How much timing is too much timing?

[talon1979]

Here are some of my mods quickly
190lph fuel pump, safc, small 16g, 680cc injectors, 2g mas, dsm chip to compensate for bigger injectors, and 2g mas. I tune w/ my pocketlogger & EGT's.

I know you usually aim for about 20 degrees of timing, but that is not happening on my 90. I am getting about 20-22 degrees of timing, but when I reach 6k my timing advance is clear up to 27 degrees! Keep in mind that my safc is at about +15 at this point and my car is not seeing any knock. This is on 91 pump piss. My EGT's are not getting higher than about 780C. How much timing advance is too much that I will start doing damage? I am thinking of lowering my base timing, and/or getting a fuel pressure regulator so I can lower my fuel pressure and up things on the safc to reduce timing. Something else that scares me is that my car will see 10 counts of knock and my timing will still be at 17 deg which seems like too much timing for that much knock. I am afraid of putting in race fuel, leaning out my safc, and getting far too much advance. Please help!

 

[talon1979]

Well I did some searching on a variety of places and it people have said on 18psi of boost on a small 16g, no knock, and 27degrees of advance they have destroyed their head gasket, even with ARP headstuds. Some people lowered the base timing, but it made the car feel sluggish. It seemed that the only solution was to lower the base fuel pressure then richen things up w/ an SAFC. But I do not have a fuel pressure regulator so my question is this...

What will happen if you disconnect the vaccum line that runs from the stock FPR to the solenoid on the firewall? What will it lower my fuel pressure to and will it cause any other problems? Thanks!

 

[talon1979]

Hopefully someday this thread will help somebody out.

I AM SOOO HAPPY!!! I found out the MAS signal had not been rescaled on my chip and that is most likely my problem. I am extremely happy w/ the customer service I have received. I have always gotten quick responses and been taken car of very well. I will let everyone know how things work out w/ a new chip.

 

[doug]

Originally posted by talon1979
What will happen if you disconnect the vaccum line that runs from the stock FPR to the solenoid on the firewall? What will it lower my fuel pressure to and will it cause any other problems? Thanks!

It will not lower fuel pressure. The Fuel Pressure Solenoid (FPS) helps keep fuel pressure up only when the car is off, to help with warm starts. After the car cranks, it does nothing. You can disconnect it with no ill effects.

 

[boostin]

I'm pretty sure the fpr needs the vaccum line to keep the 1:1 ratio for boost and fuel pressure. I would not recommend disconnecting the line, it could cause some very serious problems.

 

[doug]

I said nothing about disconnecting the FPR. You can disconnect the FPS and just run the vacuum line straight from the intake manifold to the FPR.

 

[talon1979]

Thanks for your replies. I am waiting on my new chip to see if my problems disappear.

 

[Defiant]

More than your particular setup can handle. The factory starts with a balance of efficiency, durability, performance, mileage and emissions. In tuning, you usually dump emissions, and sometimes mileage and durability (whether intentionally or not).

Still given your personal parameters, the motor will dictate its maximum timing advance within the specifics of the fuel, atmosphere, state of tune and running condition.

You just have to be careful to never overstep its maximum.