i have a 1986 lb9 tpi motor and i would like to advance the timing so i can run premium fuel(93 octane) to get a little more power, but im not sure how much to advance it. the stock setting for my car is 6 degrees advanced.

all your help is greatly appreciated!

 

10-12 base should be good...

 

wow 10 - 12 seems kinda high, i was thinking more like 9-10, but ill do some more research.

 

i run 12 degree's base on 91 with my LB9 with no issues.... but every engine likes different things...

 

Higher octane doesn't mean more power unless your getting knock with lower octane.

 

I went from 6 to 8 and it was fine. So I went from 8 to 10 and everything is ok. Running 93 octane.

 

thanks for all the help guys. once i run out of my 87 ill fill her up with some shell v-power 93 then bring her home and advance the timing. i think ill start with 9 and adjust from there.

 

Unfortunately, just twisting the dissy does not usually give more spark advance on these cars. These engines are extremely prone to detonation. So much so, that EVEN with the stock timing, at WOT (if you monitor it with a scan tool), that it triggers so much knock to the Knock Sensor that the engine starts to pull timing out of the engine.

I have seen it where adding a couple of degrees results in LESS overall timing in WOT than when it was stock due to the Knock Sensor pulling out far more timing than when the dissy was left in the stock position.
I have done a TON of experimentation and the only effective way to increase the timing is to add the timing via the eprom and then control the Knock Sensor. In fact, the BEST way on a basically stock engine is to control the Knock Sensor so it only pulls out 1* @ WOT and find the amount of spark advance the engine can handle WITHOUT incurring detonation.

I have observed that if the Knock Sensor starts to pull tiing and causes the overall spark to "bounce around", you usually can't run as much timing as if you had just "controlled" the Knock Sensor properly and then found the maximum amount of timing the engine can handle without incurring detonation.

Using "mechanical methods" to gain more performance on these cars just don't work very effectively. Eliminating the KS entirely is not a good idea either as it is a great "safeguard" in case you get a "bad tank of gas"...which seems to happen more often these days. I tend to control the KS only in WOT and let it "do its job" in part-throttle cruise.

BTW, once you properly control the KS and optimize the spark for premium, there IS a definite power gain (over tuning for 87). This is based on a number of years of experimenting and programming the eprom on my car (after finding the mechanical methods just didn't work).

 

Hi Glenn.....good to know your still around, havent seen to many of your posts lately.

As always your posts are straight forward and very informative!