blackbullitt

I have a quick question i have a steeda 93 tune on my car at the moment. I just realized that when i head in to west texas and eastern NM i might not be able to find gas, my wife and i leave tomorrow for x-mas. I would retune to stock but i got my tune at the time when people were having all the problems when they retuned to stock. so im worried about that. Im going to look at my tuner to see i I have the 91 tune, loaded if so i will just use that. so my question is if i had to run lower octane gas for a bit how much harm would it do? the other though i had was to run octane boost, has anyone ever used these products if so how well do they work?

thanks

josh

wannabe

I have no idea what the tune does, but I don't have one and ran regular (87 here in San Antonio metro I think) for several months before switching to 93. I see a little better MPG, and it seems to run a bit smoother... but it also ran just fine on 87.

MJJ

Avoid running 90 at all costs on a 93 tune. I would take it back to stock or add a can of torco. You can look up torco dealers on their website. Not cheap but cheap insurance.

If neither are option take another car or rent one.

db2797

you should never run lower octane on a higher octane tune. Going the opposite direction should be ok. Running higher octane on a lower tune should be fine. But ideally, you want to avoid at all costs especially running that lower octane if you are tuned higher. I have the 93 tune and might go back to the 91 for the winter to save a few bucks when I can't open up my car in the snow. But I plan on loading the lower tune first, and then when I want to tune back up, running through a full tank of gas at the higher octane and then refilling a second time before loading the higher tune.

And the octane booster's do practically nothing. You have to put a ton of that stuff in for it to make any difference. Not really worth it.

jaywoo

Just drive the tank out and take it easy. The 93 tune adds a little timing and leans the fuel a little bit vs the 91 tune. That's where the extra power comes from. If you get on it too hard you will get some pinging and the KR sensor will pull timing. The pinging is detonation. If it gets bad enough you can damage the motor, but if you just don't romp on the car it will be ok. Cooler weather helps with detonation also. the colder the better. If you still have the 91, go with that, but otherwise just go easy.

grabberblue 5.0

Have you not heard about all of the engine failure due to detonation? If you have not, low octane/too much timing/heat are the largest contributing factors to this. DO NOT run this motor on lower octane than the car is tuned for. The stock tune on the PCM causes the motor to run slightly lean at higher rpms anyways, and tuners base their tunes off the stock tune (obviously). Don't do it, like earlier mentioned, rent a car or retune car

jaywoo

Yeah, I have. That's why I said to take it easy. No high RPMs, no engine stress. He will be fine. I've ran 91 octane on a 93 tune in my 2011 several times when I couldn't get 93. No problems at all.

blackbullitt

I have heard of the problems, but i think the tune i have from steeda is on the conservative side. Also i think the problems had to do with more than just the octane used. it would seem to me that it would be foolish of a tuner to make it so running a lower octane than tuned for for a short time would result in a failure, what if you got bad gas. i would think the is some margin for error. i could be wrong, i hope i can find good gas, just looking to see the experience of others.

grabberblue 5.0

He COULD be fine, not my car though so encourage him to do that then. I prefer not too gamble too much with my car

grabberblue 5.0

Sounds like you already have your mind made up so why ask the question? I actually said 3 reasons why these motors are failing, not just octane. Whatever though your car, good luck

jaywoo

Then find an example and post it where someone blew an engine running 91 octane on a 93 tune. I just told you I've done it several times with no problem.

BTR-75

Use GasBuddy.com and plan your route carefully, you might be able to do it and stay on 93.

http://www.gasbuddy.com/Trip_Calculator.aspx

grabberblue 5.0

Do you not understand how detonation works? Detonation is caused by too much timing for the conditions of your vehicle at that moment in time. Too high of altitude will cause detonation, too much heat will cause detonation, too low of octane will cause detonation, oil getting into the motor will cause detonation. All of these are directly affected by running a certain octane fuel.

Because 91 octane is less stable than 93 octane it will ignite sooner than 93 octane and if any of these factors mentioned above create enough destabilization of the fuel (even 93 octane can be compromised) then detonation will occur.

This combined with the fact that a number of tuners are known to desensitize knock sensors will result in too much timing for the conditions the motor is being subject to. The knock sensors pull timing to prevent detonation, and if they are not doing their job properly bad stuff happens.

Just because YOU have done it doesn't mean that everyone else will be so lucky.

jaywoo

Yes, I do. If you read my first post I even said how cars are tuned for more power. I've tuned cars myself with HPTuners and LS1edit. Post me an example of someone that has hurt their motor running a 93 tune with 91 octane.

grabberblue 5.0

I honestly can't tell you there is, but what I do know, as you should also know, is that all of the factors that I mentioned compounded with low octane fuel are detrimental to the engine. And I know, just as well as you know that octane can be a direct or indirect factor in causing detonation. I'm trying to protect the guys motor by telling him that lower octane fuel can lead to spark knock, and you, as a self proclaimed tuner should know this also. Again, just because you have been so lucky does not mean that he will too. And probably the reason you do not hear about lower octane fuel hurting someone's engine is because a) no one is dumb enough to run too low of octane, b) no one wants to admit to doing that after blowing their motor so that they may try to blame their tuner and get something for blowing their motor out of said tuner.

Maybe you have been lucky because you have a conservative/super conservative tune. Maybe the OP does not have such a conservative tune.

Go ahead and tell him it's ok to run low octane fuel and maybe he'll be ok for a while but when it starts getting hot again and he decides its ok to run low octane fuel... There goes his motor

jaywoo

I do know. That's why I said take it easy, no racing, no hard on the engine. It's only one tank. Yes, you should run 93 with a 93 tune. I'm not disagreeing. It's cooler weather now, not 110 out (he's in Texas after all). I also said if he had a 91 tune on it the. Put that on.

grabberblue 5.0

One tank? He said he was taking a trip. And maybe just once he forgets and woops now I'm wot at 7k rpms.

O well

jaywoo

I took it to mean he may have to put some 91 in it at some point, that he was just cruising down the highway not being hard on the car and highway miles.

blackbullitt

correct just going down a boring west Texas highway. noting exiting, just me and my wife in the middle of nothing.

grabberblue 5.0

Well I apologize I was only trying to be the voice of reason and let you know what can happen. If you'd rather just take the chance... Well it's your car. Just make sure none of those long open stretches tempt you. Good luck