PREFACE

How many of you have tried to run the performance tune on lower than 91 octane?

RESEARCH

Let me start off by saying that when I first got my superchips, I had read more superchips threads than I can count. The one thing I remember most is people using a higher octane than the tune requires for. So taking advise, When I first got my tuner I ran 91 tune with 93 octane. After two weeks, I couldn't take the price of rising gas, and paying premium on top of that. So for the past few months, I have been running the 87 tune with 87 octane.

THE TEST

What would happen if I ran 89 octane gas with the 91 octane performance tune? My guess is... I won't have a problem considering my driving style. Lets give it a shot...

91 tune loaded, 89 octane in the tank (w/ 10% ethanol).

Initial thoughts.... glad to have the performance tune back vs. the 87 tune. 91 tune also allows overdrive to dip lower, but im sure those who have the tune know what I am talking about.

Took it out for a test drive to get things going yesterday. Took the truck out again today. The roads have been pretty busy (being the first non-rainy day in a few days so everyone and their mom was out). I was only able to get the RPMS up to 4 grand so it isn't a very accurate test (to see if I experience ping), but at the same time I am almost never up in the RPM range that high to being with so the fact that I haven't had a problem is good to me.


FINAL THOUGHTS

In my opinion if I can utilize more timing without ping with a lower grade octane, that is just gravy to me. I can't see any harm in doing what I am doing as long as I don't ping. Right? Why pay more for a higher grade gas if it isn't necessary? Haha, and just to make some of you jealous, like I have said before I am still on my stock plenum at 104K. She may blow smoke at startup, but she still runs like a champ.

 

A ping might be coming back. If i where you just run 87 with 87 tune. Your heads are on the way out. Better just play it safe! New heads intake and 1.7's is in order for you. Let me know when you plan on taking it apart! I'm done school now so I have nothing but time on my hands.

 

I run mine on performance tune with 87 octane from day one. No probs for me.

 

if it doesn't knock, there's no problem.

 

Just wanted to make sure I wasn't missing something. I do notice that 89 octane lasts longer than 87 mileage wise (which is kind of a given). I have always been skeptable on the gains of the superchips, but after being on the 87 tune for a couple months, there definately is a difference that I can notice... all for ten cents more per gallon, I think I can handle that. Thanks guys.

 

If the RAM is Rockin' please don't start Knockin' I also have a Hypertech , and I ran it on the performance tune with 87 octane fuel, and had no probs with it either. However, I got better miles per gallon with it then I do with the SC (about 2 mpg), and only a slight difference ,if any performance hit. Needless to say, times are tough and I need some cash, and since the HT is locked for my vin and a PITA to sell without the buyer sending it back to get it unlocked, I'm considering selling the SC.

 

no probs here either running 87 on 91 performance tune

 

WHAT???? Why would that happen? Octane rating is simply the resistance to knock. Our trucks don't have a knock sensor, so there's nothing changing the PCM programming based on the octane of the gas. You truck's PCM doesn't care what's in the tank, it'll run the preprogrammed timing advancement and it'll knock all the way to Georgia and back (or until you destroy your engine) without altering the advancement to compensate for octane. You get nothing out of putting 89 or 93 octane in a stock truck. No bump in performance, no mileage boost, NOTHING. In other words:

 

I had a hypertech a couple years ago and I really didn't give it an accurate test. I was more scared than anything. I programed the truck and the truck had a completely different feel to it (almost bad). I programed the 87 tune w/ 87 because thats what was in the tank. Well when I went to go drive it, it made my truck strain more imho. Unprogramed my truck and put it in my buddys truck (01 2500 5.9). His truck always made a sound that I describe as a bunch of marbles in a coffee can, and someone swirling them around in the can in the upper RPM's with stock tune. Lets just say my lack of knowledge about vehicles was just about zip two years ago, and now I can rattle off stuff like it is no big deal. Anyway back to the point. His truck always made a sound when he was WOT. Anyway we tune it, 87 w/ 87 just like I did mine to see if he could feel a difference. He goes to take it out and the "marble sound" was even more intense. ( I guess that goes to show that the hypertech 87 tune does advance timing so it is a gain over stock). Anway this thing is "making all kinds of racket". He still decides to drive it around. I later look it up and found out it was Ping Lol. Go ahead laugh it up... Like I said I had no knowledge of vehicles two years ago. Anyway back to the point we decide to can this idea and unprogram it. But wait..... theres a problem. After the tune is removed, the abs and brake light are on, and the speedo is way way way off (faster than actual speed. more speed = more off). Well I reprogram and now the lights are still on. Well I unprogram it again and they are still on. Now I feel like an *** even though I said if you push program, it is on you whatever happens. He agreed, but after something did happen he wasn't so happy. Being the nice guy I am, I offered to pay a portion to get his PCM reprogramed at the dealer. So he did all was well and traded that truck in 6 months ago on a new hemi. My trans failed a few days later after all of this so it was in the shop. After it got out of the shop, i went to the dealer to have my pcm reprogramed out of precaution and they did it. They programed the pcm and they put the trans update in which they said I had available to me. Then went back because the trans was shifting funny after the reprogram (they put the trans update in which increased the Overdrive gear kick in from 45 to 50.) They said all was good and it wasn't until later that I looked up the TSB's and found the trans update they did. All was well after all lol. Anyway two years later I am thinking I want to give the superchips a shot since I didn't like the hypertech. Picked up a good deal for it and have had it for a few months now and here I am.

 

Yep, you are right. Idk what I was thinking this morning. I ment to say so far I notice that the 89 lasts longer (with the 91 tune) than the 87 did (with 87).