gsf-87IROC

I am working on tuning my 383 and was wondering...I'm off the MAF Tables...so I've reverted back to the 6E stock MAF tables(ARAP) and am starting to tweak MAF Scalars to drive the values in each table up.

Well, Tunerpro has its max limits for each table MAF Table(not scalar)set in the XDF. Is it just a matter of going into the XDF and tweaking these numbers so the max can go higher....or is this playing with hex and will it cause an error in the chip when I burn it to the Ostrich?

It seemed like I was maxing out my tables today and MAF scalars weren't being of much help to drive those numbers higher. Sometimes...the tables would let you go higher...but when popping into the graph to smooth things out...I couldn't drag points that were off the graph w/o them jumping down to the max level.

Thanks
Greg

gsf-87IROC

This appears to NOT work. I tweaked the limits in Tunercat and was tuning fine, making progress...I 'thought'...and then when I saved, shut down...it appears it reverted back to the old limits and the MAF tables were flat.

Maybe this is common knowledge...but as never having to tweak the MAF table limits before, it seemed logical.

So I am going to tune the MAF Scalars...I think...until everything is rich...then start tuning from there. Seems like the WB needs to all be 15.5? or less for you to have enough room with a 383 in the MAF Tables(not scalar) to be able to get it tuned in. Thats a rough number....but I'm trying to figure it out.

funstick2

Convert to a 1227730 and end your misery.

Duts87ss

iTrader: (10)

Have you tried adjusting your Batt Voltage vs BPW tables? Bumping the numbers in this table will give you more fuel across the board at a given voltage; so you'll have to readjust all of your MAF table cells more than likely.

gsf-87IROC

I got it figured out with the MAF Scalars. By tweaking what I commented on above...it just adjusted the XDF>..but if the scalar's weren't adjusted to allow that higher range in the table, it would just snap back to the highest allowed value the scalar was controlling.


It was a matter of me learning the adjustment and how XDFs work with bins. I went in and adjusted those upper values as I got off the tables with the MAF scalars....this was so I could tweak the graphs rather than the cells in the tables to smooth things out.

As for converting to SD...Why didn't I think of that! I just chose not to do it at the same time as an engine swap so I wasn't chasing my tail on errors...something I have seen others pain with over the years.

customblackbird

iTrader: (15)

can u explain how much the scalars effect the MAF tables? im almost to the point of you... i cant really add much MAF to my 2,3,4,5 tables since the first and last value can only go so high. so im kinda stuck. i got all my idle and low throttle running good. but im afraid to increase the scalars since im having a lean condition after AE and before PE. its in the 65-100gram MAF range and around the 160LV8 range. this shows me that its my 3,4 MAF tables. i would like to increase the scalars in these tables but i dnt know how to blend it in with the other stock tables. can u explain this?

my lean condition isnt bad, i got it running 14:1's in all low throttle situations but just after i press the gas and steady out and then give it more gas it gets lean like 15-16.5:1.

gsf-87IROC

Each click of the MAF Scalar 'up' seems to move the upward value maybe 1 gms/sec...or it may have been 2 clicks got you about an extra gms/sec.

The lower bound appears to be easier. When you adjust the MAF scalar up...do a save, then reopen your MAF tables and they'll adjust with the new maf scalar. Then simply adjust the upper and lower bounds so they match the above and below table. If you use the graph, you'll have to go in and adjust hte upper bound in your xdf so you're not off the chart. It will not allow you to adjust if you are higher than what it thinks you should be at for your upper value(this applies ONLY to using the graph...not to the chart itself)

Hope this makes sense.

305sbc

iTrader: (3)

+1
This would be my first choice.

If sticking with the MAF I would just let the table do it's job for lower RPM part throttle like it is meant to.
For anything more I would either bring some of the global factors like injector size more in line with what I needed, and/or use the PE table to handle the extra fueling needed.

Realistically if you're NOT in PE mode, then how much could you be exceeding the MAF limits with normal driving ?

If you're really into working with MAF tables, then you should study the Hack more and then add the constants you need to work with to your xdf file.
I don't work with Cat, but I've heard they will update the file with needed changes for you on request.

funstick2

Make a bigger housing for your MAF. This will resolved the issue but you'll have to start by manipulating the injector constant to get it to run.

funstick2

Ok the scalar is pretty easy.

255 is the maximum value in table 5

255 is 8 bit for all bytes on

to get decimal places in the table you have to divide the maximum number of bytes to get more table resolution. although you could in thoery just set all the scalars in MAF tables 3,4,5 the same as table 5 but the thing is that you cannot get around the fact that you are going to hit the 255 speed limit.

My advice. Make the maf housing bigger or figure out how to get a different MAF to work.

but you could always repin to 1227730 and end your misery.

customblackbird

iTrader: (15)

thanks i actually played with it for a while and figured it out before u posted but you are correct... 1 scalar increase is roughly 1g increase globally.

a 165ECM with MAF is much easier to tune than a 730... not to mention the MAF is much user friendly to changes in temperature and engine mods. THE only limitation to MAF is the housing flow and limits of the ECM with 255g. But there are MAFs out there that will program the stock ECM for a 550g MAX which is more than enough for MOST HI PO applicaitons.

now i have a grannelli adjustable high flow MAF but ive tried it in the past. seems to cause a throttle BOG/hesiation when i step on the gas from a stop/light cruize. i couldnt get around it with tuning for some reason. pluggin in the stock MAF would cure the problem. right now im running the stock bosch MAF without screens. Now changing the stock MAF or increasing the MAFs DIA will cause u to inevitably change the scalars. since your changing how much air the MAF is flowing at a given rate that cools the wire etc. Now older MAFs will read a lower voltage than whats there due to the age of the electronics etc so the scalars would have to be changed also.

ive tried injector constants, my injectors are ford SVO 30lb red tops. set at 43.5psi ish.... that makes them a 30.76lb injector... i had lowered the injector constants to 28lb and it still didnt correct the MAF issue/lean condition. ive got it running better now and this is what i had to do. I increased the scalars for 1,2,3,4,5. table 1 i increased up 3 scalars, table 2= increased 3 scalars, table 3 increased 4 scalars, table 4 increased 3 scalars. table 5 was 2 scalars then i minipulated the values at idle and in my lean range to get where i wanted it. it runs pretty good but i still get a lean condition after i have pressed the accelerator say 15% and then quickly press it to say 35% the wideband shoots to 15.5-16.:1 but as i hold the pedal the WB will work its way down to 14.5ish. so this seems to happen around 160LV8 and in the range of 40-95grams on my MAF.

I would think its AE vs LV8 but there is no AE setting for 160LV8. all i have is 128LV8 and 192 LV8. does this sound like a AE problem or a MAF gram issue? if i press the pedal to 39% i have PE set in and it shoots to 12.5:1 and the car takes off lol so its right before PE.

Orr89RocZ

iTrader: (20)

Seems like alot of people are having issues with MAF tables. Its not all that complicated. There is no need to go with 730 ecm.

Like said somewhere above, you can adjust the tables manually to a certain point. Once you hit that limit, you need to jump the scalars to allow more range of adjustment.

I did the stock MAF to 3.5" custom MAF setup and had to adjust my scalars drastically to allow me to adjust the table values high enough to account for the incredible amount of air that was now coming in. The car wouldnt start up at first with the stock MAF sized tables I ran. You should beable to adjust the MAF tables to whatever you want.

My 383 never ran below 15 to 1 after tuning was 'done'. I had idle running as low as 18 to 1 at times with stock like tables before tweaking it more. WOT was in the 12.8-13.0 to 1 range when finally done

You would need an incredible motor combination to exceed the MAF at normal driving and not in PE mode. IF you disable PE mode, you would likely have to be WOT at higher rpms to max the MAF.
My 400whp 383 maxed the 255 g/s limit at 4500-5000 rpm range at WOT from what i remember. PE mode was needed to control fuel after that point which can handle fuel input as high as 6400 rpm which will carry farther than any sensible street motor will need. I shifted 6800 rpm alof of the time and had plenty of fuel room. I had approx. 70% extra PE at the 6000-6400 rpm ranges.

Guest

Honestly with a stock maf in a larger housing " or any large housing" I would make the bottom 3 tables high resolution with a large divisor to give you good low speed fueling and maybe even stretch that into table 4. Leave table 5 for big airflow where small errors won;t account for much. Still the best way to do this in reality if you a die hard maf fan is to read the $32b sticky. You can simply state injector time by LV8 and rpm. Pretty much resolves the issues with trying to screw with the injector constant and the maf tables. resize housing and go after the Pulsewidth table.

Orr89RocZ

iTrader: (20)

I didnt notice any low speed fueling problems with my setup. I wish I had my bin file for that large MAF to check my values but that laptop died on me. I think I had 255 in table 4. HUGE scalar difference from a 3" stock housing. It basically made resolution worse than stock but it was more than enough to have good fueling from idle to part throttle. WOT is all PE mode so no worries there.

customblackbird

iTrader: (15)

do you have the link?

doc

With my MegaMAF (Bosch MAF stuffed into a 3.5" aluminum tube), in order to register 38% more airflow, which is just about right for the change in flow areas, I used the following MAF scalars: 20, 42, 73, BA, FF, FF

Yes, the MAF values pegged out in the 5th table, but by then you best be in PE mode, so its no issue.

EDIT: I always use the correct injector flow constant; I adjust the airflow when a change in the MAF has thrown the fueling off according to my wide band and the BLMs. I usually let the BLMs guide me to the correct MAF scalar values. Then follow up with the WOT tuning.