SI with 87 octane gas *Threads merged*

[bossman]

I would consider the Quality of the fuel as well as the octane...There are some places I would'nt trust 100 octane in my tank.

[bluek20z3]

Suncco or vp fuels when it comes to 100+ oct for me they have real good flash points and good qaulity gas too....

[milestoneiii]

Originally Posted by bossman

I personally don't se a HUGE problem with using low octane fuel

It doesn't matter what you do as far as running the engine hard, bottom line is if you fire a cylinder at the wrong time, in the wrong direction (WHICH WILL BE AN INEVITABILITY WITH 87 OCTANE) then you will destroy your motor. If the people on here can't pay for premium, then get rid of the car.

If not, all you will do is increase the value of mine by making less Si's out there that run WELL. If you want to put 87 in, you could use it for years without damage, or only once. The choice is yours. A few bucks to keep it running smooth, or an engine swap. Your money either way.

I personally want people to know that anyone who has an Si and knew what they were getting will NEVER run less than the highest octane they can find. It is what it was made for. Those of you who bought it and didn't plan on premium fuel or the additional maintenance for this special car won't be using it for it's potential and makes the rest of us angry. We'll laugh at you when we're passing you in our cars that run like champs while you're either hesitating or have had to buy a clunker after your car quit.

I don't mean to offend anyone, just reiterating what serious owners are trying to convince you all of (not you in particular Bossman. I wasn't singling you out, I promise).

For the sake of the fuel door, the owner's manual, and other Si enthusiasts, don't skimp on fuel. It's not worth it. $20 gets me 320 Mi. at 72MPH easily. I would only use 87 if it were an extreme emergency. No exceptions. No one here wants to see an Si out of commission. We're only trying to help, not bash. Do what the car tells you.

[p nut]

Originally Posted by MaddMatt

I don't see how when the owners manual does NOT specifically say to avoid 87 octane, and does NOT state that the use of 87 octane will cause any damage. It only specifically states to not use anything LESS than 87 octane. It also states to not use any gas with MMT addative.

Now, if you put in some 85 octane like they have in places in the northeast, they may have a point....

You've got to understand that generally speaking, owners manuals say "use 87 octane", which really means use "regular". In most parts of the country, 87 is regular. However, places like CO, UT, etc. where we're at a much higher elevation, 85 is the norm. Every single vehicle I've owned has said to use 87 in the manual, but 85 is fine. I wish they'd just put in "use regular."

My parents have used 85 for as long as they've owned their MDX (premium recommended). Still runs great like it did on the day they bought it new, and it now has over 120k miles. 23 MPG on the highway.

[bossman]

Originally Posted by p nut

You've got to understand that generally speaking, owners manuals say "use 87 octane", which really means use "regular". In most parts of the country, 87 is regular. However, places like CO, UT, etc. where we're at a much higher elevation, 85 is the norm. Every single vehicle I've owned has said to use 87 in the manual, but 85 is fine. I wish they'd just put in "use regular."

My parents have used 85 for as long as they've owned their MDX (premium recommended). Still runs great like it did on the day they bought it new, and it now has over 120k miles. 23 MPG on the highway.

sooo...your suggesting that 85 octane is ok in an Si? I don't think so.If the put "use regular" gas in the manual or on the fuel door you would have that idiot that would think all gas is regular and that they should'nt use special gas.The MDX is'nt an Si and does'nt have an 11:1 static compression ratio much less the dynamic compression ratio of the K20 motor.

[p nut]

Originally Posted by bossman

sooo...your suggesting that 85 octane is ok in an Si? I don't think so.If the put "use regular" gas in the manual or on the fuel door you would have that idiot that would think all gas is regular and that they should'nt use special gas.The MDX is'nt an Si and does'nt have an 11:1 static compression ratio much less the dynamic compression ratio of the K20 motor.

I'm saying that you CAN use it in an Si. It is RECOMMENDED that you use premium, but doesn't mean the end of the world if you choose 85. What makes you think that you can't? Most modern engines have knock sensors that automatically retard timing, so it's not going to blow up your engine if you use it.

The MDX has the same fuel recommendation.

[EchoHawk7]

use 91 or your car EXPLODES!!!

[b.rock]

Don't be cheap. Use 91 octane - you should've factored in the extra cost of premium gas before you signed on the car.

[OrdnanceMarine]

Originally Posted by p nut

I'm saying that you CAN use it in an Si. It is RECOMMENDED that you use premium, but doesn't mean the end of the world if you choose 85. What makes you think that you can't? Most modern engines have knock sensors that automatically retard timing, so it's not going to blow up your engine if you use it.

The MDX has the same fuel recommendation.

Maybe I'm wrong, but the everywhere I look the Si says "Premium Required" and the MDX says "Premium Recommended". "Required" generally means just that while "recommended" means you just take a few lbf*ft hit because the engine cannot advance ignition to the optimal point.

If you average 25 MPG (lower than most do with the Si) and 91/93 costs you the usual $.20/gallon premium over 87 then you'd be saving yourself a whopping $80 per 10,000 miles driven.

Use 87 if you're stuck with no alternative and drive it easy, then immediately go back to 91 or higher as soon as possible. That should really be the end of this discussion.

[AllShowNoGo]

is this thread really going on for 10+ pages about whether it's okay to use regular 87 octane gas for the Si's? are ppl just DUMB? i mean damn, forget the part about offending people.....as, IMO, we're past that now. the gas cap CLEARLY says "PREMIUM FUEL ONLY". the manual states "premium fuel only". is it ppl can't afford to put $5ish more towards a full tank of gas to use premium than regular?

[AllShowNoGo]

Originally Posted by p nut

I'm saying that you CAN use it in an Si. It is RECOMMENDED that you use premium, but doesn't mean the end of the world if you choose 85. What makes you think that you can't? Most modern engines have knock sensors that automatically retard timing, so it's not going to blow up your engine if you use it.

The MDX has the same fuel recommendation.

lol ok u keep using regular octane gas in your Si

[its_errick]

Originally Posted by p nut

I'm saying that you CAN use it in an Si. It is RECOMMENDED that you use premium, but doesn't mean the end of the world if you choose 85. What makes you think that you can't? Most modern engines have knock sensors that automatically retard timing, so it's not going to blow up your engine if you use it.

The MDX has the same fuel recommendation.

HAHAHAHAHAHA FUNNY THING! if you look in the fuel door... hm most cars say recommended premium fuel but in our cars (Si ONLY) says PREMIUM FUEL ONLY <= ONLY O.N.L.Y.

but im not saying the car wont run. haha

[p nut]

Originally Posted by AllShowNoGo

lol ok u keep using regular octane gas in your Si

Are all of your posts this infused with intelligence?

Originally Posted by its_errick

HAHAHAHAHAHA FUNNY THING! if you look in the fuel door... hm most cars say recommended premium fuel but in our cars (Si ONLY) says PREMIUM FUEL ONLY <= ONLY O.N.L.Y.

but im not saying the car wont run. haha

It also says in the owners manual to change out the motor oil every 5k miles with 5w-30 and to have Honda do all of the servicing. What would you do if you ran out of gas out in the middle of nowhere and the closest gas station only had regular?

Originally Posted by OrdnanceMarine

Maybe I'm wrong, but the everywhere I look the Si says "Premium Required" and the MDX says "Premium Recommended". "Required" generally means just that while "recommended" means you just take a few lbf*ft hit because the engine cannot advance ignition to the optimal point.

Use 87 if you're stuck with no alternative and drive it easy, then immediately go back to 91 or higher as soon as possible. That should really be the end of this discussion.

You may be right about the "recommended" and "required" part. However, I don't know if too much thought was put behind the phrasing from Honda. IIRC, the Legends also had "Premium Only", as did the GSR's. I know plenty of friends from back then that used regular in both of those cars. My ITR also saw a couple of tanks of regular and saw no ill effects. I never experienced knocking/pinging.

But let me be clear in saying that I never did endorse using just regular. The difference between regular and premium comes out to a couple hundred dollars per year. Not a big deal. So, yes, USE PREMIUM. If people would read the whole thread and put people's remarks in context, they'd see I was merely referring back to the other poster's comment between "regular" and 87 octane. Nothing more.

[AllShowNoGo]

Originally Posted by p nut

Are all of your posts this infused with intelligence?

lol this coming from the person who thinks it's okay to use regular gas in the Si

[p nut]

Originally Posted by AllShowNoGo

lol this coming from the person who thinks it's okay to use regular gas in the Si

Your SN says it all.

[AllShowNoGo]

Originally Posted by p nut

Your SN says it all.

lol b/c i don't beat up my Si?

and what does that have ANYTHING to do with premium gas? not only will my Si last ALOT longer than yours b/c i use premium gas, it will also last longer b/c i dont drive it like a racecar.

[rmfa]

Originally Posted by p nut

I'm saying that you CAN use it in an Si. It is RECOMMENDED that you use premium, but doesn't mean the end of the world if you choose 85. What makes you think that you can't? Most modern engines have knock sensors that automatically retard timing, so it's not going to blow up your engine if you use it.

The MDX has the same fuel recommendation.

It would really help you if you just READ a little.

Originally Posted by soxfan143

Octane is directly related to burn efficiency. The lower the octane the easier the fuel will ignite under pressure and possibly ignite prematurely. Premature ignition as also known as the dreaded knock. Now with a high compression motor like the Si the compression in the chamber on the compression stroke is way too much for 87 octane fuel. And with the high ignition timing this car runs on, the 87 octane gas is a recipe for disaster. You WILL get detonation from this. You might not hear it and the knock sensor will retard timing enough for you not to cause significant damage. But I would not run 87 octane ever in this car.

Originally Posted by soxfan143

Do you even know how bad that ping-klang-tik-tik is for your motor? The pistins are trying to be spun backwards. The fuel is igniting while the piston is on it's way up on the compression stroke. This will cause serious problems. Like bent rods and broken pistons. So please don't make it out to be OK to use cheap gas in this car. Or there will be a lot of unhappy owners at the dealers with voided warranty claims when they test the fuel and find out it was run on 87 octane and the motor is rubbish.

[blacksi]

Originally Posted by jumboshrimp23

I did not know u Si people had to put 91 + octane in ur cars. Sux when gas prices are high

you dont its recommended,they never say use 93 they say it is recommended that you use 93, regular gas is not going to mess up the car, with engines these days it does not matter, back in the day it might have caused a problem but now its no big deal...

[OrdnanceMarine]

Originally Posted by p nut

It also says in the owners manual to change out the motor oil every 5k miles with 5w-30

Which owners manual are you looking at?

[Southernace76]

I'll stick with recommended
I'll use 87 ONLY if the gas stations are all out of premium and use additives.
I would retire my car before putting 85 in.
Just me though I won't bash people for not using it. We aren't having major threads on "used 87 in my si and blew up engine"....yet.