JimMueller

iTrader: (9)

My friend had bought a rebuilt ~430ci LS7 motor for his '02 Z06 from a local LS performance shop, that has been in business and also performing tuning for at least 10 years. The shop had problems eliminating the knock on their non-load bearing dyno, so a decision was made to add E85 and a boost-a-pump.

After getting the car back a couple of months ago (it's not a daily driver), he finally autocrossed it a week or so ago (which my friend knew in advance would cause the warranty to expire on the engine). He complained about hearing detonation during racing that wasn't picked up by his scanner, and he's heard it when using both 50% and 70% E85. He wanted to buy his own setup and take classes instead of me helping him out, so he finally bought HPT and he sent me the tune as found last night. I'm disappointed to see the knock and misfire desensitization from the shop, among other questionable changes. He doesn't yet have a wideband to clean up the fueling, and we don't yet know if the injector data is correct. I'm trying to encourage him to restore the misfire and knock changes to factory settings and we'll gradually desensitize the misfire tables and see what can be done with the timing advance. Yes, there is a concern about his ~.060 quench, but that was brought up while the engine was disassembled and I think he had hoped it wouldn't be a big deal... he doesn't need more torque... he actually needs less wheel spin on competition tires.

I've attached the initial tune from the shop and a factory tune provided from the HPT forum. The initial tune was pulled using the latest HPT beta.

Here are my notes of his build from our chat.
----final build per notes---
RPM transmission, stock rebuild
Diff with 10K miles
Quartermaster clutch, 10lbs

New LS7 block
Callies 4" Magnum crank
Oliver 6.125" billet rods
Mahle pistons PN 930221635, +2.5cc, about 10 thou in the hole
Mast Motorsports heads, 65cc chambers
* Pro Flow intake valves
* Inconel exhaust valves

Stock 1.8 rockers
EPS cam 230/242 (284/296) 116+3 .629/.604
stock head gasket, .052
LSXR intake manifold
SCR 11.83 SCR
DCR 8.67
E85 kit with Boost-a-pump, typically running 50% E85
60lb Siemens Deka injectors for LS2 fuel rail
LS30 oil
Fuel pressure at idle is ~62psi
--------------

NicD

iTrader: (7)

Looking at how much they desensitized the knock sensors it looks like they were battling false knock, but it's not increased by much. However good luck getting the Gen3 knock sensors to be totally accurate running with a Gen4 block.

As for misfires I would be disabling them anyways since it will never be accurate with that cam and lightweight clutch. Of course you could spend hours tweaking the misfire tables in every possible condition you can think of but down the road at some point it will throw a misfire code again or read misfires and it's going to be false and just a spot you couldn't get to.

JimMueller

iTrader: (9)

He says can hear the detonation with 50% E85 and 70% E85 fuel under certain RPM ranges. If he's truly hearing detonation but it's not showing up in the logs, something needs to be adjusted. If I was to play with the knock sensor settings, I had planned to use Ed & Russ's idea here. I've gradually desensitized my misfire tables for my 418 LS3 (232/242 114+4) but I still have the heavy LS7 clutch (which is acting up a few months after meeting the 418).
https://forum.hptuners.com/showthrea...Block-Settings

I recall reading that desensitizing misfire and knock should only be done as a last resort. Personally I'd rather have a false P0300 than no indicator of a pending serious mechanical failure. His car, his choice, as long as he knows the pros and cons.

NicD

iTrader: (7)

Agreed. I just looked at the timing table, WTF? No wonder it's detonating even on ethanol. Looking at the VE table that's way low as well, then I saw the inj flow rate and stock offsets, geez the whole thing looks terrible.

Yeah that's pretty typical as you just want to work your way up little by little until you can verify you no longer get false knock. Problem is unless you have a mechanical ear on the block good luck because not all knock is super audible to the ear and Gen3 knock sensors aren't great in the Gen4 location no matter what. I've had Gen4 engines audibly knock with Gen3 knock sensors/PCM installed even with stock settings and it never even registered, then it would pick up some random knock event sitting still. It's just not good no matter what.

Yeah that's all fine and dandy until you have to make adjustment after adjustment months and months after the tune is "done" because it still throws random P0300 codes. The reality of slowly backing off the misfires tables is fine if you want to endlessly tinker but that's not what you are going to get from a shop as they don't have endless time to tinker over and over as it will come back repeatedly guaranteed and then you look like a jackass. Now slowly desensitizing the knock sensors is pretty straight forward, quick, and easy compared to the misfire stuff.

JimMueller

iTrader: (9)

Pretty sure I saw something under dynamic airflow where the rpm filter was set at 400, indicating it's running purely off the MAF. Since he has a manual transmission and the auto shift settings are modified, it looks a lot like a template was applied.

When asked about the audible detination, the shop told him that knock was not desensitized. They should at least be forthright about the changes so the customer isn't left chasing their tail.

NicD

iTrader: (7)

Problem is that it still blends for transients no matter what dynamic disable is set to.

Well then they lied but not like it matters when gen3 knock sensors will never work properly with a gen4 block no matter how you massage the tables. Hell even trying to use Gen4 sensors, wiring the extra ground, and setting it to flat response doesn't work right when you don't have good base knock sensor levels to start with for that configuration with the Gen3 PCM... and no 4.3L tables aren't accurate either.

JimMueller

iTrader: (9)

Should he be able to use premium gasoline (E10 or E0) without (or with acceptably minimal) knock, and with reasonable timing, on his combination? On the last log he took, knock learn factor was in the 0.1x range at WOT, and I've read that Gen3 goes from 1 to 0 as it moves more towards the low timing table. Right now his stoich is 14.37 and his PE ratios are 1.1-1.2, but he's been using E50-E70 blends trying to see whether they reduce/remove the knock, and often logging at WOT because that's where he generally hears the detonation. He did say he was going to try filling up with Sunoco unleaded 100 but I don't think he's done it yet. I'm a bit concerned he may be running lean as a result of that blend/tune mismatch, but I'm not well versed on tuning fuels other than gasoline. Would a PE of 1.17-1.20 be safe to use while he figures out which fuel he's going to run?

Even though he just bought HPT, he's suddenly overwhelmed by the task of doing it himself and he's not taken me up on any offers to help in person. I've known him for close to 10 years through racing, so I did buy a pair of credits simply to help him with remote changes. I loaded the Siemens Deka 60lb injector settings from Greg's DVD into a tune for him but I don't think he's written it. I'm trying to talk him into getting an AFR500v2 & NTK production sensor so that we can verify the fueling; I have an AFX with a fairly new sensor but it's not installed in a manner that makes it easy to move between vehicles.

Darth_V8r

iTrader: (4)

What balancer is on the motor? I had a vette di this and two other I'm connected with. The stock dampener was toast. Caused audible knock. Replaced with ATI. Problem solved.

JimMueller

iTrader: (9)

Stock, but it only has 800 miles on it. Is there a way to visually ascertain a problem with the stock balancer? There wasn't any knock (heard or logged) yesterday when the PCM was using the low octane table

Darth_V8r

iTrader: (4)

When i have seen it ve an issue you could see it wobbling