Author Topic: Holy Crap Batman, these computers are getting smart! (Read 1894 times)

KY_BOB · « **on:** August 09, 2011, 08:52:16 PM »

I think I'm going t tune the 5.3 DOD/AFM, 6L80 myself. I got a copy of a professional 6L80 tune from a very nice guy on PTnet. I'm going to start there. There are hundreds of fields that I haven't seen before.

I do not copy and paste tunes but he gave me enough info that I feel like I have a starting point and know what fields to start looking at. His truck has a 6.2 in it so everything other than the TM reduction inis the engine tune useless to me.

I still feel like getting the TM out of it (since the trans will handle it) and getting my shifts where and as firm as I want is a good start.

Wish me luck

MS03 2500 · « **Reply #1 on:** August 09, 2011, 09:22:48 PM »

I'm sure it is way different from what you saw in the 02.

KY_BOB · « **Reply #2 on:** August 09, 2011, 09:46:36 PM »

Quote from: MS03 2500 on August 09, 2011, 09:22:48 PM

I'm sure it is way different from what you saw in the 02.

It's kind of like having 3 channels on TV and having modern cable/satellite. It's different but most of it makes since if you spend the time reading the descriptions that HPT gives you. The catch is that you don't know which way to go or how much without a little guidance.

I have some good ideas now. I just have to ease them into the truck. I really think that I can get a 20ish mpg truck on the highway but that will still get with the program when you get on it. At least, that's my goal.

MyBigToy · « **Reply #3 on:** August 10, 2011, 07:19:56 AM »

I'll let you be the guinea pig and see how successful you are. Once you know your way around I'll pick your brain so that I have an idea about how TM works and where to make changes. Like I said before, I spent some time looking around at an 07 Vette program and there are so many different parameters and inter-relations between them that it's mind-boggling.

I hadn't thought about approaching someone on corvette forum about sending me a tweaked HPT file to nose around in and compare to the stock tune.

Good luck and keep up posted.

Main One · « **Reply #4 on:** August 10, 2011, 07:41:19 AM »

I knew you wouldn't "bluedevil out" and would eventually start doing some tuning on that thing!

KY_BOB · « **Reply #5 on:** August 10, 2011, 11:20:23 AM »

I have tons of info and parameters to tinker with but here is the lowdown on tune #1:

Eliminated the speed limit that the TB could open in 1st gear
Lowered PE delay from 5000 to 2500rpm
Eliminated speed limiter (actually set it for 150)
TCM commanded TM disabled
Brake stall rpm eliminated (it was 1500 rpm)
slightly raised 1-2 shift points under light throttle
Reduced shift time "normal" (non-TH mode) adder by 50% on all upshifts

The tune that I am looking at is a lot more radical than the changes that I made. This is a baby step.

I haven't touched the line pressures or the engine TM yet. I'm going to load it in the truck at lunch and take it for a spin. Anyone have any thoughts on this step or any others that I might should do?

Main One · « **Reply #6 on:** August 10, 2011, 11:56:50 AM »

Looks like a good start to me!

Alaska_AV · « **Reply #7 on:** August 10, 2011, 12:26:00 PM »

Good luck

KY_BOB · « **Reply #8 on:** August 10, 2011, 01:47:15 PM »

OMG!!! I've created a monster!

I flashed it at the office and drove it home for lunch. The shifts in town were noticeably firmer but not annoying. On the way out of town, I punched it from about 10mph, it down shifted to 1st and the back tires screamed for 10-15'. I got traction before the 1-2 shift. When it hit 2nd the back tires screamed again, I don't mean chirped, it spun them enough that it wheel hopped. WOT 2-3 and 3-4 shifts felt like it had a shift kit in it. I also tried a stalled launch, it will now launch spinning the back tires even with T/C on (I forgot to turn it off)

It's down right scary what my "mild" removal of TM and shortening shift times did.

Main One · « **Reply #9 on:** August 10, 2011, 02:19:14 PM »

Quote from: KY_BOB on August 10, 2011, 01:47:15 PM

OMG!!! I've created a monster!

I flashed it at the office and drove it home for lunch. The shifts in town were noticeably firmer but not annoying. On the way out of town, I punched it from about 10mph, it down shifted to 1st and the back tires screamed for 10-15'. I got traction before the 1-2 shift. When it hit 2nd the back tires screamed again, I don't mean chirped, it spun them enough that it wheel hopped. WOT 2-3 and 3-4 shifts felt like it had a shift kit in it. I also tried a stalled launch, it will now launch spinning the back tires even with T/C on (I forgot to turn it off)

It's down right scary what my "mild" removal of TM and shortening shift times did.

Sounds like your little tuning business is going to be continuing.

KY_BOB · « **Reply #10 on:** August 10, 2011, 02:34:44 PM »

I drove it around town a little before coming back to work. I think the adaptive learning may be easing up my shifts a little. I can turn that off if I want to. To be honest, it was so harsh that I'm worried about the transmission. It's shifting as hard at WOT as the AV did with a shift kit and tune.

KY_BOB · « **Reply #11 on:** August 10, 2011, 04:32:45 PM »

OK, so I'm having a slow day at work and getting to play a little for a change.

GM left so much on the table on a stock tune. At one point in PE my commanded AFR is 11.05. That's richer than most people run with forced induction.

There is also a lot of engine TM below 3000 rpm in first gear. Why, just so you won't spin your tires? It's not during the shift, it just eases the max torque up until you reach 3000 rpm and then lets go.

KY_BOB · « **Reply #12 on:** August 10, 2011, 05:46:51 PM »

OK, I'm kind of turning this into my personal blog about a truck that isn't even an Avalanche.

I left work and drove it far enough to get a log of varying conditions. My LTFT's are running a little lower than I like. I can tell you that the 100mph speed limiter is gone. The transmission is still amazing me, it spins enough when it hits 2nd that it kicks the traction control on (if I don't have it turned off) and at 94mph it shifted into 4th and my head bounced off of the headrest.

Anyone think that I took it too far?

Think I should add some more 1st gear torque in it? Lean it out a bit on the top? I know that I can get a little more out of it on both the top and bottom. (M1, what do you think?)

oHIobellboy · « **Reply #13 on:** August 10, 2011, 07:47:30 PM »

So what the hell is this gonna do to your mileage? You better put a brick under the pedal.

KY_BOB · « **Reply #14 on:** August 10, 2011, 08:16:16 PM »

Quote from: oHIobellboy on August 10, 2011, 07:47:30 PM

So what the hell is this gonna do to your mileage? You better put a brick under the pedal.

I haven't made any changes yet that would hurt my mileage other than the temptation to step on the "go" pedal. When I get a little deeper into the engine tune, I hope to actually improve the economy (if I can keep my foot out of it)

Main One · « **Reply #15 on:** August 11, 2011, 07:45:03 AM »

Quote from: KY_BOB on August 10, 2011, 05:46:51 PM

Think I should add some more 1st gear torque in it? Lean it out a bit on the top? I know that I can get a little more out of it on both the top and bottom. (M1, what do you think?)

Bob, every time you ask me a question like this unless I tell you you will be breaking something, you're going to do it!

KY_BOB · « **Reply #16 on:** August 11, 2011, 09:30:00 AM »

Quote from: Main One on August 11, 2011, 07:45:03 AM

Bob, every time you ask me a question like this unless I tell you you will be breaking something, you're going to do it!

Yea, yea, I know.

Can you think of any reason they would have the PE so rich? I just did the math on it and 12 to 1 AFR (and that's still rich for a NA motor) would only require a PE ratio of 1.23. Mine crosses that point at 3250rpm and keeps climbing until 1.33 @ 4750rpm.

BTW: you can see that plainly in the logs. Once it's past 3000rpm the O2 voltage continues to creep up all the way to the shift.

MyBigToy · « **Reply #17 on:** August 11, 2011, 10:31:19 AM »

Quote from: Main One on August 11, 2011, 07:45:03 AM

Bob, every time you ask me a question like this unless I tell you you will be breaking something, you're going to do it!

What do you mean unless you tell him he'll break something he's going to do it? He'll do it even if you tell him that! Bob's the one that's like my son - he doesn't just push it to the edge, he pushes it over the edge every time.

But that's good for the rest of us; we end up knowing what we can and can't do without the pain of breaking something.

KY_BOB · « **Reply #18 on:** August 11, 2011, 10:40:22 AM »

Quote from: MyBigToy on August 11, 2011, 10:31:19 AM

What do you mean unless you tell him he'll break something he's going to do it? He'll do it even if you tell him that! Bob's the one that's like my son - he doesn't just push it to the edge, he pushes it over the edge every time. But that's good for the rest of us; we end up knowing what we can and can't do without the pain of breaking something.

Email me that Vette tune and let me play with it.

On a slightly more serious note, they say that the 6L80 is one tough SOB but I'm not sure about letting it shift as hard as it is now. It's almost scary. Any idea what the weak point in it would be? I may have gone a bit over the edge on the shift times.

Main One · « **Reply #19 on:** August 11, 2011, 12:39:15 PM »

Quote from: KY_BOB on August 11, 2011, 09:30:00 AM

Yea, yea, I know.

Can you think of any reason they would have the PE so rich? I just did the math on it and 12 to 1 AFR (and that's still rich for a NA motor) would only require a PE ratio of 1.23. Mine crosses that point at 3250rpm and keeps climbing until 1.33 @ 4750rpm.

BTW: you can see that plainly in the logs. Once it's past 3000rpm the O2 voltage continues to creep up all the way to the shift.

I would say they do that because they don't have confidence in how well dialed in the MAF is for the high-flow conditions and are erring on the side of being too rich rather than not rich enough.

Alaska_AV · « **Reply #20 on:** August 11, 2011, 01:30:59 PM »

Keep posting. I'm reading, your way more into this than I am now but some day. I finally got my impala un bricked so at least I'm using my HPT ........

KY_BOB · « **Reply #21 on:** August 11, 2011, 01:46:53 PM »

Quote from: Main One on August 11, 2011, 12:39:15 PM

I would say they do that because they don't have confidence in how well dialed in the MAF is for the high-flow conditions and are erring on the side of being too rich rather than not rich enough.

I just changed the PE table where it will never command richer than 12 to 1. (Stoich 14.67/1.24) IMO, that's still way rich but I'll log it, make sure that there isn't any KR before leaning it out any more. See, I can take baby steps.

Main One · « **Reply #22 on:** August 11, 2011, 02:06:12 PM »

I probably should be changing my PE since I am now mildly boosted. Probably isn't too bad with only 3 pounds of boost.

KY_BOB · « **Reply #23 on:** August 11, 2011, 02:39:49 PM »

Quote from: Main One on August 11, 2011, 02:06:12 PM

I probably should be changing my PE since I am now mildly boosted. Probably isn't too bad with only 3 pounds of boost.

Probably so.

You don't happen to remember off the top of your head what you commanded AFR or PE multiplier are do you?

I've looked at a few tunes and have seen some guys with commanded AFR's as high as 13/1. I'm not ever going that lean but I may take it a little leaner than it is now.

I just logged it at WOT, no hint of KR and my O2's never got below 900mV. If fact, they mostly stayed in the 920-930mV range.

Main One · « **Reply #24 on:** August 11, 2011, 02:47:55 PM »

Quote from: KY_BOB on August 11, 2011, 02:39:49 PM

Probably so.

You don't happen to remember off the top of your head what you commanded AFR or PE multiplier are do you?

I've looked at a few tunes and have seen some guys with commanded AFR's as high as 13/1. I'm not ever going that lean but I may take it a little leaner than it is now.

I just logged it at WOT, no hint of KR and my O2's never got below 900mV. If fact, they mostly stayed in the 920-930mV range.

No, I don't recall off hand what my PE was AFR-wise.

Since putting in the Vortech aux fuel pump, my O2 readings are staying above 900 mV during PE, which is good with a bit of boost. Yours probably don't need to be as high as they are for NA. I think if they are above 890 you should be good, but it is a bit of a guess with the narrowband sensors.

FAST has a new wideband O2 setup with a display that can also mimick what narrowband sensors would be outputting. You therefore don't need to weld in new bungs for the wideband sensors - you put them in where you took out the narrowband and wire the narrowband leads to the wideband's box. I may get that before I go for more boost.

KY_BOB · « **Reply #25 on:** August 11, 2011, 04:36:53 PM »

Quote from: Main One on August 11, 2011, 02:47:55 PM

No, I don't recall off hand what my PE was AFR-wise.

Since putting in the Vortech aux fuel pump, my O2 readings are staying above 900 mV during PE, which is good with a bit of boost. Yours probably don't need to be as high as they are for NA. I think if they are above 890 you should be good, but it is a bit of a guess with the narrowband sensors.

FAST has a new wideband O2 setup with a display that can also mimick what narrowband sensors would be outputting. You therefore don't need to weld in new bungs for the wideband sensors - you put them in where you took out the narrowband and wire the narrowband leads to the wideband's box. I may get that before I go for more boost.

I know that you aren't supposed to tune off of narrow band O2's but that's all that I have. I just pulled a hint more fuel out of it. Going leaner makes me nervous but with those O2 readings it has to be too rich. The blown AV at the drag strip, the day you were there was reading about 920mv on the first run. When we leaned out the nitrous setup it dropped to to 890mV and that was FI times 2. If you remember it picked up over a .1 sec on the second run.

The FAST O2's could be a tuners dream.

KY_BOB · « **Reply #26 on:** August 11, 2011, 08:10:43 PM »

OK, logged the last revision to the latest tune. A strange thing happened. So I was scrolling through it frame by frame, it started out in the 930mV range in PE at 3000rpm in 2nd gear. When it hit the very peak )5300rpm) it leaned out a bit (probably about where it should be) to 900mV BUT when it shifted it stayed in the 890-910mV range even though it dropped to 4150 rpm and stayed there all the way through 3rd.

I guess this is why they tell you not to tune off of narrow bands.

So, now what happens when I raise the shift rpm?

oHIobellboy · « **Reply #27 on:** August 11, 2011, 08:17:02 PM »

Quote from: KY_BOB on August 11, 2011, 08:10:43 PM

OK, logged the last revision to the latest tune. A strange thing happened. So I was scrolling through it frame by frame, it started out in the 930mV range in PE at 3000rpm in 2nd gear. When it hit the very peak )5300rpm) it leaned out a bit (probably about where it should be) to 900mV BUT when it shifted it stayed in the 890-910mV range even though it dropped to 4150 rpm and stayed there all the way through 3rd.

I guess this is why they tell you not to tune off of narrow bands.

So, now what happens when I raise the shift rpm?

Just restore the stock tune before you have it towed to the dealer with something broken.

Alaska_AV · « **Reply #28 on:** August 11, 2011, 08:27:53 PM »

Quote from: oHIobellboy

link=topic=13512.msg104582#msg104582 date=1313111822

Just restore the stock tune before you have it towed to the dealer with something broken.

Amen Just towed mine to the dealer felt crappy.........

KY_BOB · « **Reply #29 on:** August 11, 2011, 08:30:05 PM »

Quote from: oHIobellboy on August 11, 2011, 08:17:02 PM

Just restore the stock tune before you have it towed to the dealer with something broken.

That's part of the "+" of having tuning software. As long as it has a working battery and I have a laptop, the computer can be returned to 100% stock. There is no way they could say that my cat-back caused a broken trans or a burned piston. ...and that damn 3rd catalytic converter must have just fallen apart on it's own

Gota love the 5 year 100,000 mile GM powertrain warranty.

MyBigToy · « **Reply #30 on:** August 11, 2011, 09:15:01 PM »

Quote from: KY_BOB on August 11, 2011, 08:30:05 PM

That's part of the "+" of having tuning software. As long as it has a working battery and I have a laptop, the computer can be returned to 100% stock. There is no way they could say that my cat-back caused a broken trans or a burned piston. ...and that damn 3rd catalytic converter must have just fallen apart on it's own

Gota love the 5 year 100,000 mile GM powertrain warranty.

I've read an awful lot of people who swear that GM has included a "counter" on the PCM flashes so they can tell if it's been flashed more times than it should have been. It really wouldn't surprise me if they did.

KY_BOB · « **Reply #31 on:** August 11, 2011, 09:29:35 PM »

Quote from: MyBigToy on August 11, 2011, 09:15:01 PM

I've read an awful lot of people who swear that GM has included a "counter" on the PCM flashes so they can tell if it's been flashed more times than it should have been. It really wouldn't surprise me if they did.

I'm going to hold out hope that it's limited the the Vette computers (since you guys are speed freaks) and truck drivers are mild mannered old guys, like me.

Mine was flashed 3 times today. If nothing else, I have a feeling that the the technicians in West KY are the best that we have but not the sharpest knives in the drawer.

KY_BOB · « **Reply #32 on:** August 12, 2011, 07:32:26 PM »

No tuning today, just driving it letting the fuel trims settle in. It still has less than 100 miles with the new intake so it's still learning. The trans continues to amaze me. There are a couple of very minor drivability issues that I need to deal with.

I wish the Gen4's had a conventional VE table. I am totally lost about the whole "virtual VE" table programs. I have been told that they aren't bad from the factory.

As for timing, it's pretty conservative too. 20.5deg on the top end on gasoline. There are a few hp to be gained there. I am a bit concerned about what the changes will do on E85 or a mix of it and gas.

Overall, I'm blown away with the tunability (I think I made a new word) of this truck.

Just keeping my blog alive and open to any thoughts...

Main One · « **Reply #33 on:** August 13, 2011, 10:26:12 AM »

Back to Power Enrichment. When I said I was staying above 900 mV, that was from memory and not having actually looked to see where it was the lowest - my truck looks to be staying above 890 mV.

At some point I've made some pretty big changes to my VE table. I've leaned it at the top but made it quite a bit richer in the 2400-3200 range or so. I'll have to see when I made that change and try to correlate that to something or someone that may have convinced me to do that. My PE values are over 1.3 in that 2400-3200 range.

MyBigToy · « **Reply #34 on:** August 13, 2011, 11:31:21 AM »

Quote from: Main One on August 13, 2011, 10:26:12 AM

Back to Power Enrichment. When I said I was staying above 900 mV, that was from memory and not having actually looked to see where it was the lowest - my truck looks to be staying above 890 mV.

At some point I've made some pretty big changes to my VE table. I've leaned it at the top but made it quite a bit richer in the 2400-3200 range or so. I'll have to see when I made that change and try to correlate that to something or someone that may have convinced me to do that. My PE values are over 1.3 in that 2400-3200 range.

Could it have been adjustments for the ram-air hood?

KY_BOB · « **Reply #35 on:** August 13, 2011, 04:12:40 PM »

Quote from: Main One on August 13, 2011, 10:26:12 AM

Back to Power Enrichment. When I said I was staying above 900 mV, that was from memory and not having actually looked to see where it was the lowest - my truck looks to be staying above 890 mV.

At some point I've made some pretty big changes to my VE table. I've leaned it at the top but made it quite a bit richer in the 2400-3200 range or so. I'll have to see when I made that change and try to correlate that to something or someone that may have convinced me to do that. My PE values are over 1.3 in that 2400-3200 range.

Right now I have my PE multiplier set at 1.23 from 3250rpm up to 6000 (which I'll never hit on this motor). Then it goes way rich, just in case. It's starting to lean out a bit on the very top end. I've been told by a pro that I need to raise my shift points a little. When I do, I'm going to add a little fuel from 5250 up.

Factory WOT shift rpm is 5525rpm for 1-2 and 5425rpm for the rest. I've been told that the motor will pull hard to 6k totally stock. With peak torque at 4700and the close ratio of the 6 speed, I dont see any reason to pull it that far but I'll add a couple of hundred rpm to it. I just want to make sure that it doesn't get any leaner than it already is, even though I think it's still very safe.

Main One · « **Reply #36 on:** August 14, 2011, 06:32:03 PM »

Quote from: MyBigToy on August 13, 2011, 11:31:21 AM

Could it have been adjustments for the ram-air hood?

Hmmm.... - I doubt it. Can't think of a reason off-hand to add fuel due to where the air is coming from. The ram air wasn't adding much pressure.

I suspect I read something somewhere that in general for gas engines it was good to be richer down low, then less rich at peak torque, and then richer again at peak hp.

KY_BOB · « **Reply #37 on:** August 14, 2011, 07:39:46 PM »

Quote from: Main One on August 14, 2011, 06:32:03 PM

I suspect I read something somewhere that in general for gas engines it was good to be richer down low, then less rich at peak torque, and then richer again at peak hp.

That could be but it goes against GM's factory tune. Mine got richer all the way from the bottom to the top. I've now got mine where I think it needs to be and level from 3250 up. I am going to add a little on the top end for safety when I turn up the shift rpms.

Just a thought, if the PE delay was at the stock 5000rpm, it might have been lean until it got through the delay. Enriching it during the delay might be another to get it to the desired AFR quickly. Again, just a thought.

Main One · « **Reply #38 on:** August 14, 2011, 07:53:46 PM »

Quote from: KY_BOB on August 14, 2011, 07:39:46 PM

Just a thought, if the PE delay was at the stock 5000rpm, it might have been lean until it got through the delay. Enriching it during the delay might be another to get it to the desired AFR quickly. Again, just a thought.

You lost me there buddy.

KY_BOB · « **Reply #39 on:** August 14, 2011, 08:25:39 PM »

Quote from: Main One on August 14, 2011, 07:53:46 PM

You lost me there buddy.

The factory PE delay is set for 5000rpm, at least on my Silvy. It eases into the PE commanded ratio below that rpm. If your PE was richer at the lower rpm it would offset the fact that it's easing into it. Make any since? I just lowered my delay rpm. It's just 2 different ways to get the same result.

MyBigToy · « **Reply #40 on:** August 14, 2011, 08:27:10 PM »

Quote from: KY_BOB on August 14, 2011, 07:39:46 PM

Just a thought, if the PE delay was at the stock 5000rpm, it might have been lean until it got through the delay. Enriching it during the delay might be another to get it to the desired AFR quickly. Again, just a thought.

Mine's set at zero delay on my tune. It's one of the things I noticed that is different between your Vortec Av tune and my tune.

Main One · « **Reply #41 on:** August 15, 2011, 07:29:16 AM »

Quote from: KY_BOB on August 14, 2011, 08:25:39 PM

The factory PE delay is set for 5000rpm, at least on my Silvy. It eases into the PE commanded ratio below that rpm. If your PE was richer at the lower rpm it would offset the fact that it's easing into it. Make any since? I just lowered my delay rpm. It's just 2 different ways to get the same result.

I believe the easing into it would be limited between the 5000 rpm cell of the delay table and the next-lower rpm cell of said table and therefore you wouldn't be getting any PE below 4000 or so and thus there wouldn't be any making up to do.

KY_BOB · « **Reply #42 on:** August 15, 2011, 09:56:04 AM »

Quote from: Main One on August 15, 2011, 07:29:16 AM

I believe the easing into it would be limited between the 5000 rpm cell of the delay table and the next-lower rpm cell of said table and therefore you wouldn't be getting any PE below 4000 or so and thus there wouldn't be any making up to do.

Hmmm, that makes since. In that case, I'm not sure why you would have the factor higher at the lower rpm.

oHIobellboy · « **Reply #43 on:** August 15, 2011, 07:23:54 PM »

So when are you guys gonna start posting any pix of these tables so the rest of us can follow along?

KY_BOB · « **Reply #44 on:** August 17, 2011, 05:54:50 PM »

Quote from: oHIobellboy on August 15, 2011, 07:23:54 PM

So when are you guys gonna start posting any pix of these tables so the rest of us can follow along?

2 reasons:

1. My internet computer doesn't have HPT (still can't get the d@mn drivers right) My tuning laptop is too slow for internet surfing, I took all anti-virus and safety measures off of it to speed it up for tuning. I'm afraid to get it on the internet now.

2. I don't know how to do a screen save, screen capture, or whatever it called, so I could post it.

If you have a copy of HPT 2.23 I'll email you any of my tunes. I can email them straight off of my zipdrive without opening them on this computer.

I'll share anything, if I know how

KY_BOB · « **Reply #45 on:** August 17, 2011, 06:11:43 PM »

As for tuning, I ask a question on PT.net about shift rpm with a 5.3/6 speed. I was told by a professional tuner to WOT shift it at 5800-6000, that these motors pull well to there. With the close ratio of the 6 speed and the peak torque at 4700, that seems a bit high to me. I'm not worried about the motor, it will take it.

The factory shift points are 5525rpm for 1-2 and 5425 for all other shifts. I'm thinking about going to 5625 and 5550. That is a real baby step but I would like to see if I can tell any difference without stressing this 1000 mile motor.

Any thoughts? Go higher? Is that enough to even be able to feel it?

KY_BOB · « **Reply #46 on:** August 17, 2011, 06:38:53 PM »

The torque curve is pretty flat on these.

MyBigToy · « **Reply #47 on:** August 17, 2011, 07:00:51 PM »

Quote from: KY_BOB on August 17, 2011, 06:11:43 PM

As for tuning, I ask a question on PT.net about shift rpm with a 5.3/6 speed. I was told by a professional tuner to WOT shift it at 5800-6000, that these motors pull well to there. With the close ratio of the 6 speed and the peak torque at 4700, that seems a bit high to me. I'm not worried about the motor, it will take it.

The factory shift points are 5525rpm for 1-2 and 5425 for all other shifts. I'm thinking about going to 5625 and 5550. That is a real baby step but I would like to see if I can tell any difference without stressing this 1000 mile motor.

Any thoughts? Go higher? Is that enough to even be able to feel it?

If the stock cam pulls that high I say just go ahead and do it. You know that's where you'll end up anyway so why not just go ahead? If you don't like it you can change it back in about 3 minutes.

KY_BOB · « **Reply #48 on:** August 17, 2011, 08:10:58 PM »

Quote from: MyBigToy on August 17, 2011, 07:00:51 PM

If the stock cam pulls that high I say just go ahead and do it. You know that's where you'll end up anyway so why not just go ahead? If you don't like it you can change it back in about 3 minutes.

OK, I'll give a little. I just changed it to 5675 and 5625.

I have a serious traction issues when it hits 2nd. That's why I'm leary about taking 1-2 too high. If I turn off T/C, it wheel hops and stibilitrak applies the rear brakes (not to mention the stress on the driveshaft and u-joints). I can shut off stibilatrack, if I want, maybe it would be better if I just let it spin. If I leave T/C on it drops from 20 deg advance to -8 deg timing to control wheel spin. It even pulls some timing on the 2-3 shift due to wheel spin. I know that I can tune that out but I'm getting about 3mph of wheel spin during the 2-3 shift. This 6L80 is amazing.

I'll flash it in the morning and try it.

Zora Arkus-Duntov · « **Reply #49 on:** August 17, 2011, 09:40:59 PM »

....sounds like the results of (Sildenafil Citrate)

Quote from: KY_BOB on August 17, 2011, 08:10:58 PM

OK, I'll give a little. I just changed it to 5675 and 5625.

I have a serious traction issues when it hits 2nd. That's why I'm leary about taking 1-2 too high. If I turn off T/C, it wheel hops and stibilitrak applies the rear brakes (not to mention the stress on the driveshaft and u-joints). I can shut off stibilatrack, if I want, maybe it would be better if I just let it spin. If I leave T/C on it drops from 20 deg advance to -8 deg timing to control wheel spin. It even pulls some timing on the 2-3 shift due to wheel spin. I know that I can tune that out but I'm getting about 3mph of wheel spin during the 2-3 shift. This 6L80 is amazing.

I'll flash it in the morning and try it.

KY_BOB · « **Reply #50 on:** August 17, 2011, 10:48:20 PM »

Quote from: Zora Arkus-Duntov on August 17, 2011, 09:40:59 PM

....sounds like the results of (Sildenafil Citrate)

I'm still young enough to hit a 2nd and 3rd without Sildenafil Citrate.

(granted, my desired shift time isn't what it used to be but I can still get a good squeal when it shifts and at least I don't have to worry about TM, just traction)

MyBigToy · « **Reply #51 on:** August 18, 2011, 11:40:01 AM »

Quote from: KY_BOB on August 17, 2011, 08:10:58 PM

OK, I'll give a little. I just changed it to 5675 and 5625.

I have a serious traction issues when it hits 2nd. That's why I'm leary about taking 1-2 too high. If I turn off T/C, it wheel hops and stibilitrak applies the rear brakes (not to mention the stress on the driveshaft and u-joints). I can shut off stibilatrack, if I want, maybe it would be better if I just let it spin. If I leave T/C on it drops from 20 deg advance to -8 deg timing to control wheel spin. It even pulls some timing on the 2-3 shift due to wheel spin. I know that I can tune that out but I'm getting about 3mph of wheel spin during the 2-3 shift. This 6L80 is amazing.

I'll flash it in the morning and try it.

You must be busy at work today.......

KY_BOB · « **Reply #52 on:** August 18, 2011, 03:03:01 PM »

Quote from: MyBigToy on August 18, 2011, 11:40:01 AM

You must be busy at work today.......

No, I didn't get to flash it until lunch. Looking over the log right now.

KY_BOB · « **Reply #53 on:** August 18, 2011, 03:43:23 PM »

OK, a couple of observations. Even with the shift points set at 5675 and 5625, the highest logged rpm in 1st was 5634 (that's close) but the highest I logged in 2nd was 5557. I'm wondering why it didn't get above 5600 in 2nd

I only pulled it to 5350 (91mph) in 3rd, I ran out of road before it could shift to 4th.

LTFT's are too negative at cruising speed but straighten up to -1 to -3 before entering PE.

As for seat of the pants, I couldn't tell any difference in it.

I don't know what size injectors this thing has in it but 66% duty cycle is the most they hit. They can flow some fuel.

KY_BOB · « **Reply #54 on:** August 18, 2011, 04:19:44 PM »

OK, after reviewing some older logs, I feel better. It has always shifted earlier than the tune called for. I am getting another 100-125 rpm out of it.

Just FYI: I did a brake stalled launch for the first time today. I logged a 0-60 time of 8.28 seconds and a 0-80 time of 13.67 seconds. I wish I had done one before pulling out the TM but I'm not going back stock unless it has to go to the dealer.

Main One · « **Reply #55 on:** August 19, 2011, 07:02:28 AM »

Quote from: KY_BOB on August 18, 2011, 03:43:23 PM

OK, a couple of observations. Even with the shift points set at 5675 and 5625, the highest logged rpm in 1st was 5634 (that's close) but the highest I logged in 2nd was 5557. I'm wondering why it didn't get above 5600 in 2nd

I'd say that you aren't seeing it closer to the specified shift points due to the data logging frequency not being fast enough relative to how quickly the rpms were climbing. In other words, your log wasn't capturing the peak rpm - it was in between data points.

Look at the difference between the next to highest rpm point and the one before it so that you can get a feel for how much the rpm increases between data points. I say next to highest because your highest one could possibly be after the peak. I suspect that the amount of increase between those points is larger than the difference between your selected shift point and the data you are looking at.

MyBigToy · « **Reply #56 on:** August 19, 2011, 11:07:34 AM »

Quote from: Main One on August 19, 2011, 07:02:28 AM

I'd say that you aren't seeing it closer to the specified shift points due to the data logging frequency not being fast enough relative to how quickly the rpms were climbing. In other words, your log wasn't capturing the peak rpm - it was in between data points.

Look at the difference between the next to highest rpm point and the one before it so that you can get a feel for how much the rpm increases between data points. I say next to highest because your highest one could possibly be after the peak. I suspect that the amount of increase between those points is larger than the difference between your selected shift point and the data you are looking at.

Now you sound like an engineer talking! Data sampling/refresh rates and interpolating between points. We'll be losing everyone watching this thread if you continue to go on like that!

Zora Arkus-Duntov · « **Reply #57 on:** August 19, 2011, 11:18:49 AM »

Quote from: MyBigToy on August 19, 2011, 11:07:34 AM

Now you sound like an engineer talking! Data sampling/refresh rates and interpolating between points. We'll be losing everyone watching this thread if you continue to go on like that!

Gregmanese .....but were learning.

Main One · « **Reply #58 on:** August 19, 2011, 11:39:57 AM »

Quote from: Zora Arkus-Duntov on August 19, 2011, 11:18:49 AM

Gregmanese .....but were learning.

Bob's used to it

KY_BOB · « **Reply #59 on:** August 19, 2011, 03:28:14 PM »

Quote from: Main One on August 19, 2011, 11:39:57 AM

Bob's used to it

Oh yea, and I understand him.

I may play with tuning a little over the weekend and early next week but I'm spending most of my weekend packing my dive gear for next weekend. I'm doing the opposite of "Cheers". I'm going where no body knows my name, as a matter of fact, I don't even speak their language.

OK, I got off topic. As for tuning, I may put a few more rpm into it but then I'm going to start looking at timing. I'm already past the rpm with the highest timing. I'm seeing the timing drop from 20 deg down to 18 just prior to the shift. I'm thinking that I can get by with around 24 degrees at the higher rpms. M1? (of course I will keep a close eye on the logs for KR when I start adding timing.

I've only seen KR once in one log and I think that was burst KR. It was only 1 degree and at a low rpm as I was easing into the throttle.

Main One · « **Reply #60 on:** August 19, 2011, 03:41:15 PM »

Quote from: KY_BOB on August 19, 2011, 03:28:14 PM

Oh yea, and I understand him.

I may play with tuning a little over the weekend and early next week but I'm spending most of my weekend packing my dive gear for next weekend. I'm doing the opposite of "Cheers". I'm going where no body knows my name, as a matter of fact, I don't even speak their language.

OK, I got off topic. As for tuning, I may put a few more rpm into it but then I'm going to start looking at timing. I'm already past the rpm with the highest timing. I'm seeing the timing drop from 20 deg down to 18 just prior to the shift. I'm thinking that I can get by with around 24 degrees at the higher rpms. M1? (of course I will keep a close eye on the logs for KR when I start adding timing.

I've only seen KR once in one log and I think that was burst KR. It was only 1 degree and at a low rpm as I was easing into the throttle.

I'll have to look at some of my logs and/or tunes at home and get back to you.

Edit - what octane fuel are you thinking of running in that thing???

KY_BOB · « **Reply #61 on:** August 19, 2011, 03:56:27 PM »

Quote from: Main One on August 19, 2011, 03:41:15 PM

I'll have to look at some of my logs and/or tunes at home and get back to you.

Edit - what octane fuel are you thinking of running in that thing???

I'm tuning it for 87. It will be interesting to see what it does on 105 octane E85 if I add some timing to it. I'm pretty sure that they run off of the same timing table. The fuel tables are drastically different.

Main One · « **Reply #62 on:** August 19, 2011, 04:34:07 PM »

I presume it has to be able to accommodate filling up one week with E85 and the next with gas, etc. so that it has to be able to operate in between.

KY_BOB · « **Reply #63 on:** August 21, 2011, 05:33:31 PM »

Quote from: Main One on August 19, 2011, 04:34:07 PM

I presume it has to be able to accommodate filling up one week with E85 and the next with gas, etc. so that it has to be able to operate in between.

Yea, for example there are 2 PE tables. one gas, and one alcohol and a percentage table to chose where to go to on mixed fuel. I hope my leaning out the gas table won't run it too lean on mixtures. I assume they use the same level of conservatism on the alky tables. We'll see. I don't even have a clue as to what AFR makes the most power with alky. I know that gas likes about 12.5/1 for max power. Stoich for 100% alky is about 9.7/1. I would guess that max power would be around 8/1.

Main One · « **Reply #64 on:** August 22, 2011, 07:47:46 AM »

Sorry for not getting around to this over the weekend. It was not a normal weekend. Amber witnessed her father having a heart attack on Saturday. She thought he had died. He's doing fairly well now.

KY_BOB · « **Reply #65 on:** August 22, 2011, 03:32:01 PM »

Quote from: Main One on August 22, 2011, 07:47:46 AM

Sorry for not getting around to this over the weekend. It was not a normal weekend. Amber witnessed her father having a heart attack on Saturday. She thought he had died. He's doing fairly well now.

Wow, sorry to hear about the family health issues. I didn't even open my tune this weekend. Unless work slows down, I may not touch it until I get back from vacation.