Tuning help needed!!

[Kingtal0n]

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.

[smoked240]

Originally Posted by Kingtal0n

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.

Very helpful info!! I'll pull up my map tonight and do some adjusting. My timing on the aem shows 36* while boosting but I'm assuming you subtract the 15* the timing was synced at?

Thanks for the help!

[Kingtal0n]

Originally Posted by smoked240

Very helpful info!! I'll pull up my map tonight and do some adjusting. My timing on the aem shows 36* while boosting but I'm assuming you subtract the 15* the timing was synced at?

Thanks for the help!

no, no.

You set the timing in the ECU to match the crankshaft. I go over how to set sr20 timing in several threads. You need to verify the timing matches the crankshaft, or else nothing you do will matter and the engine will blow or give terrible performance/economy to say the least.

Once you can see (some number) at the crank, and it matches some reported number (at the ECU) then you check multiple rpm: does it match at idle? 2000rpm? 4000rpm? Make sure it always matches up.

Then you can make your changes. If you want 9* in boost you put 9* in the map. It runs where you tell it to. There are trims in the ECU "behind the scenes" such as TPS trims and coolant trims, AEM has more trims than I can count. So you have to go through the entire instruction manual looking for all the timing trims or at the very least be sure you are getting the timing you think you are getting.

It is very common for "tuners" to over time the sr20det engine. 36* is way too much timing. What does your knock sensor say about that? Further more the a/f should be consistent. It should not jump 10x units (from 13 to 14 for example) while holding steady throttle (steady vacuum signal) the only "jumping" it should do is from 14.5 to 14.8 during closed loop operation, such as cruise and idle, off the narrowband Oxygen sensor, if closed loop is enabled. A good fuel map has very gradual, smooth changes.

random example, notice how it smoothly goes from one value at the bottom to another at the top, there are no jagged areas, no dips or crevices "pot holes" in the map, the engine will transition smoothly and the a/f remains consistent when you hold a load value.

http://smg.photobucket.com/user/jonb...emmap.png.html

[smoked240]

Originally Posted by Kingtal0n

no, no.

You set the timing in the ECU to match the crankshaft. I go over how to set sr20 timing in several threads. You need to verify the timing matches the crankshaft, or else nothing you do will matter and the engine will blow or give terrible performance/economy to say the least.

Once you can see (some number) at the crank, and it matches some reported number (at the ECU) then you check multiple rpm: does it match at idle? 2000rpm? 4000rpm? Make sure it always matches up.

Then you can make your changes. If you want 9* in boost you put 9* in the map. It runs where you tell it to. There are trims in the ECU "behind the scenes" such as TPS trims and coolant trims, AEM has more trims than I can count. So you have to go through the entire instruction manual looking for all the timing trims or at the very least be sure you are getting the timing you think you are getting.

It is very common for "tuners" to over time the sr20det engine. 36* is way too much timing. What does your knock sensor say about that? Further more the a/f should be consistent. It should not jump 10x units (from 13 to 14 for example) while holding steady throttle (steady vacuum signal) the only "jumping" it should do is from 14.5 to 14.8 during closed loop operation, such as cruise and idle, off the narrowband Oxygen sensor, if closed loop is enabled. A good fuel map has very gradual, smooth changes.

random example, notice how it smoothly goes from one value at the bottom to another at the top, there are no jagged areas, no dips or crevices "pot holes" in the map, the engine will transition smoothly and the a/f remains consistent.

http://smg.photobucket.com/user/jonb...emmap.png.html

Ahh that makes much more sense! My tuner did all that and updated my software at the time but now that you mention it I'm pretty sure my map is all jagged. I'm not sure if I stated in the beginning I thought I did but it's an Rb25det. The tune he did ran beautifully and since than I added top mount manifold and large turbo. It is boost comp tuning.

Yeah the only time my afr stays solid is boosting.
So far I've been able to see 1 bar of boost but I cannot for the life of me remember what my afr was, I wanna say something like 10.4-11