Regular or Premium fuel? [merged]

[Eclipse_98_RS]

Hi guys, my car is an all-stock RS, but I'm going to start doing some mods to it. Right now I just use regular unleaded gas, but when should I start going up in the octane? After intake/exhaust, or beyond that? I don't want to screw up my engine but I don't want to have to shell out more cash on fuel than I do now. I know, I'm a cheap bastage.

 

[2G_RFF_GST]

either buy a impreza RS or buy the premium. don't deal with all the headaches of trying to make your car something it's not. i've heard of people putting V-8's in place of a 4-cylinder for more power. but i've never heard of someone wanting to spend money to make there car slower?

 

[higaran]

Most southern dwellers probably never think about this, but in many parts of Canada, we spend over half our lives driving in icy conditions. I bought the car for its AWD handling, not its performance. It's easy, even with studs, to pull away from a green light with all four tires spinning like crazy. I have even ditched this car in snowbanks as high as the sideview mirrors, only to pull back up on the road and drive away as if nothing ever happened. Not many Land Rover owners can tell stories like that.

Better yet, the low center of gravity is an incredible advantage; the car doesn't roll! When the Dodge Rams and Hummers are sitting in the ditch with four wheels pointing up in the sky, I feel perfectly safe going 60 mph on sheer ice.

That's why I bought this car. If the car would have been available with AWD and the 1.8 engine, I would have gladly bought it instead. I don't think I'll ever find a winter car that I am happier with.

I realize that the focus of this forum is generally on making DSMs faster, but I don't have the interest (or the pocketbook) to start bolting on mods that would only make my car less driveable on ice and snow.

Are there ways of reducing the turbo boost, or modding the engine in another way to make it safe to run on low-octane fuels?

Just a thought. Thanks!

 

[alex]

You could lower the boost, just buy a manual boost controller.

 

[SkyLineGtR-R34]

Reduce the boost?
I don't think there's a way to reduce boost (stock boost, lower than 8 psi) unless you get an electronic boost controler or a different accutator. Almost everyone is asking how to turn it up a bit. I guess if you could get a accutator from smaller turbo or something, maybe that could help you.
As someone already suggested: either buy the premium or get an imreza rs (they are awd non-turbo) you have an DSM buddy, be happy it's still running

 

[alex]

Reduce the boost?
I don't think there's a way to reduce boost unless you get an electronic boost controler or a different accutator. Almost everyone is asking how to turn it up a bit. I guess if you could get a accutator from smaller turbo or something, maybe that could help you.
As someone already suggested: either buy the premium or get an imreza rs (they are awd non-turbo) you have an DSM buddy, be happy it's still running

You can turn down the boost. I've done it before.

 

[a_scobel]

I used to put the middle-grade stuff in. It didn't hurt my engine. Here's how I began looking at it though..

Gas prices here in my city right now..
$2.59 a gallon for premium (91 Octane) = $28.49 for 11 gallons
$2.49 a gallon for mid-grade (89 Octane)=$27.39 for 11 gallons

If I fill up once a week, that's only $4.40 more a month. Not exactly enough to break anybody's bank. Might as well go with the premium (Well, best stuff I can get anyways..damn Cali & their 91 Octane cap )

 

[oldman]

You could lower the boost, just buy a manual boost controller.

The lowest boost you can run is the actuator spring rating, this can be achieved without a mbc by connecting the pressure source directly to the actuator.

unless you get an electronic boost controler

How will a EBC lower boost level below the actuator spring rating?

 

[98DropTop]

Premium , all we got over here is 91 as well.

 

[Cool Mr Steve]

OK, what if I turn down my boost so that it barely does anything? I'm not at all familiar with the process, but I understand that it's possible.

Really, if I had a chance to ditch the turbo and drive without it, I probably would. I'm not in this for performance. I'm driving the car because it's Canada, it's wintertime, and an AWD car with ABS and four studded snow tires is really much safer to drive on ice than a Ford Explorer.

Take the wastegate actuator arm off of the flapper. Your turbo shouldn't even spool as the air will be bypassing the exhaust turbine too rapidly. My prediction, though, is that you drive with it off for less than a day before deciding to put it back on. My cotter pin fell off of my actuator arm and I drove it that way for about 10 minutes. I nearly burnt the crap out of my arm trying to re-attach the actuator on the side of the road, but driving a "non-turbo" turbo car is no bueno.

 

[underradar92]

A mod or a wiseman may correct me on this but, at stock boost levels the knock sensor is there to HELP prevent damage in just this situation. It is possible to reduce the actuator spring pressure.

 

[oldman]

A mod or a wiseman may correct me on this but, at stock boost levels the knock sensor is there to HELP prevent damage in just this situation. It is possible to reduce the actuator spring pressure.

When the knock sensor detects knock, timing will be pulled leading to lost of power but a knock sensor will not reduce the actuator spring pressure. Nothing short of physically changing the spring or actuator will lower the spring pressure.

 

[VicBoost]

i was running on 87 or "sliver" and i'm never gonna do it again imma stick with 91 octane just spend the extra 4 cents/litre who cares its worth it and your car will run much better!!

 

[underradar92]

When the knock sensor detects knock, timing will be pulled leading to lost of power but a knock sensor will not reduce the actuator spring pressure. Nothing short of physically changing the spring or actuator will lower the spring pressure.

Understood. That is essentially what I was getting at. One could lengthen the actuator to reduce boost.

 

[oldman]

Understood. That is essentially what I was getting at. One could lengthen the actuator to reduce boost.

Aside from completely unhook the actuator arm like Cool Mr Steve suggested, reasonable lengthening of the actuator arm will not reduce boost level, it will keep the flapper slightly open resulting in longer spool time but still hitting the same boost level.

 

[Diplomat]

Before I bought my first 4G63T, I expected to be spending about $30 more a month in gas. After I sat down and did the math, I realized the same thing that Scobel concluded. The difference that you'll spend each month putting the right fuel in the tank is miniscule.

Replace some of the 60 watt incandescent light bulbs in your house with fluorescent bulbs, if you're that concerned. You're wallet will never feel the difference.

 

[DSMHowtness]

In my daily I use 91 but in my "weekend GST" nothing lower than 93 has ever touched it. It's worth the extra IMO.

 

[Shane2GSX]

Mods/Wisemen please correct me or ellaborate on this if it's correct:

I would think that when timing is pulled from running a lower octance fuel that you would also see a dip in gas milage. If this is the case, you are paying less for the gas but you're getting worse gas milage and probably are not saving much if any by using a lower octane fuel. Therefore, you might as well run premium in the first place.

 

[EVO-00X]

We get 92 (normal), 96 (premium unleaded) and 98 (ultra unleaded) octane in Australia. 4G63 cars can run up to 22psi boost on 98 octane without any dramas Current prices are around $1.20 a litre.

 

[D_Eclipse9916]

We get 92 (normal), 96 (premium unleaded) and 98 (ultra unleaded) octane in Australia. 4G63 cars can run up to 22psi boost on 98 octane without any dramas Current prices are around $1.20 a litre.

We hate you, leave the forum now....goddamnit. The most we get in the US is 94, in my area only 93.

 

[alex]

Same here.

 

[wret]

At $4.50 a gallon, I don't think too many people would buy it even if it was available.

 

[Joe'sTalon]

Wow. Cya guys later I'm off to Australia land of high octane and extreme boost levels!

On topic tho I think you should stick with premium to avoid problems and the hassle of trying to rob your turbo's dignity.

 

[oldman]

Copy the address from the address bar and paste it on here when you reply.

 

[underradar92]

http://dsmtuners.com/forums/showthread.php?t=211040 You mean like this? I had to take a refresher course... Like I said, illiterate. Thanks again.

 

[Keshav]

We get 92 (normal), 96 (premium unleaded) and 98 (ultra unleaded) octane in Australia. 4G63 cars can run up to 22psi boost on 98 octane without any dramas Current prices are around $1.20 a litre.

Australia uses RON to measure octane. the US uses (R + M)/2

http://en.wikipedia.org/wiki/Octane_rating