Hi,

I use 95 RON fuel in my maxima and I can advance the timing a HUGE amount over stock 15 degrees BTDC. I haven't measured it but judging by how much I have turned the distributor, it'd be at AT LEAST 30 degrees BTDC now. My spark plugs have died early at 12000km's.

Does the use of higher grade fuel and advanced timing create more heat and need a colder plug?

Thanks.

 

is this a ve dohc or a vg sohc?

 

It's a VG30E

 

I dont know what else you can get there, but 95 RON is pretty close (if not lower) in AKI (whats used in america) to 91. In some states thats the best you can get, but in IL I use 93. When I have traveled to states with only 91 and my timing advanced 30 btdc, this caused the rotor and distrubutor to corrode (white stuff on the contacts) and make a loud clicking noise after about 500 miles.
Bottom line, I would stay under 25* if you are using anything less than 98 RON (approx 93 AKI). And get a timing gun if you are advancing your timing so far.......

 

It's going to be hard to put a exact timing number on what you can run with a given fuel. If your going for the power then get a www.casperselectronics.com knock gauge so you can tell when you detonate. That'd be a easy way to see when the timing is too much for the fuel. Too much timing won't hurt the plugs but heat caused by detonation sure will in a hurry! Timing won't effect the dist. cap or rotor.. it'll have the burnt/corroded look regardless of timing positions.
~Scott

 

Is your Knock Sensor workin? At 30 dgrees u'll lose whole engine if no KS... Std plugs lose their edge already after 5k km.

I have VGE, 17BTDC, 95RON, mild to cold weather, std range NGK PFR5C-11 2271 Laser Platinum, with 30.000km running clean. AND KS bypass.

Check NGK.com site to read plugs...

Octane 'info':
http://www.faqs.org/faqs/autos/gasoline-faq/part3/
http://www.turborx7.com/fuel.htm

 

I don't know what the exact figure is but I have a very sensitive ear for knocking and i test it under a wide range of conditions and it definately doesn't knock. I would imagine it'd be at about 25 degrees BTDC.

I think I answered my own question with a bit of research. I found out that mor advanced timing DOES make the combustion chamber up to 100 degrees celsius hotter so I'll be purchasing colder plugs this time. I'll probably get the NKG Iridium IX BKR7EIX-11

 

I have mine at 20 or 22 degrees. I used to use 95 octane but have been using koolaid 89 since the energy crisis. I don't use cold3er plugs, just ngk's.

....Colder pluggs are only only used for nos.

I wouldn't go over 22 degrees for sure. It won't give that much benifit anyhow. The point is to get the most effective time.

 

.. hmm.. while we're on the advance timing subject. would someone be kind enuf to take a picture of his distributor so i can see about how far is 15 degrees? cuz' i was messin with my timing and don't have a light gun, i advanced it a little, now i got no idea where i'm at.

i haven't noticed any ill effects on the motor yet. but i just wanna know where abouts i need to be safe.

 

Who can take such pic? I will if u tell how.

Adj. at a shop costs maybe 10$. One car, once.

Lamp costs maybe 20$. Lifetime savings over 500$ as lamp is yours.

 

there is no point in going past 20* BTDC