New Rotrex C38-91 Supercharger

[goodfellow]

1 7/8...?

you mean 1 7/8 o.d. no?



greg

 

[hombre]

you mean 1 7/8 o.d. no?



greg

Yes, of course... Thanks, Greg!!

Corrected above, but not in all the quotes.

 

[hombre]

I'm certain that 6000+ views for this thread are for formulae, not for the photos, so here's the relationship between airflow, engine size, RPM, and manifold pressure in a boosted engine:



Where:

· MAPreq = Manifold Absolute Pressure (PSI) required to meet the horsepower target
· Wa = Airflow (lb/min)
· R = Gas Constant = 639.6
· Tm = Intake Manifold Temperature (degrees F)
· VE = Volumetric Efficiency
· N = Engine speed (RPM)
· Vd = Engine Displacement (in Cubic Inches)

Astute forced-air aficionados will immediately notice that larger displacement engines will require less manifold pressure than smaller engines for the same HP (Airflow). Notice also, the major effect of reducing your IAT (Intercooling). Head porting & valve size are accounted for in VE, and look what happens to MAP as you increase the engine RPM limit.

Remember that MAP is Manifold Absolute Pressure, and subtract atmospheric pressure to get gauge pressure (aka boost). Have fun!

 

[hombre]

Engine Volumetric Efficiency (VE): Typical numbers for peak Volumetric Efficiency (VE) range in the 95%-99% for modern 4-valve heads. If you have a torque curve for your engine, you can use this to estimate VE at various engine speeds.

Brake Specific Fuel Consumption (BSFC): The fuel flow rate required to generate each horsepower. The units of BSFC are . General values of BSFC for supercharged gasoline engines range from 0.50 to 0.55. Lower BSFC means that the engine requires less fuel to generate a given horsepower. Race fuels and aggressive tuning are required to reach the low end of the BSFC range.



We got triple trouser snakes going to da BIG intercooler.

 

[hombre]

We chewed up another custom front seal for the supercharger crank drive, and TTS has declined to supply them (Richard prefers to sell his complete replacement front case for $$$$).



So we'll CAD out the original part and duplicate it by CNC. Since program will then be in our computer, I'll be happy to supply the part to any owners of the original TTS kit that may find themselves in need.

 

[hombre]

Just in case anyone is interested, the bearing is German manufactured HK 20162RS with a speed limit of 14,000 RPM.

 

[hombre]

Learn PRESSURE RATIO if you intend to race your supercharged R3:

In determining pressure ratio, the absolute pressure at the compressor inlet (P1c) is often LESS than the ambient pressure, especially at high load. Why? Any restriction (caused by the air filter or restrictive ducting) will result in a “depression,” or pressure loss, upstream of the compressor that needs to be accounted for when determining pressure ratio. This depression can be 1 psi or more on some intake systems. Direct measurement of P1c is always best (but must be recorded under actual conditions).



Where:

· P1c = Compressor Inlet Pressure (psi)
· Pamb = Ambient Air pressure (psi)
· ΔPloss = Pressure Loss due to Air Filter/Piping (psi)

Next, determine the compressor discharge pressure (P2c). This is also best done by direct measurement. On restrictive intake setups the pressure drop can be 4 psi or greater (like TTS 180 degree intercooler-plumbing nightmare).



Where:

· P2c = Compressor Discharge Pressure (psi)
· MAP = Manifold Absolute Pressure (psi)
· ΔPloss = Pressure Loss Between the Compressor and the Manifold (psi)

Now we can calculate Pressure Ratio () using the equation:



Why would this be important for racing? Would change greatly if P1c changed slightly? Does your supercharged R3 air intake pressurize over 160 MPH? Mine certainly does.

 

[hombre]

Here you may compare my supercharger intake plenum to that of Lynx Engineering on their 2 liter Peugeot GTi-6 (also using big Rotrex):



Mon travail est plus joli, non?

 

[albertaduke]

here you may compare my supercharger intake plenum to that of lynx engineering on their 2 liter peugeot gti-6 (also using big rotrex):



mon travail est plus joli, non?

absolument..

 

[roosie]

engine

wow,thats full on,blow them