91 or 94 octane advise

[naheed187]

I have a 1991 240 sx. With

Red top sr20det
Full 3 inch apexi n1 exhaust from turbo back
Hks type s intercooler
Hks 2530 turbo
550cc injectors
Hks f-con s tuned for 94 octane

My car is tuned for 94 octane but since the gas station that serves 94 octane she really far so I have been putting shell v power 91 is that okay. Or since my car has been tuned for 94 should I be putting 94? Any help would be great.

[Viggs]

If its tuned for 94, I would run 94. Unless you know that its not really been tuned to push the limits of that octane then it might be okay.

[naheed187]

Are there really any bad advantages of running 91 shell v power and yes it was tuned for 94 octane

[Risu2112]

If you're getting ping with 91 then go back to 94. Also, your engine probably could care less about the "V-power" sticker shell puts on their pumps.

[GSXRJJordan]

Yup, you'll probably be fine with 91, but if you notice ping/breakup @ high load, stick with the 94.

[naheed187]

How do you know if it's pinging or breakup at high loads?

[Risu2112]

How do you know if it's pinging or breakup at high loads?

Light pinging should be pretty obvious with your exhaust, you'll hear either pings or grinding noises (more likely the later). they'll usually occur at or around the peak of your power band while the engine is under load.

Basically get on the freeway, open it up all the way a few times, if it's grinding increase octane, if it feels the same with 91 as it does with 94, use the 91 and save some money.

[fliprayzin240sx]

How about you just not figure out if its gonna ping by lowering you're boost on lower grade gas???

If you use shitty gas, just stay off boost and you'll be fine. I wouldnt wanna peg it at full boost knowing the tune is set for a higher octane gas. Thats how you eat rod bearings...

[Massimo Power]

Get it retuned for 91... the higher the octane the leaner the car will run.. if you dont have the 94 octane in there to supress the leaner condition then it will knock maybe even misfire and maybe even Blow after prolonged heavy use. If you are just going to drive out of boost.. you are fine..