How does this look?
Setting up a boost map for my car. I have the timing set at 32* at the crank trigger. The distributor is locked out and diconnected. The engine is a 500" BBM with a Precision PT 114 turbo. Heres my map.
Also, I have a question about the pressure reading. Does this indicate a bad map sensor? The car is off and just the MSD is on. Would 0 be the atomospheric pressure? My location it is 14.5.
BTW its a 6530
Senior Member
14.5 is atmospheric pressure, 0 is perfect vacuum.
In your case, you would be pulling 23 degrees at 15lbs of boost. (30 psia)
Regards, Gary
So mine reads 2 while not running. What does that mean? 2nd pict.. 23 sounds like too much for 15 psi whan I am starting at 32*. Dont you think?Originally Posted by Gaz64
The reason the red line is on 2 is because #1 the MAP sensor is not plugged in, #2 you have a bad connection off the weather pack, #3 you have a bad MAP sensor.
You are on the right track as far as you plot goes, starting at 14.5 is close but you will need to get the MAP situation taken care of before you begin your plot. As for the retard amount on that curve, looks like you are taking out 23° of timing. You need to remember that the Run Curve also comes into to play as far as retards go.
To explain:
If you're taking away say 10° on the Run Curve and another 15° on the Boost Retard Curve at the same time you are actually taking out 25° of total timing at one time. Remember the box can only take out a max of 30°.
Another thing to remember is rotor phasing!! This is very important because on a fixed rotor you can only take away a total of 18° before you run into the possibility of crossfire. This crossfire will cause engine damage, so care should be taken when playing with a large amount of retard.
Ok I did check that the map was plugged in but I didnt double check the weather pack plug at the MSD, I will check that. I am not pulling timing on the run map. I only pull timing at 0-500 rpm to aid in starting. So with that being said would I be better off pulling 2 degrees per 2 psi and start with less initial timing? What do you think? I burnt 6 pistons last year because of maybe a bad map sensor and trying to do to much on pump gas. I want it to be on the safe side.
is your distributor locked out?
what do you have your total timing set to?
how much boost are you building?
what fuel are you running?
do you have a phasable rotor?
I can't have you do anything without know more about your setup.
If you go to my first post it has that. 32* at the crank trigger, dist locked and zero'd at #1 tdc. I have a off the shelf msd pro billet distributor for the 440 Chrysler. I assume the rotor isn't phasable?? Max boost will be in the 15-20 range. Just before it blows! Lol
make sure your rotor is phased properly, you need to have the LEADING EDGE of the rotor to the LEADING EDGE of the terminal. you will need to drill a hole in your cap to verify.
as soon as you are done with that then you can pull 2° for every 2lbs of boost that will be safe.
also get the MAP sensor situated before you proceed.
How big of hole and does this ruin the cap? Its new! LOL
Posting Permissions
Reply With Quote