Octane/Tire Pressure

[dfw240_EE]

I just bought my 240SX about a week and a half ago. It did not come with an owner's manual. So I was wondering if anyone could give me the Nissan recommended tire pressure and octane ratings for a USDM 1992 Nissan 240SX stock with a KA24DE.

[[s3]]

87 Octane and about 33Psi

[navysnail]

in my glove box the sticker sugests 29psi all around, but i usually put a little more in, like s3 said, 33 psi is good, i usually go about 31 to allow some seepage

[dfw240_EE]

Thank you, so I can probably put in midgrade 89 and it will be just fine. (I go to Chevron, they don't seem to monkey with the gas)

[drifts14x]

Always premium, check the gas door, PREMIUM FOR MAXIMUM PERFORMANCE!

Be good to your 240

[atcq110]

dont even bother with 89, its crap. Either go 87 or 93

[Spartan265]

The owners manual recomends about 32 psi i think. And 91 or whatever the highest octane is. Just put premium or mid grade.

[hamsterball]

Always premium, check the gas door, PREMIUM FOR MAXIMUM PERFORMANCE!

Be good to your 240

Idiot.

[Luke]

Idiot.

How is he an idiot? Because Nissan recommended that at least 91 AKI fuel be used for best performance in the owners manual? Because it says use premium for best performance on the fuel door? No, it's not required, the KA will run with 87.

Based on experience, my KA did not perform nearly as well as it did when I used premium. I filled up on 87 one time and didn't again after that. No the engine won't detonate with 87. Higher octane allows for more advanced spark timing. Think about it before you call people an idiot.

[dfw240_EE]

So how does the car tell if the gas is of a higher octane to run a more aggressive spark timing profile? Knock sensor? Or do they have some sort of octane sensor in the gas tank? The later sounds difficult but possible. I read once that the Ford FFV engines have some sort of chemical sensor in the gas tank to tell how much alcohol is in the gasoline. So I guess an "octane sensor" is possible.

I do feel like an idiot not noticing the label on the gas door. It would be the sort of thing to slip by my sight, or it might just not be there. Stickers do tend to come off after some 12 years.

[gabossie]

Use 87. As long as you are not in danger of detonation (which you're not), then your engine will run best with the lowest octane possible. It allows for a hotter combustion and easier combustion. Your max performance will always be as close to knocking as possible without actually knocking. Don't waste your money thinking you're being "good" to your car, because it doesn't care either way. It will not advance timing for better gas, it will only retard timing for crappy gas because it senses knock. As long as you stick to good gas, 87 is plenty for the ol KA.

[guyaverage]

In normal day to day driving in my '93 vert, I use 87 because I am cheap and gas is not. It runs fine, and I have from time to time filled it with premium just to see if there is a difference. In my vert, there isnt, it runs like a champ with either one. I do get a slight knock when taking off from a standstill, if the weather is warm (using 87). Using 93 I dont get that, but the benefit is really limited to that, as it runs very strong all other times. Not worth it in my opinion. Timing is set to 20 BTDC.

Strangely, in the '93 hatch I had a few years ago the difference between 87 and 93 was incredible. It would surge and hesitate on 87, and really came alive and ran like a scalded dog on 93. I switched back and forth multiple times just to test if I was just fooling myself into thinking premium was running better. It wasnt in my mind. I bought the car new, so there were no mods and timing was stock also. It made a VERY noticeable difference. I checked everything a dozen times over on that car to make sure nothing was wrong. The car was a gem, it was perfect inside and out. It just didnt like 87 at all. 89 didnt do much to help anything. 93 really woke it up.

My vert on the other hand, it doesnt care what I feed it.

Like gabossie said, use the LOWEST grade yours runs best at.