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  #1  
Old 03-16-2009, 09:10 PM
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Q Regarding EGR/Engine Performance/Tuning

This sort of popped into my head the other day, maybe you guys who have looked into the engine's software can help me out here.

An EGR system basically siphons off a small portion of the exhaust gases and circulates them back into the engine intake, with the whole goal of reducing emissions of Nitrogen Oxide, with a few potential side benefits. When I took a look at the EGR system on the EG33 I got to wondering just how it applies and how well it was factored into the engine's software.

If you take a look at the system, you'll see it only works with the #5 cylinder (rear passenger side). The pickup is off the exhaust manifold, just after the #5 exhaust port, before the pipes have merged, and the dump is into the intake manifold, just before the #5 injector stack. This to me basically indicates that cylinder #5 is going to be developing less power than the other 5, because it has less oxygen coming into it. However, does the engine's computer know this? In a nutshell, are the injectors compensating for there being less burn-able air in that specific cylinder, or are all 6 injectors working at the same duty rate? If they're all the same, then that cylinder will be running relatively rich (less air, same fuel), and the others a bit lean (same fuel, but perhaps a bit more air than expected).

I don't know if finely tuning (with a Hydra probably) for this would have much of an effect on HP and performance levels, since EGR's are usually closed under load, but maybe during daily driving it would have a small effect. (mileage mostly). This is more to stop my own head scratching than anything else.
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  #2  
Old 03-17-2009, 08:10 AM
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Re: Q Regarding EGR/Engine Performance/Tuning

the egr inlet on the intake manifold goes through a cast passageway to a pair of holes each directly in front of the throttle body openings so that each plenum gets equal egr no matter the position of the iris butterfly.
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  #3  
Old 03-17-2009, 11:51 AM
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Re: Q Regarding EGR/Engine Performance/Tuning

Ah, I see. Thanks for clearing that up. I've never taken the intake off my car, so I've never had a real in-depth look at it.
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92 Ebony Mica LS-L "A Rolling Restoration": 223,250 KM - Sleeping
2007 STi 6MT, Stance GR+ coilovers, PWR Rad, JDM hood badge, svxfiles 6000K HIDs, JDM Clear Corners, $15/15 min mod, $20/20 min mod, Energy Swaybar Bushings, Hella Supertones horns, Gold STi BBS rims, Group A lightweight crank pulley, A/C system removed, Custom header-back exhaust, Hybrid carbon/metal rear sway bar, restored headlights with CCFL halos
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  #4  
Old 03-17-2009, 07:58 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

Is there any performance or mileage gain in disabling the EGR system? Any negatives besides environmental?
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  #5  
Old 03-17-2009, 08:22 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

As far as my experience, mine has been stuck closed since last year and I get great gas mileage..... more than the EPA 25 on the freeway..... so I know it doesnt hurt mileage at least....
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  #6  
Old 03-17-2009, 08:53 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

Quote:
Originally Posted by immortal_suby View Post
Is there any performance or mileage gain in disabling the EGR system? Any negatives besides environmental?
Naturally, a Wiki entry is not necessarily always accurate, but <here> is their piece.
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  #7  
Old 03-17-2009, 08:55 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

Quote:
Originally Posted by SoCal LS-L View Post
As far as my experience, mine has been stuck closed since last year and I get great gas mileage..... more than the EPA 25 on the freeway..... so I know it doesnt hurt mileage at least....
I get 30 with my EGR working fine, but a bum O2 sensor.
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92 Ebony Mica LS-L "A Rolling Restoration": 223,250 KM - Sleeping
2007 STi 6MT, Stance GR+ coilovers, PWR Rad, JDM hood badge, svxfiles 6000K HIDs, JDM Clear Corners, $15/15 min mod, $20/20 min mod, Energy Swaybar Bushings, Hella Supertones horns, Gold STi BBS rims, Group A lightweight crank pulley, A/C system removed, Custom header-back exhaust, Hybrid carbon/metal rear sway bar, restored headlights with CCFL halos
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  #8  
Old 03-17-2009, 09:51 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

Quote:
Originally Posted by Crazy_pilot View Post
I get 30 with my EGR working fine, but a bum O2 sensor.
Nice! Im right up there with you. My O2 codes for both sensors cleared on the way back from reno, as well as my speed sensor code, so maybe your O2 could just use a nice long freeway burnoff ??
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  #9  
Old 03-17-2009, 10:38 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

The code for mine is intermittent. It could be a fraying wire or some oil dripping into the sensor that's causing the code.
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92 Ebony Mica LS-L "A Rolling Restoration": 223,250 KM - Sleeping
2007 STi 6MT, Stance GR+ coilovers, PWR Rad, JDM hood badge, svxfiles 6000K HIDs, JDM Clear Corners, $15/15 min mod, $20/20 min mod, Energy Swaybar Bushings, Hella Supertones horns, Gold STi BBS rims, Group A lightweight crank pulley, A/C system removed, Custom header-back exhaust, Hybrid carbon/metal rear sway bar, restored headlights with CCFL halos
2008 Subaru Legacy Spec B - Diamond Grey Metallic - Sold
2020 Ram 1500 Longhorn - Red Pearl

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  #10  
Old 08-03-2009, 08:27 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

I thought this thread would be the most appropriate to ask:

With my 92, which has the funky 94-up EGR system, I have postulated that its because of the California emissions that my EGR system even exists on it. Now as far as the SVX goes, does having CA emission mean anything is different with the A/F or timing maps? Am I driving a slower SVX because of the extra smog requirements here?

Because if so, id like to swap the ECU out of a federal '92, and get rid of the crappy EGR altogether.
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  #11  
Old 08-04-2009, 08:09 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

All SVXs had egr. Some of the early non california models didn't have a temp sensor to track the functioning of the egr but they still had egr. My suggestion is to order a stage 1av1 from me asap and then your car will most certainly be faster and drive better.

After that order a valve body from me so your transmission becomes a beast instead of a slushbox.

After that order a tcu so that it drives nice and gets better mpg.
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  #12  
Old 08-04-2009, 08:31 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

Quote:
Originally Posted by longassname View Post
All SVXs had egr. Some of the early non california models didn't have a temp sensor to track the functioning of the egr but they still had egr. My suggestion is to order a stage 1av1 from me asap and then your car will most certainly be faster and drive better.

After that order a valve body from me so your transmission becomes a beast instead of a slushbox.

After that order a tcu so that it drives nice and gets better mpg.
Why certainly, do you take Monopoly money ?

Because thats about all I can afford to spend on performance parts at the moment.

However, for your accommodation of my available funds, ill throw in an extra orange $500 bill and a free pass the next time you land on my railroads (I own all 4!!)
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New?? Find the downloadable SVX Online Service Manual Here
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  #13  
Old 08-04-2009, 08:33 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

you can't be a true player with no bling bling
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  #14  
Old 08-04-2009, 10:22 PM
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Re: Q Regarding EGR/Engine Performance/Tuning

Quote:
Originally Posted by longassname View Post
you can't be a true player with no bling bling
PLAAAYAAAAAAAAAAAAA !!!!!!!!!!!

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