Tom400CFI

How are you going to damage a PCM w/table/program altering??

I also agree that you could end up w/extrememly wacky engine behavior w/poor changes. You can alwasy push in the clutch and kill the engine though, just like the old days.

Tom400CFI

None of the above was really helpful. I asked how to accomplish the above, not "what is your opinion on these changes?"

Covered thoroughly in another thread with vid clips. It's not the firing order. http://forums.corvetteforum.com/show...hlight=exhaust
and here are some clips for your listening pleasure:
http://forums.corvetteforum.com/show...&postcount=182
and here is just ONE of the posts about firing order. Read it carefully..
http://forums.corvetteforum.com/show...&postcount=200


No, it's not.

No, it's not. How does the clutch pedal "weight" affect throttle response?? BTW, the clutch on a C6 is FAR from "heavy as hell". "Honda Civic-like" is a better description.

I'm not looking for "F1" response. I'd just like it to be somewhat close to what my '83 Trans Am w/Crossfire Injection had for response. Or my '96 Silverado 5.7 Vortec. Also, in this "mode", I'm not talking about how quickly the engine's RPMs increase; I'm talking about how quickly the engine responds to the throttle's command, which is....not quick. You can put the pedal to the floor, then release it completely...all before the motor changes 1 RPM. THEN it rev's up and back down.

No, it's not. Have you driven a stock C6? Have you paid attention? The last 1" or so of pedal travel does very little to change the engine's tq output. And if that's not true on all of them, it is on mine, and it's a waste of valuable throttle travel.

Which doesn't require any "magic". A 400 horse engine w/a 4 bbl carb can do it fine. IT'S ALL ABOUT CONTROLLING THE POSITION OF THE THROTTLE PLATE. Let's face it; the calabration is a "massed produced" one that "meets the criteria" (GM's). Most people don't even care about it, but I do. If the car had a throttle cable, I'd remove the rubber band between teh gas pedal the the throttle cable, then change the cam profile of the linkage on the throttle shaft, and it would meet my criteria. I'm trying to find the electornic solution equivelent. Other's here have begun to point me in the right direction. Thanks again to those folks!

Possibly the only helpful part of this whole post. How will that help me meet my criteria?

not08crmanymore

Voice your displeasure with this so called tuner,put your car back to stock and go find a real tuner who knows corvettes and what to do with them.I've never heard of "improved exhaust sound" after getting a tune.Buy yourself a new exhaust.There's your improved sound.

Tom400CFI

Good idea.

I've already done that, 3 times. Doesn't improve it, just makes it LOUDER. Read that thread about exhaust I posted above, as I don't want to reiterated everything that was already posted there. I will say this; Have you ever worked on an older engine w/a distributor? Have you ever turned the dist to retard the timing, WHILE simultaneously opening the throttle (to keep the RPM the same)? The character and quality of the exhaust sound changes dramatically. Then, ever notice what happens when you twist the distributor to advance the timing? The sound mellows, smooths, and becomes much more melodious. There is your evidence and example of how timing can affect the exhaust tone.

I know that you've never heard of that concept. That's because I don't believe that anyone has considered it before. Which is why I wanted to EXPERIMENT with this with the tuner on Saturday.

-Tom

DSteck

The folks at HPTuners just recently talked about this, and EFILive is actually considering withdrawing this capability because people have been killing PCMs after improper changes.

http://www.hptuners.com/forum/showthread.php?t=19715

EDIT: It seems Bill @ HP Tuners deleted the conversation regarding EFILive, but it basically said people have already killed PCMs from trying to mess with ETC calibration.

I'm simply trying to tell you that you're biting off more than you can chew. If you don't understand that, and choose to be a dick, then you should probably look elsewhere for advice. You admittedly don't know about tuning, and you're asking for too much from the PCM's capability.

I wasn't giving you opinions, I was stating facts about the requests you made. You asked if they are unreasonable, and I'm telling you that they are.

As I said, bumping idle timing is going to be counteracted by the proportional controls and brought right back down, unless you want to disable proportional controls and deal with idle surging.

Your physical clutch assembly has a very high rotational moment of inertia. I wasn't talking about the pedal stiffness... The weight of the clutch takes a while to accelerate, and likewise takes a while to slow down (hence the whole point of a flywheel). There's part of the lazy rev and lazy recovery.

Like I said, add timing in the low rpm, high load cells. Air pulses generate a false load calculation, which ends up running in the -10º timing range. My car lost a lot of initial idle rev delay when I cleaned up this area of my timing map. If I stabbed the throttle when the engine was above about 1600rpm, it was always crisp and instant. Now, the rpm doesn't matter.

Yes, I've driven a 2005 C6 w/ Z51. I found the throttle pedal to be predictable after about ten minutes of driving.

You're not going to find anything to perfectly correlate your pedal to your throttle. The point of the electronic throttle is to take the pedal input and use the change in pedal position as well as the absolute pedal position to determine an actual throttle blade position. This is done for fuel economy and emissions reasons... Go figure, GM is required to make the car pass emissions requirements. The right direction involves a GM calibration engineer with access to the entire VCM calibration. A local tuner generally isn't going to have the know-how and equipment to reprogram the algorithms involved with what you want to accomplish. Cleaning up response is one thing, but changing how the pedal correlates to a throttle blade position is beyond the scope of anybody I know.

Speed density uses the MAP sensor in combination with MAT (manifold air temperature) and engine RPM. MAT is the intake air temperature plus the delta of engine coolant temperature and intake air temperature multipled by a bias value, which is based upon airflow in terms of grams per second. The faster the airflow, the lower the bias value, which makes sense because at faster airflows, the incoming air has less time to get heat soaked by the heat of the engine. At low air speeds, the bias value sways the MAT towards the engine coolant temperature since the air is moving slow enough to take in heat given off by the engine itself. Speed density ignores the MAF sensor reading (which is metered airflow based on a frequency generated by the air rushing over the sensor element, and that frequency is assigned an airflow value). The MAF is not very good at dealing with transient airflow situations (ie: part throttle to wide open throttle, no throttle to part throttle, light throttle to medium throttle, etc). Your MAP sensor reacts instantly, though, and is able to quickly spit out the right airflow value, which results in the right fueling value, which ultimately results in the right injector pulsewidth at any given instance. This means the engine is being correctly fueled since the speed density calculations react much quicker to sudden airflow changes. The downside is that there are all kinds of modifiers in order to make a speed density tune accurate in any weather condition (low/high humidity, low/high temperature, etc).

Experiment all you want with timing at idle... it's going to cap out. I can set mine to 40º of advance at idle, and it'll never see higher than an average of about 18º. All it accomplishes is destroying idle quality. Set timing for the most vacuum at idle, and not according to sound.

0euro@EFIAlchemy.com

Any tuning suite is nothing more then a glorified hack of GM's proprietary software, which is not without its glitches before we hack into it. That being said, there are problems that can arise when messing with the ETC calibrations that will induce an unrecoverable reduced engine power condition.

Some of the setting's in the ETC cal can set the PCM into a reduced engine power state that it cannot recover from, and it render's the PCM unable to be re-flashed.

This exact problem is why the ETC segment has not been included (up till now) in HP Tuner's software. EFI Live has offered this capability with a huge warning attached to it, basically buyer beware they are not responsible for any PCM damage resulting from you tuning the ETC.

Ben Diss

I think you'd be well served by learning to tune it yourself. You sound like a tinkerer. Rather than throwing money at a tuner everytime you want to try something, why not get the software and do it yourself?


EFI Live is not taking it out and HP Tuners is now adding it.

DSteck

Not more than three days ago, Bill quoted something from EFILive saying they might remove it. Too bad the thread had anything pertinent to the conversation deleted.

I'm still an advocate for a rock under the gas pedal.

Ben Diss

http://forums.corvetteforum.com/show....php?t=2122908

Tom400CFI

I AM a tinkerer, and always have been. You're right, this is the road I need to go down. I talked myself into paying someone to do work for me, and that was a big mistake. With all my experience, I should have known better.

Tom400CFI

Thanks for a MUCH more useful and helpful post. I do appreciate it. I totally understand what your saying about the MAP tune now, and how it can help response.

I also now understand what you meant by "heavy clutch" (that it's actually heavy -lol), but again, I wan't talking about the RATE of RPM increase; but rather the TIME from pedal input, to the beginning of a resulting change in RPM.

I've been driving my car for 2-1/2 years now. I've certainly gotten "used to" working the gas pedal...I just don't like it, and I'd like to do something abou it. Anyway, thanks for putting up a good post. Again, I appreciate the useful info.

05vettelag

You will get all the help you need on the HP tuners forum and here. You love doing it yourself once you learn everything. I still dont know all the stuff but have a good basic idea of what the changes do.

M_Searle

Sorry to here about the tune. I really thought it would be better. I think that I am the one that told you about that tuner coming. I wonder if the A4s and A6s had better luck. The autos really perk up when the tranny gets tuned.

All though you all ready have a tune now, I think you should call Chuck at Chuck CoW and talk to him about what you want from your car. He is a very nice person and will talk to you. He will let you know what is possible and not with your MN6 car. He has been doing tunes for a long time and knows vettes inside and out. He tuned my 07 C6 A6 a year ago and I couldn't be happier. When Chuck does a tune and later you need a retune he claims it will be free. It is to bad that he is in New York. I wait until he travels closer to do tunes and meet him there.

By the way, a group is getting together and doing the Trapper Loop this Sat Sept 13th. Come join in.

Link to the discussion here.
http://utahvettes.proboards99.com/in...lay&thread=305


Mike

Tom400CFI

I can't go; I'm going to be in Maine. Nikki is going to take my car and go on the drive though, so you'll see my car and her there.

highpockets

I wish you could make it this weekend,I would like to discuss in person the changes made as well as offer my personal HPT for your use in "experimenting" with the adj that have been discussed. Oh well,I will just say Hi ! to Nikki and admire your car once again,all the while you are on an airplane headed to work ! No,I too,had a part in convincing you to tune as well. I should have realized with the qty of cars involved that WOT tuning would be a priority,in my instance,THAT was exactly what I wanted/needed to the tune of 150+ HP gains Again,Tom,you are welcome to use my laptop/HPT interface to experiment on your throttle controls/timing but until HPT does their next update the ETC code/tables is NOT adj and as referenced by others here CAN induce unrecoverable damage to the PCM. Call me if you like or PM me on Utah vettes,I would like to discuss this more.

tjwong

Is there some actual documented instances of PCM failures due to people mucking up the ETC tables? I can't see how this could happen as all one is doing is changing constants within a table and not changing the actual strategy or logic of the controller. I spent hours and hours on ETC control developement in a MEFI controlled 427 small block in a street rod. And I never once had any kind of failure. I also have 25+ years in the process control industry and on some very rare occasions can a PLC be screwed up because of a programming error.

highpockets

Since I do NOT have personal experience with this,being an HPT user,I am going by my research only. However,if someone is willing to donate a PCM,I will happily program away as a test dummy. My theory (take this and a dollar and you can get a cup of coffee !) is that the processor,when improperly programmed,strives to drive the throttle blade beyond 100% TPS,mechanically topping out the stepper motors and killing the driver modules for said stepper motor inside the PCM. As I said,not having personal experience leads me only to theorize what MAY happen,however,both of the tuner platforms mentioned do NOT advocate playing with these tables. The PCM probably looks at this as a HARD fault,thus setting it into reduced power mode.Now,MY question,unless there is HARD board or driver damage(shorting ?) why CAN'T this be refalshed to stock settings ? Anyone ?

0foff667

Not sure if there are documented instances for the ETC however I know I've read about people frying their pcm by changing the gear/tire settings too far one way or the other. Just goes to show how fragile the stock pcm can be.

highpockets

Just curious ? Since Chris,or whoever at HPT controls what exactly is allowed in the suite as far as programmable tables,couldnt the ETC control tables be set up such that they could be modified "within safe parameters" thus allowing for SOME adjustability such as Tom is looking for without the dreaded dead PCM ? Something along the lines of a table that will NOT allow incorrect or unsafe #s to be input ? Just thinking out loud .

Tom400CFI

Since there was so much discussion about throttle performance on this thread, at least by me, I figured that I'd post this.

I finally had time today to run a little test on the throttle reaction on my C6. I couldn't believe what I saw (you'll hear it in the vid!):

http://www.youtube.com/watch?v=mQeKmLnYnQA

http://www.youtube.com/watch?v=rXr_0dmSvr0

Basically, just as quick as a throttle cable. Unreal how fast that thing can move, IMO! The problem lies elsewhere, I guess.