Flatland2D

I just wanted to get some input from you guys about my gas mileage. I recently got a '94 Del Sol (130k on car) with a B18C1 (70k on engine). When I first bought it I filled up on premium for the first few tanks until I could research it more. I got about 35mpg highway. After reading old threads on here I came to the conclusion I didn't need premium and went back to 87 octane. Now yesterday I went on a short road trip (about 240 miles) and I only got 25mpg highway. I had the top off (got sunburned real bad) and thought that may have hurt mileage so I put it on for the second half of the trip. I ended up with the same 25mpg I was getting before. Today I made the final drive home (about 60 miles) and I filled up on premium before leaving. Judging from my gas gauge, it looks like I'm back in the 35mpg range. I know it's hard to tell, but it looks like I've lost a little less than 2 gallons out of the 6 that were in there. I'm thinking this is pretty obvious that my car likes premium, and if you factor in the better gas mileage, it's actually cheaper for me to fill up on premium. I know premium usually gives a little better gas mileage, but 10mpg more?! What do you guys think? Was a '98 Acura Integra made for premium only?

I just have one quick thing to add instead of making another thread. My check engine light has been coming on every once in a while, and I think pretty early on after driving. Out of 240 miles yesterday it didn't come on once, then it comes on today during the 10 mile drive to the gas station, and is off for the 60 miles home. Should I be concerned?

Thanks for any input.

Edit: changed title as the original could have been misleading.

Running925

B18C! would be a GSR motor bud.. high compression likes higher octane fuel much better & it's probably not the greatest idea to be running 87 in it anyways.. i believe your compression is about 10.5:1 in there.

bluetwo

No Fawking Sh!t.... just kidding...

Yeah it'll do that. Some people believe that the reason Honda engines last so long for those of us outside of Japan is that they've essentially been made to withstand the pressures of using a higher octane fuel. Because that's what they have in Japan.... the electronics have been set up to use our particular brand of fuel, as well as some the other more complicated things that I don't know about with engines, so I guess it stands to reason that this could be true.

But don't quote me on that...

I'm sure your Sols engine will thank you in the long for using higher octane gas too. Without it your going to see an engine that isn't working like it's supposed to.

Flatland2D

Well yeah I'm aware of that. It didn't occur to me until now to track down the recommended fuel for a '98 Integra GSR. Sure enough it's 91 premium. I guess I now have a reason to tell my wife I need premium gas. She got mad at me the last time I filled up with premium on her card. But hey, 35mpg, it's worth it.

I still need to take some good pics of my new car to show everyone. I've been lazy and it's been rainy the last few days. Hopefully I can get around to this soon.

Any ideas about the check engine light?

nhatters

So would I get similar results with a Civic and CR-V?

mistacee

I use premium in my cars and i do get better milage!

94civicEX

When you're filling up 10 gallons, and premium is only 10 cents more than mid-grade...what the hell difference is a dollar. I don't know why people flip out about gas prices cause all in all it's only a 1-2 dollar difference.

But, yes, your motor requires premium fuel.

chimchim

Running925 is the only one who said anything sensible in this thread. The GSR motor is somewhere is the 10.x:1 compression ratio so like he said, you're gonna need 91 octane.

You probably got crappy gas mileage because the ECU detected knocking with 87 and retarded the timing or put it in limp mode.

For most models, no.

Unless you have a high compression engine (like the Si), then most Honda's are about 9.5ish:1 which only need 87. Assuming you haven't modified your internals or used forced induction of course.

flixx

about the check engine light which no one commented on yet, yes you should be concerned that it is coming on. Do yourself a favor and see what kind of code you are throwing. If you dont know how, search the forums. I am sure plenty of people have asked how to pull codes.

chimchim

Check engine light could be due to the 87 octane gas. If knocking is occuring such that the ECU cannot correct it by retarding the timing, etc, then you're going to get a code.

But to be sure, you need to read the code to find out what it is. Doesn't Kragen or the autostores do this for free? It's like 30 seconds to read a code with the tool.