SheDrivesIt

Shocked and Disgusted at both of you (87 users).

Think about this, though. The ECU will change the timing for you to eliminate knock when it detects it. Remember ... AFTER it detects it. You may not hear it but the sensor will catch it. The fuel is igniting at the wrong time when it knocks and it is a bad thing.

This engine is rather low on torque (don't start, people) but that is what we bought. This also means that it is often under a pretty heavy load when you are just tooling around town.

IMO, you are asking for trouble running 87 continuously.

PeaceLove&S2K

Performance will be lower. At least in theory. The ECU detects the occurance of knocks and compensates accordingly (at least that' my understanding).

And I'm pretty sure it doesn't compensate by increasing performance.

glagola1

It'll run fine but once the ECU sees some knock, it will pull back timing and may even richen the air/fuel mixture. I would love to see a dyno of two cars that have been running premium for a week and then come back a week later after one of the cars has been running 87. I say a week later just to let the ECU aclimate to the 87.

This would be pretty difinitive. I say run what ever gas you want. It's none of my busines but if you are looking for max performance, you'll not run the risk of allowing the ECU to take it away from you.

Silverstreak HX

Uh... this is not a Civic motor under the hood so do NOT use Civic gas!

ayS

hehe...

FO2K

It will go to 9K on regular gas, but take longer to get there. When you run regular in a car designed for premium you reduce the HP output. Not to mention the potential long term damage to your car that others have mentioned.

Read up on the subject. You are wrong.

youngjun91

[QUOTE=Squeezer,Mar 10 2005, 08:10 AM] I take it to 9k all the time on 87, no problems, no knock, no hesitation, nothing.

TubeDriver

In reality, you want to use the minimum octane rating needed to prevent detonation. 89 may be fine under most conditions but if engine temps go up, altitude increses etc you are more likely to encounter possibe engine damaging detonation. Another thing to think about, gas quality can vary a bit so poor 93 octane gas might still be at 90 octane or better while poor 87 or 89 octane gas might actually be ~85-87 octane.

Higher octane gas has an additional safety net over lower octane gas in a high compression engine like ours.

The ECU will adjust but as has been mentioned 1) will react to existing detonation (bad) and 2) will reduce performance somewhat.

Bane

Just a slight correction... the ECU doesn't know what fuel you are running at any given time. It compensates AFTER receiving the input from the knock sensor.

It only tries to minimize damage, it won't prevent the car from knocking in the first place.

Therefore, one good knock can destroy the motor. The sensor will have detected it and tried to compensate but by that time it's already too late. The S2000 probably has a pretty good knock-control system so it likely eliminates the knock before it becomes audible to the human ear. That doesn't mean it's not happening though. I'm willing to bet the car(s) running on 87 octane experience moderate to heavy knock everytime they are floored in VTEC.

Wisconsin S2k

i doubt this. i can gaurantee you are suffering from detonation, however, your ecu adjusts your timing and compensates for this, because you've put the wrong gas in.

you may not notice anything, but you're losing power and still may be suffering from detonation.


if you do not put premium in your S2000 you are hurting your performance and possibly even your engine. i can't even believe this is a topic of discussion.