Hi Mike, Please comment on this. 06 Mag, CAI, Cat back. r20 CAI 91oct I adjusted WOT fuel in all three ranges to get my AFR to 12.5 +2.5, +5, +5 I didn't see what it was without any adjustment since I had added a lot of fuel before getting my wideband while I was fiddleing to see if I could eliminate KnR. So when I got the wideband I just figured the delta I needed to lean it out from 11.3 to 12.5 (yea, I added a LOT of fuel, oops). So here is what I posted on that thread. Can you explain why it appears there are gaps for the adjustment?
The 200 rpm gap is where the fueling is blended. You cant just have an instant lean spike, assuming someone tried leaning the upper range only for example, as soon as the motor went lean in the matter of like 50 rpms it would likely pop. If it went lean over a wider range of say 200rpm, it wouldn't be so bad as it would gradually lose power from going lean, keeping things safer. Thanks Mike
I'm not sure I understand. I have an AFR of 12.6 to 12.7 in the 1K - 3.8K range. (I added 2.5% with the Predator) I have an AFR of 12.4 to 12.5 in the 4k - 4.8K range. (I added 5% with the Predator) When I go WOT from 3.5K to 4.5K my AFR goes from 12.6 up to 13.1 and back down to 12.5 as I go through the transition from one range to the next. So it doesn't look as if the 200 rpm is used to blend from one range to the next. It does look as if the blend is from one range to a fixed value and then to the next range. If this is the case and the purpose is to prevent a spike to a lean condition then that fixed value would be towards a the boundary of lean? Assuming my speculation above is correct what is the transition value? or what AFR do you expect it to result in? As soon as I can I will try the CAI 91oct tune with no adjustments. Should I expect an AFR of 13.1 to 13.2 throughout all 3 ranges and through the 200 rpm transitions?
OK, you're just looking at it kinda wrong.... The reason it goes lean there is you are getting in to the peak torque area, where the motor will use the most fuel and tend to go a bit lean, so its not the 200rpm gap causing the lean out, its the actual motors use of fuel...This can be corrected in a custom tune, or band aided with the adjustable parameters, Thanks Mike
Hmmm, ok... I'll try that. Just to be sure that I explained it correctly it appears to be ONLY in that 200 rpms that it leans out. I did not try the 4800 to 5000 area as it difficult to find an area to go that fast in 3rd numerous times and it winds up to fast in 2nd (gauge is up on the overhead console and tach is down on the dash...). I did add fuel. 2.5% to 1-3.8K and 5% to 4K-4.8K which brought both of those to ~12.5 I will try doubling both of those and see if it stays lower in the 3800 to 4000 range. I hope to get a chance to try this today. thanks, Mike
Hi Mike, Did some experimentation. Below I've listed my observations. To check AFR I'm using a wideband (digital display), sensor in front of the cat. To get a reading in the 1K-3.8K rpm range I would lock it in 5th gear and floor it at about 2.5K rpm. To get a reading for the 3.8K-4K range I would lock it in 3rd gear, get stable at 3.5K rpm and floor it while watching the gauge. In all 3 cases the AFR would match that observed at 2.5K and then it looks like you simply lean it out (gradually) by about 5% in the 200 rpms between 3.8K and 4K. Above 4K I would watch it go past 4K to get the AFR there and I tried a couple of WOT pulls in 2nd gear starting at about 5K to verify that range (always the same percentage added in the top 2 ranges). Remember that I started with fuel that gave a pretty flat AFR across all three ranges so I kept the same proportions. It does look like the fuel for 1 or both ranges on either side of the 200 rpm gap is taken into account but it's not used to make a smooth or linear transition between them. It always goes lean. It appears to go about 5% leaner than the setting for either side of the 200 rpm gap. If this is actually the case I think it's really bad. I can understand a smooth transition from one fuel setting to another but I would expect it to be a "ramp" from one setting to the other. It seems that if I don't want to see 13.0 or above I'm forced to run very rich most of the time to avoid that in the 200 rpm transition. Here is what I observed. Just to fill in again: 2006 Mag SRT8 AFE Stage II CAI Mopar/Corsa cat back 180* T-stat Predator version r20, Performance CAI 91 Octane tune. 1) NO fuel modifications to the CAI 91oct tune. Only selected raised shift points. 1K - 3.8K : AFR 13.0 to 13.1 3.8K -4K : AFR 13.5 to 13.6 4K - 5K : AFR 13.1 to 13.2 2) Added fuel and raised shift points. 1K - 3.8K (added 2.5%) : AFR 12.6 to 12.7 3.8K - 4K : AFR 13.0 to 13.1 4K - 4.8K (added 5%) : AFR 12.4 to 12.5 3) Added more fuel and raised shift points 1K - 3.8K (added 5%) : AFR 12.1 to 12.2 3.8K - 4K : AFR 12.6 to 12.7 4K - 4.8K (added 10%) : AFR 11.8 to 11.9 Can we get this changed so the transition trends from one range to the next?
I didn't do any 1/4 miles. They all felt and sounded about the same :dunno2:haha. I want #2 but I'm not sure I like the idea of hitting 13 or over between ranges...
Get it on the dyno my friend..at least once this year. You'll be happy you did..or you should be happy anyways.
Interesting findings.... Were you logging this on the wideband? Do you have these logs available? I'd love to let our guys look them over, and I'll look into it tomorrow as well. Thanks Mike
If you have the FAST wideband you can now buy and add on RPM reader that overlaps the A/F with the exact RPM's
Sorry, no logs. Sooner or later DashHawk will have the Hawkeye to integrate wideband logging with the DashHawk logging. The PLX gauge I'm using (SM-AFR with a DM-100) does have a 0-5v out but I don't have a logger (or even a laptop -- might be able to borrow one of those but I don't have a logger). For description I can offer this: When locking the car in 5th at 2500 rpm and then flooring the car the reading transitions is less than a second. Maybe 1/2 second or a little more? I see one or two AFR numbers flash by on the digital display before it stablizes. Then it's either solid or alternates between 1/10th. For example I'm now running WOT fuel at +3%, +5.5%, +5.5%. So it will be doing the back and forth between about 14.5 and 15.5. When I floor it I'll see one or two numbers between there and 12.4. Then it sort of alternates between 12.4 and 12.5 or just solid at 12.4. Same at 4500 rpm (locked in 3rd). When I watch the gauge at WOT while it moves through the 200 rpm from 3800 to 4000 there does appear to be some "blending" going on. I will see 3 or 4 numbers on the way up to 13.0 and then 3 or 4 numbers on the way back down to 12.4/12.5 I always see it hit 13.0 in about the middle of the transition though. I'm sure that will be evident in algorithm used to adjust the pulse width through the transition between rpm ranges. For the 3 trials I did, the AFR numbers I listed for the 3.8K-4K were the peaks I saw during that transition. The AFR would go up to those peaks and then back down. The AFR numbers for the 1K-3.8K and 4K-5K were "solid" in that they would toggle back and forth between the two numbers listed 1/10 apart. Hope that helps. Very interested is what your guys say about it. thanks, -Dave
OK, I talked to Johan about this. He said to go ahead and set the tune how you like it, and then extract the last tune written, and send it to me. He'll make sure the 3.8k to 4k range is set properly. Thanks Mike
That's great Mike. Give me some time to fiddle with it and I'll get it off to you. Thanks for the great service! -Dave
