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Discussion Starter #1
Ok, we all pretty much know the difference between the WRX & the STI. MY ? is what are the exact differences between the JDM and the UK version which is what we will probably get? The HP difference for example... Yeah, yeah, I know the whole octane issue, but do they run the same boost? Is it because the JDM revs higher???
I guess I want to know if when the glorious day arrives.... can I "fix" my future STI WAGON!! with a JDM ECU? I'd like to think that it would take it to 8k, more fuel, boost, etc.. Does anyone know if the stock JDM, UK exhausts are very different?? Yes, I know we will surely have a different exhaust here in California, but I'd plan to go aftermarket to get at least as good a flow as JDM, and most likely even better flow. I wanna see 8K on the tach!!!!!

<font size=-1>[ This Message was edited by: super_bean21 on 2002-03-21 18:05 ]</font>

<font size=-1>[ This Message was edited by: super_bean21 on 2002-03-21 18:08 ]</font>

<font size=-1>[ This Message was edited by: super_bean21 on 2002-03-23 02:01 ]</font>
 

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I believe they both rev to 8000 so its not that. There are some emissions differences so I'm sure the JDM version flows a little more freely. By the way, based on acceleration number the JDM version has to have more like 300 - 320 bhp. I think the ECU and exhaust and interior and all are the same? JJ am I right?


The big deal is the octane. You can run much higher boost and more aggressive timing schedules with higher octane.



The octane rating of gas is the number of carbon chains per molecule. This translates into how much the gas can be compressed before the gas just explodes from compression. If you can compress the gas in your engine more, you can run higher boost.
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So, the short answer to your question is more boost!
 

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Discussion Starter #3
Yeah, I understand the octane, and yes I AM willing to drive around with a bunch of octane booster so I can add it every time I pump some gas to allow higher boost without knocking. ....But even on the video clip that is available to download here on this site, not the topgear one, the STI one, it shows the UK STI, & prodrive models, and a close up of the tach/shift light and it redlines @ 7300. oh yeah, I am also well aware of the "276" figure being a gentleman's agreement. I'm just using it to differentiate between UK and JDM. Point being, I want my future STI wagon to perform at least as well as JDM. Guess i'm just mad for revs! Does anyone know if they have identical cams and/or engagement point of the variable control??

<font size=-1>[ This Message was edited by: super_bean21 on 2002-03-22 15:15 ]</font>
 

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I mentioned this before when this came up. Just as a warning, I have heard that adding octane booster to gas leaves a sludge in the engine. Over time, repeated use, I am sure is not good. I think you would be better off finding a gas station that sells 100 to 104 octane race fuel if you are really concerned.
 

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The difference in the JDM and UK/Euro spec STi does lie in the:

ECU - tuned for lower octane
Exhaust- More cats, I HATE CATS!! :smile:

That's it. Japanese gas is 100RON+, ours is 98RON+ (Premium) and UK/Euro is 95 RON. So technically, all California emissions bullshit aside, they would have to de-tune ours LESS than UK/Euro Spec. :smile:

JJ
 

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Discussion Starter #6
What = 98 RON?? 92, 93 octane? Here in CA we recently got stuck with 91. :evil: My ? still stands for the RPM's... Will the JDM ECU take us into 8K RPM bliss??? It seems like a little octane booster, or race fuel mix will cure all of our ills. Who's with me people?? 8K!!!
 

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JDM ECU + 100 RON = 8K RPM's

On the gas issue, yours truly checked it out. :smile: Here in the US, and with BP Amoco (I would assume it is the same for other brands), all of thier PREMIUM fuels are 98 RON. Only the MON varies and produces 91, 92, 93 etc..

So if you fill up with BP Amoco GOLD you are getting 98 RON for your engine.. :smile:

JJ
 

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I think you can still do higher revs with engine management and different cams/lifters/valves. Cobb tuning (my hero) has kits they sell that can give you an 8k rev limit for a WRX. I'm sure they'll tune the hell out of the STi whent he time comes.

PS You can also add touline(sp?) to your gas to increase Octane rating. Its a chemical commonly found in paint thinner but you can get it from other things. It doesn't leave sludge but is supposed to burn out your MAF or something over time.
 

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isnt dynamite tri-nitro-toluene. Hence TNT :lol:

Maybe im wrong....

Glen

<font size=-1>[ This Message was edited by: thermite on 2002-03-23 20:02 ]</font>
 

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the STi is supposed to be coming over 50 state legal on emmissions, and exhaust sound. There is an exhaust upgrade that is offered by Subaru for about $900.. From what I understand its, 3" turbo back, and drops the cats.
 

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Super_Bean: Sunoco sells "Ultra 94" gas in Canada, which is rated at 99-100 RON. We should be able to get pretty close to Japanese spec. gas-wise, anyway.

JJ: Does the "JDM ECU + 100 RON = 8K RPM's" mean that the ecu raises the engine rev limiter, and calls for 100 RON? I am wondering if there are other "bits" that the engine would need to be able to spin safely at those (albeit slightly) higher speeds?

Thanks,

Eric
 

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Yeah, we have PetroCan-- the highest octane they have is 91 AKI (I think about 96 RON). Esso (Exxon) sells 92, and Shell 91. I am secretly hoping that Canadian Tire will start selling 94 or higher, and we can get some canadian tire money with our gas :wink:.

One more thing about fuel-- one complaint about North American fuel is the high sulphur content-- I have heard that it is not good for high-boost turbo engines, and is one reason why they have kept many out of NA. If that is true, I wonder if the new fuel regulations which will drop the allowable sulphur content over the next few years are one reason so many high performance turbo cars are finally making it here?

Eric
 
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