Rb20/nistune - Timing For Quicker Spool

[iruvyouskyrine]

If my crank angle sensor was off center would it adjust my timing on the tables or just increase/decrease my timing depending on how much it's out?

It would just change you values depending how far out it is. Your ECU (and therefore timing map) assumes you have the mechanical timing set correctly.

[GTSBoy]

We cannot tell you what a safe map looks like. We have absolutely no idea how your engine is breathing. We have no idea how much oil vapour is getting in with the mixture. We have no idea about the real quality of your fuel, etc etc etc.

The full load timing #s you have (~22°) would be safe on a stock motor. They'd also be pretty safe on a number of modified motors. As STATUS said above, many modified RB20s would shit themselves if fed that much timing at high load. On those you'd possibly be down to 17 - 18°.

BUT WE CANNOT TELL YOU. Every motor is different, even with the same mods.

Look at the factory map from Nistune. Your map will be the same basic shape. High where it's high, low where it's low. Its just that all the numbers will actually be different, and the only way to find out where they should be is to run it (preferably on the dyno) and advance it 'til it pings then back it off a couple of degrees. And then take into consideration the difference in load between a dyno and a road and the possibility that you are tuning on a hotter or colder day than average, etc etc, and adjust your timing to account for that too. And a few other similar factors on top.

As to your CAS......if it's not set to give you 15° then of course all your map numbers will be off by the same amount. The ECU looks at that table expecting that the CAS is set correctly. It can't tell when it's not.

[rx-line]

I hear ya loud and clear, I have it worked out to run on a dyno a few hours from here. Timing has been pulled back in boost transition and boost.

I have noticed that all of the sudden the car is running rich when cold like 10.9 afr's on idle and is rich right accross the map. I have reduce the crank enrich + temp enrich figures down to the same as they are when warm with no change. I am not running the cold start FYI, Any ideas?

[rx-line]

FYI - Nistune RB20det base map timing

Why so high?

[GTSBoy]

What do you mean "why so high"? The 40s in the low load mid rev region are because it will pull that timing there without any problem, and if you have less timing there you actually get backfires and crap going on too. The other aspect of it is emissions. A lot of what OEM tunes have are for emissions reasons rather than just the best performance.

The moderate load (30-50 TP) and mid rev area also carries a fair bit of timing, but it drops off immediately to the right of that as boost comes on.

You can see that the 5000rpm and 80 TP area is 24° or so. That's a sensible amount of timing in there (for a stocker). They can use a bit more, but Nissan were conservative. At the far right is Nissan's little R&R exercise where they really kill the timing to stop you from having too much fun. That's special. Not as bad as on an RB25 though.

A lot of the other areas are a bit meaningless. You cannot access the top left side of the map "on load"...it's more of an overrun area, hence the flat timing. You also cant access the bottom right corner of the map - its not possible to flow that much air at those revs - you need the turbo spinning and it won't.

[rx-line]

So this would be even more aggressive than what my map was? I am glad you explained the left mid range side of the map, I was really off put by this initially. I was wondering why the base map was higher nearly everywhere compared to my map. And why it was exactly that the timing map I was using was so outlandish? And that most rb20's with this timing map would "eat themselves"?

I understand stock vs modified, 10psi vs 15psi.

But stock I would think would be much more prone to knock due to much higher intake temps and breathing restrictions?

Ultimately I am learning and not by any means not listening to what you have to offer, clearly you folks know more than myself. I will do a bit of remapping tonight and start from the base map -3 to -4 degrees and smooth the mid/right max load area. I did find another rb20 base timing map in nistune that was much smoother ande very different from this style that most share.

[GTSBoy]

We didn't say that most 20s would eat themselves with that much timing. Just that there are certainly many boosted up 20s that would. And don't go thinking that 15psi is boosted up either. Think more like 20 psi for a stock motor being pushed fairly hard, or 25+ for a built motor.

[Dose Pipe Sutututu]

very basic tuning, of course you need to also factor in EGT, knock, IAT, etc.

download something like Virtual Dyno...

start with timing figures as low as 10 and flat across the board, but make sure your AFR is nice and rich to keep things from going bang

Do a 3rd gear run, inspect power/torque made

Increase timing by x degrees

Do a 3rd gear run, inspect power/torque made

Increase timing by x degrees

when you add 1x extra degree and you're making crap all gains - it's time to back off the timing a little..

of course you need to repeat this process multiple times to get it right...

another thing to note, you can ramp up timing as torque decreases... this is where you need to properly overlay readouts to determine this.. then repeat the same process but only after peak torque to redline.

If you live in Australia (which you don't) I wouldn't recommend this on the streets at all.. but I'm assuming you're from the states.. so go nuts.

[KiwiRS4T]

Do some googling and buy yourself some det cans or knock detectors or what ever they are called in your part of the world...and search here for Trent's article on detonation. - actually there is a link at the bottom of his post - under the name of Status