Spark Advance 91 Octane Tune

[seigl740]

Hello All:
Thanks for all the help to a Newby! Since I reside in So Calif, I can't find more than 91 Octane Gasoline, 93 and higher are not available. Per the Forum, I have installed the 91 Octane tune with a 2 degree spark advance. The car runs great. would a couple of more degrees provide better excelleration, so long as it doesn't ping? In younger days we would advanve the spark a bunch before a race, and take it back down after. Your opinion is greatly appreciated. Any members with direct experience are welcome!
Best/ Bill

[amsounds]

Hi seiql740,
I would not advance it another 2* running 91 Octane! Motors built today have very close tolerances! If it misfires you can damage the internals! A extra hot day is all it takes to ruin a good motor! Two degrees is not going to make a big difference from the seat of the pants performance now! I would have the motor dyno'd for the setup you have! Gas is not as good at every station, some are better than others! You get some bad gas and you got a blown motor! Stick to what you have or run some illegal nitrous setup hidden of course!

[mikel]

Hello All:
Thanks for all the help to a Newby! Since I reside in So Calif, I can't find more than 91 Octane Gasoline, 93 and higher are not available. Per the Forum, I have installed the 91 Octane tune with a 2 degree spark advance. The car runs great. would a couple of more degrees provide better excelleration, so long as it doesn't ping? In younger days we would advanve the spark a bunch before a race, and take it back down after. Your opinion is greatly appreciated. Any members with direct experience are welcome!
Best/ Bill

Yeah, the 2* you added made it the same as the 93 octane tune...

[seigl740]

OK,OK.OK!!!
I went back into the 91 Octane Tune and changed the spark advance .5 degrees. Surely this is safe! I use only Mobil Gas and avoid all Jiffi, Arco and cheapo stations in general. If anyone can point me to a brand that offers 93 Octane or higher, I would be very appreciative. It is unfortunate when some one wants the performance og a GT-500, yet, only has a pocketbook for the Shelby GT!

[mikel]

Thing to remember is we have already optimized the timing in these tunes in our testing on the dyno.

Thanks

[40thmustang]

how can you go 2 degrees.. . you cant. you can go 10% advance but that is 1 degree.... ???

[seigl740]

My understanding is that each percentile is equal to one degree!

[wayniac_00]

each percent is a reflection of your intial timing from the factory. IE 20deg initial -10% = 2deg retarded I had to set mine back -16% on my mach 1 because the timing on the predator is to advanced (almost 4 degrees and this was recommend by a well know dyno engine builder and tunner) because of the predator not being set up efficiently for 32V mach 1.

[Shaken]

each percent is a reflection of your initial timing from the factory. IE 20deg initial -10% = 2deg retarded I had to set mine back -16% on my mach 1 because the timing on the predator is to advanced (almost 4 degrees and this was recommend by a well know dyno engine builder and tunner) because of the predator not being set up efficiently for 32V mach 1.

Initial timing on a 32 valve Mach 1 is 10 degrees.

[wayniac_00]

diablo sport said it was 20 degrees

[seigl740]

Shaken:

The owners manual on the U7140, not the small brochere that comes with it, states that yoy can add timing, globaly, up to 4 degrees and retard it by 10 degrees. Plus two, is two degrees? Don,t understand your statement of "How Could You" add two degrees that is?
Best/ Bill

[Shaken]

Shaken:

The owners manual on the U7140, not the small brochere that comes with it, states that yoy can add timing, globaly, up to 4 degrees and retard it by 10 degrees. Plus two, is two degrees? Don,t understand your statement of "How Could You" add two degrees that is?
Best/ Bill

Hi Bill,

My mistake wayniac_00 and myself have U7146 Predators which use % instead of actual degrees glad they fix that for others.

[Shaken]

diablo sport said it was 20 degrees

That kind of initial would make it really hard if not impossible for a starter to turn the engine over.

[seigl740]

Wheew!!
I thought I was going crazy!!!

[40thmustang]

Stock timing on a 99-04 gt is 10 degrees. on the u7146 the most you can advance it is 10% which= 11 degrees. Hope this helps, also if running the 1 degree advance then you must run atleast 92 octane, therefore at the pump it would be 93. I run 93 with 11 degrees and it is fine, no ping or nothin, also as soon as i get a new airfilter becuase mine is pretty dirty I will richen my wot fuel .5 .. I will let you know how that works when I do so