2.1 psi
September-28th-2004, 08:22 AM
#2
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Join Date: Nov 2003
Location: Rockhill, MO
Posts: 706
dude come on...we need so much more info then that....2.1 psi of what??? Boost, tire pressure, cylinder pressure what are we talking about here...
2.1psi of any sort of forced induction is not worth it...2.1psi of tire pressure means you have a flat tire. 2.1 psi of cylinder pressure means you have a dead cylinder or bad valve...
2.1psi of any sort of forced induction is not worth it...2.1psi of tire pressure means you have a flat tire. 2.1 psi of cylinder pressure means you have a dead cylinder or bad valve...
September-28th-2004, 08:26 PM
#5
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Join Date: May 2003
Location: Remington, VA
Posts: 198
Well, that's not true...it will probably give you about 15-25whp gain from 2.1psi. However, I definitely will say that the $/hp won't be worth it with any supercharger. You're talking probably like $2k at least for a supercharger.
September-29th-2004, 02:27 AM
#7
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Join Date: Jul 2004
Location: Lansing, MI
Posts: 166
Originally Posted by Stueck
125$ for an electric supercharger.
September-29th-2004, 07:36 AM
#8
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Join Date: Nov 2003
Location: Rockhill, MO
Posts: 706
vielster, it may add HP (assuming belt driven blower) but as pointed out, how much of that is negated due to the extra peripheral drag on the motor..it takes HP to make HP in that case. The electric blowers are unique, and in time may actually be a good route..so far the best one (electric SC) I have seen is only used like NOS, for quick short bursts...
September-29th-2004, 12:31 PM
#9
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Join Date: May 2003
Location: Remington, VA
Posts: 198
The gross hp by 2.1psi will probably be more like 35hp (using physics), subtracting the inefficiencies and power to drive the blower will give around 15-25hp, depending on how efficient the blower is.
September-29th-2004, 01:47 PM
#10
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Join Date: Aug 2002
Location: New Jersey
Posts: 349
HP output is almost directly proportional to the density of the atmosphere which itself is directly proportional to to the barometric pressure.
For reference consult:
High Speed Combustion Engines by P.M. Heldt, 16th edition, p.638-39
A chart relating air density to barometric pressure (in.Hg) at various elevations from sea level to 15,000' can be found in: Maximum Boost by Corky Bell, p.28
You can convert in.Hg to PSI using: www.onlineconversion.com/pressure.htm
Finally, you can obtain the~HP of your engine at any elevation up to 10,000' based on your sea level HP from: www.slowgt.com/Calc2.htm#BasAltCal
Because the HP/Pressure relationship is linear, you can work backwards from the elevation charts to determine HP increase with INCREASE in pressure. The 2.0L Protege engine develops 130 HP at 14.7 PSI (nomal atmospheric pressure). At 2.1 lbs boost (16.8 PSI), the same engine will develop 148.6 HP (18.6 HP more than stock). Bear in mind this is a rule of thumb, quick and dirty calculation and represents the most achievable at this pressure. If you were using a supercharger to obtain this boost, you'd have to subtract the HP consumed by the blower. Incidently, because of this linear relationship, WWII piston engine aircraft used MAP gauges that read absolute rather than gauge pressure as this better represented the actual engine output.
For reference consult:
High Speed Combustion Engines by P.M. Heldt, 16th edition, p.638-39
A chart relating air density to barometric pressure (in.Hg) at various elevations from sea level to 15,000' can be found in: Maximum Boost by Corky Bell, p.28
You can convert in.Hg to PSI using: www.onlineconversion.com/pressure.htm
Finally, you can obtain the~HP of your engine at any elevation up to 10,000' based on your sea level HP from: www.slowgt.com/Calc2.htm#BasAltCal
Because the HP/Pressure relationship is linear, you can work backwards from the elevation charts to determine HP increase with INCREASE in pressure. The 2.0L Protege engine develops 130 HP at 14.7 PSI (nomal atmospheric pressure). At 2.1 lbs boost (16.8 PSI), the same engine will develop 148.6 HP (18.6 HP more than stock). Bear in mind this is a rule of thumb, quick and dirty calculation and represents the most achievable at this pressure. If you were using a supercharger to obtain this boost, you'd have to subtract the HP consumed by the blower. Incidently, because of this linear relationship, WWII piston engine aircraft used MAP gauges that read absolute rather than gauge pressure as this better represented the actual engine output.
September-29th-2004, 03:14 PM
#11
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Join Date: Jul 2004
Location: Lansing, MI
Posts: 166
Originally Posted by Racing Beat
vielster, it may add HP (assuming belt driven blower) but as pointed out, how much of that is negated due to the extra peripheral drag on the motor..it takes HP to make HP in that case. The electric blowers are unique, and in time may actually be a good route..so far the best one (electric SC) I have seen is only used like NOS, for quick short bursts...
October-1st-2004, 07:28 PM
#15
The man behind the mask
Join Date: Oct 2003
Location: Birmingham, AL
Posts: 11,572
just a little fyi guys. I've been working with powerdyne pretty closely and they told me (take it as you will) that their 6psi Mustang 5.0L kits only draw about 8-13hp to add over 100whp.
e-chargers are a waste. Don't waste your money but you should see my other thread about accepting donations to buy these gimicks and dyno them for everyone's sake....anyone know where I put that??
e-chargers are a waste. Don't waste your money but you should see my other thread about accepting donations to buy these gimicks and dyno them for everyone's sake....anyone know where I put that??