I think I made my pistons ''too efficient''. Logs inside....

[earlbrown]

Unfortunately, my boost logging doesn't work since I removed my boost/tach module to get it rebuilt....    and I haven't hooked up my FP transducer yet...

My engine is a 4.2L with a little over 9:1 static, max ported 8445s with O/S valves, 215/220 roller, GT3255, and an extender chip on 93 with 19/17*.

PL is with a PLX wideband.

First pass is tuner style with the wastegate backed off as far as it will go. (about 5ps when I'm forced to let off, I think)  What's odd is that .7* is LOUD AS HOLY HELL. It literally sounds like drunk gnomes with hammers and marbles under my hood. I suspected the knock circuit wasn't reading right but it works fine...

#2.   So I popped the wastgate arm loose.  It makes right at 2PSI at the top of second  The knock readings not parrallel what I expect to see and hear with that amount of knock.  No freaking idea why PL shows .7 when you can hare it in the next county.

#3.   I upped the BLM adjust to 13 (of 18) to see what putting the BLMs closer to 128 would do. (since high compression likes more fuel it makes seance. ESP with my extra cubes and flow)

#4  Seemed to be the right direction, so I set the BLM adjust to 18.

#5 Made two changes at once. Maxed out the LoGear fuel and got rid of the default +2* 1st/2nd ignition advance.  It was SOGGY as hell driving to my turnaround spot then flooring it.

#6 Same as above. but much less soggy than #5. Still soggy and still knocking at @2PSI. Honestly, I don't think I'm knocking from cylinder pressure. I think I increased my burn rate and I'm just lighting the spark too soon.


I spend a lot of time with my piston engineer when I was designing my pistons. He mentioned that he like his inverted domes to require as little advance as possible. I agreed.   From the passes I made today it would appear that I've just increased the efficiency of my engine 'too much' and tuned myself right out of my chips' window. 

What I do know.  It started out lean as hell and adding fuel brought my numbers closer to where it's a good starting point to find 'the magic number'.  Pulling timing <i>seemed</i> to help, but without a way to pull it until I see a difference, that's speculation.

Thots?

I'm am surprised that I can knock the 295's loose without boost. That's one stout N/A V6 with a cork in the exhaust 

[motorhead]

Try changing the type of fuel you are using.  Adjusting the burn rate could be a positive influence.

[earlbrown]

Screw that. If I can't run plain ole gas station pump gas, I'll part this damn thing out and have a covered place to park my jetboat.

[Pyro6]

What about the timing? Crap, just re read and saw the "as little advance as possible". Is it possible to retard it more?

[earlbrown]

No, from what I can tell my extender allowed me to mess with 1/2 timing but only down to ''no more additional''. Once the 3rd gear signal lights up, it appears to be set in stone.  I really thought they were more adjustable than that.

If the knock would have waited until after 3rd to flare up, I would have unplugged the transmission plug so the ECM always thinks I'm in low gear. (I don't need TC lockup to tune).   From what I can tell, 'my N/A V6 is maxed out with timing'...   once the boost comes up ANY, that's it. Time to spick the cylinder temps.

I briefly glanced at Eric's site and it look like the TT chips have more timing latitute but his won't take advantage of the Extenders doubling of the g/sec of airflow with a Translator.

I wish I had an engine on a stand. It'd be easier to look at what it would take to drop the crank trigger down a few hundred thou.

It literally looks like I'm just outside of the tuning window to know where to go.  I hate the idea of spending $100 on a chip just to learn what I need to ask for so I can spend another $100 on a chip (then hope I haven't blown my car up spending all these 100's on chips learning what my engine wants)

[Scoobum]

Is the timing I'm seeing correct?

[earlbrown]

If you're looking at the timing on my logs......    probably.

Honestly they make no sense.   If I was old schooling it and messing with a distributor, there's no way in hell I was try some of the shit my computer is trying.


I actually ignore that a little when I look at the wastegate (I'm tuner style now so it doesn't effect me at the moment). It'll start knocking and the computer is still commanding 100% solenoid duty cycle...  WTF?   Not to mention my chip code indicates I should have 85 and 80% duty cycle.

[Scoobum]

WB, NB are showing lean...and the timing is also showing it going through the roof. You say you can hear it knocking...but it shows minimal KR in the first file. If the KR is real you're hearing...then why isn't it picking it up?

[earlbrown]

No idea. But that first file makes enough racket that it would have blown non-cometic head gaskets, or cracked a hyper pistons with NO problem. Ive cracked three pistons. Two on the first pull. rebuild the engine, one on the second pull. (That's why there are forged pistons with my name on the bottom now. lol)

Look at the TPS in the first file.  I can get NOWHERE near full throttle with the wastegate hooked up. That's only partial throttle.  I can't floor it until I let the wastegate rod hang loose.

It's seriously so loud I'm considering pulling the engine and shotgunning the rod bearings. I've thought about making an audio recording of the physical noise but I'm literally scared I'll bust my only 4.1 block and rip the bottom out of my transmission.

It's that loud.


I truly have NO idea why it's only.7 on the log and sounds like a parking lot carnival ride at the same time.

[Scoobum]

Contact Bob and ask if bypassing the wastegate solenoid messes with the timing in his chip. Timing should stay fixed at 19/17. If that chip isn't burned for your combo...that might explain it running lean. Are you showing KR on the SM or your in car knock sensor?

At the end of the day, I think this is gonna be a chip issue...and possibly a bad knock sensor.

[earlbrown]

I'm showing knock on my scanmaster, my powerloger, and the actual real life audio scares schoolchildren and gives them nightmares.

[earlbrown]

Frankly with the shit I'm catching on the other board, I'm REALLY thinking about walking way and either burning this car to the ground and parting it out.

I honestly don't enjoy owning this car anymore.


this is coming from some one that has over 10 motorcycles, a TVR, a pimp ass '72 Dodge van and some other toys that haven't been driven in over 10 years.....    but if the fucking Buick gets gone, I really think I'd feel better.

[Scoobum]

It's not your pistons that are the problem. Don't let them get to ya'. If ya' do...then they win.

[motorhead]

It literally looks like I'm just outside of the tuning window to know where to go.  I hate the idea of spending $100 on a chip just to learn what I need to ask for so I can spend another $100 on a chip (then hope I haven't blown my car up spending all these 100's on chips learning what my engine wants)

Pick up a cheap used MAF T Pro and Extender Pro chip and gain all of that functionality you desire.

There are limits on what you can do with straight pump gas, the quality is always suspect, and it really is limiting.  Maybe order up some "Race Gas" octane booster and/or toss in some home-brewed additives (paint thinners) to make up the difference - if you don't own an alcohol injection kit already.

As for burning it...  Yes, do that - because the platform is pretty self-limiting if you are unwilling to start chopping it up to get modern tuning benefits - kinda like an Atari vs. Xbox One.  Maybe go with Mega Squirt and expand your options?

[daveismissing]

Maybe with those pistons you need a lower compression ratio?
Spend $125 on a mcumall GQ-4X programmer and another 25 on an eraser and start tweaking your own tables in the chip.