LS7 tune question. Need second set of eyes please

[HCIC6Z]

Hey guys, long time reader first time poster. I am having some issues with my tune and i'm wanting someone to take a look and maybe tell me if some changes can be made or what you think.

Mods are:
PRC 285cc heads w/ 70cc chambers
TSP LS7R cam, 248/256 .655/.655 144+4 LSA
Compression was originally 11.7:1 with a .051 head gasket but I had to change it and i was sent a .041. So the compression is probably closer to 12.1:1 now.
Fast 102 intake w/ fast rails (not ported)
stock TB
Callaway intake
Pfadt 1 7/8 headers with catted x-pipe
ATI damper

My issue has been since day one. I initially had it tuned after breaking in the new engine and it was pulling timing up top, around 7* after 6200rpm. I had some "cheap" off brand 93 left in it because i was not really beating on it, mixed in with BP 93 when it was being tuned.

I leave disappointed with 522/444.

I don't drive the car much, i come back about a year later and i want to try to get this sorted out. The only change now is the head gaskets were changed because i was having a small coolant problem, its since been fixed. I also added a catch can.

Back on the dyno it makes 562/494 and its pulling up to 8* up top. Some how it made more power but its still pulling timing. This was with a tank of BP 93 and probably had some shell 93 in it too.

Tuner says you need race gas or e85, compression is too high and its pulling timing. I'm like okay, im not filling this up with race gas and I DO have a flex sensor but not installed, i don't have PTFE lines yet.

Does this seem like something that is too much for 93 pump? A friend on an almost identical build got on the same dyno and made 622whp, he's using the same gas I am.

I never threw a light for a knock sensor or any DTC's for that matter. I did change the knock sensors the other day though, I am planning on doing a log tomorrow and i'll post those. I'm thinking i'm getting some kind of false knock possibly?? The car should be making much more power.

I attached my tune so hopefully someone with some experienced eyes can have a look and tell me if something might be off? I'm in Florida at sea level btw.

[TCSS07]

do you have a log of this happening? maybe get a octane booster (i use boostane personally) or do one tank with race fuel and see if the timing issue is still present or not. if it is then maybe start looking around for any possible signs of exhaust hitting,mechanical issue or maybe your car is picking up engine harmonics causing false knock in which you would need to absolutely make sure its false before you start to alter any knock sensor settings (they may be to sensitive). what afr are you running - your commanding what seems to be a 12 afr but is that what your actually getting? to lean or too rich of a afr can cause knock also. im not to keen of how your ho spark is set up from 1k-2600 under .40 cylinder air mass - it goes from 21* and drops to a lower advance and builds back up - i always prefer to have a smooth transition with spark. not saying thats your problem given you stated its up top where the issue happens - just making a observation.
under knock retard - trying lowering your burst knock settings in half and if you want - i set the knock recovery rate to .500 from 3k-8k

[HCIC6Z]

do you have a log of this happening? maybe get a octane booster (i use boostane personally) or do one tank with race fuel and see if the timing issue is still present or not. if it is then maybe start looking around for any possible signs of exhaust hitting,mechanical issue or maybe your car is picking up engine harmonics causing false knock in which you would need to absolutely make sure its false before you start to alter any knock sensor settings (they may be to sensitive). what afr are you running - your commanding what seems to be a 12 afr but is that what your actually getting? to lean or too rich of a afr can cause knock also. im not to keen of how your ho spark is set up from 1k-2600 under .40 cylinder air mass - it goes from 21* and drops to a lower advance and builds back up - i always prefer to have a smooth transition with spark. not saying thats your problem given you stated its up top where the issue happens - just making a observation.
under knock retard - trying lowering your burst knock settings in half and if you want - i set the knock recovery rate to .500 from 3k-8k

Last it was on the Dyno my AFR was in the 11.3-11.7 range. I noticed the spark dip but didn't quite understand why, he said it was pulling timing in lower rpm at certain points as well, so maybe that is why?

I'll do a log today for pump and some booster. I've checked everything and nothing seems to be touching. I've had the exhaust off and back on. I have valve train sewing machine noise but to me it isn't bad. Could cats cause it? Or maybe the header thickness or way it's bent?
Either way, I'll report back and thanks I'll try the burst knock settings.

[HCIC6Z]

I started the car and let the oil temps get up and i went on the road and did a pull. The only things i changed were i cut Decay in half from 14 to 7. And I set Knock Retard maximum from 12.0 to 1.3... I had read somewhere the newer Vettes had a lower number. I attached the log.

[TCSS07]

can you post up the tune you just did with the changes you made? do you have a wideband installed? theres a few things you should add to your logs such as injector pulse for both banks, injector duty cycle, o2 sensors,MAF Hz, MAP. Remember also that no 2 cars are alike even if the mods are so maybe your car doesn't want that much timing up top within that rpm section as your friends car does. Your trims were lean some what before you did a wot pull so a little touching up will be needed. As for the timing issue if nothings hitting and you know the afr is spot on and mechanically everything is ok then either add 100 octane and see if the knock goes away and if it does then you'll probably have to remove a 1 degree from the cells to start until it goes away but if it doesn't go away with the added octane i would suspect it to be false but without seeing the actual afr is hard to say because 22 degrees isnt like crazy advanced but again your car just might not want that much timing. most n/a set ups i tune i shoot for a 12.5afr. the 11.3-11.7afr is more so a boost afr imo but at this point you'll have to do a little bit of process of elimination to get it fixed

[HCIC6Z]

I have the KR basically gone. I haven't touched spark or fuel (still learning) plus my wideband isn't hooked up for some reason the AEM wideband doesn't want to thread into the bung on my PFadt header? Anyway

I zeroed out burst knock and changed the KR Maximum to 1.3. I am not picking up any KR at all. Before i turned off the burst knock each time i'd get on the throttle it would spike like 7* then taper down. I'm going to do logs today with everything you suggested and i'll post. I would definitely like to make some changes to my fuel/spark somehow because i know the tuner was tuning around the KR so the tables are not ideal.

[HCIC6Z]

Here is another log, please let me know if i'm missing something.

Also, it pulled about 1.3* around 5600rpm on one wot pull and then another it didnt. Timing is commanded around 25* when it did it.

Is it safe to adjust any of these spark tables in small increments until i get KR? I'm not trying to add more exactly, but i'd like to smooth it out if possible.wot2.hpl

[TCSS07]

could you post up the current file please with the knock sensor changes you've done
you would usually want to adjust the timing by 1 degree until you get knock then back it off like 2 degrees or so for safety but to find best spark and afr is only found on a dyno so you can actually see on a graph what works best for your vehicle but i wouldn't mess with it until you can verify the afr yourself - maybe remove .5* from the cells that still show up with knock
if it knocked on one pull then didnt on the other it could of just been a fluke or a slight fueling error from one pull to the next because it didnt seem like there was too much down time before each pull so you probably still had the fuel saturation from the first pull.
you need larger injectors though because your pretty much static - when the injector duty cycle gets to be that high the ecm has a harder time controlling the afr and fueling so you will need larger injectors to move forward and get that wideband working again to just verify the afr at wot and make sure its spot on
what size injectors are your running?is fuel pressure ok?

[5FDP]

Yeah it's plausible he has room still if the fueling is too rich but it's probably still going to be at over 90%.

I don't suggest telling the computer the max knock it can do is 1.3 degrees. What if it's really knocking at 5 or 8 degrees and now you won't let the computer remove the needed amount of timing to be safe.

Not sure if it was said yet but another issue is mirroring the timing curves. The low octane table needs to have less timing in it so that it can use a lower timing value if knock is present. The knock learn factor will determine whether or not it can use the just the high octane table or interpolate between the high/low values in that given cell so that it stays safe.

[TCSS07]

5FDP - I agree about the idc still going to be high it was more a spit balling idea of the sorts and since he doesnt have a wideband hooked up worth taking a peak at and yeah I agree about the knock sensor settings which is why I asked to see the tune he did with the changes because all I talked about was knock decay rate and burst knock not actual ecm ability to remove timing. He may if mis understood what I said about it. I believe I forgot the low octane chart but I did see his timing curve and didnt like how it went from like 20 degrees and drops down to like 7 and builds back up which I found odd since I like to keep the timing to have a smooth curve

[HCIC6Z]

Okay here is my most recent file as of today and a log with a brief WOT pull in there. I have been getting most of my KR at certain lower RPM and low cylinder airmass where the spark advance is too high (it was in the 45's and 40's so i went across the top and changed the value to 35 until about .28g) So whenever i get KR on a log i have taken the values and subtracted the advance accordingly but most of it has been at partial throttle/cruising and if i dip into it at certain RPM it will KR because the advance is just so damn high on the table at those levels. Not sure if that is the correct way but that's how i did it and it has worked.

I'll change the max knock from 1.3 to a higher value like suggested.

I have not touched anything related to fuel.

Again thanks for the input and please if you have suggestions let me know what i can do. I know i gotta do my wideband but this damn Bosch LSU 4.2 won't thread into the bung on my Pfadt header, it's the bung where wideband is supposed to go. Maybe i need an adapter, i dunno, the thread should be m18x1.5 like every thing else.

HERE ARE THE FILESC6z tune Feb 14.hptwot6.hpl

[TCSS07]

I'm mobile atm but will check it later. What I suggested was burst knock and knock decay rate

edit - i would put the spark retard tables back to how it was in the first tune and the tables i was talking about was knock retard recovery rate set to .5 from 3k to 8k and burst knock (base vs cylairdelta) just cut that table in half

[HCIC6Z]

I'm mobile atm but will check it later. What I suggested was burst knock and knock decay rate

edit - i would put the spark retard tables back to how it was in the first tune and the tables i was talking about was knock retard recovery rate set to .5 from 3k to 8k and burst knock (base vs cylairdelta) just cut that table in half

Man, so I changed the recovery to .500 from 3k to 8k. And the burst knock. I logged it and I wasn't getting more than like .2 kr in some places. At WOT I have ZERO.

This weekend I'll do my wide band and maybe I'll try some of the fuel. The PE table is 1.340 to as low as 1.200 so it has room for improvement I think.

Right now driveability is perfect. Throttle response is good and it pulls really well. Big thanks and I'm gonna keep this updated.

[TCSS07]

glad to hear it and yeah get that wideband up and running just to see where your at but you definitely need larger injectors though - your really pushing them buggers lol

[HCIC6Z]

Yeah i have some 72 lb injectors but then i have no idea how to even scale them.

I do have a question though, about my PE.

It doesn't come on til about 4000-4100rpm.

My PCM is set to:
Enable MAP 15kpa
Delay RPM 2,000rpm
Delay throttle bypass 0.0%
Enable RPM 300

What could be a reason it comes on so much higher in the RPM?

[TCSS07]

Your going to have to drop the throttle enable setting a bit more to have pe kick in a little sooner. The throttle enable is what you set plus idle % i believe or something like that so even though you have it set at 36% at 3500rpm its really like 70% for actual throttle position. i usually just add 30% (in my head) to whatever i put in the pe throttle enable for the actual enable throttle % so if you wanted 50% actual enable throttle you'd want to put 20% in for the pe throttle enable
in the most current log you posted it came on around 3750rpm at 73% actual tps - so try setting the throttle enable to 20-25% and see if pe enables sooner