Logging Questions...

[JustROLLIN]

Well I made my first few pulls on my car today, and decided to log the runs. I was running a minimum boost level of 12psi. But, I am a little confused about the readings that I am receiving back. At one point during the log I am showing that my Injector Cycle Duty was 94.3%. Does this indicate that I was running my 550s to nearly 100% of their capacity?

If so, I dont understand how that could be. I use to run 450s pushing 15psi with no problems. Now, I did change to a ported 2g Exh mani, Small 16g, and larger exhaust. I do have a 255 walbro that I have not installed yet, but I thought I would be ok on the stock pump until I hit higher boost levels.

Also, when I do install the pump, I dont see how that would lower the duty cycle. I still need to dump as much fuel into the cylinder?

Last point. I do have an S-AFC waiting to go in as well. I am guessing this would really help b/c I would be able to pull fuel out and lower the duty cycle if EGTs and knock counts allow it. Any help would be appreciated. Thanks!

[Khadgar]

I think the more fuel pressure you have, the injetors can work less to get the same amount of fuel in to the cylinders.

[LightningGSX]

So you have no fuel control at the moment?

[john]

Don't worry about the duty cycle. A bigger pump will flow more fuel. Most aftermarket pumps overrun your FPR. With higher fuel pressure, the injectors do not have to work as hard. That will not be the case until you get some fuel control (SAFC). You need to install your SAFC to take out some fuel or atleast hack your mas (or upgrade to a 2g MAS). You should be running very rich right now.

[TheBlizzard]

He doesn't have the pump installed so he is no running rich.

CRAIG

[JustROLLIN]

Fuel Pump - Not Installed
FPR - Stock
SAFC - Not Installed
550s - Installed

[LightningGSX]

It doesn't matter whether you have 450cc or 900cc injectors, your ECU "thinks" you have 450cc injectors installed, your pulsewidths/dutycycle will be the same regardless of the size of the injectors without fuel control(in open loop that is).Hook up the AFC and your problem will be solved.And yes, you are most likely running very rich.

[JustROLLIN]

Ahhhh, that makes sense. Thanks for the info.

[john]

Originally posted by CUSTOMDSM@Aug 26 2004, 12:21 PM
He doesn't have the pump installed so he is no running rich.

CRAIG

He is running rich as he has in 550's and no way to tune them down. The ecu is sending fuel for 450's as Eric explained. Don't worry about pulse width though.

[TheBlizzard]

Originally posted by 92tsiawd84@Aug 26 2004, 02:08 PM
CRAIG

He is running rich as he has in 550's and no way to tune them down. The ecu is sending fuel for 450's as Eric explained. Don't worry about pulse width though. [/quote]
I didn't see that he had the 550s installed. I thought he had the 16g and exhaust with only stock fuel totally.

CRAIG

[JustROLLIN]

Since I have no way to tune except for knock counts, what do you guys feel a safe boost level would be? I was thinking 17psi on pump and 19-20 on race gas until I get my SAFC and an EGT installed. Sound decent?