Timing on SR20VE with SR16VE.N1 Head

[TheStigP11GT]

I have recently rebuild a new SR20VE.N1 engine, with the N1 head ect, I am running the 1N410 ECU with it with Nistune, I currently already have a base map on it for the VE engine as the car was mapped on another SR20VE so it was just a case of increasing a little fuel at some points to prevent leaning out.

Basically we have a small teething problem with our VZR's new Engine Build, engine runs fine, but the idle seems to sit at 1100 Constant.

I initially set the timing once the engine warmed up on it's first start. Been fine ever since, however I thought now the engine has bedded in it is time to sort this daft problem out.

Now we use a GSpec Pulley, so it is not standard Nissan. so I am thinking this may be the issue with the timing.

I fiddled with the timing, with thinking this is an N1 head and higher flow, I thought perhaps it might need to run Stock VE timing, which is 10* for the N1. Set it to this but still seemed a little high. I then set the timing to 5* (stock SR16VE) and was a little better again. I then set the timing to 0* and idles perfect at around 850 RPM. I changed the timing and base idle as per Ant-Dat's write up on NPOC

I also hooked up the Consult for Nistune. so I could read what they ECU says.

Running at 15* (of so I thought) shows the timing at 21* on Nistune, ~12* shows around 15*. If I set it to 0*, Nistune says it is 5*. So I am thinking that the Pulley marks are all out.

Does anyone know if I am able to use Nistune as a reference for timing the engine?

Initially I thought it was the compression on the engine, but I know someone who has the same setup and his Idle is good.

Just another note, that it is an SR20DE Crank in there.

Hope I can get some suggestions, The engine will be getting mapped again next year but I want to solve all the problems before I book it in.

[UNISA JECS]

You have to do the whole Nissan rain dance to set timing to make your mechanical timing and computer timing match, Nistune will not know if your mechanical (districtor) timing is correct or incorrect that is up to you to set correctly with a timing light. So set the base timing and idle correctly then go from there.

[CoZZm0]

Depending which version of the pulley you have, its possible your markings are wrong/out.

http://www.sr20-forum.com/vvl/9934-gspe ... post131346

Link above shows the issue, its a few degrees out for the early version.

Timing can be done without any rain dance stuff, you just need to set the car into base idle setting mode with an active test in consult and it will lock the timing and the AAC so you can set the idle speed, then set the timing.

Its VERY IMPORTANT (when running normally) that the AAC valve value when the car is at warm idle is between 10-16 (or close to) otherwise the ECU may retard or advance the timing to hit the target idle speed. It can also show very inconsistent (fast changing) timing readings.

Example:
If the AAC bypass screw is open too far (so its closed shut to a value of 10) and the idle is still too high, the ECU will try to cut timing to hit the target idle speed.

[TheStigP11GT]

Thanks for the response guys, What I think I will do, is change the Crank Pulley to the Stock one and then time it up with the timing light, At least then I know it will be correct, It is a bit of doing a rain dance but I think it will certainly give me an accurate way of dealing with it. I can then change this back after the engine has been re-mapped. as when it get's mapped the cams will be dialled in, so to make things all good I will just do that.