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What afrs should u be running on stock turbo under max boost/cruise?

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What afrs should u be running on stock turbo under max boost/cruise?

Old 03-01-14, 06:55 PM
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What afrs should u be running on stock turbo under max boost/cruise?

I'm running rtek 1.7 , 550/720, and walbro 255 lph, car has stock ports , s5 turbo and full exhaust 2.5".

Under maximum boost 8-12 psi 'ish or really at any boost level I'm in the 12's , 12.5 give or take, under cruise I've seen it go up to around 15.5 , both values seem high for my taste...I am going to rewire my fuel pump and see if they go lower....Under idle I'm running stupid rich at 12.5-13.0 with over 20 vacuum @ 950'ish rpm.

I've been told 12s are fine but I don't think there really is a safety margin if it decides to go up , it rather be in the 11s and or high 10s, 10.8-11.2 and 15.0 at cruise.

I'll see what I can do to test my sensors, afm etc.
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Old 03-01-14, 07:36 PM
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idle will be rich, like mid 12's, its adjustable with the idle mixture adjuster, but best idle will be mid 12's

15's at cruise is normal too.

i've never seen anyone put a wideband on a stock T2....
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Old 03-01-14, 07:43 PM
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It all depends on your AITs. If it were me and I were building a second gen again I'd shoot for flat 12 until 10 psi and then taper down to 11/11.5 to 15+psi. Idle should be in the range you're seeing.

When I had my second gen with a stock turbo and microtech I was running 11.7 at 14 psi.
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Old 03-01-14, 08:06 PM
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How is my car stock only thing stock is the turbo and top mount, and I plan on upgrading...not getting a wide band is just asking for trouble.

Idle air mixture screw isn't hooked up because it's not working, tested it
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Old 03-01-14, 09:23 PM
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Air pump will throw off values on any stock car. But I guess you are not stock in that regard...
Under boost you want 11's over 10psi (general consensus I'd say). For cruise in vacuum on the highway 15.5 is perfect. There is no danger in leaning under full vacuum, the engine will just buck/hesitate and be unhappy. Then you will know to adjust.

If I try hard enough, I can get about 16 on the highway, and the engine is happy.
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Old 03-01-14, 10:27 PM
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Originally Posted by beefhole View Post
Air pump will throw off values on any stock car. But I guess you are not stock in that regard...
Under boost you want 11's over 10psi (general consensus I'd say). For cruise in vacuum on the highway 15.5 is perfect. There is no danger in leaning under full vacuum, the engine will just buck/hesitate and be unhappy. Then you will know to adjust.

If I try hard enough, I can get about 16 on the highway, and the engine is happy.
I generally find that I can only get above 15 afrs when port air is running. But you're right, lean it out until it gets soft and you're good to go.
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Old 03-02-14, 07:08 AM
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I'll see what she does after I rewire the fuel pump, the wastegate flapper is messed up so I either get max boost with no control 12+ psi at full boost or minimum boost at like 4 psi or so when it's stuck in the other manner.

I'm not sure what I'm doing to remedy the problem, it's just been a nuisance.

Either way I wanna be in the 11's , the rtek pulls timing after 9 psi 1 degree per psi but I'm really not counting on that to stop detonation.

I never boost for long periods of time and with how cold it is I'd say my aits aren't getting too high, my downpipe does have a small exhaust leak at the flange , not sure if that'd affect afrs, the wide band is a plx sm-afr2 utilizing a bosch sensor which i have mounted in the stock o2 spot, I have dei reflect a cool cooling tape on the bottom of my top mount.
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Old 03-02-14, 08:10 AM
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" the wastegate flapper is messed up so I either get max boost with no control 12+ psi at full boost or minimum boost at like 4 psi or so when it's stuck in the other manner."
obviously, you have to fix this before you go playing with the tune. This is a big no no! Shame on you, behaving this wayyyyyyy
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Old 03-02-14, 08:24 AM
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Don't judge, I gotta get this car on the road it's been worked on for over a year now , I'm gonna be running it on low boost , wastegate is messed up that's just how it is...it will be getting addressed/fixed in due time.
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Old 03-02-14, 08:58 AM
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haha i was being facetious.
Just be easy on the go pedal.
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Old 03-02-14, 02:18 PM
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I'm gonna get another set of gsl se injectors so I can have the option of having some more fuel for peace of mind and have the wiggle room for am upgraded hybrid turbo in the future.
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