Check my math please.

[PRAY]

Using the formula below I get .18519 for one Milliseconds = to one crank degree at idle. With this being true I am seeing averages of 1.8470 with the small pulse adder added. So that means that it is only taking 10 or so degrees of crank rotation for my injector to be completely fired at idle? I am messing with my injector timing vs. ECT and I need to verify my math. I need to figure some stuff out. I know it backwards calculates from EOIT which is how the table is set up at 220* at operating temps. I am trying to figure out SOIT so I can see the complete firing vs. crank degrees equation. I want to see how that compares to my new cam specs vs. stock.

At 900 rpm the crank rotates one degree in 0.18519 milliseconds.
The crank turns 360 degrees in one rpm. Therefore 360 degrees X 900 rpm = 324,000 degrees per minute = 5,400 degrees per second = 1/5400 of a second per degree = 0.00018519 seconds or 0.18519 milliseconds per degree.

[turbo_bu]

Yes, that is what I get too. From what you have written up, it is taking ~10 crank degrees for the injector to fire at idle.

[PRAY]

So I am doing g the math correctly. Do you know if that is the correct formula. That seems like a minuscule amount of time/degrees of rotation. Not sure what I was expecting though.

[joecar]

...

At 900 rpm the crank rotates one degree in 0.18519 milliseconds.
The crank turns 360 degrees in one rpm. Therefore 360 degrees X 900 rpm = 324,000 degrees per minute = 5,400 degrees per second = 1/5400 of a second per degree = 0.00018519 seconds or 0.18519 milliseconds per degree.Yes, correct.

[turbo_bu]

So I am doing g the math correctly. Do you know if that is the correct formula. That seems like a minuscule amount of time/degrees of rotation. Not sure what I was expecting though.

I do the math a little differently, but you are correctly converting from RPM to degrees per second. That's the main thing that allows you to then convert from pulsewidth to crank degrees.

If it makes you feel any better, see how big of pulsewidth you get during like a WOT run and see how many degrees your are spraying fuel :).

[PRAY]

Thanks guys. That is the next test to see if I am going to mess with the timing vs. Rpm table. Mine is 0 from the factory.

[joecar]

Yes, at WOT, injector pulsewidth will use up all of your 720 degrees.

[PRAY]

I figured 52's on this motor would hit 85% or so which should leave me a bit if off time. I will have to see what IPW comes to and do the math. I did advance the timing some more and things really smoothed out. No more fuel smell either. I may have gone a hair to far as my average IPW want to around 2 from 1.8. Idles really nice now and revs up cleaner. I like it so far. It does feel a little weaker now but it was warmer today and the MAF is on. It always feels sluggish with the MAF. I think that is in the dynamics though. I pulled out my degree wheel and just started marking all my valve events vs. Injector timing to see what was going on. Not until it hit me to use advertised/.006" cam timing that everything started to become very clear. I hope backing up the timing originally didn't wash down my rings. That is the last time I listen to advice on HPT. It seems the consensus over there is to back up the injector timing until after the EVC event. That didn't work for me at all. The missing piece was also using IPW to find SOIT. That tells you a lot about what is going on in there. Using only the .050" cam specs will only get you half way to the solution. Hopefully I have this nailed down now and I didn't hurt the motor. I now see why correct sized injectors are so critical. Time and tuning will tell.

Last piece is to get the honey comb in place and figure out this hot start issue I am having. I got the new elbow in place and moved the MAF back. Things cleaned up pretty well with just that but my mafreqhz went down by 400 on average. I will say the elbow is pretty thin and I suspect it is collapsing under hard throttle. I was seeing 98-100 KPA before it went on and now I am only seeing 96 or so. Always a work in progress. Thanks for the help guys. I really appreciate it.