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1985 L98 TPI Fine Tuning What's Your Timing Set At?
1985 L98 TPI Fine Tuning - What's Your Timing Set At?
It's a new/used Vette for me. I'm upgrading, updating, replacing, fine tuning... my timing light shows 0/TDC (the Big notch). Book says it should be 6 BTC, but would like to know if that is correct, or if there's a setting better than that.
Generally you can bump it up from 6 to 8 or 10 and be fine. Check it out and test for pinging. Once you have pinging the knock sensor can't pull out anymore so back it off a couple degrees. I didn't notice much of a difference going to 13 so I left it around 8.
To me it all boils down to the "quality" of the fuel you have access to, at 6 degrees your engine shouldn't ping, 8 degrees is a bit more fun and that is as far as I pushed mine.
If you buy premium for the car all the time you can advance it a bit to 8 and still be safe.
All I have access too is this 10% Ethanol, (90% who knows what) they call Gasoline.
But running regular (87 Octane at Sunoco) most of the time, I keep the timing set at 6 degrees. When fuel cost comes down I will on occasion put premium in the car.
Before any venturing into the "unknown zones" of timing be sure that the Knock Sensor on your engine is functioning properly!
Good luck and keep that "RED HOT 85 VETTE" on the road!
1985 L98 TPI Fine Tuning - What's Your Timing Set At?
It's a new/used Vette for me. I'm upgrading, updating, replacing, fine tuning... my timing light shows 0/TDC (the Big notch). Book says it should be 6 BTC, but would like to know if that is correct, or if there's a setting better than that.
Yes, 6 is factory, but your engine will love a bit more. Try 8 then 10. As long as you are not pinging, feed her advance until she lets you know different.
Checking for pinging, as said, it will ping once the ECM cannot adjust any more. Also, there is another factor. With the engine roaring, it will drown out some of the ping so by the time you hear it, it is bad. Now if the engine noise is removed, perhaps you might be able to hear it AFTER the ECM is unable to adjust. Best solution is to install a knock sensor that will light up when there is knock so you will KNOW when it is occuring and not guessing when it occurs.,
Best solution is to install a knock sensor that will light up when there is knock so you will KNOW when it is occuring and not guessing when it occurs.,
I didn't know there was such an animal. where do I find one?
Jacobs electronics used to make them not sure if they are still around.
Aklims on the money, by the time pinging is audible its been doing damage.
Never noticed any improvement bumping it up, left it alone. (Ran the same times)
Or plug in a real scanner and monitor what your ECM sees if it is a short term monitoring You are going to need a scanner sooner or later. Make it easy on yourself and get 1 now, while you can.
Or plug in a real scanner and monitor what your ECM sees if it is a short term monitoring You are going to need a scanner sooner or later. Make it easy on yourself and get 1 now, while you can.
I have OBD I. I jump "A" & "B" on the ALDL and read the flashes of my "Service Engine Soon" light to get my codes. II keep forgetting to do that! 'm going to order that Knock Light. I think Summit has the best deal. I'm going to order a new Knock Sensor from RockAuto just in case I need it. The car is 33 years old... I've been updating sensors as I go along fixing her up. I still have yet to lay eyes oh the Knock Sensor, so I believe it's only accessible from underneath the car... or am I just blind. I don't see the O2 sensor where the book says it should be neither... I could go on... I suspect my IAC may be bad as well. I'll get a new one of those too. I have more questions but I think I'll do separate posts for the benefit of others who may have similar questions/issues as I do.
I have OBD I. I jump "A" & "B" on the ALDL and read the flashes of my "Service Engine Soon" light to get my codes. II keep forgetting to do that! 'm going to order that Knock Light. I think Summit has the best deal. I'm going to order a new Knock Sensor from RockAuto just in case I need it. The car is 33 years old... I've been updating sensors as I go along fixing her up. I still have yet to lay eyes oh the Knock Sensor, so I believe it's only accessible from underneath the car... or am I just blind. I don't see the O2 sensor where the book says it should be neither... I could go on... I suspect my IAC may be bad as well. I'll get a new one of those too. I have more questions but I think I'll do separate posts for the benefit of others who may have similar questions/issues as I do.
John
What do you think the codes will tell you that a scan of the ECM cannot? I keep a scanner in the car not a paperclip to read codes. Before I go tossing money at the part, I think it is better to see what data you get from it instead of adding new variables to the equation
Typically I always recommend that people set the timing at 6 degrees like the factory recommends, the factory timing is usually pretty aggressive and you do not want to be pulling timing with the knock sensor when you are looking for best performance. That being said I decided to look at the 1985 sock vette tune and it is pretty tame, you could try 8 or 10 degrees and see how it performs.
08-24-2018, 03:29 PM
1985 L98 TPI Fine Tuning What's Your Timing Set At?
