wheni was at joes cycle , we did w.o.t runs to get it near ,then with the load imposing dyno could do straet simulated loads and do timing ,fuel ,and so on it takes a lot of time from what i remember, as every and i mean every motor is diff and likes diff setups no 2 motors are the same even with identical setups one may like more timing or suttin ellse
yah exactly, with the load imposing dyno it is close to street tuning, then a half hour out on the street your 110%.
yeah
i dont think everyone else in this thread is on the same page as us! they think you need to pick A or B and not C all of the above! They hear of some new tuner flying into town and its like god just came down and tuned there car, ahahah
thats cause its someone new ,in a few months my car is goin to jennings northeast speed and get dyno tuned for the jug and motor …obv the jug tune will be on as its only when im w.o.t .but the motor is the long tune its the area under the curve that takes the time .any stunad can do w.o.t. tables shit on most gm,s its the easiest as most sensors go back to open loop and only really need m.a.f and t.p.s signals to see what needs to be done
i mean look at drews car ,runs great at w.o.t but it runs so fuckin rich and inconsistant its not even funny .get a great tuner in there " And a better driver " that car will be fuckin serious
thats why Brandon will be tuning it come spring…
I completely understand where you’re coming from, but I’m pretty sure the “new tuner” was the one that brought up the load-bearing dyno in the first place as something he would like and is looking for.
Other people have valid points as well, about how Howard really isn’t interested in the small projects anymore as he has all this big-business stuff going on now.
I think everyone is a little-bit on the same page here.
What both Brandon and Howard understand is that dyno tuning is wonderful when you have that load, but nothing can simulate the airflow that creates the final cell readings while driving the car on the open road. Dialing in those cells on the dyno will get them damn close, but having it out on the street and logging the cells with that airflow is where you get it perfect…
The A, B, C comment is the truest thus far…
Tuning only on a dyno will produce a tune perfect on the dyno.
Tuning only on the street will produce a tune perfect for the street.
Tuning using the dyno and then the street nets the best overall tune.
Dialing in the MAF and VE have nothing to do with road airflow OR road load. That’s what all the adder and correction tables are for. GM doesn’t even use an engine to calibrate the MAF table. The VE is also done on an engine dyno that uses a AC motor to turn the engine through various loads and rpm to determine the dynamic airflow through the engine. Its a complete bunch of shit of road vs. dyno unless you know how the PCM is actually looking at this info.
Better left this conversation to the guys that actually tune these cars and know what the hell is going on inside.
I can tell you the GM PCM is a lot more involved then the aftermarket and import stuff. Not trying to discredit anyone but when I guy like Howard gets access out to the Milford calibrations lab in Detriot…I think he knows what is going on.
And if guys like the ones in this thread don’t start participating and getting correcting (i.e. - learning more), how the hell is the next generation going to be able to contribute and grow the automotive industry?
I think it’s sad that some of the industry leaders feel the need to shit on people and act arrogant towards the people with less experience. Thanks for the suggestions though. I’m well aware that Howard knows what he is doing and is connected to GM.
Let’s get this thread back on track and leave the side-bashing to PM’s…
…if you want to keep it on track:
Wouldn’t the reason that GM doing what they do be because they have to tune vehicles for a variety of geographic locations? Ideally, wouldn’t it be better for the control module to have to stray (use modifier tables) less because the calibration is more accurate for the geographic location the vehicle is operated in? You yourself said that it is “50/50” and Howard tunes on the dyno first and then takes it on the road. What would be the actual reasons for that if not for the reasons I have stated? Again, I’m not trying to attack anyone, just learn…
i just purchased new tuning software for lt1 ,s so the lt1 crowd will now be covered as its not vin locked and i can save a ton of files
I completely agree in keeping this thread on line…although somehow they always trend south! LOL!
My understanding of factory calibrating is that the first thing they do is figure out how the engine moves air through it. Since the engine is nothing more then an air pump. This is what the VE table represents. If the vehicle is equipped with a MAF (like the GEN3 and 4 GM vehicles are) then the MAF also needs to be recalibrated IF the intake side of the MAF has been changed. As noted prior the MAF does not not care what its attached to. Its only job is to report how many grams/sec of air are entering the motor. Because its based upon grams (which is weight) temperature and barometric pressure is “baked” into that value. Hence driving the car on the road is not ultimately needed. The MAF is properly calibrated when at a given MAF Hertz the amount of air is correct. For Ford guys this is AD counts. GM does this by attaching the entire air intake system on to a flow bench and moves a predetermined amount of air through the unit. That airflow is matched against the MAF hertz scale. They then give that data to the calibrations department and move on. Since most shops don’t own a flow bench like this, they use the engine as a flow bench. If you command a specific AFR (or lambda in the real world) and you get something different that specific hertz needs to be adjusted accordingly…long and the short is better done on a steady state device as you do not want any “transient” air changes to effect the readings. Of course you can do enough driving and get close that works for most. Just depends how accurate you want to get.
The VE table (which does not truly exist in any 2006 and up GM PCM), is the second half of the air modeling that is needed. The GEN3/4 motors used blended MAF and SD (speed density) which is why they are more involved then tuning a FORD which is typically MAF based with SD as a default if the MAF fails. The 2006 and up processors use a 15 string polynominal formula that determines the final reported airflow. This is used in liue of a real MAP/RPM VE table which is traditionally used in pre 2006 and aftermarket processors. The reason for this is all the cool features today like variable valve timing (VVT), variable intake runners, boosted engines, cam phasing and multiple cams. Traditional computer technology would require huge bulky computers (to todays standards). Using a formula allows all of these inputs to be factored in for a final sum of air flow. Its an infinite VE table. Flip side is they are very involved to dial in properly unless you understand all the inputs.
Sinces its afr (LAMBDA) is what is being used to make these corrections, the type of meter used and where it is places is also a huge factor.
Much like the MAF calibration the coefficients (the formula) needs to be corrected during steady state. Again since its a based upon grams/sec temp is also baked into it which has no bearing on road driving. I don’t know all the steps in doing it but I’ve seen it setup and its a lot of shit. I also drove a few cars before and after with all these things done and was blown away on how some big sloppy camshafts actually drove when done.
The factory PCM has a ton of “adder” correction tables to deal with real world conditions. Things like air temp vs spark retard, aggressive knock retard tables and some coast down stuff most certain can be fined tuned on the street but all this stuff requires minimal adjustment if all the airflow modeling is done correctly. I have heard Howard say a millions times " the ECM is nothing more then a glorified calculator. Garbage in…garbage out".
I hope this kind of gives some insight on what happens in the thought processor of the ECM and keeps this thread more informational then instigatable!
i <3 GM Sensors.
Great info! I’ve played around w/ HPT on my own car but still need a lot more experience before I should be doing anything other than tweaking a good tune. My first mistake after my compressor swap was thinking that I could “tweak” a base-map into a solid all-around tune. I was able to get satisfactory daily driving results, but nothing that closely resembled a good end result…
My personal experience is definitely a great example of “leaving things to professionals…” lulz
Howard, Happy Holidays and I wish you the best with your current/future endeavors.
lol
Howard your ass, you pick up quite a bit of knowledge when you hang out/ work for the best. The best teachers put out the best students.
And Smokin, if i were you i wouldnt lol about shit, your the one who thought your “new tune” really “woke the car up” When really all it does what get your ass handed to you by a stock ls3 w/ a passenger.
ahhhh here we go again
you really cant let shit go can ya?
dont really care what you have to say about me or my car, personally…seems like you do tho sense you keep carrying on about it.
im gonna leave this here for y’all
:clap