dual exhaust systems will improve high rpm horsepower, but in some cases, will reduce low speed torque.  >  Why is this Harvey?<   I can't remember the details sufficiently to provide a convincing explanation; the thought comes from books and magazine articles I have read on building and dyno testing performance engines.  I think it is because of the scavenging effect of increasing exhaust flow that leans the incoming fuel air mixture because of more complete removal of the exhaust gasses from the prior power stroke.  It is a known fact that gasoline engines such as small block Chevys used in pickup truck engines have smaller intake and exhaust valves than high rpm horsepower engines used in Corvettes, Camaros, etc. for the same reason.   >Hope I can prove you wrong on the gas mileage thing.  Only time will tell.>   I hope you can also but I must have read 100 test articles on those old trucks back in the '60s and '70s, some factory stock and others testing aftermarket products advertised to improve performance and efficiency.  I have never read of one that attained much more than 10 mpg in documented testing.   Harvey 1966 Airstream "Safari"  WBCCI #2857 1966 Ford F-250 "Camper Special" Mira Mar Mobile Community Oceanside, California