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  • Users: SWB
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  1. SWB

    DI Engines

    I can envision a day where the inlet valves are replaced by a multitude of air/fuel injectors, at least partially so.
  2. SWB

    Calculation of dynamic compression ratio?

    I hear you. Sean
  3. SWB

    Calculation of dynamic compression ratio?

    Ivymike, Take the formula you stated in your first post. "CR.dyn = (Vol.tdc + Vol.IVC_swept) / Vol.tdc" This is great, but prior to the piston making it to TDC the spark plug will fire. At that point, you not only have the piston compressing the gas, but the now burning and rapidly...
  4. SWB

    Calculation of dynamic compression ratio?

    My question is, we light the charge off prior to TDC, why do we pretend (in our calculations) that this doesn't happen? "Real" pre-combustion-compression ends when the spark plug fires. The longer you wait, the more compression you have. Naturally there is a compromise point, but that...
  5. SWB

    DOH Cam Head Design

    Try this, Mean piston speed in feet per second = 2 * desired peak torque RPM * stroke in feet / 60. Assume valve throat diameter 87% of valve head diameter and figure the respective cross sectional area. Then, Mean port velocity in feet per second = piston area in square feet / valve throat...
  6. SWB

    jaguar rear anti squat

    Here is how I visualize it. Tire wants to go forward in a hurry. Chassis has massive, inertial-based reasons to stay still. If the tire moves forward in squat, it will allow the tire to move forward to an extent, while the chassis stays still (to an extent). If the tire moves backwards in...
  7. SWB

    Roll Center Position & Migration

    Move the roll center 2 feet to the left of the left front tire in a left turn and both front springs will be in compression. Conversely, if we move the roll center 2 feet to the right of the right front tire in a left turn, we will have both springs in extension as the car attempts to trip over...
  8. SWB

    DOH Cam Head Design

    You should open and close the exhausts at the same time. Send me an E-mail at a_racerr@hotmail.com and I will send you a line drawing. Sean
  9. SWB

    jaguar rear anti squat

    The more the rear tires move rearward as the chassis squats, the more anti-squat you have. You will do this by pointing the pivot axis (in side view) upward at the front. You will have to be careful however, to make sure the radius arms do not pull the wheels forward as the car squats. They will...
  10. SWB

    "Nitride coated valves"

    TiN is used on Titanium valves so that the stems will not gall the guides. Some manufactures use this process while others use a ceramic coating. You can not run Titanium valves without some kind of coating or the stems will gall very quickly. Titanium is also very notch sensitive, so that will...
  11. SWB

    DOH Cam Head Design

    Marquis, I think it's SAAB that's doing the exhaust gas reversion technology, correct? Have other OEM's jumped on the bandwagon to your knowledge? While not all of my research has been along the following lines concerning the quenching off of the inlet side, some of it has. One very well...
  12. SWB

    DOH Cam Head Design

    You won't have to worry about "shock waves!" There are numerous examples of engines running two plugs per cylinder and I have never heard of them having such a problem. Nearly all light aircraft engines use two plugs per cylinder and dual magnetos. When you switch between mags on a...
  13. SWB

    DOH Cam Head Design

    The following are my beliefs only, based on more theoretical knowledge than first-hand factual experience. 1) There is no one magic bullet to economy. For more, see the tornado swirling device thread of a month ago. 2) Economy is about combustion efficiency and the transference of this force...
  14. SWB

    Bad/Silly practices and exploding Engine myths!

    Marquis, Do you find BSAC more important that BSFC, or do you use them in conjunction for a more accurate picture of thermal efficiency? How would either be analyzed in part or as a group? Sean
  15. SWB

    Bad/Silly practices and exploding Engine myths!

    Marquis, Would you please send me an E-mail? I'd be interested in learning more about your work. a_racerr@hotmail.com You said it when you stated the 'virtues' of the Siamese inlet port! I've had some experience with these and I can attest to the poor flow quality inherent with their design...
  16. SWB

    Shock mount angle for ladder bar suspension

    OK, Vertical is fine. Ideally the rate would be maximum at full bump and that is something you can check easily as you build the car. The more the shocks compress for each inch of axle travel, the greater the rate. They usually angle the shocks inward at the top to give an increasing rate (as...
  17. SWB

    Shock mount angle for ladder bar suspension

    If possible, you would be best to keep them no more than about 20 degrees inboard. The rate will change as they compress and the more you angle them the more the rate decreases as they compress, which is undesireable. Sean
  18. SWB

    I need some suspension systems information...

    Search for "DAX" and see what you get. Sean
  19. SWB

    4-Valve camshaft selection

    I went through and did some Q&D calculations to come up with a closure point of around 45-55 degrees after bottom dead center (like advertised closing point). Point is, if you close the intake too late, you'll largely be pushing air out until you get up to your torque peak and above. If you know...
  20. SWB

    4-Valve camshaft selection

    I'll take the time to look at the numbers and see what I can. Good news is that the flow comes in early, so it's not peaky. One thing you will really need to look out for though when you get this done, is to spend the time to dial in the LSA of the two cams. Hopefully you will have adjustable...

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