Lower octane needed with FP

[mechtech]

After 2000 mi of FP, [recomended dosages], I tried using 89 instead of 91 octane. No knocks! I have a Superchip and require premium, normally. I attribute this to deposit removal in the C.C. and piston dome. The car idles smoother, also - that happened rather quickly after FP. I haven't made a reliable +/- gas mileage check, however.
Now, FP has become really cost effective for all the gains.
I guess I'll have to try LC soon.

 

[ToyotaNSaturn]

Why vehicle did you run the FP in? I would think that the FP/Lower Octane way of thinking is based soley upon the application, assuming the engine has been cleaned up by FP.

I just filled up my Saturn with with 89 octane and LC just this morning, it pinged at the shift points compared to the 93 I have been running in the hotter weather. Piniging is FAR reduced from what it was, but still it rears its ugly head. Saturns require 90 octane gas. Are they the ONLY ones requiring this odd increment? I mean I've NEVER seen 90 octane gas.

 

[sifan]

ToyotaNSaturn - Can you tell me the model year of your Saturn and its odo mileage? With FP/LC my 2003 Toyota Echo (17k miles on odo) pings with 89 recommended octane gas just as you described during shift points under load.

 

[ToyotaNSaturn]

96 SL2 DOHC 1.9L model, 115K miles. I've owned 5 Saturns and they all do this outside of winter weather when not using 93 octane. The only method I've found to getting rid of the pinging is using 93 octane gas. I'm not sure if 91 octane gas would do the trick as well as I've never really paid any attention to it.

With FP, at least I know that there won't be any carbon buildup with using the high octane fuels in this car.

This may seem like a waste of money to use FP and high octane gas, but it's not. FP is keeping things VERY clean--allowing better MPG to boot. FP is paying for itself with those extra MPGs and a better running engine.

 

[mechtech]

Yes, it's a very individual thing if you can lower your octance requirements after a cleaning out with FP. But I'll enjoy it. Vehicle is a Ford ZX2 2.0 liter 16V,intake, exhaust, superchip, crank underdrive pulley.