Progress Thread Grover: Window motor replacement & OEM rebuild

We'll see. The track is a 2.5 hour drive towing. I'd like to tune the timing a bit more before my next TNT.

I'm tuning for 91 octane. It's an AFR 205 head. Compression at ~9.6. Current timing at max boost is 14.8*. However, I'm not really trying to see that amount of boost. So, 15.8* t at 13-14 psi, though you can see that through a run, the boost spikes, goes over target by about 2psi and gradually drops to target through the run. Here's my setting that targets 11 psi. It makes 13.9 at the beggining of the spike and 11.2 at the end. This kinda sucks, because if anything, the opposite is preferred to reduce traction issues early. I'm hoping that powershifting will allow boost to stabilize at target, as opposed to spiking in each gear. This observation doesn't seem to be just related to the boost controller. Even on the spring, the effect is similar.

Anyways, Here's a snippet of my recent data log. I've made some minor adjustments to AFR. I was setting the boost controller at the time, but I was using it to help dial in the AFR. It's obviously running pretty rich at this point. I think I pulled out around 5% more fuel at those points after this run, and that's where she currently sits: I cannot find MAT temps, unless 70-80* sounds right at WOT, which I find hard to believe. I'm guessing that's measuring ambient air.



After I get the AFR where I want it to be, I'd like to try my hand at reading plugs to adjust spark. Some of the best tuners in my area say that's the best way to do it.

Another thing to note in this graph, I'm not impressed with the transient tuning of this box and/or my ability to tune it. You can see how rapidly MAP spikes, yet the dmap doesn't even leave its cell after that AFR low valley that intersects the TPS going WOT. So, I've resorted to using the 3500 RPM column in the VE table to compensate and have values there considerably higher than surrounding values to deal with the boost threshold there.So, part of that rich AFR thereafter is the computer recovering from VE values that are intentionally too high, but there's still room for adjustment afterwards.

Oh yes, you very much can tune with TPS values, but as you can see from the graph above, it's going plenty rich at the instant of WOT, now. In fact, I'm pulling out the enrichment there, because it's going too rich. It's shortly thereafter where the AFR crosses desired, goes lean, and nothing in the transient seems to affect that. So, I compensate in the VE table, but the trouble with that is that it while it keeps the car from spiking lean, if forces it to go too rich once boost stabilizes, at least until it completely exits those cells.

I'm with you on the math, and that's exactly what I've been doing between runs. I'll approximate the percentage, and then put a conservative adjustment in. I'd rather creep up on the rich side. Now, Steve, don't take this the wrong way. I well know that your tuning experience is vast compared to mine, but everything I've been reading, and videos I've been watching, lately says that once you're in the ballpark with AFR, you don't get those kind of gains. The only massive gains you'll see from AFR, according to those reads is 1) if you go too lean, you'll lose a lot of power, and 2) if you're so rich that it's interfering with the burn and/or spark. Most of these articles and videos were n/a cars, though.

The takeaway to me was that conservative fueling, say 11.5:1, will give me a nice hedge against detonation without costing much power. Now, I would very much like to see a back-to-back comparison, dyno or track, on a turbo application with no timing changes going from a rich AFR of say 11:1 to say 12:1, or whatever optimum is. 15% is A BUNCH of power to give up when you're making 600+. This is the kinda thing I will test for myself on a dyno if necessary.

I'm also with you on getting AFR where I want it first before adjusting timing. I haven't changed timing at all to date. In fact, I'm planning to swap plugs after I'm happy with AFR values, before I begin messing with timing.

If you'd still like to read up on the BS3, here's the link you asked for: http://bigstuff3.com/pdf/GEN3 User Manual - Feb 2011 - Rev 2.2.pdf

As this is becoming increasingly technical, I think it's time to exchange numbers so we can go direct. Check your pm.

So, check this out. I think I modified these cells in the box once since this log. So, the numbers in the cells are not exactly what the computer used in this run, but it serves the purpose. It's the same run as before. As you can see, the boost spike goes through the 3500 column and when it gets levels off, the top cell is 98. The one to its right is 91. Even with the 98 at the top, you can see that where the spike apexes, it still goes slightly lean. Now, we're only talking about 12.2:1, and that exact lean spike occurs at the 100 cell in the table (it was 98 at the time of this log). I have to be careful where it initially goes too rich, because I must also consider that at higher boost levels, the spike will go through this cell on the way up, and I don't want it to lean out there. So, the 98 cell at (4000,13.6) is causing it to drop AFR deep into the low 10s. Way too rich. It does transition up close to the desired AFR when it gets into the 91 cells.

If I transition through these cells at flat boost, the Actual AFR is far richer than if I'm transitioning through with a vertical boost line. Transient should be what I'm using to compensate, but the MAP transient tables just aren't getting the job done. So, the only thing I know to do is compensate in the main table. It puts me in the position of either running too rich when the boost levels off, or running too lean when boost is still going up. I choose the safer option.

they are possible. In fact, I am using both in this log. However, the only place that they are applied is in the immediate 10th or two of a second after going wot. I'll try to get another screenshot when I get back to the computer. it's like the D map is not sensitive enough to pick up the Boost Spike.