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Discussion Starter #1
will u guys buy those NOS/-> fuel additives or just use 91?

ppl told me 93 and 91 main difference are more detergent or something, some said there is a lot of differnece, such as immediate pinging and knocking, some said there is just a difference only thru reading dyno numbers

what do u all running?
 

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91 > 93 is higher octane. There may be more detergents as well, but octane is completely different.

Simple...just run as high as you can find. 91 SHOULD be sufficient....we'll see if it actually is.

Just as a side note..with all this pinging discussion going on....people are freaking about some light pinging. We buy this high end performance car and complain about something we'd probably be experiencing if we modified a WRX a decent amount....and now we want it gone.
 

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Discussion Starter #3
so 91 octane is fine in a 93 required car hmmm....

the dealer said he somehow got 92 and used it and the car is fine so far
hmmm
 

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Really, I try to give everyone the benefit of the doubt here because I know that we all really like the STi and our enthusiasm is a good thing for this forum, but to suggest that detonation is somthing that we should live with from a brand new car is misleading to others who read here. Everyone is of course entitled to their own opinion, but I think it's irresponsible to equate a factory STi with a modified WRX. With the latter, the owner takes responsibility for the tuning of the engine. With the former, it's all up to Subaru, and they dropped the ball.

It's just awful to see Subaru letting the car out of the gates in this fashion. As I am sure most are aware, several very reputable tuners (TubroXS, etc.) have reproduced the pinging problem on the dyno and have described the issue extremely clearly--namely, that the "learning" feature of the spark advance does not really learn, but instead drives the car into detonation over and over again. This hasn't happend on all the cars, but a cursory poll at NASIOC has shown that a significant minority have experienced ping on 91, 92, and even 93 octane. I fully realize that this car is a fantasitc vehicle, and I very much look forward to owning one, but we cannot let Subaru get away with this sort of thing. We should complain loudly about a poorly-tuned ECU that could *significanlty* compromise the reliability and resale value of the car.

For those who have not yet read anything on the subject, I'd suggest following Nathan's posts on this thread:
http://forums.nasioc.com/forums/showthread.php?s=&threadid=371994

Here's a full writeup from his site:
http://www.turboxs.com/TXS TECH STI 1.htm

I've seen a few anechdotes from Shiv--he heard some pinging at the track day at Willow; we'll have to wait to see a definitive writeup from the Vishnu angle. I suspect 91 octane will only make things worse.

The fact that the STi is a "high-end performance car" should not affect the discussion at all. Whether it's your Geo Metro or your Porsche GT2, if it pings, it's a problem. Subaru should make it right, and it's up to us to convince them to do it. I don't want to see a repeat of the E46 M3 bearing issue--and BMW is usually better to their owners than SOA.

Ping is bad! Subaru: fix it! If you hear pinging, report it to your dealer! Playing it down will only make it harder for all of us to get this issue fixed,

-ch
 

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You may want to check out this site for a 76 station in your area that sells race gas. I'm lucky enough to have one 10 min from my house. I also found a couple of paint stores that sell Toulene. I haven't heard any pinging. The site below even has a chart showing the proper ratios to mix 100 octane with 91. I think its 4 gallons of 100 octane in our tanks will make 93.2 octane. (11.9*91)+(4*100)/15.9=93.26

http://www.76.com/cgi-bin/b2cpt01/scripts/[email protected]@@@[email protected]@@@&BV_EngineID=cccladcihjlgfflcfimcemndhhgdgjg.0&Site=76&Nav=locator&Key=land&Cat=locator

http://www.76.com/cgi-bin/b2cpt01/scripts/[email protected]@@@[email protected]@@@&BV_EngineID=cccladcihjlgfflcfimcemndhhgdgjg.0&Tool=null&Nav=products&Task=null&Site=76&oid=13571&catoid=-8318
 

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In reality, yeah, if this is a consistent problem out of the gate, it is a big f*&^ up by Subaru. A few questions though....

- What is the magnitude of the problem? Do we know how many people out of the thousands have this problem? Would these people know pinging from a pebble bouncing off their forehead? Question the source.

- Would you rather Suburu pull all the timing back in a car and leave you with 275 hp instead? This is probably a problem that can be fixed with a very mild aftermarket tuning.....IF this is even a problem at all.

Don't go assuming the worst right away. Let's see what happens. If you're car is doing it....hit Subaru with it. Otherwise, don't be so paranoid early.
 

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CloNeGTS said:
In reality, yeah, if this is a consistent problem out of the gate, it is a big f*&^ up by Subaru. A few questions though....

- Would you rather Suburu pull all the timing back in a car and leave you with 275 hp instead? This is probably a problem that can be fixed with a very mild aftermarket tuning.....IF this is even a problem at all.
Most stock STis are dynoing around 255HP/255 Ib-ft. which is about 325HP/325 Ib-ft at the crank (assuming 22% drivetrain loss). So even if we lost some HP due to an ECU change to prevent detonation, it would probably end up at the advertised 300HP/300 Ib-ft.
 
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Re: 1/4 MILE TIMES

Hyperion:


Bear in mind that not one of those tuners actually broke in the car. They literally drove them to their dyno and started revving them up to redline to get charts made before anyone else.

I have a lot of respect for the development work those guys do, but I don't consider their detonation issue a common occurence amongst people who take care of their cars. You have to remember they will probably own the car only 6 months or so and then just get rid of it. So they don't care if they abuse the crap out of it.
 

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RE: power loss from retarded spark

I think that it's clear from the evidence out there that the STi is more than capable of making its advertised numbers without pinging. I have high confidence of this fact considering the larger turbo and extra displacement that the EJ25 brings. The issue is that the ECU continues to run through it's "learning" loop forever, pushing the timing too far until detonation occurs. I think that it's probably possible to get 325-350HP out of the stock system with careful engine tuning, BUT not with an ECU that tries to advance the hell out of the timing all day. I'd rather have 300HP and no ping than 325HP with intermittent ping. Any kind of detonation damage is cumulative.

RE: breaking in the car

While I fully agree that breaking in a car is a good idea, ask yourself this important question:

What effect does break-in have on detonation? The answer is very little or none at all. The primary purpose of breaking in the car is the seat the piston rings to the cylinder jackets, thus creating a better seal in the combustion chamber (and therefore more power). There are other advantages, but in a new car the only source of detonation is a mixture of too high a compression ratio and too much spark advance. As a car gets older, buildup can promote detonation but this should not be an issue in a new car.

This isn't a break-in problem, and we don't have to give up 300/300 to have our cars run well. Subaru needs to redesign the ECU routines and reflash or replace the ECU. This will almost definitely fix the issue.

-ch
 

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Very true about the break in....this has nothing to do with it. This is a fuel situation as mentioned in the other forum.

However....even if this is a problem....it should be easily solved if all that is needed is more fuel to prevent a lean condition. Should we have to do that.....no. Will we do it to fix the problem...you're damn right.
 

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cross drilled

In my car I have experienced pinging and I've found it is reproducable. I will be taking it to the dealer after I get batter gas and can reproduce the problem.

As hyperion pointed out there seems to be a problem with the computer and it's memory. Hopefully all that needs to be done is either a ecu replacement or flash if that's possible. I don't know if the ecu is flashable or not.

A car should not ping from the factory on gas that is "acceptable".

My dad runs 87 octane in his Acura TL type S, with no problems. (he is a cheap man) :p
 
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Here's what I read in The Toronto Sun's Driver Source, Vol. 6 NO 20 of May 18 2003.

And I quote...

"First, use Sunoco's 94 octane gas, especially in warm weather (in cooler weather 92 octane will surfice). If you fill the tank with regular 88 octane gas, the computer will adjust and no damage will be done, but horsepower will be reduced to the 280-290 range."
 

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??where did they get that info? they forgot to say to drive easy on 88 or you horsepower could also drop to 0; detonation and boxer guts everywhere. :( i still wanna know where they got that from. i don't recall seeing it in the owners manual.
 

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I've been driving my STi for two weeks now on 93 and I haven't experienced any problems. Would I really know if the enjoy was pinging?
 

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Note to all who may not be aware: Higher elevation areas run what appears to be lower octane fuel due to difference in air levels, but in reality it is the equivelent of higher octane at a lower altitude.
(ie, 93 octane in Minnesota is the same as 91 octane in Colorado.)
I am aware that some areas don't offer a higher octane fuel at all, but some areas towards higher elevations don't need the big number octane to have the same benefits.
If your not sure, or want to pay for the "insurance" buy 104 Octane boost, or Outlaw octane boost to protect your animal. You could also open up the spark gap just a tiny bit (.005) to help reduce chances of pinging on lower octane fuel.
 

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silent B0b said:
I've been driving my STi for two weeks now on 93 and I haven't experienced any problems. Would I really know if the enjoy was pinging?
If you expereince pinging it will probably be at wide open throttle around 4k rpms under some load. So far on my car I can get pinging in 3-5th gears. It sounds like something is lose in the engine or bb's in a can. On the nasioc forum they have a link to a .wav file that has an example of what it might sound like. If you have a radio and it's on you might not be able to heard the pinging since it would probably be pretty loud in the first place to hear it over the engine/tire noise.
 

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darwood said:
My dad runs 87 octane in his Acura TL type S, with no problems. (he is a cheap man) :p
This is a bit off topic but if your dad is so cheap WHY did he buy a Type S? Doesn't make a whole lot of sense if you are too cheap to buy the correct octane gas.
 

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The only 93 octane in my area is 10% ethanol. I've heard somewhere that gasoline with ethanol can be worse for your engine (not sure how??) and that it can sap performance. Has anyone been using it in their STI??
 
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