HAHAHAHAAHAAA...... you have no idea of the hex you just landed on yourself.... hope you got a thick wallet dude.... LOL :crazy:Quote:
Originally Posted by mkriebs
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HAHAHAHAAHAAA...... you have no idea of the hex you just landed on yourself.... hope you got a thick wallet dude.... LOL :crazy:Quote:
Originally Posted by mkriebs
Sure do. got alot of resources too. I wouldn't be building a car if i didn't.Quote:
Originally Posted by MMGT1
So, I have been messing around in HPT tonight, and I got to thinking... I really need to change the axis loads on my tables since I am seeing nearly 250% load (or higher). And I got to wondering how this would affect higher end knock... Since I am technically moving higher advance to higher load, will I need to change this all around?
Right now I am in the process of writing a whole new map, so I am still at stock timing, and i figure I can get this all panned out on the dyno if I make it up there.
Also, would it be unwise to modify the ignition base correction for coolant temp vs engine speed? Of course, if it was over 210*, I would leave the correction be, since that would be very unhealthy for the engine.
And what about changing the load axis on the Cam Timing tables? Any adverse effects that could arise from that? I would imagine it would be easier on the engine, since it would be phasing 'slower' so to speak.
Be careful it can misfire if you change the load axis. I dont think it will help much.Quote:
Originally Posted by mkriebs
Very informative thread, thanks guys!
I have a couple newb questions (I'm no newb to tuning cars, but this is the first LNF I've done, I've worked on tons but never tuned one.) 08 Kappa, GMPP turbo upgrade, Magnaflow 3.0" w/stock cat, opened up stock air cleaner w/k&n. Other than that, stock except for some first minor tweaks with HPT.
I've taken Backyard Turbo's suggestions for Max Airload Torque Table, DAL Table and richened up PE slightly. Haven't touched valve or ignition timing, or overboost settings. (The GMPP tune sets overboost dtc threshold at 26 psi I believe.) Huge difference over the GMPP tune alone!
Here's the questions...
First, I'm seeing 25 psi and logging what looks like 26 or 27 psi in the logs. (yikes!) Does that sound right for the mods I've done? (Sea level, 50 degrees ambient, 14.3 baro.)
Second, since the dash seems to peg at 25 psi and the logs show 26-27, I'm assuming the dash gauge will only read to 25?
Third, how safe is it to run it at these boost levels? Can you damage an LNF with the stock turbo and stock ignition and cam timing settings but these mods? (As long as KR is kept to a minimum or none at all.)
Thanks!
As long as it isn't knocking like crazy, that amount of boost is fine! I was running 30psi for over 10K miles and had no issues from it! You should read the: Take your pill mod to the next level thread, it will explain how to setup the spark advance table headers better for that amount of boost/airload.
I ran .88 Lambda with 30psi, just fyi.
It's been posted on another forum by a gm engineer that boost over ~25 psi causes excessive cyl temps and the rings expand more than the ring end gap allows causing the ring land failures a few have seen on their LNF's. The rings grow and gouge into the cyl walls without sufficient end gap. His explanation makes the most sense to me on the ring land failures.
Most agree that any KR seen is bad for the rings also.
Not familiar with the ranges on the Solstice gauge vs. the GMPP sensors though so I won't speculate. My Cobalt sees spikes on the analog gauge to 27 - 28 but I'm on the stock sensors so it's probably gauge windup. I max out at 255 kPa in HPT but the analog reads higher, say 24-25 on a hard pull until the turbo runs out of blow.
Stock cam tables work best for street tuning based on 60-100 mph log times.
I can run 14* advance up top as boost tapers down to 19 psi at 6300, but any more than that, I get 2-3* KR. Many can run up to 17* at redline, mine never could. I fought the WOT KR for a long time.
Edit: BYT posts faster than I... I also run .88 PE lambda in the 100% column, .98 under that for the ethanol in the fuel here to get closer to Stoich. (It's actually 5.5% Ethanol best I could research) That got rid of a bit of my low rpm mid load KR.
Thanks guys!
I'm running the same PE settings so that's ok. Stock and the GMPP tune looked a little lean to me too. Searched and found out about the 255 map sensor deal in the ECM or OS, seems even if the GMPP kit sensors can read higher, the OS still stops at 255. You're right, the analog sensor reads higher, which is what scared me. I'm seeing 29-30 psi A LOT. Not sure I like having the boost up that high, I've been working back down on the DAL table to try to lower it.
I have another question, are these LNF's sensitive to false knock? I'm getting 3-5* on accel most all the time, tried dropping timing in the cells that showed the KR but didn't change amount of KR in logs afterwards. I noticed that I was getting KR at almost no timing (0-2* a couple times and it was showing 4* KR). That has to be false knock, can these things actually knock at 0*? The other thing I noticed is it's almost always cylinders 3 and 4 that show KR, which also leads me to believe it's false. I'm going to try to swap the sensors to see if the KR goes to cylinders 1 and 2, if so I just have a super sensitive knock sensor. If not I need to look for sources of noise around the back of the motor I guess. Either that or try a tank of race gas and see if it goes away.
Thanks again for the help guys! Man I'm used to Gen 3 and 4 V8's, these things are a little different. I'm glad I can even tune it, but geez there's practically no tables in these ECM's (that we have access to so far) compared to E38 and E67's. Every time I want to change something, I look for the table and say Damn, guess that one's not there!
The LNF is very prone to reporting false knock, I have the same issues.
Like you, I see the most KR on #3 & 4. 2-3* on a throttle stab.
Make sure the ECT advance table isn't adding too much timing when it's cold. I took all that out until it gets to -5*f and it got rid of my cold engine KR altogether.
I found dialing in the MAF trims perfect allows you to run far better timing then just retarding timing to reduce knock..
That's interesting, I'm finding the same thing too as I get the maf dialed in closer (was too lean) the KR is getting better. Obviously higher maf tweaks end up using higher timing cells which would lower timing slightly.
Played around with cam timing, tried to reduce the EGR hump in the middle of both intake and exhaust tables (which would raise cylinder pressures) and ended up getting a bunch more KR, which is no surprise. It does tell me that most of the KR I'm seeing is real and not so much false knock. Seems likely that the back cylinders might be more apt to knock, that's why it's mostly 3 and 4 that show KR.
Iam Broke- you're right, a lot of the KR I was seeing was before the motor got to 200*, my stock ECT/timing table wasn't giving it any advance until the very cold rows, so I actually had it take away 2 degrees until 150 or 170*. Cold start and drive today showed no KR! I'm getting there.
BYT- thanks again for posting this tuning guide (which I've ended up hijacking, but figure this could be good info for others also). Just to see what would happen, I added 100 to the entire DAL table, except for the 0 and 10 percent columns. Holy cr#p! it did actually make the car undriveable! It was making boost at about 1/8 throttle! Pretty crazy the amount of control over the power delivery these motors and ECM's have.
Hijack away :) Check the Pill mod threads as well as Taking the pill mod to the next level for more fun stuff!
Term, Broke and myself are all running stock cam timing now (from what I remember recently anyway). I found advancing the Intake cam on the dyno picked up whp up top but it didnt translate to faster acceleration when I actually compared them. And I lost whp, the power curve took a big shit up top when we tried playing with the exhaust cam. I would just leave them stock honestly on a mostly stock car!!
QFT on the stock cam tables.Quote:
Originally Posted by BackyardTurbo_FTW
Ahhh, This is when the student becomes the master! Ha Ha.
The biggest problem for most people is cam timing cannot fully be assessed on a dyno. Most stock tunes at idle and full throttle the cam timing is pretty good, not much room for improvement. The big (sometimes huge) difference you can make on changing cam timing is drivability. Again, I'm new to LNF tuning, but on gen 3 and 4 V8's if it doesn't have an actual EGR valve, they'll use cam timing to reduce NOx and lower cylinder temps. If you remove the cam retard in the center of a gen 4 cam timing table, you will get WAY better response in the midrange. Idle and full throttle will be the same, as will full throttle hp and torque on a dyno. I've had some very well known tuners tell me there's nothing to be gained by changing cam timing (again, I don't know yet about LNF's, I'm talking V8's and V6's) because they get too wound up in dyno readings and don't realize most street driving isn't at full throttle but between 1/4 and 1/2 throttle and 1500 to 3000 rpms. That's why guys like you 3 (and others) that are mostly messing with their own cars and have hundreds of hours logging changes a lot of times know more than the pro's on their particular engine.
I'm still going to try messing around with the cam tables, but mostly in the middle, not full throttle or idle. With the amount of KR these little motors produce, you guys are probably right, there's not much more you can get with cam timing without raising cylinder pressures too high.
Just be careful when messing with them, makes sure to gradually increase/decrease to your changes. Someone posted some nasty valve damage from just doing the high load cells and then changing nothing else.
Smoothing is your (and the cam phasers) friend. Keep us posted. I hate to do much more in the midrange, 25-27 psi is all she can take, Cap'n. :D
^Pulled a 4.7 60-100 stabbing it at 58. ALL stock parts including the air filter even! Only mod is the airbox mod since I can't go back LOL!!! Staying away from the pill mod now, may even leave the DP and CP off. The car is nice and quiet yet smooth and powerful as fuck!
Just so I dont get called a BS'r lol...
http://forums.backyardturbo.com/pict...&pictureid=466
http://forums.backyardturbo.com/pict...&pictureid=465
Image quality sucks because I had to upload them to my photo gallery on my forum, then link the image. My lappy died at home that has my FTP info saved on it LOL! Ill upload them again when I go back to work next week, heading to Vegas baby!!!
I have tried moving the intake and exhaust cam independently in both directions in the midrange and midload areas. All you will get is either a more sluggish car or loads of part throttle misfires that you can feel happening. The programmers of this ECM did a great job with the cam tables IMHO.Quote:
Originally Posted by gmtech16450yz
Aaaalllright ladies my copy of HPT gets here Monday..can't wait to start tweaking this thing some more! Term or BYT would either of you mind looking a my current tune? I have a copy of it from my tuner somewhere on this computer.