JB3 NX nitrous integration FTW?
Just got back in the office. Much data to dig through. But the objective of today's tuning session was to identify the fueling limits and I think we found one. I'll modify this post as I go through more data.
Our automatic 135i
JB3 18 ohm board, 1.2k fueling resistors
NX dry nitrous kit. Simply the best hardware out.
Coolingmist meth injection, 100% meth
AR nitrous/meth elbow
3" ******* downpipes
Stock 135i single 2.75" catback system
No golf tee mod
We prefer our cars quiet and odor free.
I did a couple baseline runs on map 9 just to see how the air/fuel ratio would track through the tailpipe sniffer with cats. I found it wasn't very accurate/stable until around 4000rpm. Probably a combination of the lower load you see on the dynojet, a questionable tailpipe sniffer, and the cats impacting things. Ideally one would want to sample the air/fuel from a dedicated wideband bung close to the turbo. But this will have to do for now.
Run_002 was a baseline done on map 9 using our new fuel tuning with a taper value of 10. I did a couple runs and the air/fuel was about identical.
Next I did a couple tuning runs to dial in the JB3's nitrous control. For the purposes of this test it's simply acting as a wot / window switch. But on the road there are some important benefits. We can talk about that later.
Run_005 was on map 10, 35 jet, 900psi bottle pressure, 2000ml/min of meth (maxed out). Fuel mapping/meth volume was unchanged from Run_002. Interestingly the fuel pressure held very well through the run but following the air/fuel trace you can see we're leaning out at this power level despite a ton of methanol. I suspect we're at the limit of the injectors.
Just to make sure I cranked the bottle pressure up to 1000psi and did another run. Sure enough the air/fuel leaned out further.
I have a lot of other data I need to dig through but this should answer most of your questions.
PS. New record?