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Old 29-06-2007, 04:01 PM
boostm3 boostm3 is offline
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Join Date: Mar 2004
Location: White Plains, NY
Posts: 7
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I had a setup similar to yours.. Mine was a '99 M3 which I added the Dinan Vortech based superchargers kit to back in December, '99. There was no intercooler with this kit. Two yrs later, I went with a larger crank pulley and bumped my boost up from the Dinan kit's 8 psi to 11 psi. To support the increase, I installed the AA version of the Aquamist 1s kit, and drove it that way for a few years.

The water injection kit did its job at WOT, lowering peak Intake Air Temperatures (IATs) by 50-60 degrees on a dry day... In humidity, it became less effective. Here's my recommendation..... The problem with WI alone on a supercharged car like yours, and mine used to be, is that its only effective at WOT, especially if you run something similar to the 1s kit. I did alot of temperature instrumenting, and found that cruise IATs measured Ambient, as recorded by the on board computer, plus 100 degrees!!! Yup. Thats a heap of heat for just cruising around at part throttle. And Water INjection wont do a thing to help you with it. ON hot summer days after driving around for a half hour or more, the lag in responsiveness is HUGE. So, on an 80 degree day, when the brake duct thermocouple reports the ambient temperature as 80 which is what you see on the OBC in the dash, the temperature reported to the ECU by the IAT sensor is about 180 degrees F !! How does the ECU respond to these elevated IATs? Usually by pulling timing, among other things. And you, the driver, experience it has less sharp responsiveness when you press the go pedal. And of course, as temps to up through the 80s and 90s, it just gets worse.

So, its this realization which finally prompted me to do what I should have done as soon as I got the supercharger: get an Aftercooler. RMS had a good water to air unit which fit perfectly into the E36 M3. After its installation, using the 80 degree day as the example, IATs dropped from a previous 180 degrees to a current 120 degrees. In addition, the aftercooler all by itself got me an additional 20-25 whp on the dynojet, the same one I had been using to test all my other configurations. I kept the water injection system which I now use to augment the cooling provided by the aftercooler. Together, they make sure that even at wot at redline, IATs drop instead of climb!

Sorry I took this a bit off topic, but after the supercharger, adding the aftercooler was the single best upgrade I got. Water injection is a good helper system to augment the aftercooler, but as my numbers showed, I think its not the greatest substitute.
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Paul E -
'99 White M3; < 69K miles; Dinan SC kit with 6" RMS crank pulley and water/air Aftercooler: 11 psi-367 SAE rwhp/304 ftlbs; Custom Tuning by Nick G; AA Aquamist Water/Methanol Injection and AA exhaust; Fikse FM-10s;
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