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Still on a bit of a SWAG tune with regard to idle stuff and injector data, but it runs. Now I need to start tidying up the tune and various loose ends.
It drives much smoother on the milder cam, and the clutch/flywheel (RPS BC2 Carbon clutch with aluminum flywheel, 25# total) is plenty heavy enough to get the Miata rolling. Haven't driven a stick in 10 months, so I'm a bit jerky, but in two days that will be all gone. :-)
OP, maybe a dedicated MAP for LS3 would have solved your “hole too big issue” on your intake? I had some issue and found there are MAPs made for a bigger hole, it has an Oring vs a red sleeve. Some aftermarket intakes require the larger MAP.
OP, maybe a dedicated MAP for LS3 would have solved your “hole too big issue” on your intake?
This is the stock LS3 MAP sensor that came with the crate motor. The problem wasn't so much that my hole was too big, it's that it was oval after my screw up.
Made some good improvements to the tune today in the area of driveability and idle. I'll continue this tomorrow. I'm also going to yank the dash out (only takes 15 minutes) and wire in some switches that are going to be part of the next small project. I'm also going to wire in a USB charger so I can charge my phone ... USB isn't "vintage" like the rest of the car, but I'll make this exception because it's useful. This is going to be a road trip car, and I want to be able to run Waze on my phone without draining the battery in 100 miles.
I'm working on tuning the idle and low end. It's running pretty rich down there. The internet wisdom is that this is because the O2 sensors are lying to the PCM under low flow conditions and telling it the car is way too lean. I'm thinking about doing a tune where the car runs in PE mode up to 1200-2000 rpm or so. That would have it in open loop until then, and it'd ignore the O2 sensors. To do this, I need my VVE table to be better calibrated.
Some guys like to go to a complete SD tune, but I'd rather keep the MAF and O2 sensors working in regions where they work well.
Besides the excessive fuel consumption and obvious rich smell, it's running smooth. Just need to lean it out.
Personally, I’d set it to MAF only and get that tune happy. My C5 has been MAF only since day 1.
I have the older operating system, much different ECU etc.
Then I’d set it up for SD using your Virtual VE. At least thru 4000 rpm.
Then put it back to blended.
Your cam isn’t large by huge, it might be fooling the NB O2’s if the headers are long and they just don’t get hot enough? Would like to see a data log. See how well they switch.
If you have followed my “experiment”, which is quite stunning, your deal with Tony’s help will scare the crap out of you in that light car when you put the pedal down! Keep up the good work!
Personally, I’d set it to MAF only and get that tune happy. My C5 has been MAF only since day 1.
I have the older operating system, much different ECU etc.
Then I’d set it up for SD using your Virtual VE. At least thru 4000 rpm.
Then put it back to blended.
Your cam isn’t large by huge, it might be fooling the NB O2’s if the headers are long and they just don’t get hot enough? Would like to see a data log. See how well they switch.
If you have followed my “experiment”, which is quite stunning, your deal with Tony’s help will scare the crap out of you in that light car when you put the pedal down! Keep up the good work!
Ron
The NB O2s are heated, aren't they ... how would they not get hot enough? I do have long tubes on it.
Agreed that long term I want to fix the MAF tune and then SD and run blended ... but I'm not sure I can trust the NB O2s to tell me if I'm lean and which way to move the MAF curve. However, running it open loop right now, it pops quite a bit on decel, so that tells me I'm pretty lean. And the O2 signals are pegged low. I got it to cycle before by moving the MAF curve up at low flows, but I moved it up a LOT (like 30%), and the LTFT and STFT still kept trying to make it richer. I could see the O2 cycling then, though.
If the NB O2 is not reading correctly for some reason, I wonder if my wideband will be any more accurate. They use widebands stuffed up the tailpipe to tune on the dyno, though, and that seems to work. Maybe because most dyno tuning is at full throttle, so there's lots of exhaust flow.
I'm feeling my way with the tuning, I've still got lots to learn. I'll just be careful not to run it lean under load, and go from there. Realistically, there's no "load" yet, I'm working idle and light throttle cruise. I also pulled 4 degrees of timing out of the map globally to compensate for the compression jump from 10.7 to 11.8.
Correct on the O2's. I believe the heaters are there to get them online quickly at cold start. Then exh heat takes over.
My vette has headers, but they are actually more of a mid length header. I had them coated to keep the heat in. Never an issue at idle. Runs closed loop just fine.
Is your ECU from the GM plug and play setup for the LS3? I tuned one of those at the shop. It was the 480 hp version.
From the factory it was set up MAF only. I downloaded the 430 horse, and 525 horse setups from GM and they are all set up to be MAF only.
So would be interesting to see your tune.
btw, the popping on decel could be due to DCFO still being active.
Update on tuning progress. I'm just working on driveability now, getting the MAF and VVE table right, etc. The streets are too slippery here in the PNW to use any of the new power.
Ever since this engine was in the car (both with the original GM Hotcam, the subsequent GM ASA cam, and the MAMO spec cam), it's had issues with the low speed driveability between say 1200-1800 rpm in 1st and 2nd. Parking lot creeping ... it would buck and surge like crazy. I've been reading lots of posts on various forums, and it's much better. I keep pulling ignition timing out of that area, and it keeps smoothing out. I've also messed with the O2 sensor modes and injection timing, but ignition timing has by far the biggest effect on this engine. I'm very optimistic that I'll be able to get it to "drive like stock (TM)" with some more attention to this. Since it's my daily when it's running and the weather isn't awful, that's the goal.
Today it got the winter tires, 195/50R15 on 15x7 wheels. I'll use these for road trips in the summer, too.
Today it got the winter tires, 195/50R15 on 15x7 wheels. I'll use these for road trips in the summer, too.
LOL!
195/50/15 Tires!!
Thats some funny **** right there!!
This is a joke right?!?
LOL!
[/QUOTE]
i run 225/55/19 on my Camaro in the winter. Pretty normal to run tires that are a little narrow in the winter since they can cut through the snow easier than wider tires unless its hard packed snow
Still working on the tune. I got some hints from a member on here (not sure if he'd want to be named, if you read this, feel free to take credit), and the major contributor to my bucking and jerking below 2000 rpm turned out to be O2 sensor tuning. The well regarded pro that tuned it before didn't touch that, even though I have longtubes. That made a major contribution to better driveability. I also did some tweaking of end of injection timing. Another breakthrough was a blocking plate that prevents the air from blowing *across* the end of the Corvette intake tube I use. The resonance caused by that airflow was putting a ton of noise on my AFM signal, and contributing to what felt like misfires at low rpm cruise in 5th and 6th gear. That's the sort of issue that wouldn't necessarily have shown up on a dyno at all, and an argument in favor of doing your own tuning, I expect to rent some dyno time in the next few months and do some full throttle tuning, after I have the MAF and VVE stuff nailed down in the low load regions.
Today I measured the highway mpg (which I care about, this car does road trips in the summer). It got 27.6 mpg. The stock 376/480 crate motor got 26.5 mpg, and when I "upgraded" to the ASA cam, it dropped to 23 mpg. That's not near good enough in a light car like the Miata. Nobody ever believes me, but a major motivation to do the Mamo engine upgrades (better heads for more port velocity and compression, milder cam) was to improve driveability and mileage. So far I'm winning on both those counts. Power was a minor consideration, since I already had plenty of that.
Last edited by grubinski; Dec 21, 2020 at 02:44 PM.
Still working on the tune. I got some hints from a member on here (not sure if he'd want to be named, if you read this, feel free to take credit), and the major contributor to my bucking and jerking below 2000 rpm turned out to be O2 sensor tuning. The well regarded pro that tuned it before didn't touch that, even though I have longtubes. That made a major contribution to better driveability. I also did some tweaking of end of injection timing. Another breakthrough was a blocking plate that prevents the air from blowing *across* the end of the Corvette intake tube I use. The resonance caused by that airflow was putting a ton of noise on my AFM signal, and contributing to what felt like misfires at low rpm cruise in 5th and 6th gear. That's the sort of issue that wouldn't necessarily have shown up on a dyno at all, and an argument in favor of doing your own tuning, I expect to rent some dyno time in the next few months and to some full throttle tuning, after I have the MAF and VVE stuff nailed down in the low load regions.
Today I measured the highway mpg (which I care about, this car does road trips in the summer). It got 27.6 mpg. The stock 376/480 crate motor got 26.5 mpg, and when I "upgraded" to the ASA cam, it dropped to 23 mpg. That's not near good enough in a light car like the Miata. Nobody ever believes me, but a major motivation to do the Mamo engine upgrades (better heads for more port velocity and compression, milder cam) was to improve driveability and mileage. So far I'm winning on both those counts. Power was a minor consideration, since I already had plenty of that.
Looking forward to seeing some dyno numbers on this combo; want to do something similar with my LS3. Thanks for the update Sir.
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