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Lowspeed Lowside · April 24th, 2011, 07:08 PM

Rough computation:

According to the calculator (http://dairally.net/daihard/chas/Mis...s/DaiTurbo.htm) at 23psi, an ambient temperature of 25°C and a desired post-intercooler temperature of 40°C (no detonation), we require 90% intercooling, and get a mass-flow of ~0.092kg/s. With the values: 15.0m/s (~30mph), specific weight of ambient air ~1.1kg/m³, efficiency 0.5, I compute that the cross-section of the air intake for cooling would have to be (0.092/(1-0.9)-0.092)/(15.0*1.1*0.5*)m²=0.1m². Not too big, one could even mount two of these.

Notes:

With the above parameters the calculator tells us that engine would be generating 75kw (caveat - see below) of power; accordingly, the values such as 171.4 cfm airflow are extreme.
Cooling will improve at higher speeds. Approximately 45kw of power is required to maintain a vertical speed of 15m/s for a mass of 300kg.
0.10m²~12"x13". Reference: a 0.18m² intercooler designed for (I think) a 240kw (2G) Mitsubishi Eclipse is 22lbs. (http://www.alibaba.com/product-gs/23...showimage.html) shrinking two dimensions by 1/3 would result in a device that weighs ~10lbs.
A Kawasaki 650r weighs 440lbs. and costs ~$7000
According to Bell Intercoolers (http://www.bellintercoolers.com/pages/aachart125.html) an intercooler designed for 171cfm airflow (part no. A125071060) is only 1.25" x 7.10" x 6.00" and claim typical efficiency of 60%-70% (http://www.bellintercoolers.com/page...AQ.html#FAQ_14). I compute that a pair of these mounted in series could result in a combined efficiency of 84%-91%. The size would indicate a very high efficiency of heat transfer to ambient air (much better than the 0.5 assumed above), but of course they might also be assuming that you're travelling at 120 mph. At $141/piece even a pair of these would be within the allotted budget.
At 1.5 psi boost and 60% intercooling the calculator tells us we're generating a whopping 36kw - but that cannot be right. Maybe there's a bug and the output is in hp (but only when boosted). In any case, we'll definitely need a better calculator/simulator before even considering to spend actual cash.

April 24th, 2011, 07:08 PM	#2
Lowspeed Lowside Tightwad Tinker Name: Hans Location: Lexington, Ky Join Date: Apr 2011 Motorcycle(s): '09 Ninja 250R Posts: 161	intercooler considerations Rough computation: According to the calculator (http://dairally.net/daihard/chas/Mis...s/DaiTurbo.htm) at 23psi, an ambient temperature of 25°C and a desired post-intercooler temperature of 40°C (no detonation), we require 90% intercooling, and get a mass-flow of ~0.092kg/s. With the values: 15.0m/s (~30mph), specific weight of ambient air ~1.1kg/m³, efficiency 0.5, I compute that the cross-section of the air intake for cooling would have to be (0.092/(1-0.9)-0.092)/(15.01.10.5)m²=0.1m². Not too big, one could even mount two of these. Notes: With the above parameters the calculator tells us that engine would be generating 75kw (caveat - see below) of power; accordingly, the values such as 171.4 cfm airflow are extreme. Cooling will improve at higher speeds. Approximately 45kw of power is required to maintain a vertical* speed of 15m/s for a mass of 300kg. 0.10m²~12"x13". Reference: a 0.18m² intercooler designed for (I think) a 240kw (2G) Mitsubishi Eclipse is 22lbs. (http://www.alibaba.com/product-gs/23...showimage.html) shrinking two dimensions by 1/3 would result in a device that weighs ~10lbs. A Kawasaki 650r weighs 440lbs. and costs ~$7000 According to Bell Intercoolers (http://www.bellintercoolers.com/pages/aachart125.html) an intercooler designed for 171cfm airflow (part no. A125071060) is only 1.25" x 7.10" x 6.00" and claim typical efficiency of 60%-70% (http://www.bellintercoolers.com/page...AQ.html#FAQ_14). I compute that a pair of these mounted in series could result in a combined efficiency of 84%-91%. The size would indicate a very high efficiency of heat transfer to ambient air (much better than the 0.5 assumed above), but of course they might also be assuming that you're travelling at 120 mph. At $141/piece even a pair of these would be within the allotted budget. At 1.5 psi boost and 60% intercooling the calculator tells us we're generating a whopping 36kw - but that cannot be right. Maybe there's a bug and the output is in hp (but only when boosted). In any case, we'll definitely need a better calculator/simulator before even considering to spend actual cash.