Turbocharged Tuning strategy using MAF only (MS3-pro)

[E30_Driv3r]

Thanks again Subwoofer big time for the filtering tips!

Did some more correcting and logging. I've been able to move up in the range quite a bit. I think i'm headed in the right direction as in using VEAL my values after the first correction were upto 140 in the table but with the last correction they have gone down to about 123 max. It's tricky keeping the curve smooth as you apply different amounts of correction at different voltage points along the curve but afterwards I am smoothing the curve by hand. I've included a pic of the curve I hope its looking more acceptable! I've also included my log and drew what i used as the "band of correction" so again let me know if i'm on the right track. Thanks!

http://www23.zippyshare.com/v/16934485/file.html - my log

[subwoofer]

You are well on your way, now sit down with the calculator and massage the MAF curve from the data you posted as a scatter plot. Your idea about the line through the plot is spot on! (For a bit more resolution you can press the funnel again, the filters stay applied but the view expands back).

Don't forget to reset the VE1 table after you correct the curve. The next drive you take with the corrected curve should produce data with a lot closer to 100 across the band, EGO will have less to do and the car will feel smoother.

Rootin' for ya', you can get this perfect in two more iterations I think!

[Xnke]

I hope by the time I get my proper airbox ready to go again, someone has MAF tuning down solid for the MS2Extra/MS3 methods of tuning the curve...MAF support has grown by leaps and bounds in the last year and I'm really getting excited!

The drivability on MAF is just fantastic compared to MAP or Alpha-N, in my experience, especially with a big cam or ITB's.

[winstonusmc]

I think its funny when guys fight to justify speed density over MAF. Having ran and tuned the same engine on both setups, I can say I like MAF way better. Even with an open air BOV, it runs great. I am just concerned when I take my car to get it tuned, the dumbass that tunes it won't know what to do when he wants to change AFRs. Now we just need to convince Phil Tobin to write in a tab to use VEAL on said MAF curve, but that's another thread.

[E30_Driv3r]

Sorry guys for the lack of updates...I unfortunately had some det resulting combustion leakage from a bad tank of fuel and have my cyl head off for upgrades.

prior to that I was REALLY enjoying the maf setup once I got it rather dialed in. Behaves very well compared to when the car was on a SD tune. It still needs to be fully sorted in the higher boost regions but for safety as you can see in my VE1 table I fudged the fuel so It would be rich initially and I can log and set the correct G/sec values. The vacuum region I'm overall happy with and after one more log may leave alone as you can see is pretty close to little/no correction. The only thing giving me trouble is on cool nights the car seems to idle rich (11.8-12.0afr) while during the day it will sit at a perfect 14.7 all day long. One morning and if the car heat soaks I found the car to be idling rather lean(15-16afr) . I tried playing with MAT correction which did help but I remembered it would be pulling/adding fuel not just at idle but in boost as well so I set the MAT correction back to"0" everywhere. Has anyone else had to play with MAT correction on their maf setups? from reading the megamaunal MAF setups should need very little to no MAT correction since it is measuring the actual airflow into the engine. Also, any tips for keeping the curve smooth while only making changes in one area? As you can see I have very small lumps but it seems to be on the money fueling wise so I haven't tried to smooth it out for the sole purpose of it being easy on the eyes.

Should be a few more weeks until everything is back together and I am back on the road. Can't wait!

[mr_minnis]

Cool another PMAS HPX user!

I purchased one last week and got it up and running on my 88 mustang. I was using a stock meter before. I was so suprised they easily supplied a 64 point curve. I wish I would have ordered a 85mm (I am using the stock tubing and wasn't sure what would fit).

I was able to key in the the flow curve and fire it up. The arf seems to be pretty close. I am going to do the procedure subwoofer came up with to verify. I am also going to get my accurate dead time and voltage correction correct. IMHO if the dead time is off you will have the wrong amont of fuel delivered, and you can adjust for it.

MAF is the way to go, if you can get the curve and you injector data you are 90 percent there.

[PMAS]

Hey guys, this is Nick from PMAS. If you need any help from me just let me know. I would love to help you guys implement our mafs with MS. I can easily make changes to the spreadsheet as well.

[jsmcortina]

Hey guys, this is Nick from PMAS. If you need any help from me just let me know. I would love to help you guys implement our mafs with MS. I can easily make changes to the spreadsheet as well.

Welcome.

I'm not sure how much experience your company has of the Megasquirt product range, but if you were able to supply data for "new style" MAF flow curves for your products, those could be made available on our site in Megasquirt format for customers to download.

We appreciate you jumping in here and offering your support.

James
(firmware developer)

[PMAS]

I have very limited experience with MS but this is not a problem at all. How many data points are needed? 30 60? and at what voltages? 1024, 512 or 256 from 0-5v etc?

I was also thinking about purchasing a MS3 to convert my boat. IT is a supercharged dual carbed 496 BBC. I would be using dual mass air sensors and Tb's with an averaging circuit so that project might be helpful for you guys.

[subwoofer]

The new style curve is 64 points, arbitrary voltages. MS3 now integrates flow during the engine cycle, so no need for averaging circuits. They could actually reduce the accuracy significantly in the problem areas.

[PMAS]

Sorry for the delay. Here is an HPX tool with 64 points that is fully unlocked. Have fun!

[PMAS]

Also please note that the VMP Hpx maf sensor does not use the same curve as ours. so this data only applies to a PMAS HPX. THe VMP has its own curve. Similar but not the same.

[E30_Driv3r]

I'm a bit late to the thread but WOW! really awesome to have you guys at PMAS here on the forums. I am still using the HPX maf, works great! Doubt I'll be using anything else! Just cracked 601whp on pump gas with your hardware/MS MAF algorithm! Thank you for the spreadsheet as well! I will re-tune my curve with it next spring on e85

(ignore the TQ, pickup wasn't working)

[PMAS]

Nice work on the E30. Glad it's working out great for you.. We just have to get all these SD guys to convert now LOL

[EspeNS]

Very interesting E30 project.
Actually I've been helping a mate tuning a M50B25 in a E30 the last couple of years with a MS3X. First NA, so supercharged, and the engine is now out for a rebuild and stroking to B28 with a diesel crank and lower CR. It wil be getting a turbocharger.
I didn't tink the plastic manifold could stand the boost level i guess is needed for 600whp.
I wonder if you could tell which boost level you running, and maybe if you have done somthing with the engines internals?
I want to try a MAF on that engine also. I think the CR wil be low enough to maybe up to 2 bar on pump gass, so 600hp may be in the reach.

Best regards Espen