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Advice for tuning S5 TII with S-AFCII?

Old 04-15-08, 12:47 AM
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Advice for tuning S5 TII with S-AFCII?

Ok so to start out with, I have no experience whatsoever with anything to do with tuning. I have a very lightly modded or soon to be modded S5 TII.
Apexi Power Intake
Apexi N1 duals
Bonez 2.5" downpipe (to be installed)
Bonez connecting pipe (to be installed)
Bonez HF cat (to be installed)
Innovate G2 wideband (to be installed)
S-AFC II (to be installed)
Boost Gauge (to be installed)

So I'm hoping not to have to take it to a dyno. I was hoping to butt tune it but i hear it's substantially more dangerous on a turbo than an N/A. The wideband and safc were originally intended for my N/A but then I bought a TII and decided to put these on it instead. So can anyone offer advice about butt tuning it with S-AFC2? Is it pretty easy to run lean and blow it up?
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Old 04-15-08, 02:25 AM
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Oh yea i also have a Knight Sports FBCD on the way.
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Old 04-15-08, 09:14 AM
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DISCLAIMER: Follow this advice at your own risk.

Obviously, you know it's much more dangerous to tune on the street without any sort of reference.

If you want to be conservative, this is how you should tune your car.

For low load settings, since you have a cat, you don't really have to do anything. You could help the cat out, by disconnecting the O2 sensor and tuning for 14.7:1 - 15:1 at cruise.

At WOT/high-load, shoot for 11's. It may be a bit rich, but it gives you a buffer.

If you like to play with fire, ditch the cat, and get a pre-silencer.

Then, take off the O2 sensor and at cruise, lean the fuel out gradually, until the car starts to stumble a little. Then, bump the fuel back up to the last known stable level. This will get you the best possible gas mileage at cruise with your car. Mind you, that if you try this with a cat on, you run the risk of ruining your cat.

At WOT, tune for 12:1 AFR's. You'll get more power, but also run a higher risk of detonating your engine.

Make sure all vacuum hoses, hell, all hoses are nice and tight. Make sure your wastegate is large enough to handle the increased boost from a freer-flowing exhaust. Make sure you don't overrun your injectors, but I doubt you will with those mods listed above. The last thing you want is your turbo boost spiking and taking your engine with it.
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