I have yet to see anywhere stating that the new K20 (thats the name right?) iVtec engine requires premium fuel. I know the the K20a1 (Type-S right?) requires premium fuel (210hp engine), but does the engine in the 2002 Civic Si hatch need it as well? (160hp)?

 

k20a3 is the only one that doesn't.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aznboysrfr &raquo;</TD></TR><TR><TD CLASS="quote">k20a3 is the only one that doesn't.</TD></TR></TABLE>

Doesn't what, and which engine/car is that?

 

Good morning. You asked if the '02 Si requires premium fuel (91 or higher octane). No.

Now, that said, when the Si engine is under load (say, going up a 10% grade) at a constant 2500-3000 rpm, the engine will "rattle"/ping on 87 octane fuel. If you don't then open the throttle or downshift, the EMU will begin to retard the engine timing to compensate for the lower-grade fuel and prevent engine knock. It doesn't happen often, and most of the time you'll never hear the sound unless you are listening for it (windows up, radio off). Because the timing is retarded gradually, there is no engine damage whatsoever. But you have to decide whether this occasional light pinging on 87 octane fuel is enough to warrant running a higher octane. This occurs in all Honda engines, by the way. It is not a defect; it's engineered to run this way.

Let me anticipate your next question: Will the engine run better on 91 or 93 octane. You'll have to decide that for yourself. The boards are full of this debate. I can tell you the EMU will "recognize" the higher grade fuel and, thus, slightly advance the timing to take advantage of the higher octane fuel. So, if you drive long distances at a constant engine speed, over time you will get marginally better mileage on 91-93 octane fuel. Most people don't drive that way, however, and so they never notice the slight gain.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mechanic &raquo;</TD></TR><TR><TD CLASS="quote">Good morning. You asked if the '02 Si requires premium fuel (91 or higher octane). No.

Now, that said, when the Si engine is under load (say, going up a 10% grade) at a constant 2500-3000 rpm, the engine will "rattle"/ping on 87 octane fuel. If you don't then open the throttle or downshift, the EMU will begin to retard the engine timing to compensate for the lower-grade fuel and prevent engine knock. It doesn't happen often, and most of the time you'll never hear the sound unless you are listening for it (windows up, radio off). Because the timing is retarded gradually, there is no engine damage whatsoever. But you have to decide whether this occasional light pinging on 87 octane fuel is enough to warrant running a higher octane. This occurs in all Honda engines, by the way. It is not a defect; it's engineered to run this way.

Let me anticipate your next question: Will the engine run better on 91 or 93 octane. You'll have to decide that for yourself. The boards are full of this debate. I can tell you the EMU will "recognize" the higher grade fuel and, thus, slightly advance the timing to take advantage of the higher octane fuel. So, if you drive long distances at a constant engine speed, over time you will get marginally better mileage on 91-93 octane fuel. Most people don't drive that way, however, and so they never notice the slight gain.

</TD></TR></TABLE>

That about sums it up, good answer. I have not noticed any gains with higher octane gas, I stick with Shell 87.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mechanic &raquo;</TD></TR><TR><TD CLASS="quote">Good morning. You asked if the '02 Si requires premium fuel (91 or higher octane). No.

Now, that said, when the Si engine is under load (say, going up a 10% grade) at a constant 2500-3000 rpm, the engine will "rattle"/ping on 87 octane fuel. If you don't then open the throttle or downshift, the EMU will begin to retard the engine timing to compensate for the lower-grade fuel and prevent engine knock. It doesn't happen often, and most of the time you'll never hear the sound unless you are listening for it (windows up, radio off). Because the timing is retarded gradually, there is no engine damage whatsoever. But you have to decide whether this occasional light pinging on 87 octane fuel is enough to warrant running a higher octane. This occurs in all Honda engines, by the way. It is not a defect; it's engineered to run this way.

Let me anticipate your next question: Will the engine run better on 91 or 93 octane. You'll have to decide that for yourself. The boards are full of this debate. I can tell you the EMU will "recognize" the higher grade fuel and, thus, slightly advance the timing to take advantage of the higher octane fuel. So, if you drive long distances at a constant engine speed, over time you will get marginally better mileage on 91-93 octane fuel. Most people don't drive that way, however, and so they never notice the slight gain.

</TD></TR></TABLE>


So the answer is yes, it is a high compresion engine that requires high octane fuel, just like the 210hp version, the B16 and the any turbocharged engine. Now I know for a fact, that in a Turbo car it is seer stupidity to run on a lower grade fuel, because, as you mentioned the ECU will be forced to retarded timing. This then causes the engine to ping, because it will retard, then slowly bring the timing back to normal, only to be forced to retard it again, adding additinonal wear. On a turbo-car this will then lead to the engien knocking.. obviously bad.

Is the K20 any different? Also, what is the K20a3 as well.

 

Also, what does everyone average for fuel mileage? (Please no, I get 550 on a tank, that means nothing to most).

 

Also, what does everyone average for fuel mileage?


with the 5sp you'll never get over 31

the 6sp will let you enter the 33-34 area

 

30mpg consistantly in mixed driving. the best i can recall was all superslab in cold winter air. i belive i averaged 35-36mpg on that trip.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18CXr &raquo;</TD></TR><TR><TD CLASS="quote">with the 5sp you'll never get over 31

the 6sp will let you enter the 33-34 area
</TD></TR></TABLE>

Jack, please, didn't you dyno an EP3 K20A3 on high octane and regular fuel, and draw the conclusion that it didn't make any difference at all?

Or am I confusing you w/somebody else?

 

There are dynos on the net that show the improvement with higher octane fuel. I think last I saw some were on the ep3 forum.

Problem is, it seems to take a few hundred miles for the ECU to learn what's going on with the better fuel. I was feeling cheap one day and put in 87 and it seems that within 10 miles the ECU compensated. Maybe it was my imagination, but the engine just wasn't pulling as hard after the tank of 87.

A few tanks of 9x later and it was back to where it should have been.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Todd00 &raquo;</TD></TR><TR><TD CLASS="quote">There are dynos on the net that show the improvement with higher octane fuel.</TD></TR></TABLE>
Can you summarise for us? In your opinion, is it worth the extra expense?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Problem is, it seems to take a few hundred miles for the ECU to learn what's going on with the better fuel. </TD></TR></TABLE>
That's probably what must've been wrong w/the dyno I am remembering, whosever it was.

Lovely. Something else to waste money on.

 

IIRC, it was a tuner like Hondata or Church that showed the extra HP with the higher octane fuel. It was around when the Hondata was being developed for the Ep3.

 

Honestly, I beleive in using 93 no matter what unless of course you have to use higher octane.. even in my 1991 pontiac lemans.. i babied that car with 93 octane gas.. cause... well... in my opinion it's better for the car in the end

 

I Have Been putting Shell 87 ever since i got my Car...its the best i think