quick q, i have been putting in unleaded gasoline in my ss/sc since ive had it about 3-4 months...not knowing it needs premium.. can that harm my engine in any way making that switch? i am now using premium.

thanks, tried to search for it on the site but it doesnt work for me..haha

 

I used mid grade for awhile.. I didnt know it needed it either.

Then my car started doing weird things, like trying to stay running when i turned it off, so I went to premium. Then learned it needed it.

I havent had any issues.. but I dont know if it can cause issues.

 

It doesn't NEED it per se, unless you plan to race it or otherwise get into boost on a regular basis.

Keep in mind that for 95% of the time that you're driving it, it's just a normal little 4banger. Regular unleaded should work fine under most circumstances.

 

Here's the issue at hand guys. There are 2 timing maps, your low octane and your high octane. If your run 87-89 you are defaulted to your low octane map which runs next to no timing and leaves you at very low power levels, probably around high 190s, low 200s roughly if you are stock. If you run 91-93 you are running on your high octane map and you have the full potential of your car, so to speak. You don't truly have the full potential of your car until you are tuned though, but that is besides the point.

The point is however, if you are going to be beating on the car at all, or really have any common sense, you will run premium fuel. This is the analogy that I always give. It's sort of like buying a brand new ferrari, but only being allowed to drive 30mph. It's just not right is it? Why buy a 25,000 dollar 220whp car, and only have a high 190hp car when your driving it? I dunno, not only that but it can actually HARM the motor on certain cobalts.

Going into the harming part further. A lot of cobalts have been traded into dealerships etc and people really don't know what has been done, especially on tunes. If you have a cobalt that is tuned and is running more then stock timing, or has the octane maps copied from high to low like most tuners do, then if you run low quality 87-89 fuel you have a VERY GOOD chance of blowing the motor due to knock. The reason you can run more timing on premium fuel is because it has a higher octane rating. This is why it is recommended that we run premium fuel, so we don't knock, and so we can have the full potential of our cars. Not only that it is stated in the manual that gm stage 2 cars MUST run premium fuel at all times.

So what it really boils down to is whether or not it's worth it to you. If you were just driving from point a to point b on the highway and new you were stock/untuned could you get away with running crappy 87-89 absolutely people do it every day. Do I recommend it, absolutely NOT. Besides the above mentioned issues, you will also have to change your fuel filter more often due to the low grade fuel and the crap that's in it.

Last but not least this leads me to my next point on which why I believe e85 is amazing and EVERY cobalt owner who has it in there area should run it. Not only is it better for our environment *dont care*, but you can run A LOT of timing on it, still get *decent* gas mileage, and not have to worry about knock at all. E85 really is amazing fuel for high powered cars, runs cooler, etc. Look into it boys.

 

Good advice ^

Whats E85?

Edit - I remember, but I thought you had to have that flex fuel thing?

 

I have only put 93 octane in mine. All except once, and that one time the car ran like ****. It shifted harded(jerked), 1st gear was terrable, and I got **** gas milage. Never again will i go less then 90-93octane

 

Before I realized my car was stage 2, I ran 91 in it and it just felt slow. Since I corrected that error and started using 93, it has been better.

E85 (Ethanol) is nice for the LSJ engines. It allows the PCM to run at a very advanced timing, and is even a few cents cheaper a gallon than 87 is. The only downside is that you have reduced mileage and the fact that E85 isn't common in many areas (Closest E85 capable station that I know of to me is 30 miles away.)

 

Theres actually quite a few around where I live (Columbus Ohio) Id love to run it, but dont have the money to convert over.

 

I just did some searching, and it says you need a tune for e85?

 

Yes you will need a tune.

 

if youre car is your dd i wouldnt go e85 ya you can get more out of your car but you lose close to 10 mpg so the price difference isnt worth it (to me at least) but if your balt is your fun car then i say hell why not

 

I don't disagree with the points you're making (as far as getting it tuned without the high/low table difference and the power loss), but strictly speaking, if you're on a base car (or a tuned car that didn't have its low octane tables erased), you can safely run regular.

I've actually considered putting 87 into my car and retuning the low spark table, just to see if there'd be any significant mileage difference. Obviously the performance would still take a hit, but I just use it to get from home to work and back so it's not something I'd miss anyhow.

But yea, 9/10 of the time it's just easier to stick to premium so you don't have to think about it.

 

All I did is copy any paste my timing tables high to low octane maps..... Running 19 degrees and no kr.... I would actually recommend e85 because I've helped tune a syclone with e85 and a lsx block and a mac turbo off a semi and we boosted 25 lbs and got 1500 whp. And we retuned it for pump gass and only got around 1300 mark. I am wanting to switch but I have to get the 79z lol.....

 

uhhh If you build a motor to hold 1500hp, you're sure as hell not going to skimp out and put a random turbo from a diesel motor that's designed for a diesel motor

and you're sure as hell not making 1300hp on ******* pump gas

 

the ecm doesn't know what octane is in the system. the ONLY way it will switch timing maps is due to excessive knock.

you can tune the car on whatever octane level you want.

 

Area47 - Thanks for the knowledge, I really thought the ecu was able to tell the difference between octane levels and always wondered how it did it. If it's just straight from knock that makes sense. How much knock, or how often does it need to knock etc before you are brought down to your low octane map?

 

i forget who it was taht told me, but someone(a tuner) said that our cars had octane sniffers...and the 08+ had better sniffers that the 04-07 cars...just what i was told, dunno troof haha

 

The lsx block did make 1500 with e85 with alot if timing. The turbo was built for this build. Te turbo actually goes to mac trucks ect... But my buddy bought the turbo from some company that builds the turbos for the mac trucks I am not sure if it was honeywell or whom ever but the syclone did make the power I'm not exaggerating. Every time the truck was taken out u could not get traction it had the 4l80e trans built and tuned with a program just for that tranny. And the truck did get 1300 on 93 pump. There should be a video of it on streetfire he has one with his v6 making 600ish not built just tuned and meth. But. His video should be on it...........