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  1. carwhisperer

    Maximum tilt for an inline 4 cylinder

    I am contemplating an engine swap into a 1974 VW super beetle. I want to avoid using an adapter plate or combining an engine and trans that did not come married from the factory. The idea that I am considering the most is to take a transverse 4 cylinder and it's FWD transmission and tilting it...
  2. carwhisperer

    Why is 60 degrees the preferred bank angle for a V6 and 90 for a V8?

    My understanding is that 90 degrees is the best bank angle for a V8 while 60 degrees is best for a V6. I have studied the math that suggests that a bank angle of 90 degrees permits equating the effects of two pistons/rods sharing one crank pin to a rotating mass, which can then be counteracted...
  3. carwhisperer

    Anyone ever used the EPA database to find road load HP vs. Fuel Economy?

    I am trying to find some data with corresponding road load horsepower and fuel economy values so I can do some examples for calculating BSFC. This data seems particularly difficult to find/read. I found these two links: EPA Road Load DataBase xl Files EPA Road Load Data Explained pdf I can...
  4. carwhisperer

    Flame Velocity vs. Ignition Timing

    I am trying to do some calculations to estimate/replicate the timing table for an LS1. Here are my assumptions. The spark plug is offset approximately 1/3 of the way across a 99mm bore, so max flame travel distance is 66mm (I got this by estimating from a picture. Stock timing for 600rpm is 11...
  5. carwhisperer

    Why retard ignition timing for forced induction?

    My understanding is that it is beneficial/common practice to retard ignition timing (i.e., fire the spark plug later in the compression stroke, closer to TDC) for a boosted engine vs. a comparable normally aspirated engine, and, to further retard timing in a way that is proportional to boost...
  6. carwhisperer

    Why can't diesels rev as high as spark ignition engines?

    It is my understanding that diesels generally rev slower than gas engines for the following reasons. 1. Diesel burns/combusts more slowly than gasoline. 2. With the diesel cycle, and clever injector pulsing, combustion can be prolonged by continuing to inject fuel after combustion has started...
  7. carwhisperer

    Anyone have any PV data I can use?

    I am looking for some raw PV data that I can use? I'm teaching a class and I want to have students find the area of the work loop and pumping loop using the trapezoid rule or simpson's rule. I need some raw data.
  8. carwhisperer

    BSFC at cruising speed in a car from power=kspeed^3 to estimate horsepower?

    I have a 1995 Ferrari F355. The published crankshaft power rating and published top speed are 375hp and 183mph, respectively. I wish to estimate the horsepower needed at 70mph and thereby estimate the BSFC at that cruising speed, at which the car gets 22mpg. I made the assumption that power is...
  9. carwhisperer

    Q1=Q2(P2/P1)^.5 for predicting injector flow rate. From where does this come?

    I have seen the above formula in several places around the world wide web. Q2=Q1(P2/P1)^.5, where Q2 is new mass flow rate, Q1 is original mass flow rate, P2 is new pressure and P1 is original pressure. The formula is supposed to predict flow rate of an injector using different fuel pressures...

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