highly Posted October 29, 2008 Share Posted October 29, 2008 Now that I have most of the issues with my MS1extra / EDIS sorted out and real tuning can begin, I'd love some opinions on my target AFR table. The engine is a stock 83 turbo motor, stock injectors, stock turbo running stock boost for now. Wideband set to 10-20 = 0-5v. Here's the table: Thoughts? Please feel free to weigh in here. The forum seems to lack any definitive information where AFR target tables are concerned, and they seem to vary greatly. I have attempted to aim for the following with the table: 13.8 for idle 14-15 under light cruise 12.5 low/no boost 11.5 under boost I'm in Oklahoma City and my MAP value before cranking is basically always "95". This is always lower than reported barometric pressure, but it'w what the sensor reads Quote Link to comment Share on other sites More sharing options...
evildky Posted October 31, 2008 Share Posted October 31, 2008 looks pretty safe, but I'd lean out the idle a bit, no need for a rich idle Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted October 31, 2008 Administrators Share Posted October 31, 2008 looks pretty safe, but I'd lean out the idle a bit, no need for a rich idle Maybe not a need, but the old L just loves a fat idle. The forum seems to lack any definitive information where AFR target tables are concerned, Probably because an awful lot of it is art/preference... not absolute science. 13.8 for idle Since you've implied a heavily stock engine, you'll probably find 'cleanest' idle between 12.8 and 13.4. 14-15 under light cruise 14 is unnecessarily rich. 15 is a fair target... slightly lean of best emmisons, and slighty rich of best economy. Dont be afraid to experiment here. Risk is low. 12.5 low/no boost 13 to 13.5 will probably provide best performance at atmospheric loads. Blend those into your peak boost. I don't tune any richer than 14 for anything other than heavy atmo loads. 11.5 under boost With a stock L28ET @ 5/6 psi, you shouldn't NEED to run that rich. 12.5 is more than enough fuel. Quote Link to comment Share on other sites More sharing options...
highly Posted October 31, 2008 Author Share Posted October 31, 2008 Thank you very much for the advice. My previous tuning experience has been on a 1st gen DSM years ago (took it to 535 whp) and on my Honda D15 (tuned to 43-45 avg MPG). They are both a far cry from the L which seems to like things a bit different. All I've had to work with on the L is what I've managed to gather here, and the numbers seemed richer overall than from my previous experience. Since holed pistons tend not to support tuning, any experience I can gain here is goooood. I went MS first before all the other mods begin to get a better understanding of both the L and the MS. I can see now that was, indeed, a wise choice. At what point should I aim for richer AFRs as the boost starts to get turned up? Assuming my current fuel system keeps up, does just hitting 11.5 or so at 10-12 psi seem more like it? Do the cell selections seem OK or should I weigh things more heavily towards off-boost driving by shifing the table down and adding rows in that area? All this power (in MS) means lots of decisions, and some of them seem a bit arbitrary at first. I expect to be adding knock control before too much longer to aid tuning and provide some safety against iffy fuel, and once the T3/T04e is on in the spring I expect to take it to the dyno to "peak" the tune, but in the meantime really prefer it to stay together. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted October 31, 2008 Administrators Share Posted October 31, 2008 At what point should I aim for richer AFRs as the boost starts to get turned up? Assuming my current fuel system keeps up, does just hitting 11.5 or so at 10-12 psi seem more like it? There is no magic AFR. Read the thread below. You'll find some useful AFR tidbits buried in there. Pay particular attention to TonyD's EGT's vs AFR's. http://forums.hybridz.org/showthread.php?t=127356 Also, TimZ is currently making over 750HP and has shared some AFR experiences. Do a member search for him, as well as JeffP, another heavy hitter with some reports on AFR's. They're pushing things a lot farther then you intend, but the trends they report have value. Do the cell selections seem OK or should I weigh things more heavily towards off-boost driving by shifing the table down and adding rows in that area? Actually, I would not be very contented running a nearly 2-bar car with only 8 load bands. Doesn't MS have a 12x12 table available now? If so, I'd be all over it. Quote Link to comment Share on other sites More sharing options...
highly Posted October 31, 2008 Author Share Posted October 31, 2008 Actually, I would not be very contented running a nearly 2-bar car with only 8 load bands. Doesn't MS have a 12x12 table available now? If so, I'd be all over it.MS-I V3 running Extra code. Maybe Hires and MSII have 12x12 AFR tables, but in 1-Extra, this is it. Fuel and spark tables are 12x12, though. Thanks, and I will do some more looking around. Thanks for the help and direction! I'll be posting current street-tuned tables in the sticky before long. Hopefully fill in the gap for an all-stock car on MS1-Extra and EDIS. Quote Link to comment Share on other sites More sharing options...
highly Posted November 2, 2008 Author Share Posted November 2, 2008 Revised, and running MUUUUUUCH better. Let the tweaking continue! Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted November 2, 2008 Share Posted November 2, 2008 Congrats. If I can get megatune to stop locking up I need to work on mine too. The MSQ I borrowed from another member had the bottom of the afr table VERY lean, causing surging at light throttle. 1st and some of second was unusable at light throttle. I've richened it up a little and it's much better, looks like you've done the same. Now I just need to work on the backfiring on decel. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted November 2, 2008 Share Posted November 2, 2008 Congrats. If I can get megatune to stop locking up I need to work on mine too. The MSQ I borrowed from another member had the bottom of the afr table VERY lean, causing surging at light throttle. 1st and some of second was unusable at light throttle. I've richened it up a little and it's much better, looks like you've done the same. Now I just need to work on the backfiring on decel. Backfiring on decel....if it's just a put...put.....put.put......put....then it's normal if you have a fairly open exhaust. I think it's due to oxygen getting up in the hot exhaust and burning off some of the remaining volatiles. My Z won't tolerate much leaner than 14.5 just about anywhere. Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted November 2, 2008 Administrators Share Posted November 2, 2008 My Z won't tolerate much leaner than 14.5 just about anywhere. I can cruise all day long at 17. Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted November 2, 2008 Share Posted November 2, 2008 Ah, it is just a put put put. I have headers and straight 2.5" through a turbo bullet, so pretty open That explains that. I attached my afr table as a reference. I'm still working on it, but it's running fairly well like this. I idle around 800rpm at 50-55kpa. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 2, 2008 Share Posted November 2, 2008 Yes, 16:1 at cruise is not anything untoward. Fuel cut being properly set up will eliminate the put-put-put...and if you lean it out, chances are there won't be enough HC in the exhaust for one put, much less a three-putter. On turbos, past the torque peak, you can pull much more fuel than you would think. Even on JeffP's heavily modified setup, we were closer to 13:1 than 12:1 past the torque peak! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted November 2, 2008 Share Posted November 2, 2008 Well maybe my O2 sensor is wrong (I do fresh air cal's regularly). She will have MAJOR holes in the power, or outright misfiring, at 15+. Unfortunately MSII doesn't have fuel cut on overrun. I'll have to look at other firmware revisions... Could be my injectors aren't misting nicely too? Quote Link to comment Share on other sites More sharing options...
highly Posted November 2, 2008 Author Share Posted November 2, 2008 Huh. I dip anywhere near 16 (15.8 or so) and I can feel it chugging. This is under light driving around 40-45 mph, low vac (25-35 kPa) and rpm (about 2100). Maybe I will try leaving it at 15 and targeting 16 with EGO Control. See what that buys me. TrumpetRhapsody: I don't see that this engine (lower compression boosted) is going to "like" driving around with AFRs that low below atmo. I'm in the same boat as Cygnusx1. I get below 15 by much at all and it starts in with very slight hesitations as felt on the SOTP sensor (seat of the pants sensor...you know, the Butt Dyno. No, I can't log that one.) RonTyler: I am going to have to pay more attention to your setup! My high compression Honda D15 will do that (17 and lower AFRs) all day long and smile. The Z will just laugh at me. Possibly even snort in the process. Is this a batch fire/ wasted spark vs sequential issue? Timing values in cruise? Oh, thanks again for the reading material! I started out with Metro's settings from the Mobythevan sticky. I am running it in 2 squirt alternating, and have ended up pulling a good bit of fuel out. I haven't touched timing yet. I'm also trying to keep with safe (rich) values in boost until I can get that knock sensor in to keep the engine together. Destructive testing is NOT the goal. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted November 3, 2008 Share Posted November 3, 2008 Actually, I would not be very contented running a nearly 2-bar car with only 8 load bands. Doesn't MS have a 12x12 table available now? If so, I'd be all over it. MSI extra code has 12x12 VE tables and spark tables, but only 8x8 target AFR tables. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 4, 2008 Share Posted November 4, 2008 "This is under light driving around 40-45 mph, low vac (25-35 kPa) and rpm (about 2100). Maybe I will try leaving it at 15 and targeting 16 with EGO Control. See what that buys me." The answer there is 'wrong gear for speed'! Shift down one gear, raise your rpms to around 2700-2800 and try again. You're lugging the car, and mistaking the bucking for 'lean surge'. Do a datalog on injector pulsewidth the way your currently driving, and then make another pass under the same conditions using the lower gear and you may be suprised by what you find. You should not be putting a load on an L6 much below 2500, and ideally 2700. Same as a 5.7L V8 turning at 1200. They don't like much of a load that low in the rpm band in a stick. Quote Link to comment Share on other sites More sharing options...
highly Posted November 4, 2008 Author Share Posted November 4, 2008 I'm not talking about accelerating from 1500 rpm here. Steady state cruise on a flat road between 21-2500 rpm doesn't seem like lugging to me, but it may be. I would expect poor transient response in that range, and if I were to accelerate from there I would indeed downshift. I will look at it as you suggest, though. Maybe it is the driver. Quote Link to comment Share on other sites More sharing options...
ktm Posted November 6, 2008 Share Posted November 6, 2008 I can not go any leaner than 16 myself. Once the AFRs swing north of 16, I can feel the car lean surge on me. It is quite happy at 15.5 to 15.8ish and will do that all day long. However, my idle is at 14ish and the car is happy. I can not go any leaner because I am at the minium PW of my injectors without them acting up (right around 1.3 ms). Any richer and I am burning unnecessary fuel. I've got overrun fuel cut setup on my car (not MS) and not a single decel backfire. Works like a charm. Quote Link to comment Share on other sites More sharing options...
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