Recent content by coolingchips

Great conversation. I had originally intended the question to address the short term effects of low temperature exposure.

There's an earlier thread here on the effect of low storage temperature on track tires. The conclusion was that the risk is in cracking of the tire. I'd love to see if someone can conclusively say that there are no permanent chemical or structural effects to the tire if it is returned to a...

Can anyone explalin why they don't advance timing at idle? Wouldn't a lean idle mixture be beneficial?

JWaterstreet, any chance we can get a scan of that diagram?

OK, I think I know where I was going wrong. I was looking at this as a constant pressure problem, but it's a constant mass flow problem. Then it all makes sense. The only thing though is that there is some dynamic effect at this location that wouldn't be seen a bit further downstream into the...

Here's the results of a CFD simulation that I ran. -2atm (-202 kPa) on the vacuum side. The throttle plate is at 15, 45, and 80 degrees from vertical. Notice that the pressure below the center of the throttle plate is decreasing with the more open plate...

Does anyone have a diagram or picture. I'm having trouble understanding that the throttle itself isn't acting as a venturi and lowering static pressure.

It does expose the port to vacuum, but as the throttle opens further with no change in engine speed, the pressure decreases further because of the increase in flow, right?

I'm sure this must have come up before, but I did a search and couldn't find it, so here it goes. My question is on distributor vacuum advance, old school, I know. I know because of lean mixtures at light loads it's desireable to advance spark timing for optimal pressure peak timing, with...

I picked up version 11 just to be safe, thanks. By the way, walmart.com has the best price that I could find.

Does anyone know if there's a big difference between the 10th and 11th editions of the Mechanical Engineering Reference Manual by M R Lindeburg? Is the companion book of practice problems worth while? Thanks.

Wow, not at all? When I studied small engines (lawn mowers and such)in grad school I remember that they had an estimate of misfire percentage. I just don't remember what that estimate was. I know it depends on the engine design, but I was just looking for a very general number. Zero suprises me.

I wouldn't do it with gas analysis. OBDII does it with cranckshaft angular velocity changes, I believe. It could also be done with an in-cylinder pressure transducer accurately. I just don't know how often it happens. Lets say at high speed, 5500-6000rpm.

Does anyone know the typical misfire frequency of a generic SI passenger car engine? Is it 5% or somewhere in that neighborhood?