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What to watch for to keep it from gernading

 
Old 08-09-2018, 11:06 AM
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Default What to watch for to keep it from gernading

I am a newbie tuner self tuning an LQ4/cam/799 fbody swap with HPTuners pro, have it idling pretty well and driving it while babying it because it's a necessary DD for me. It's been getting me to work and back.

Other than watching that it never goes too lean under higher RPM/load (I have a wideband, will be watching for anything worse than 15AFR normal driving for now, because other threads imply I safe numbers are around 12.8 under power and a leaner 14.8 for normal cruising), what else is CRITICAL that I must watch to keep the engine from blowing up? Anything? I mean other than the obvious of overheating or low oil pressure, which mostly have nothing to do with the tune I assume.

EDIT: also logging and listening for KR/detonation

I have been copying a lot of stuff from other tunes, am worried I'm going to do the wrong thing while I am learning this stuff, killing this LQ4 would be a big problem for me.

Last edited by mk3cn4; 08-09-2018 at 01:18 PM.
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Old 08-09-2018, 02:54 PM
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Originally Posted by mk3cn4 View Post
I am a newbie tuner self tuning an LQ4/cam/799 fbody swap with HPTuners pro, have it idling pretty well and driving it while babying it because it's a necessary DD for me. It's been getting me to work and back.

Other than watching that it never goes too lean under higher RPM/load (I have a wideband, will be watching for anything worse than 15AFR normal driving for now, because other threads imply I safe numbers are around 12.8 under power and a leaner 14.8 for normal cruising), what else is CRITICAL that I must watch to keep the engine from blowing up? Anything? I mean other than the obvious of overheating or low oil pressure, which mostly have nothing to do with the tune I assume.

EDIT: also logging and listening for KR/detonation

I have been copying a lot of stuff from other tunes, am worried I'm going to do the wrong thing while I am learning this stuff, killing this LQ4 would be a big problem for me.
That's the gist of it to my knowledge. Being NA you will be fine I'm sure. The BIG thing is don't let it get lean and spark knock at the same time
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Old 08-10-2018, 03:11 AM
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im new to tuning so i might be wrong but from what i learned these last few months, your idle and cruise can go to 15.5 maybe even leaner but im not sure how lean, 14.7 is for emission around 15.5 might give you better fuel mileage but i think you should test that for your self, two days ago i took hpacademy remote tuning lesson two which basically let me mess around with afr and see the torque change in real time and exhaust gas temperature and i found that afr leaner than 14.7 is actually colder egt at low load i went to 16.17 then i stopped,

so at light load dont worry about going little bit lean but i wouldnt go leaner than 15.5 maybe 15.1 but idk i dont have any real experience so mess around and test it for your self you are not really gonna hurt the engine on a light load as long as you are not knocking and by the way the knock sensor could pick up some false knock so if you see knock on 1 cylinder it could be false you need two cylinder to confirm sometimes knock sensor need to be calibrated using knock monitor system like plex, now unless you have a 1 bad injector that something else.

now about wot this is a question im gonna ask the forum later where did afr 12.7 or 13.2 peak power came from is it tested on dyno or just old school tuning maybe even on carb, when i was messing with the afr i found that on 1zz-fe engine the peak power is at .8-.83 lambda which is 11.76-12.2 anything leaner losses power then it kinda picks up a little bit around 13.6 but still less than 11.76, and the egt increases by 122f so i dont see why you should run 12.8 unless you can test the power difference in a drag race or 60 mile highway pulls.

i have a ls2 engine tuned by cbm and my afr is 11.8 it has small cam and it made 395whp, cbm tune is conservative so idk know if it would make more power running leaner but after my experience two days ago i understand why he did it, i used to think the first thing i would do when i buy hptuner i would lean it out to 12.7 but now without a dyno i wont touch it,

when i tuned 1zz-fe at 13.6 i got 16 degreee of timing and at 11.76 i got 22 degree of timing but there is 0 torque difference for that engine so there is no point of running leaner than 11.8 or 16 degree of timing but i would tune to 12 as sometimes the engine would run richer or leaner than target afr so i want to be near peak torque as afr changes your tune will never be the same alot of factors can change it, now i dont know if you can fix that using compensation table but i believe a good tuner would make sure his tune is good for all different conditions.

let say you tune 12.8 and get 24 degree of timing and if you tune 11.8 get 28 degree of timing and then you get an issue where your fuel pump start to die or injector flow get weak and your car leans to 12.8 and your engine starts to knock because you are over advanced by 4 degree most of the time you wont realize its lean or knocking until its blow up keep in mind the tune out always be 100% sometimes you would get some issues like wiring or bad sensor or something that could trick your ecu and destroy your engine so always account for worse case scenario as its your daily if it was track only it depends if it drag run it as aggressive as you can and monitor afr and knock and retune if something change , if it under heavy load under extended time like endurance racing or drifting, rich is better to make sure you dont melt a piston,but on a daily leave it as conservative as you can as most of the times you wont notice 10whp difference but you will notice 2-5mpg difference.

so try find the timing your engine wont knock at while running lean and then richen it for safety what i mean is if your car would knock at 22 degree lean dont tune 22 rich go with 20 rich,

and dont copy someone else tune especially ignition map just dont this is how people blow up engines,and most important thing i think is the compensation maps like iat and ect make sure the timing pulls and maybe enrichen afr to cool down egt, i believe the secrect to tuning is the other maps rather than pe or timing.

if you can try finding mbt maximum brake torque or minimum best timing , the reason its called minimum best timing cause you are not gonna make more power if you over advance and i think you might have more risk of doing engine damage if you are over advanced now im not 100% sure, i forgot what happens to cylinder pressure after mbt but i know its peaks at rpm max torque(4400rpm i think) and mbt, so use less timing than you need leave 5whp by using less timing than mbt just to be conservative until you learn more about tuning but too much retard will increase egt.

Andre at hpacademy found that on ls engine he tuned when the afr was richer he got few more degrees of timing and got 9whp more so its not always smart running 13.2 or even 12.5, one of the things is ls engine runs hot and extra fuel cools it better.

and there is an advice i got from one of the tuners i asked this same question to he said to make sure you never blow up any ls engine never tune past 24 degree of timing and without a dyno i think this number might be too much, thetuningschool recommend on some engines to run no more than 21 degree i think this was truck gen 3 like lq4 i don't remember, the max they recommend is 23 the minimum is 19 if my memory serves me but that could change with different heads and cam maybe more maybe even less.

this basically summarize every thing i know about tuning an engine i leaned alot about timing and afr from my experience doing a remote tune which was the opposite from what half the people on the internet says, i used to hear people say you cant know what afr to run until you put your car on a dyno it didn't make any sense and i didn't believe them no matter what they said i thought 12.7 is the golden ratio for every engine but now if im gonna tune any engine i would start with 11.8-12.2 and then test on a dyno or by racing at rolling speed which is easier for me.

if any one disagrees with me or have an argument they want to share i would love to hear it so i could learn more from other people experience and any tips about tuning in general is highly appreciated.

Last edited by QTR FMS; 08-10-2018 at 04:24 AM.
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Old 08-10-2018, 02:30 PM
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Originally Posted by QTR FMS View Post
now about wot this is a question im gonna ask the forum later where did afr 12.7 or 13.2 peak power came from is it tested on dyno or just old school tuning maybe even on carb, when i was messing with the afr i found that on 1zz-fe engine the peak power is at .8-.83 lambda which is 11.76-12.2 anything leaner losses power then it kinda picks up a little bit around 13.6 but still less than 11.76, and the egt increases by 122f so i dont see why you should run 12.8 unless you can test the power difference in a drag race or 60 mile highway pulls.
I think this comes from the factory tune actually, I think it has PE that applies, which throws a richening multiplier in there under WOT. Not sure if it's the same number you quote but the concept is in the factory stuff.

I need to get better with the timing like you describe. I don't have a "feel" of what is good/bad under what conditions at all. Your post gives a lot of info I'm going to make mental note of!!!

Good advice about not copying other people's tunes. When I first started this I was looking at it at a very fundamental way, applying all my experience using normal scanners and data loggers that only logged like 20 things, I thought tuning would come easy for me because I do have a fundamental understanding of troubleshooting the cars. But wow, there is so much in HPTUNERS, it's not just a matter of setting what you want timing and A/F to be, there are like a thousand factors that you have to consider and so many things contribute to the final A/F and spark. And every car is SO different, copying a tune is certainly not a guarantee even with exact mods, might not even be close!

Overwhelming, but I'm going to try my hand at tuning using the guides. As long as I know I won't destroy the motor by watching these few things I think I can get a good basic tune in there and even start taking it to the track.

Thanks for the info
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