does 93 octane help in a 4 cyl?

[c0dy]

Ive read people swearing by both sides. I have a 96 corolla, it needs all the help it can get, i mean its great for just driving, but no umph at all (although in first gear you better watch out :thumbsup: )For my wonderful 1.8L I4, will using higher octane make any difference? or does my ecu even know what octane is?

 

[BlueSHO]

it wont make any difference. it will probobly hurt performance if anything. you want the LEAST amount of octane you can use without detonation. so premium fuel in a 1.8L wont do you any good at all. premium dosent have any more "power" than regular, the difference is its more resistant to heat and can withstand higher compression. which is why it does help in sports cars, and cars with forced induction.

 

[zzzzzer]

BlueSHO is right. The only time I've seen octane levels make a huge difference is when there's a "pinging" noise coming from the engine. In that case one of the first solutions you should try is going with a higher octane. On the other hand, you're playing with fire to put 87 in a car calling for Premium only (Mercedes-Benz S-Class for example).

 

[c0dy]

i know that in lower octanes they replace the 8 strand with septane or ethanol or whatever, i just wasnt sure if a car would automatically adjust for the difference... so unless im running high compression N/A or low compression FI it wouldnt make a diff?

 

[h2opoloplyr_11]

i dont know....but my bucket runs up to about 105 MPH when i have 91 and when i have 87 it only goes up to 90.....(see speed-o-meter thread) and both i have floored and waited 5 seconds as soon as the speedo stops moving......

 

[Rearpl8tsinsite]

Both of the above answers are accurate and correct. The only reason you would have to move from 87 to 89 would be pinging. If it is not pinging don't change.


I have recently been testing 87 vs 89 and the gas mileage difference. I don't know how but I seem to get about 20 more miles on a tank if I use 89. Every time I have gone to 89 my miles have increased between 15-30 per tank. Maybe I'm crazy.

 

[HISSMAN]

It depends on what compression ratio you engine has. Cylinders and the amount you have makes no difference.

 

[Vancouver83LTD]

I know someone with an 87' or so S10 and that thing will not have ANY pickup (no pun intended) if he doesn't use premium.
I thought those S10's were supposed to run on anything short of piss in the gastank?

 

[NeedaCobra]

if you run a lot of timing or have high compressino or run a turbo or SCer or a combination thereof, higher octane is usually needed. If you have a modular DOHC engine, you can run more timing/boost/compression due to the efficiency of the cylinder heads. If you have a regular 2v engine, it'll need higher octane than the DOHC-headed engine would

 

[c0dy]

okay so i have a DOHC, 16v I-4. Compression is said to be 10.0 by msn. its probably lower from wear and tear, i think im going to buy the compression tester thingy when i get paid its like $30. What would advancing timing do for me? I know you're supposed to retard it when you run FI, but would advancing it help at all?? Thanks for all your help
Cody

 

[LBguy]

Asking on a corolla board would be more usefull IMO. I have the same engine as some corolla's, I'm not sure if it's corolla's from 96' though. Mine's the 1zz (says vvtli on engine), it runs fine on 89. 91 is 'premium' here in cali.

edit: Do you have your owner's manual still?

 

[c0dy]

yours is the corolla engine from 98+ i have the celica ST engine. I have the manual... ill look in there. I was just asking on here about timing and all that because the corolla boards are full or wannabe thugs that think euro tails is a performance add on =\
I have the 7A-FE, the 4a-FE is the 1.6 which is in the base version of the corolla for my gen.

 

[mx_9]

My car has a flat 4 Boxer engine with a compression ration of 8.2:1. It also has a Turbo. Having said that, when I run 100 octane gas I have a noticeable increase in mid-range power. That's from a butt-dyno perspective. I am horrible at shiftiing so the power increase may be more broad than just midrange. Regardless, 100 octane v. 93 oct is noticeable by me.

 

[f_rice]

The only thing increased octane does is reduce premature combustion. Forced induction and high compression engines create a more unstable combustion chamber.

This is why some people run a water injection system. Water has a much higher octane than race gas. This sounds odd but remember octane is not a measure of potential energy just a measure of knock prevention.

All this being said 87 is fine unless the manufacturer calls for something higher or if you decide to use forced induction. Higher octane may yield better performance in an older vehicle, if that vehicle is in need of a tune-up. But on a properly maintained vehicle that does not call for mid-grade or premium the only thing moving faster is the money from your wallet.

 

[505BB]

Always run the lowest octane you can without pinging. Too high will not burn correctly and you will not maximize your potential. Even at the track you really dont need too high of octane. A stock car doesnt need Supra Juice (Race gas). Only cars that really need it are heavy modded ones with pinging worries. A higher octane number isnt going to magically make your engine perform better

 

[c0dy]

okay thanks everyone, I guess i'll just keep trying to make my engine young (or feel young at least... its got 133k on her and she runs great, i change mobil 1 every 3500 or so.) Noone answered the timing question, would it be bad for me to increase the timing (advance it) ? i know too much would be bad but would a couple degrees help at all? thx again,
Cody

 

[99SVTAddict]

The higher the octane the slower the burn rate the cooler the cylinder. This helps prevent detonation...most useful in a forced induction car.

Tuners can often add back timing while tuning under gas such as unleaded 100 or leaded 110 race gas. This allows them to up the horsepower and torque without detonation.

By just adding race gas, you do nothing to increase power. The only thing it does is burn the gas slower and more completely....but without tuning this could actually rob power.

I was tuned and run on 94 octane....occasionally on hot summer days I will run with a gallon or two of 110 race gas mixed with my 94 to protect the stock block from detonation. This adds NO power, but keeps me safe. Detonation is what kills engines.

Simple as that.