Proper dyno tuning procedure

[PAracer]

I'm getting closer to the time when I would want to tune my car on a dyno. Assuming that I have tuned it in my driveway so that i have decent enough driveability to take the car to work and back, what should I look to change?

From my research, I have come up with an order that seems to make sense to me. MAF transfer --> Injector high slope --> injector breakpoint --> stabilized fuel table --> base spark --> stabilized fuel --> base spark --> repeat untill satisfied.

Am I missing something important here? I would appreciate hearing about the methods that others are using to get to a happy ending.

Thanks!

 

[yamahaSHO]

I'm getting closer to the time when I would want to tune my car on a dyno. Assuming that I have tuned it in my driveway so that i have decent enough driveability to take the car to work and back, what should I look to change?

From my research, I have come up with an order that seems to make sense to me. MAF transfer --> Injector high slope --> injector breakpoint --> stabilized fuel table --> base spark --> stabilized fuel --> base spark --> repeat untill satisfied.

Am I missing something important here? I would appreciate hearing about the methods that others are using to get to a happy ending.

Thanks!

Why would you just adjust your high slope? If they both need adjusted, adjust them.

I'd change the fuel and spark to what you want it to be, then tune the fuel slopes and MAF. I wouldn't worry about the breakpoint until you've done more work with the slopes and MAF.

Once you have everything close to tuned, then you can play with adding spark and such. For safety, the WOT spark tables will be what you're looking at, mainly (especially on the dyno).

BTW, you don't need to tune the car on the dyno. In fact, if you can't do it by data logging, what good are you going to be on the dyno???

 

[SHOZ123]

See how close the commanded AF mix is compared to the actual. If it's rich then either the commanded values need to be leaned up, or if they are mathematically close then the MAF needs to be leaned or lowered. Check over the entire range too.

If the MAF is way out of whack then the PCM will use the failed maf transfer values which may be all screwed up if you've made a lot of changes to the motor. This table is based on load.

 

[yamahaSHO]

Not exactly.... Commanded values should be set prior to tuning. You should know what you want to run. If you're not hitting your commanded mark, you'll want to start with your injector slopes, then work on the MAF. If you have odd spikes in you KAM 'rolling average', then you will want to look at playing with the breakpoint.

 

[Axianator]

If the MAF is way out of whack then the PCM will use the failed maf transfer values which may be all screwed up if you've made a lot of changes to the motor. This table is based on load.

FWIW, this does not apply to the '89-'95 V6 SHO calibrations, where the EEC only refers to the MAF FMEM table when the EEC has determined that MAF failure management logic is deemed appropriate (e.g. when the rolling average for the reported MAF voltage to the EEC has either exceeded or dropped below the preset voltage values specified for the MAF test, etc).

Not exactly.... Commanded values should be set prior to tuning. You should know what you want to run. If you're not hitting your commanded mark, you'll want to start with your injector slopes, then work on the MAF. If you have odd spikes in you KAM 'rolling average', then you will want to look at playing with the breakpoint.

While Jason has given you the correct (and presently, the best) method for dyno tuning your car here (e.g. setting your commanded values where you want them and then tuning your MAF curve and injector slopes to match), I think there is an even more fundamental point that needs quick clarification before any further tuning advice is given - what type of computer are you utilizing in your MTX swap car, Mike? Since the two types of V6 SHO computers (ATX vs. MTX) can be quite different in both the number of parameters that they contain and in the way they handle things like fuel delivery, spark advance, injector breakpoint and more, the answer to this question will determine the route(s) that you should take when tuning your new setup.

 

[PAracer]

I am currently using a D4U1 computer. At some point when someone finds a way to mate the x2j engine harness with the atx main harness, I would swap over.

I've been noticing a few of the differences between the two computers.

Just so I'm clear on something. I have a TwEECer RT. I have a laptop, but no other software programs. How much can I really datalog without getting into needing a wideband o2 or other software enhancements? Is it actually possible for me to tune the car without a dyno at this point?

 

[NJSHO]

I would spend the money on a wide-band instead of dyno time. That way you can datalog as often as you want at no additional cost. Plus, don't dyno shops use tail pipe sniffers? If they do, you could get inaccurate A/F readings from what I hear. I don't have much experience here, just throwing out ideas.

 

[PAracer]

I just tried datalogging for the first time. It looked like many of the numbers were way off of what I was epecting. The most alarming thing was that the MAF flow was showing nearly max flow at idle. I have my MAF max flow set to 1300 in the CalCon setup tab. Also, it looked like I was only seeing half of the information that I had requested. RPM, load, advance, HEGO2, battery and a few others were fine, but most others were not registering. Perhaps I will try again and log to a file.

 

[Axianator]

Just so I'm clear on something. I have a TwEECer RT. I have a laptop, but no other software programs. How much can I really datalog without getting into needing a wideband o2 or other software enhancements? Is it actually possible for me to tune the car without a dyno at this point?

I have to agree with NJSHO's comments above - without a good, loggable wideband sensor and some good analysis software (like the EEC Analyzer), your ability to effectively tune your new setup will be severely limited. This is why Josh, myself and others are always pushing new DIY tuners to seriously consider the addition of a good, loggable wideband to complement their new TwEECer setup.

I just tried datalogging for the first time. It looked like many of the numbers were way off of what I was epecting. The most alarming thing was that the MAF flow was showing nearly max flow at idle. I have my MAF max flow set to 1300 in the CalCon setup tab. Also, it looked like I was only seeing half of the information that I had requested. RPM, load, advance, HEGO2, battery and a few others were fine, but most others were not registering. Perhaps I will try again and log to a file.

See this recent thread here for more information about the problems you've described:

http://www.shoforum.com/showthread.php?t=62060