91 Octane For A 318IS??

[FrustratedMunky]

Alright, I know I'm gonna get bitched at for making this thread but I don't care, I have to know what the hell is going on.

Since April, when I bought the car, I've put in 87 octane. I didn't know that you HAD to run 91 octane atleast in the M42 engine and in the M3 engines, so I continued to put 87 octane in. Since then, I have yet to hear the pinging or detonation that I have heard of. Even driving uphill or under hard acceleration, I have not heard this pinging that people say is likely to happen, but now that I've found out that it's pretty much a requirement that the M42's take 91 octane, I'm very worried that something might have happened already that I didn't notice previously or maybe I've just been lucky and it hasn't happened yet.

In my situation, should my mentality be, "OK good, atleast something bad hasn't happened to the engine YET, but now is the chance to change that and run 91 octane all the time so it will for sure not happen in the future"?

Even 89 octane isn't good enough apparently to prevent the detonation? I MUST run 91 octane?

Thanks for any help that you guys can give, I know I'll get pwned on this thread but I just need to know what to do.

[Rob]

My bone stock m42 had pinging on the dyno in warm (80s) weather on 87 octane.

dont chance it with a motor that doesn't have a knock sensor, use 91 octane

[Mystikal]

Have you ever heard what detonation sounds like? It's not extremely noticeable really, I wouldn't be surprised if it was actually pinging and you never caught it.

[FrustratedMunky]

Have you ever heard what detonation sounds like? It's not extremely noticeable really, I wouldn't be surprised if it was actually pinging and you never caught it.

I haven't heard it before but from the impression that I got from different threads that I've read and from friends, it sounds like it would be pretty noticable. I'd like to think I have a pretty sensitive ear for shit that ain't going right in my car, so I think I would be able to notice a knocking or a pinging from the engine bay... But I could be wrong, depends on how "unnoticable" it is.

[Rob]

Its hard to hear from the inside the car with the hood down

[FrustratedMunky]

Its hard to hear from the inside the car with the hood down

Aw shit...

Well, I guess if something has happened already, it hasn't been so bad as to do a shitload of harm to my engine then or else I would notice the effects for sure? I'm just a little worried that something has happened that is pretty severe and I haven't noticed it or that I don't know about it. But as long as my car runs well right now, I guess I shouldn't worry about it and just start filling with 91 octane?

Should I be worried and have the engine checked out asap to see what the condition of the pistons are or anything like that? Or would it be pointless because I wouldn't be able to do anything about it anyways?

[Rob]

if its otherwise running fine, I would be too worried. I run 93 exclusively now though

[FrustratedMunky]

if its otherwise running fine, I would be too worried. I run 93 exclusively now though

If I run higher octanes now, will it "make up" for not using it previously? Like octane booster or something like that, or will it not matter and I should just use 91 octane religiously now?

[Rob]

just run 91 from now on. If there is damage (and that's a big if), running extra octane wont undue it. If anything, save that octane booster $$$ for 'what if's' down the road

[FrustratedMunky]

just run 91 from now on. If there is damage (and that's a big if), running extra octane wont undue it. If anything, save that octane booster $$$ for 'what if's' down the road

OK thanks a lot. Do you think I should have it checked out just to see if somethings messed up or if something bad isn't noticeable right now I shouldn't worry about it?

If you run low octane levels, is it more likely than not that detonation will occur with severe damage? Am I just really lucky?

[Wes325]

Dont cheap out man. I have to run 93 because thats all I can get instead of 91. Its no big deal.

[BS87]

Yeah, we get 87,89,and 93 here. Costs me $30 a tank but i throw in 93, especially since the engine was just rebuilt, I'm not going to run cruddy cheap gas through a re-done engine.

[Jared K]

Check your spark plugs for signs of detonation. If there are tiny pieces of melted aluminum stuck all over the porcelain, then you know that damage has occured. The electrode might be melted too. In that case, replace your plugs. Otherwise, you are probably ok.

I found this guide in a google search...

http://www.dragstuff.com/techarticles/how-to-read-plugs.htmll

Jared K

[FrustratedMunky]

Check your spark plugs for signs of detonation. If there are tiny pieces of melted aluminum stuck all over the porcelain, then you know that damage has occured. The electrode might be melted too. In that case, replace your plugs. Otherwise, you are probably ok.

I found this guide in a google search...

http://www.dragstuff.com/techarticles/how-to-read-plugs.htmll

Jared K

Ah okay, thanks a lot. The link didn't work, but I'll check the spark plugs, thanks.

[FrustratedMunky]

I have seen the black bottle of Techron® Concentrate in Chevron service stations. What is the difference between Techron® and Techron® Concentrate?

The principal difference between Techron® and Techron® Concentrate is additive concentration and rate of deposit clean-up. At the concentration present in Chevron gasolines, Techron® over many tankfuls will help clean up deposits on intake valves without contributing to combustion chamber deposits. So, over time, Chevron gasolines with Techron® are able to reduce or eliminate deposit-related hesitation and stumbling during acceleration caused by deposits. A bottle of Techron® Concentrate, when added to gasoline according to the label instructions, results in an additive concentration roughly 10 times stronger than the dose in our gasolines. This mega-dose of Techron® provides a much quicker clean up of intake valve deposits left by lower quality gasolines. In addition, the high concentration of Techron® reduces combustion chamber deposits, which can help reduce or eliminate deposit-related engine knock and run-on.

Anyways, I'm going a little crazy about this and I want to take all the precautions that I can. I just went on the Chevron website and found this product that they sell, Chevron Techron Concentrate? Has anyone ever used this, and if so, does this sound like it's something that I should try to have a good flush of all the deposits that might be in there?

Was there another product that someone said that I should use as well? This sounds pretty good, I don't know if it's just a big scam that doesn't really work, but if it does, I'd sure like to try it out.