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-   3rd gen Engine/Drivetrain (https://www.mazda3club.com/3rd-gen-engine-drivetrain-57/)
-   -   2.1 psi (https://www.mazda3club.com/3rd-gen-engine-drivetrain-57/2-1-psi-36672/)

Stueck September-27th-2004 09:03 PM

2.1 psi
 
how much HP does 2.1 PSI give you? 2.0l stock protege.


just curious...

Racing Beat September-28th-2004 08:22 AM

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...

Stueck September-28th-2004 03:01 PM

sorry, i ment as supercharger wise

JeffyBear September-28th-2004 06:00 PM

not worth it... why only 2.1lbs? thats prolly not even enough to compensate for the extra pulley the motor has to turn

vielster September-28th-2004 08:26 PM

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.

Stueck September-28th-2004 08:49 PM

125$ for an electric supercharger.

JHew84 September-29th-2004 02:27 AM


Originally Posted by Stueck
125$ for an electric supercharger.

not worth it, one of the oldest ebay scams, waste of money and in the long run will just end up blocking the airflow to your intake...

Racing Beat September-29th-2004 07:36 AM

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...

vielster September-29th-2004 12:31 PM

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.

goldstar September-29th-2004 01:47 PM

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.

JHew84 September-29th-2004 03:14 PM


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...

personally i dont see elec. superchargers going anywhere anytime soon at all, if they were going to take off it would have happened, even if it was only a small following... to get an electric motor to produce enough air flow to make power in the engine, is going to be a HUGE drag on the electrical system, and i dont know if you've noticed that when your at idle, and put your windows up/down the idle drops, so electric motors do have a drag on the engine, just like a belt driven one... i dunno, i think it would be cool for someone to revolutionize it, but i dont see it happening...

THEGOLDPRO September-29th-2004 03:25 PM

hey i have an idea, waist your money on it, then dyno it and tell us how 2.1 psi feels :bonk:

kargoboy September-29th-2004 03:36 PM

:rolleyes:

JHew84 September-30th-2004 02:35 PM


Originally Posted by THEGOLDPRO
hey i have an idea, waist your money on it, then dyno it and tell us how 2.1 psi feels :bonk:

:bt:

Roddimus Prime October-1st-2004 07:28 PM

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??


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