Can you have a TOG value higher than the suggested max controllable pulse width? Meaning the wizard shoots a number out and you are running lean. I adjust the TOG up to fatten up the car but the max controllable value is less than that number. Would this cause a issue? In other words the wiz says max controlable will be 12 ish and I have a 14 in the TOG. Trying to figure out what made the car lean.

One of two things happened to produce a TOG that is too low: 1. you underestimated how mouch power your actually making and your injectors are too small, 2. Your program was set up to use all of the MAP sensor's range and your not acutally using it (usinga 3 bar sensor and going to only 25PSI for example).

In the case of 1 to only solution is to upgrade your injectors or push to a higher fuel pressure. Make sure your fuel pump can keep up. In the case of 2, it's actually quite likely that you'll have a TOG larger than the maximum controllable pulsewidth.

In either case, maximum controllable pulsewidth is the largest pulsewidth you can produce at max RPM without going static. If you're bumping up against that, you're running out of fuel system.

thansk jon for hte reply

the fuel pump is a magnafuel mp-4303 which will go to 120 psi and support 2k hp. we lowered the fuel pressure down to 50lbs becuase of the fuel issue (learning issue, lol) we had. we didnt nkow what the issue was at that time but now know it was not enough fuel in vaccum state.

at 50psi the injectors are at 1050cc/min or roughly 100 lbs/hr which should be good to about 593hp @ 80% dc. at 100psi they are at 1530 cc/min and good too 844 hp @ 80% dc.

maybe going back up to 100psi would be a good idea.

ty
dean

It depends on the injectors, but you want to be careful will really high fuel pressure (relative to the manifold). With the Lucas disc style injectors that RC Engineering is so fond of, you will start really having problems with the injectors opening slowly or not at all above about 70-75psi. Bosch/Siemens injectors have a needle pintle and will do better, but will have the same problem above a certain point. I don't remember what that point is right now. The flow capability of the fuel pump will also drop dramatically as the fuel pressure goes beyond the basic rated pressure. Don't forget that with 100psi referenced pressure and, say 40 PSI boost, you have 140psi fuel rail pressure. That fuel pump may well be very short on flow rate and not flowing the amount of fuel you expect. Magnaflow says that 2000HP is supported with a naturally asperated engine. Flow rate goes down very rapidly with increasing fuel pressure.

I would recommend that you run the lowest pressure you can that will support the power you're making. If you find you're needing to run these extremely high pressures, consider going to larger injectors or staged injection rathar than pushing the fuel pressure higher.