Better off trying a 50% lead and 50% premium unlead fuel mix and see how you go ... I don't know how the knock sensor works but if you run too rich the car isn't gonna be pulling like you mentioned, try getting the V-AFC dyno tuned by a professional there though I don't really suggest that device as a matter of fact. Sorry can't help you much there ... I don't really have such problems on my JDM machine.

 

THE PROBLEM IS THE LEADED GAS HERE HAS WORST OCTANE RATING THAN THE UNLEADED I AM USING NOW, SO I DONT THINK MIXING THEM WOULD BE BENEFICIAL. IS AVGAS GOING TO DAMAGE MY ENGINE OR JUST THE CATALYTIC? BECAUSE I DONT HAVE A CATALYTIC ON THE CAR NOW. I KNOW MY FRIEND'S MODIFIED INTEGRAS TYPE R RUNS GREAT WITH SOME AVGAS MIX. BEFORE HIS CAR WAS KNOCKING AT IDLE DUE TO THE HIGH COMPRESSION, AND MIXING AVGAS HAS SOLVED HIS PROBLEM.

 

Please don't shout

If you mix premium unleaded with leaded you can get higher octane than either fuel, even if the leaded is low octane. This is because the lead acts as a further octane booster in the premium unleaded. It's not guaranteed but it may work. Avgas will probably solve your problem without damaging the car, but you already knew that Personally I'd want to do it without lead to be a little more socially responsible. Try to get some toluene.

 

[QUOTE]Originally posted by RHH
[B]tried mixing 2 bottles of 104 octane boosters to 3/4 tank of gas but it still knocks.

 

Are you sure? Lead was originally put in fuel to protect valves and seats as well as to increase knock resistance. Cars designed for unleaded have hardened seats to compensate for the lack of lubrication that used to be provided by lead. I can't imagine how lead would damage those. Also, how would it make the car engine run hotter?

 

[QUOTE]Originally posted by naishou
[B]The JDM car requires 100 RON, not 103.

 

[QUOTE]Originally posted by bbsilver
[B]MTBE is carcinogenic as well.

 

Lead is a great soft metal lubricant for the valve train.

While the octane level is high in AV gas (103-105) it contains lead in the form of either tetramethyl lead (Pb(CH3)4, or Tetraehtyl Lead (Pb(C2H5)4. In short order the catalyst in your catalytic convertor would be "poisoned" and the oxygen sensor system in the car would freak. I would look towards the additives or by-products in the fuel. A simple test is to add one once of fuel to one once of water in a graduated cylinder or measuring cup. Alchohols and other "problems" are water soluble. In really clean gas after you mix, the gas will float on the top of the water and you will have 1 once of each. If the gas is "dirty" (i.e. alchohols) the volume of water will increase as the alchohol mixes with the water. This test is known as "water miscibility testing" and can readilly show if the fuel is contaminated or has been cut......it's an old pilot trick I learned while flying with people I can't talk about here in places like Indonesia .

Yoiu may just need to change gas suppliers.......

Utah

 

i managed to solve the knocking problem by resetting the ecu and the v-afc. the car runs great now. i guess the v-afc setting prevented the ecu's knock sensor to do its job optimally. i think the v-afc is better tuned at wide open throttle and only at the 5000+ rpm range. especially on track events where adding more fuel may be better for the engine reliability. i am surprise to see some of the settings posted somewhere at the forum. they seemed to be subtracting a bit much. do they tuned it based on dyno only? what about reliability? under real condition the car is sucking in much more air which is different at dyno, so it is actually running much leaner. isnt it dangerous? at 7000+rpm the s2k is loud so you can't really listen to any pinging noises. anyway i am glad the problem is solved without resorting to mixing leaded avgas, although i think using 5% avgas occasionally is not a bad idea

 

[QUOTE]Originally posted by naishou
[B]Are you sure?