• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

tune advise

Juanmiguel

Juanmiguel

New member
So I just recently went cammed and droped to a 3.25 pulley. Now I'm in the process of acquiring a DHP power tuner (thanks Bbptech). I've also been reading the wiki page stickied in this section on how to do a VE tune.

My question is, given that I'm planning on using a basic DHP tune as start point. In order to adjust the tune to accommodate the new mods, do I need to modify all the tables (VE, MAF, timming and O2) or just a couple of them like O2 and timing?
 


Concentrate on one table at a time.....watch your fuel trims, and your KR. If you're positive on the trims too much, you need to add fuel, subtract if the trims are too negative. +/- 4 is your goal, and make sure when you're in PE mode they lock in at 0.0

The first thing you should do, is find the section in your timing that is where your WOT timing will be, on the DHP it is usually the bottom portion of the timing tables where it's lowest. Pull about 6* out of that to keep things down at first until you get the fueling taken care of.
 
Most people skip the VE tune. You can try it, but it's not the easiest and most productive way to start.

Get on the powrtuner forum right away after you get the serial # from the powrtuner to get access to the downloads section. Make sure you have all of the .net and keyspan drivers downloaded. Download UVscan and use that for scanning. Download Eddies table modifier and use that for maf tuning, do not do too much at one time like Reptile said.

One of the most important parts is learning how to get a good scan. Going WOT right away will not get you anywhere. You want to start small and work your way up the maf table, if your tuning via fuel trims and maf table, it would be a good idea to disable PE and never go WOT with PE disabled. This means slow, easy cruising going through various throttle positions very slowly. A scanner does not collect data in real time and the slower you go the more info. that can be gathered and analyzed. After getting a good scan and either using eddies table modifier or manually changing your maf table, make small changes and then upload and reset the fuel trims when playing with fuel tables.

Once you have reset the trims, it really does take up to 30 minutes of driving through various throttle positions and restarts sometimes for them to re-learn. If you start logging before the fuel trims are learned, it may not help your next change or throw things off. Then repeat enough times and slowly work up to 60% throttle or until you see some knock, well at anytime if you see 2+ degrees of knock, stop and back off some timing/pulley down. After you have things pretty well figured out, enable PE. This should get your maf chart dialed in pretty decent.

After that it is WOT tuning and this is where a wideband comes in very handy.
 
Ok so I'm at my 4th pass tunning the VE table. I still see 2 digit numbers in my fuel trims at idle, besides that I can say it's fairly between +- 10 when moving.

Should the trims also be between -4 and 0 at idle?

I'm not sure how many passes should I be doing, seems like getting the trims between -4 and 0 will take a long time.

I'm using the table modifier thing at 50% and using ltft and stft for calculation with 3 hit counts or more.
 


this is the adjustments from the modifier out put. I guess the trims are in the positive numbers in average, although i'm not sure if the quantities added are enough to make a significant difference in the trims:

MAP kPa|RPM Cell|Old Value|Average FT|Adjustment Amount|New Value|Hits
=======================================================================================================
20 0 0.3688965 0 0 0.3688965 4275
20 1600 0.514079 1.603618 0.006182899 0.5202619 19
20 2000 0.5212091 -0.1420455 -0.0005552653 0.5206538 11
20 2400 0.5196945 -1.450893 -0.005655157 0.5140393 7
20 2800 0.5167581 -4.296875 -0.01665334 0.5001047 6
30 800 0.5020993 0.4261364 0.001604721 0.503704 11
30 1200 0.5450789 -0.0813408 -0.0003325286 0.5447463 413
30 1600 0.5679294 0.940534 0.004006177 0.5719355 103
30 2000 0.572019 1.367188 0.005865429 0.5778844 16
40 800 0.5320979 2.154216 0.008596903 0.5406948 507
40 1200 0.5746939 6.960227 0.03 0.6046939 132
40 1600 0.6126699 4.862608 0.0223438 0.6350137 58
40 2000 0.622858 5.989583 0.02797995 0.650838 21
50 800 0.5596333 3.90625 0.01639551 0.5760288 22
50 1200 0.6185703 6.933594 0.03216687 0.6507372 16
50 1600 0.6493966 5.380155 0.0262039 0.6756005 97
50 2000 0.6775228 4.427083 0.02249587 0.7000186 24
60 1200 0.6116282 5.902778 0.02707729 0.6387055 9
60 1600 0.6629663 3.515625 0.01748056 0.6804469 24
60 2000 0.6825233 4.805425 0.02459861 0.7071219 53
60 2400 0.7000269 3.359375 0.0176374 0.7176643 10
70 1600 0.7215499 8.258928 0.04469422 0.7662442 14
70 2000 0.7101685 6.008732 0.03200409 0.7421726 68
70 2400 0.7260638 5.553668 0.03024238 0.7563062 46
70 2800 0.7044055 4.785156 0.02528018 0.7296857 8
80 1600 0.7561182 4.947917 0.02805907 0.7841772 3
80 2000 0.7057804 5.829327 0.03085669 0.7366371 13
80 2400 0.7378831 4.744318 0.02625564 0.7641388 55
80 2800 0.7602965 3.125 0.01781945 0.778116 10
80 3200 0.7661721 4.947917 0.02843217 0.7946043 3
90 2000 0.7744392 6.705729 0.03894885 0.813388 12
90 2400 0.7730451 2.709961 0.01571191 0.788757 64
90 2800 0.7689871 1.204427 0.006946417 0.7759336 24
100 2400 0.7757413 6.054688 0.03522653 0.8109678 8
100 2800 0.7895724 1.192434 0.007061348 0.7966338 38
110 2800 0.807003 3.385417 0.02049031 0.8274933 24
110 3200 0.7903881 2.929688 0.01736693 0.8077551 8
120 2800 0.8211598 0.5208333 0.003207655 0.8243675 6
130 3200 0.8068758 1.71875 0.01040113 0.817277 15
130 3600 0.7944646 3.28125 0.01955128 0.8140159 5
130 4400 0.7977614 3.385417 0.02025566 0.8180171 3
 
Way I always did my LFT's Was I used maf Hz Vs Lft. I would then add or minus according to where the Lft's were off on the HZ scale. I can usually get close on one shot now after doing a few
 
When in maf fail mode, the LTFT area is not reporting readings from the o2 sensor as much as it is just adjusting the afr based on conditional situations, such as intake air temp, engine coolant temp, and a few other params.

Not only does the "ve tune" go away when you plug the maf back in, it also is impossible to do using LTFT (aka the narrowband sensor).
 
I have a few scans from different VE tables, I'm going to do a manual adjustment using whatever value in a specific cell resulted in an average -3 to 0 fuel trim and see if it that gets me closer to the target.
 


I was wondering myself why would I need to tune the VE table and I came across a write up on how to tune VE tables for LS1 engines and it said the following:

"So, if we have a
MAF, why do we have a VE table at all? One thing the VE table does is provide a
reference airmass calculation. The PCM uses this reference to compare the measured
airmass supplied by the MAF to so it can ensure that the MAF is operating correctly.
Also, while the MAF is accurate at measuring airmass that is entering the engine at a
constant rate, it is not at all accurate when the airmass is changing, like during throttle
transitions during normal driving. At these times, the PCM blends the MAF signal with
the airmass calculations derived by the VE table to provide accurate fueling. So, above
4000 RPM, or during steady MAP conditions, fueling is set using the airmass
measurement provided by the MAF alone. Under 4000 RPM, during unsteady MAP
conditions, fueling is set using the airmass measurement provided by the MAF, modified
by the airmass calculation derived from the VE table. Understanding the close interaction
between the MAF and VE table, it is easy to see why it is important that they both are
correct and working together."
 
That Does not Apply to us. Our cars ONLY referance this table when the maf fails. You could Zero the table out and it wouldnt do anything. Many have done it as a test.
 
yes i was talking about the RPM vs MAP table. It's the first time I'm doing a custom tune, I'm just following a couple of guides on how to.
 


01gpgt01 said:
That Does not Apply to us. Our cars ONLY referance this table when the maf fails. You could Zero the table out and it wouldnt do anything. Many have done it as a test.
Click to expand...


Lol then I guess I'll have no problems running my car if that ever happens XD.
 
Juanmiguel said:
crap... so I should just leave the VE table as is and move on with the MAF table?
Click to expand...


:th_thumbsup-wink: you got it. Start with the cruise Maf Hz range thru 7500. Then when you get them dialed in move into the WOT hz ranges. Also with your mod level you should be widebanding so you can dial in your WOT ranges. Even with my 02's in the 910 range I was at 10.8 afr! Im sitting at 865-870 02's Wot with a afr of 11.7
 
You must log in or register to reply here.
Back
Top