Engine/Power - EJ20T (pre-2006 WRX and JDM) There is replacement for displacement, it is forced induction - OEM 2.0 liter turbo engines in the USDM WRX. 90-94 Legacy Turbo EJ22 turbo engines can also be discussed here.

The cold air intake debate

Old 09-30-2004, 12:23 AM
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Originally Posted by Donkey
Well most stand alone systems use speed density over mass air.Electromotive,Haltech,Motech,SDS..thats gotta tell ya something.
Tells you that it's cheaper. Look at it this way- MAF systems are more expensive than speed density systems. Try pricing an RS MAP sensor (the '00-'04 EJ25 uses speed-density) compared to a WRX or Phase I EJ25 MAF. Now ask yourself, why would a company as frugal as Subaru Choose the more expensive option? Anser: MAF is more acurate and dependable for forced induction applications. I must admit I'm confused about the switch back to MAF for the '05 EJ25 though.
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Old 09-30-2004, 02:04 PM
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Originally Posted by BAN SUVS
Tells you that it's cheaper. Look at it this way- MAF systems are more expensive than speed density systems. Try pricing an RS MAP sensor (the '00-'04 EJ25 uses speed-density) compared to a WRX or Phase I EJ25 MAF. Now ask yourself, why would a company as frugal as Subaru Choose the more expensive option? Anser: MAF is more acurate and dependable for forced induction applications. I must admit I'm confused about the switch back to MAF for the '05 EJ25 though.
If your spending almost 2K for a stand alone don't you think they are going to go with a setup that will provide the most performance and not the cheapest performance?I mean the cost of the sensor at that point is minute.Plus when you use a BOV it causes a momentary over rich condition in MAF cars durring the shift.This doesn't happen with MAP sensors because they are after the valve and not before it.The MAF has already metered the air and the ECU can't react fast enough to change the value.
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Old 09-30-2004, 03:07 PM
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i wouldn't switch to speed density to avoid rich shifts while VTA!

remember, there are ALWAYS tradeoffs. saying that one system is ALWAYS better than another is myopic.

when you go to speed density anything you do that changes the VE of the motor has to be RETUNED around. pretty much all the bolt on mods we do commonly to our cars changes the VE of the motor... turbo backs, manifolds, turbo swaps, etc.
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Old 09-30-2004, 05:58 PM
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Originally Posted by ride5000
i wouldn't switch to speed density to avoid rich shifts while VTA!

remember, there are ALWAYS tradeoffs. saying that one system is ALWAYS better than another is myopic.

when you go to speed density anything you do that changes the VE of the motor has to be RETUNED around. pretty much all the bolt on mods we do commonly to our cars changes the VE of the motor... turbo backs, manifolds, turbo swaps, etc.
So with Mass Air do you just reset the computer and it recalibrates for all those parts you mentioned or do you have to retune as well the ECU settings?I would imagine its the same for both systems.But i agree there is definatly trade offs with each.I was just under the impression MAF was better suited for N/A motors and speed density for boosted applications.
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Old 09-30-2004, 11:28 PM
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Originally Posted by Donkey
So with Mass Air do you just reset the computer and it recalibrates for all those parts you mentioned or do you have to retune as well the ECU settings?I would imagine its the same for both systems.But i agree there is definatly trade offs with each.I was just under the impression MAF was better suited for N/A motors and speed density for boosted applications.
There's usually no "resetting" involved. If you improve VE, then the extra air that flows automatically gets picked up by the MAF sensor, provided it has enough capacity.
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Old 10-01-2004, 04:37 PM
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Originally Posted by BAN SUVS
There's usually no "resetting" involved. If you improve VE, then the extra air that flows automatically gets picked up by the MAF sensor, provided it has enough capacity.
But if that is true then why would you need ECU tuning like the Cobb AP,Ecutek...?
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Old 10-01-2004, 06:42 PM
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the extra air is fueled accordingly; the tuning optimises timing.
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Old 10-01-2004, 08:58 PM
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Fueling needs to be optimized too.
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Old 10-11-2004, 10:22 AM
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I removed the intake silencer on my car. should I put it back on?
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Old 10-11-2004, 03:57 PM
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^^^
Wrong thread
If you're concerned that your engine bay is getting dirty, feel free to put if back on. If you like things the way they are, leave it be.
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Old 10-11-2004, 08:13 PM
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Originally Posted by mysterymarker
I removed the intake silencer on my car. should I put it back on?
Nah, it's fine.
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Old 10-14-2004, 02:10 PM
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Originally Posted by ScoobieSnack
I may be mistaken but i believe you lose the intake temp sensor when you remove the MAF in favor of just the MAP sensor. I'm sure an aftermarket sensor could be fitted but if you just remove the MAF you may see some odd idle fueling as a result of quick variation in intake temperatures. It doesn;t seem to have much of an effect while moving because the air in the engine bay is moving aroung a lot and it therefore a more consistent temp than when your stopped and all the hot air is rising up into your intake.
Speed density (MAP) still uses an intake air temp.Maybe if someone would make an ugraded MAF unit like they use in the GM'S &Fords that are build into an oriffice and pre-calibrated to work with the stock ECU programming you could run any aftermarket intake with no problem i would imagine.
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Old 10-28-2004, 01:31 PM
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^^ Vote or Die!!!

j/p im here to mess up the mix.
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