Regular gas OK for turbo?

[2GTsi311]

I usually fill up with premium (as needed), but I was told for long trips (i.e. 3 hour drive back to college) I can use regular and save myself some much needed money, although I still have about a 1/4 tank of premium left. Would the mixing have an effect on my engine? Good idea or bad idea? I was told if my 95 talon has a knock-sensor it will prevent anything negative from occurring within my engine. I appreciate your feedback. -Sebastian

 

[98RedDragon]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

 

[dave99gst]

even your owners manual says its ok to run regular gas - "performance will be sacrificed "

 

[hellotbone]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

 

[ZachM31]

just look at octane... octane rating is just the fuel resistance to knock... in a lab back when they were doing it, they used heptane (octane rating of 0) and an iso-octane (rating of 100) so 92 octane fuel has as much resistance to knock as a fuel containing 92% iso-octane and 8% heptane <-- thats what i got out of my chemistry book last year.. as for a knock sensor saving the engine.. if it detects knock it retards timing, and overtime, rasises the exhaust gas temperature.....#1 rule....don't always listen to friends!

 

[steve]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost.

That's rubbish.

The lower octane fuel might cause some engine knocking and a stock ECU will retard the timing to avoid the knocking and not activate the BSC keeping the boost lower. The ECU retains this long term correction in the "octane" variable and uses it to interpolate between the normal and "octane" timing maps.

On a car with the BCS swapped for a MBC the only thing the ECU can do is retard the timing and if your running higher than stock boost levels that may not be enough to save your engine. Once you start modifying your car you should always run premium.

Steve

 

[Crawl]

theoretically you CAN but I wouldnt and I have never heard of anyone running their GSX/TSI or GST on anything that low, some people have no choice but to use 90/91 but using anything less is just mean to your cars potential

 

[CyberEye]

For daily driving I usually just fill up with 87 octane (since 87octane in Canada is 3.10 a gallon right now) So consider yourselves lucky. If I know i'm going to be running it hard, or tuning or anything I'll fill up with 94. When I was in Ohio at the shootout last weekend all I put in was 94 octane, since I got it for 2.60 a gallon

I'm pretty sure you get better mileage out of higher octane gas too, so really it's worth the few extra bucks you pay to fill up with premium over regular

 

[hereitcomes]

if you run anything lower than what the factory suggests as a minimum octane rating, your turbo engine will get in the habbit of knocking from getting robbed of the enriched fuel. Yes performance will be sacrificed if you use low grade fuel (ie. 87) but i think that they put "Premium Unleded Fuel only" on the gas gauge. Just my opinion though...i like the way my car runs. runs better on race gas though (104)

 

[KuZo]

Octane has no effect on fuel economy and definatley has no effect on spool up time The reason our cars require higher octane is to reduce the combustability of the fuel. When you're jamming all that air into the cylinder and compressing it, the heat builds up and the lower octane spontaneously ignites before the spark ignites it. This, in effect, is called knock. What happens next is the the knocking starts to work against the natural motion of the engine. The knocking cylinder is now trying to push against the already exploded gas, to make it to top dead center (then back down when it should have ignited) before the valves open and release the exhaust gas. This is what causes the rods to bend and rings to crack, and headgaskets to blow.

In your case 2Gsi311, it might work for you if you stay out of boost the whole way. But I wouldn't risk it, knock is a bad thig and spending the extra $2 in fuel is well worth it compared to any other damage you may cause by putting the 87 in. Your knock sensor can only do so much, but if you don't have DSM link to monitor the knock you really won't have any idea how much you're getting.

 

[Booster-Shot]

I love my car and would never treat it badly by putting that watered down 87 crap in it. Just fork over the extra dough, I mean thats where all the rest of your paycheck goes anyways right?

 

[Crawl]

haha yeah thats my thought, if you cnat afford the gas you cant afford the car

 

[2GTsi311]

In your case 2Gsi311, it might work for you if you stay out of boost the whole way. But I wouldn't risk it, knock is a bad thig and spending the extra $2 in fuel is well worth it compared to any other damage you may cause by putting the 87 in. Your knock sensor can only do so much, but if you don't have DSM link to monitor the knock you really won't have any idea how much you're getting.

I was told exactly that, to stay out of boost the whole way. In my case, my car has several bolt-ons so for a modified car (as steve mentioned) Ill take all your advice and not risk the possible long term engine damage. My knowledge in chemistry has now increased. Thanks for all the feedback! -Sebass

 

[Defiant]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

Please do post more on this topic. More on. Say it ten times, really fast.

Is five bucks a tank going to make-or-break you? Buy a Greyhound ticket.

 

[maladora_ai]

That's rubbish.

a stock ECU will retard the timing to avoid the knocking and not activate the BSC keeping the boost lower. The ECU retains this long term correction in the "octane" variable and uses it to interpolate between the normal and "octane" timing maps.


Steve

is this correct? so am i understanding correctly that your ecu will remember a long span of using regular gas,when your supposed to be using supreme?

if so how do you correct this setting? ### im pretty sure the guy that owned my gst before me only used regular and maybe every once in a while splurged for the plus.

now i only run supreme but have a road trip coming up and the difference here between regular and supreme is .53 a gallon

 

[steve]

To reset the long term fuel quality value disconnect the ECU or the battery for a couple of seconds. Which ever is easiest for you.

Again, it will restate that if your no longer in stock trim and tune then you should only run 91 or better octane fuel.

 

[knochgoon24]

If you're that crushed for cash that you can't spend the extra $2.50 a tank on premium, you shouldn't own a DSM. It's one of the understood expenses when you buy a turbocharged car.

When I bought my car, I did a quick calculation on just how much more it would be to run my car each year.

12000 Miles Per Year / 22 Miles Per Gallon = 545 Gallons of Gas Per Year
545 Gallons * $0.20 Difference per Gallon = $109 more per year

 

[GsXdSmKingGsX]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

WRONG

 

[GsXdSmKingGsX]

If you're that crushed for cash that you can't spend the extra $2.50 a tank on premium, you shouldn't own a DSM. It's one of the understood expenses when you buy a turbocharged car.

When I bought my car, I did a quick calculation on just how much more it would be to run my car each year.

12000 Miles Per Year / 22 Miles Per Gallon = 545 Gallons of Gas Per Year
545 Gallons * $0.20 Difference per Gallon = $109 more per year

Absolutley correct! I mean good lord there are worse things that can happen to your car and if you cant afford an extra $2-5 for premium you probably will want to sell your car bud

 

[bagged420a]

If its for a long trip and you don't plan on seeing any boost what-so-ever, then go for it. But when the guy in the nice sports car pulls up next to you on the highway and you get into boost, don't cry when you start knocking. Its a bad idea to put low octane rating gas into your car if your planning on running boost. Besides its only going to save you a few bucks.

 

[JusMX141]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

Probably the most misinformed post I've read on this site. You've been watching too many Fast & Furious movies.

It all has to do with timing. Higher octane fuel burns slower and cooler than low octane fuel, so there's less chance of preignition and detonation (knock) when running premium fuels. Sure you can run 87 octane on 20psi, but the ECU will pull so much timing it will feel like you're towing a trailer. This is when the guy running race fuel and 25 degrees of timing at the same boost level using the same turbo as you will walk past you like you're tied to a fence post.


In a sense, you will not be able to generate as much boost with lower octane because higher boost levels will be more prone to knock....but you're making it seem as though all of this will be tuned automatically by the car, and that's not true.

Hope you've learned a little more about these cars in the past 3 years.

 

[hdoerr]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

Brutal... I hate to pile on but where was defiant for this post and why didn't he delete it.

 

[jrohner]

pretty much the only reason why you use premium is for the extra exhauste to spool up and get boost from the turbo, so regular 87 (i think 87) would leave you wil a slower spool time and less boost. so its up to you . more boost, less boost less performance, there isnt any engine damage chance on a stock engine

-5. I agree that it sounds almost like something they'd say on The Fast and the Furious. Why would higher octane give you more exhaust energy?

If you wanna save some money and you are still running stock or less boost, running midgrade 89 should be fine. I always used to run that in my talon back when it was bone stock.

 

[rEclipserGST]

Brutal... I hate to pile on but where was defiant for this post and why didn't he delete it.

That information came from a guy who drives a NT...

Its not going to save you that much money in the long run using the cheaper gas. Have you ever tried running your car on lower ocatane??? Your car will be very sluggish compared to the required ocatane your suppose to be using. And if your that cheap, why dont you just come up with a mixture of 87 & e85 since e85 is cheaper

 

[JusMX141]

Have you ever tried running your car on lower ocatane??? Your car will be very sluggish compared to the required ocatane your suppose to be using.

True that.

I first learned about octane back in my motocross days when I first jumped on the big bikes around age 14. The biggest thing I noticed when running race fuel (once I got the bike tuned for it) was there was NO loss in performance late in a race, when the bike is running super-hot. Even premium pump fuel would make the bike seem sluggish and lazy coming out of corners, like it didn't want to pull.