Tuning help needed!! - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Kingtal0n · 12-15-2015, 05:23 AM

get your wideband saying 11.5:1 for anything after 12psi of boost. interpolate the values from 13.5:1 to 11.5:1 as you move from 0psi to 12psi, then hold 11.5:1 all the way till 18psi. When you cross 18psi you go a little richer, 11:1~ then by 25psi you want 10.8:1.

These are street tuning numbers for pre-dyno. When you goto the dyno you remove fuel as the engine requires for best power vs how the engine behaves. thats advanced topics I cant cover here.

For timing, at 0psi from 2800rpm to 5000rpm there needs to be between 18 and 24* btdc of advance, more as the rpm increases slightly, perhaps 28 by redline (0psi)
when you pass into boost, 1psi-5psi, pull around 1* per psi of boost, so by 5psi you have 13* of timing for example, until you get to 9*, stop there. Using 9* of timing is a generic number also for the street tune. You don't add timing back until you hit the dyno, again, by watching what the engine does. Once you pass 19psi again you want to pull a tiny bit more, around 7* of timing for 20-25psi.

This is all for 93 octane pump fuel. BY using E85 you will need more timing, and you need to make sure the wideband is reading stoich values i.e. when it says 14.7:1 it really knows that your E85 is NOT 14.7:1 (some other stoich value) but it still reads 14.7 for simplicity. In other words E85 has a different stoichiometric value but the wideband should still read 14.7:1 when it is at the value, I think most widebands will work this way. You could probably run as much as 13-15* of timing for 18psi of boost on E85. I wouldn't try 9* its probably not nearly enough.

12-15-2015, 05:23 AM	#9
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 42 Posts: 4,829 Trader Rating: (17) Feedback Score: 17 reviews	get your wideband saying 11.5:1 for anything after 12psi of boost. interpolate the values from 13.5:1 to 11.5:1 as you move from 0psi to 12psi, then hold 11.5:1 all the way till 18psi. When you cross 18psi you go a little richer, 11:1~ then by 25psi you want 10.8:1. These are street tuning numbers for pre-dyno. When you goto the dyno you remove fuel as the engine requires for best power vs how the engine behaves. thats advanced topics I cant cover here. For timing, at 0psi from 2800rpm to 5000rpm there needs to be between 18 and 24* btdc of advance, more as the rpm increases slightly, perhaps 28 by redline (0psi) when you pass into boost, 1psi-5psi, pull around 1* per psi of boost, so by 5psi you have 13* of timing for example, until you get to 9, stop there. Using 9 of timing is a generic number also for the street tune. You don't add timing back until you hit the dyno, again, by watching what the engine does. Once you pass 19psi again you want to pull a tiny bit more, around 7* of timing for 20-25psi. This is all for 93 octane pump fuel. BY using E85 you will need more timing, and you need to make sure the wideband is reading stoich values i.e. when it says 14.7:1 it really knows that your E85 is NOT 14.7:1 (some other stoich value) but it still reads 14.7 for simplicity. In other words E85 has a different stoichiometric value but the wideband should still read 14.7:1 when it is at the value, I think most widebands will work this way. You could probably run as much as 13-15* of timing for 18psi of boost on E85. I wouldn't try 9* its probably not nearly enough.