91 and 93 Octane Questions...

[audipotential]

Im curious...
Im itching to go 1+ And wanna do this right.
My question is if I have a 93 octane program, What happens if the odd time I put in 91.


There is only 1 gas brand here (Sunoco) that offers anything hiogher than 91 and they are often hard to find. The closest one to me is about 10-15 minutes away. My job involves alot of driving so I cant exactly know where all the sunocos are. So Yeah, what would happen if the odd time you do that?

[GTMRS4]

You will just produce less power -

[audipotential]

You will just produce less power -

Are you sure?? If thats the case then why wouldnt everyone just use a 93 octane file rather than 91. I thought I would have gotten misfires or something like that

[dougyfresh]

Are you sure?? If thats the case then why wouldnt everyone just use a 93 octane file rather than 91. I thought I would have gotten misfires or something like that

Because 93 isn't available in quite a few places. Its in abundance on the east coast but I believe it is hard to find out west.

Most tuners just change timing advance for their 91 and 93 octane files. Less timing advance on 91 which equates to less power in the big picture.

[audipotential]

Because 93 isn't available in quite a few places. Its in abundance on the east coast but I believe it is hard to find out west.

Most tuners just change timing advance for their 91 and 93 octane files. Less timing advance on 91 which equates to less power in the big picture.

So if I go to 93 Octane, and I put 91 octane in the tank, there will be no issue?

[11move]

^ I would think it would cause some sort of problem as well. As they didnt make 91 for a reason... why dont you get 91 and 93?? its chunk change and worthwhile

[Papachristou]

i run regular from time to time when the company gives me some and the car doesnt feel as good, i have 93 program BTW

[audipotential]

^ I would think it would cause some sort of problem as well. As they didnt make 91 for a reason... why dont you get 91 and 93?? its chunk change and worthwhile

Because id rather get 93 and stock JUST In case.....

[audipotential]

i run regular from time to time when the company gives me some and the car doesnt feel as good, i have 93 program BTW

Actually youre an expert. If I do 93 and stock, since the 380's are larger, it wont be a problem if I drop to stock programming right? I wouldnt have to change the injectors out everytime because the injectors will know not to operate at full load right?

[festerfm]

if you are that concerned that u'r not going to get the 93 octane that u need, you can always go to u'r local autozone, or whatever carparts store, or even walmart and get a bottle of octane booster. there isnt that big a difference between 91 and 93 octane. the worst thing that's gonna happen if u put in 91 octane is if u'r boost spikes, it may cause a slight detonation that you prob wont feel. your ecu will either A)just change the timing or lower the boost a pound or 2, or B)go into safe mode until you shut it off. either way, u'r not likely to see a diff between 91 and 93. i run stage 1 from apr and premium is around $3.48 here. some of the cheaper stations here only go up to 91. i dont go there unless i'm picking up the old lady or i'm driving her stratus. but then again, i'm on the east coast and 93 octane is everywhere out here... got 94 at a few places.

i remember when i lived in Lombard, IL, there was a station on roosevelt road that had 100 octane. but back then, when regular was $1.80/g, the 100 octane was like $2.50....

[Papachristou]

Actually youre an expert. If I do 93 and stock, since the 380's are larger, it wont be a problem if I drop to stock programming right? I wouldnt have to change the injectors out everytime because the injectors will know not to operate at full load right?

you will never ever ever use stock... i talked to APR and stock programming actually isnt "stock" you still have 380/386cc injectors no matter what program you switch to whether its stock,91, 93 or race, "stock" program or 91 is just turned down to similar performance of stock.

[bhvrdr]

channel 20... knock retard... log it... make your decision then.

cheers! Mike

[audipotential]

you will never ever ever use stock... i talked to APR and stock programming actually isnt "stock" you still have 380/386cc injectors no matter what program you switch to whether its stock,91, 93 or race, "stock" program or 91 is just turned down to similar performance of stock.

Ohhhhh! Gotcha

[scorneil]

I use 91 with the GIAC FXK03 program and have no problems.

My understanding is GIAC does NOT have separate programs for 91 and 93. There is one program for both called 91-93. Correct me if I'm wrong.

[dougyfresh]

channel 20... knock retard... log it... make your decision then.

cheers! Mike

Exactly. Mike's suggestion will tell you the answer real-time.

A summary is such:
If you run 91 with a 93 file you will notice a difference in regards to how 'peppy' your vehicle is (it'll be less 'peppy'). Your knock retard (otherwise known as CFs and channel 20) will go up because the timing advance on the 93 file is too much for the 91 octane fuel. The ECM is smart enough to figure this out and take out timing advance to compensate (that would be channel 20) so the engine is safe. I would not recommend doing this all the time but only in a jamb if you can't get 93 octane.


Conversely, if you have the 91 octane file and put 93 in your car you most likely won't see any difference.... I'm willing to bet APR's program has 0CFs for knock retard when running 91octane. As a result you won't feel any difference with 93 octane on that file. Its their way of getting you to buy another file to run if you want more power (aka: more timing advance) on 93 octane.

[audipotential]

I TRIED Running 94 octane. The car didnt seem to run very well

Exactly. Mike's suggestion will tell you the answer real-time.

A summary is such:
If you run 91 with a 93 file you will notice a difference in regards to how 'peppy' your vehicle is (it'll be less 'peppy'). Your knock retard (otherwise known as CFs and channel 20) will go up because the timing advance on the 93 file is too much for the 91 octane fuel. The ECM is smart enough to figure this out and take out timing advance to compensate (that would be channel 20) so the engine is safe. I would not recommend doing this all the time but only in a jamb if you can't get 93 octane.


Conversely, if you have the 91 octane file and put 93 in your car you most likely won't see any difference.... I'm willing to bet APR's program has 0CFs for knock retard when running 91octane. As a result you won't feel any difference with 93 octane on that file. Its their way of getting you to buy another file to run if you want more power (aka: more timing advance) on 93 octane.

[dougyfresh]

I TRIED Running 94 octane. The car didnt seem to run very well

Running 94 with the 93 file? What do you mean by "didn't run well"? Define "well"?

Did it run the same as if you put 93 octane in?

[audipotential]

Running 94 with the 93 file? What do you mean by "didn't run well"? Define "well"?

Did it run the same as if you put 93 octane in?

Well Sunoco offers 87 89, 91 and 94...there is no 93 so we have to put 94 octane to run a 93 file.


Anyways I tried running 94 octane on 91 file. It might be my speculation but the car seemed sluggish..

[dougyfresh]

Well Sunoco offers 87 89, 91 and 94...there is no 93 so we have to put 94 octane to run a 93 file.


Anyways I tried running 94 octane on 91 file. It might be my speculation but the car seemed sluggish..

Some Sunoco's have 93. I guess up in Ontario they don't have 93 huh? I can't find Sunoco 94 here in the NorthEast.

From what I recall with APR's programming (and I'm no expert) you shouldn't have felt much of a difference running 94 on the 91 file. I don't think there's room in the software to give you more timing advance with a higher octane fuel. See my response a few posts up as to why.

[audipotential]

Fair enough.

Yeah they call it Ultra 94

[dougyfresh]

Yeah. Still can't find Ultra 94 around here. Its hard to come by.

[AudiAdi]

I got knocking from running 92 octane (they only sell up to 92 octane on this part of the country) on my 93 APR file. I have been using 8 fl oz. of Torco Race Fuel Concentrate on every fill up without any issues. Car is running like a champ !

[Denim'03]

100 octane in Illinois is currently $5.49, I threw in $40 worth Tuesday.

[audipotential]

100 octane in Illinois is currently $5.49, I threw in $40 worth Tuesday.

Dont you need a file to run 100 octane?

[Denim'03]

Nope, if your running a 91/93 file and you are pulling CF's in block 20, you will benifit from the higher octane. I'm running a 93 file and pulling 6-8 CF's of timing(on 93 octane fuel). I felt a nice bump in power on the 100 octane and my CF's are all 0's.

[dougyfresh]

Nope, if your running a 91/93 file and you are pulling CF's in block 20, you will benifit from the higher octane. I'm running a 93 file and pulling 6-8 CF's of timing(on 93 octane fuel). I felt a nice bump in power on the 100 octane and my CF's are all 0's.

Bingo!
That is what I've been talking about. You just got back your 6-8degrees of timing that was being pulled on 93 octane. Made the car feel more lively.

[audipotential]

I really am a noob when it comes to timing. Dougy I hate bugging you so do you have a article or something..or if youre bored explain it. Youre good at explaining things lol

[dougyfresh]

Try reading this. Hopefully it makes some sense to you.

http://mjbmotorsport.com/datalog.html

Scroll down to "channel 20" to read up on what CF's (correction factor) and Knock-Control mean/do.


When it comes to forced induction tuning you're looking at quite a few things. Most of these items are listed in that link. The key items with tuning are timing advance (degrees before top dead center) and boost. Everything else; air/fuel (aka "lambda"), exhaust gas temp (EGT) and other such items also contribute but you're using those to help make the whole package work fluently and successfully.

[audipotential]

Holy fuck this is hard , I gotta read a couple articles here a couple times

[dougyfresh]

Do you understand the concept of timing advance?

How about the basic engine operation principle?


Just thought I'd take a few steps back based on that last reaction.

[grimlock]

FWIW I've been running 92 octane with the APR 91 file for the past 5 months with no issues. I think you should also consider it from a practicality standpoint. Given that 93 isn't widely available around where you are, is the extra hassle really worth the extra 6 hp? In the event that you can't get 93 for whatever reason, do you want to run the potential risk of fuel trim issues? Reliability and longevity were important factors in my decision as well. Just my $0.02. Whatever your decision though, I think you'll love the flash. Happy modding !

[audipotential]

Engine operation ofcourse, timing advance I havent got a clue.

Do you understand the concept of timing advance?

How about the basic engine operation principle?


Just thought I'd take a few steps back based on that last reaction.