Ya I run alot of 89 octane and every once in a while I will run 91. I get about a mile or so more to the gallon on my 91 octane performance tune then 87 economy tune. Dont know how it works. More power you would think more gas but guess not.

 

Just keep in mind that platinum plugs are more fragile under a detonation event than regular old plugs and damage to the electrode can occur. I've seen more than one electrode fall out of a platinum plug from detonation.

 

I have a Superchips programmer on my 05 5.4 3V. I have it set on 91 octane setting and run 87 octane it all the time. once a month I will put 91 octane in it and it makes a differance on the way it runs but it does cost a lot more to fill up the 30 gallon black hole. M truck has not had any spark nock yet but after I fill up the tank I go to oerillys and by some octane booster and add take the 87 up a few points

 

Chemical octane boost is the worst for engines!

 

your buddy is an idiot and unlike your truck, his car can sense the fuel octane. I'm not sure how good a friend he is, but it sounds like he is trying to help you blow your motor



Unless your truck is a Flex Fuel, your PCM can only "see" 87 octane from the factory. Since you have it tuned for 93 octane, it only "sees" that value and has the spark value adjusted accordingly.

Your buddies Mustang PCM can sense the octane level in the gas tank. It then adjusts the timing before the gas ever hits the motor. Ford didn't add the programming to change the timing until 2009/2010 models, but the capability is there and most good tuning shops turn that option on.


I personally would run the 89 tuning and 89 octane. you are playing with fire by mixing and matching. as already mentioned, it only takes 1 detonation to blow the motor.

 

Well, I'm probably gonna regret having to add my two cents here but I just have to anyway. And I'm also WELL aware I'm not comparing apples to apples but here goes...
I've got a '99 F350 CC DRW with a V-10 and 4.30 rears. Had 95,000 on it when I bought it. Put a Hypertech tuner on it around 105,000. Loved the 93 octane tune up so much I couldn't stand to take it off, plus the tranny shifted WAY better. Not too long after that I ran across a steal on Ebay for a BBK throttle body and a K&N cold air kit for $10 each because noone bid against me. I also removed the cat. conv. and replaced it with a piece of straight pipe. I said all that to say this...

You know how everyone says the 99's were 1st year runs and crappy and weak compared to every other V-10 built? And I read in this thread how you will surely blow your motors up the instant you run 89 ocatne w/ a 93 octane tune? Oh yeah....where's the 'sensor' that tells a Mustang engine what octane fuel is in the tank before it is pumped to the engine?!?!

My poor old F350 just took me to Canada and back on a 30+ hour drive each way with about 3.5 hours of stop time during each segment, i.e about 3900 miles round trip; has pulled a triple axle bumper pull trailer with a gross vehicle/trailer weight most trips around 22-26,000 lbs. for most of its life; just turned over 230,000 miles and will still easily go 5k between oil changes w/o adding a drop (alway 5w-20 M'craft oil and filters) has never had a 'service engine' light to come on; never, ever had a tranny service although I did pull it out @ 220,000 miles and replace the front pump seal because it would need about a half pint of fluid every 20-25,000 miles.

I feel pretty confident in saying I can run the 93 octane tune with 87 octane fuel in my truck. YOU might not, and yes you may well blow it to kingdom come the first time you run it set up like that. But I just had to say it works for me and I work my truck harder than probably 3/4 of the users on here hauling hay. I remember V-8's in years past that "pinged like a taxi cab" before we had electronic ignitions and knock sensors and all the new goodies. They didn't blow at the first sign of spark knock and I doubt ours will these days with all the built-in safeguards. I'm pretty sure the '05 4x4 CC F-150 I just bought will be getting a tuner pretty soon and knowing me, I'll have to give it a try on the higher octane setting. I'm very aware of what detonation does because I drag race an '87 Ranger with a 351W w/ 175 shot of NOS (with Keith Black hypereutectic pistons, not forged) that runs low 10's in the 1/4 and is still street driven a good bit. Unless you've blown a motor running 87 octane on a 93 octane tune and can prove beyond a shadow of a doubt that that is the ONLY factor that caused the engine to blow, I'd be careful speculating what might happen.

Okay....flame on boys! I can take it.

Randy Morrison
2000 FFW Top Truck World Champion
2001 NMRA Truck/ Lightning World Champion

 

what an upstanding attitude to take about something so serious.

 

It seems to me that "most" people are looking for your/my input.(Our) That said, Just do some research first. I'm "old School" and I will never forget the painful transmission to unleaded! With all of the posts on this topic, you and I should put in not only our personal thoughts, but practical suggestions. Yes you can tune for, say 91, which is the most common high fuel most of us can get. (Other than racing fuel) But... these are mostly daily street drivers. A 2 point differerence (lower) will work, but if you want your car/truck to run at it's best, why would would you tune for 91 or higher, and than run 87? If it pings, (not nocks) Than you need to lower your advance, or use your programmer to adj. to the octane you use. If it knocks, well, it could wreck your engine. A little at a time. Think "Progressive tuning". A ping wont just kill it. But a knock just might.

 

Well I had 87 octane in my truck and put it on 91 performance just to see what it would do. It had no power and didnt like the way it was acting. NO spark knocks or anything just made me nervous so I hurried and changed it back. I would not recommend it at all. You got lucky but its not worth it. For the extra 10 cents a gallon just pay for it. Dont risk blowing the motor cause you didnt do what was recommended. It says 91 octane for a reason. If it was made for a lower octane it would say 87/91 octane.

 

Yeah, I guess you're right....I "got lucky" for 125,000 miles now.

And as far as spouting crap I know nothing about...

I got your spout right here mate.

 

I don't know about where you all live, but 93 only costs about 20 cents more than 87. I usually put about 20-22 gallons in when I fill up and my tank is 25 gallons. That's only $4 more per fill up no matter what the price of gas is. If you put $30 in, it's $6.

As they say, you have to pay to play. If it says use 93, use 93 if you want to be sure that it won't cause damage. If you use 87 to save $4-6, then you're rolling the dice. You'll probably be OK, but you're gambling a $2500+ engine. It doesn't get any simpler than that.

Mike

 

damn i thought this post died a few weeks ago....lol......okay, my buddy is not an idiot, he was just giving me his personal opinion as you all are doing, and I very much appriciate!


having said that, ive been running the 87 octane gas saving mode, and it runs a ton better even on that setting than stock! (a lot to do with the tighter shifts). but i like the poster that said he was actually getting better milage on the 93 performance than the 87, and almost as good as his gas saving setting.....combine that with the fact that here its only 20cents more a gallon too for 93, and i think im gunna just bite the bullet.

TO ALL THE GUYS HIDING IN THE SHADOWS WITH THEIR 4.6 TRUCKS....THE PROGRAMMER AND THE EDELBROCK STD CATBACK SYSTEM I GOT MAKES A BIG DIFFERENCE! GUNNA ORDER MY K&N NOW AND COMPLETE THE TRIO......THEN ITS OFF TO SAVE FOR SOME 4.56'S

 

I would shy away from the K&N and go with a Volant or similar system with a dry filter. The oil in the gauze on K&N's and similar filters plays havoc on the MAF and other sensors downstream from the air filter.

 

Oil can foul the mass sensor. Not much of a problem with stock mass air flow sensors. But can foul high flow sensors. I know! As always, contact the manufacture of your mass air flow sensor BEFORE you spend your $$$ on the filter/intake set-up. Volant's filter is available in dry and I understand some oiled filters. The dry filter is shown to flow a bit more than the K&N filters. But alass.... they make filters to replace your K&N oiled filter or others (by size, not application) to fit most any cold air intake you have. It's up to you if it will fit. (measure twice, buy once).

 

too late....already ordered the k&N....well actually i ordered the summit brand which had the same description and picture of the k&n on their website, and when i got it in....it had a k&n pamplet and sticker in the box! ha ha i knew it! the k&n was like 56.00 and the summit brand(k&n) was 41.00

oh and i got a can of maf cleaner in the shop....ill give it a cleaning every couple of oil changes