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(cheap & effective)
Last Updated: 11/28/2007
without alcohol with 50/50 ethanol/water
12 psi (some knocking) 16 psi (no knocks)
0.762 R/T 0.680
2.200 60' 2.112
6.408 330' 6.173
9.990 1/8 9.580
67.81 MPH 72.22
13.161 1000' 12.516
15.886 1/4 15.000
82.41 MPH 90.68
You can't see the pumps, but they fit into recesses on the outsides of the
bottles. The pump that came with the bottle was 25 psi. The pumps from the ~2002
cars have 45 psi. The red and blue wires are for the pumps. Red are hot and go
to the white wire on the wiper motor. The blues are ground and go to the
pressure switches on the inner fender (I install a second switch for the three
boost lights I have). I just alligator clip the blue wire to the switch after
sliding the electrical connector off just a touch. When the lights go one, so do
The 10 and 15 on the caps refers to the nozzle size. One pump is connected to the 9 psi light. The other is off (see it clipped to the cap). There is no low fluid light, but some GM cars had float switches, so they can easily be added.
SPRAY NOZZLES - The misting nozzle and the barb fitting get screwed into the female
coupler. The barb fitting needs to have the hole enlarged (it's either a
1/4" or a touch bigger) to receive the
misting nozzle. They are sitting in the holes where the thermal switch for
the air cleaner used to be. They held in place by the hoses underneath clamped
to the bard fittings. You can see the white check valves in the hoses.
They keep the alcohol from draining back into the bottles.
I like this configuration for the nozzles. They spray a mist, but any large drops will fall away from the carb and down the air filter duct. Since the mist goes thru the carb, it should be fully atomized (like the fuel) before reaching the turbocharger. Since this is pre-carb, there is no vacuum to suck the alcohol out of the bottles. It could be removed in five minutes and you would never know it was there.
WATER or ALCOHOL? - The Distilled water, ethanol (aka denatured), methanol or mixtures can be used. Ethanol is available at most hardware stores for about $8 gallon. Methanol might be available at the drag strip. Distilled water is available at grocery stores and is <$1/gallon. Windshield washer fluid is ~35% methanol and cheap, but I don't know what the effects of the blue dye are. I have only used straight water and 50/50 water/ethanol so far. Water provides cooling. Alcohols cool as well, but are also a fuel.
ALCOHOL FLOWRATE - The McMaster-Carr #3178K76 is labeled "M10", which means it flows 10.0 gallon/hour at 100 psi. The McMaster-Carr catalog also listed flowrates at 40 psi and the M10 flows 6.32 gal.hr @ 40 psi. An M5 flows half that and an M15 flows 1.5x the M10. Too little alcohol leads to knock, too much will cause the engine to fall flat at wide open throttle (WOT). (I also have set up a duplicate washer bottle and pump. This way I can run two different size nozzles singlely or together at different turn on points.)
TUNING - The alcohol helps suppress knock, which lead to less retard from the ESC. It also allows for more boost and more timing advance. I run a MSD 6 BTM ignition box, which provides timing retard based on boost pressure. I run 15° initial timing with ½° retard per psi of boost on the street with the 50/50 ethanol turning on at 9 psi and a flowrate 7 gal/hr (M10 @ 45 psi). With this, I run 16 psi max boost. At the track, I'll put a little race gas in, set the BTM to 0°/psi and up the boost some. These numbers are just guidelines! There are a lot of parameters to juggle here - boost, initial timing, timing retard, alcohol mixture, alcohol set point, alcohol flowrate, octane, ambient air temps, fuel mixture (secondary rods and hangers) and then the fact the every engines a little different. This is where a knock gauge, like the Casper's 10-led, becomes invaluable. A little knock kills performance - a lot of knock kills engines!
The first time I ran alcohol, I found the more I ran, the faster the car went. I started in the high 15's, and by the end of the day I 12 gal/hr and got down to 15 flat (see times above). I now know at the time I was running lean for the boost I was at (EGT's in the high 1600's). The alcohol suppress the knock and also helped richen the mixture. The next season, I swapped the stock rods and hangers in the carb for some much richer ones. Times dropped to 14.85 with the additional fuel! But I found that any richer and the car fell flat (EGT's in the low 1400's). The next time out, I didn't have any leaner rods or hangers. Instead I cut back on the alcohol to lean it up. This dropped me to 14.71! - my best so far and now the car is a consistent high 14's performer.
On the street, I can run 16psi boost without alcohol if I set the BTM retard to ~1½° / psi. With the alcohol, at the same 1½°, it will fall flat. By setting the retard to only ½° / psi, the car will not knock, and the additional timing can be felt in the seat of the pants. More timing with alcohol is much better than less timing without alcohol.
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