dllhg

I think I found a big part of the problem with my recent slow passes at the track (11.48@122.5 MPH)

2012 stock LS3 LT headers, injectors, fuel pump Eforce with 3.25 pulley. ZERO knock at any speed.

Looks like this must be using the crappy canned tune that the Eforce came with around 2012-2013.

Did some real scanning finally. IATs started at 140 cruising or at a stop it didnt matter. Did a 0-100 and a 60-90 run. Iats went up to 155 on bigger pull and 150 on second pull. KR is still zero and now I know why...

It was only commanding 4-5 degrees of timing at WOT ! Geez that's terrible. Weird blips of negative advance too up to -10 degrees. Timing tables are set to be running 12-13 advance. I am assuming they have it set to pull a lot of timing if IATs get higher but this is extreme. Super safe tune that's for sure. I'll try and post the scan shortly.
I want to tweak it enough to get by for now. Plan to get it to a reputable tuner and dyno tune it.

I will also need to start looking at cooling mods. IATs only went up 10-15 degrees during runs so it wasnt from the blower. I didnt get in to boost before the runs....

Advice on changing the IAT timing tables would be greatly appreciated.

TurboLX

Are you disagreeing with the physics that says "things that are already hotter, are more likely to burn quicker"? That's why the IAT timing adjustment exists in the first place. Even on turbocharged and supercharged applications, I find that the factory IAT timing correction is actually pretty close to what you want if the base (high octane) and other (AFR, ECT) tables are correct. I honestly don't think you have a "crappy tune" here with regard to spark vs IAT.

Instead, I would focus on whether you can reliably lower the intake temps in the first place. You will be limited by the design of the supercharger, manifold, and intercooler bricks, but there may be options for you to get more heat out of the water in the intercooler loop, which will help charge temps across the board. 140* starting temp is pretty warm...

dllhg

I get zero knock not even close to a blip even after swapping to a smaller pulley. Tells me the tune is very rich and or conservative. I know some experienced guys in here have posted that they dont normally adjust IAT timing except on boosted cars. Lastly the Eforce runs a solid 20-30 degree higher IATs than the Heartbeat blower and the only reason is placement of the IAT sensor.

I feel like I should tune it as if IATs are 20 degrees lower anyway.......

dllhg

I have attached my tune plus a scan from my 0-100 run

TurboLX

No, it tells you that they scaled the delivered spark against load (g/cyl is the y-axis of the main spark table) correctly. You can get hot or cold intake air temps on either pulley, depending on when/where you drive.
I'm one of them.
Heartbeat has the sensor unrealistically close to the discharge of the intercooler brick, numbing its sensitivity. That's a different issue. You WANT your spark to adjust relative to the actual temperature of air entering the cylinders, even if that means accounting for heat transfer after exiting the intercooler brick. The factory even has a table to adjust the estimated cylinder charge temp relative to the measured IAT, with some bias towards ECT based on conditions. This heat transfer is really happening inside the intake whether you acknowledge it or not, so you might as well let the ECU compensate spark accordingly.

One of the reasons you're not seeing much knock is that whomever built your current tune wasn't overly aggressive. Likely because they warranty their work and had time to research just how much spark the engine will tolerate, even when it's hot. If you feel like you know more based on reading some forum posts, go ahead and outsmart them. Just don't complain here when it breaks.

dllhg

I cant see how 140 degree IATs on a 70 degree day cruising before getting in to boost would be accurate and reason to run 4-5 degrees advance timing with no knock present. I wasnt going to remove the tables just adjust them so it doesnt pull as much timing. I also spoke with a very experienced tuner and they adjust those tables as well.

I'm no blindly taking advice from one forum member. There are some in here with same exact blower who set there not to pull timing until about 140 degrees. They were not getting knock either. It would stand to reason you can increase timing and adjust fueling more aggressively as long as you can keep it from knocking .

All that being said I am now reconsidering Meth injection. After talking with the builder/tuner he install them all the time and has good results. A bit steep at $2K installed. He said you definitely get some cooling but the main thing is you get increased octane. I need a good dyno tune on here either way from someone who knows what they are doing. This tune is beyond conservative IMO.

Apocolipse

If its not knocking why do you need more octane?

If people zero their IAT correction at 140 id rather add that tl the high octane table and leave iat alone.

russ472

TurboLX (greg banish) doesn't post a lot on this forum. but when he does, I would take it to the bank. Just google his name if you don't already know who he is.

dllhg

I can tell he knows a lot. I also can’t ignore that it’s pulling ridicules amounts of timing with no knock present. Also that other reputable members in here with crazy fast cars who had same blower setup changed the tables and even very reputable tuner just old me they do the same with these setup.
obviously need to go slow and not make crazy changes but if it isn’t knocking at all it should be fine unless there is something else I don’t know 🤷‍♂️

Apocolipse

Having no knock is a good thing...why would you want to see knock in a log?

Add timing to the main timing table instead of reducing IAT timing pull.

Most tuners are useless when it comes to the actual science of why things behave a certain way. "Just cause everyone else does" is typical.

realcanuk

It giving you the spark you are commanding less the amount reduced in the IAT table. The big drops to negative timing are torque management from the shifts. That is a whole other tuning story to get the trans right.

dllhg

100% agreed Wasnt saying you wanted to see knock but rather if you arent seeing knock while making small changes you should be fine. He didnt say because everyone else does . He just said that they do change values in those tables as well.

I thought about just adding timing in the other tables too. The reason I wouldnt want to do that is say I add 19 degrees timing to get an actual 9 degrees advance it could go way high when IATs are lower. If I leave the max safe values in the high and low octane tables it will never go over those amounts which are currently set to 13-14 max. Just tweak and make the IAT /timing less aggressive seems to make more sense and be safer.

dllhg

Understood, thanks for clarifying. I'm not going to raise the high/low octane tables but rather tweak the IAT/timing tables to be less aggressive.

I am going to have car tuned early December. Will just make some minor tweaks myself and familiarize myself with tuning the car. Going to the track again right after Thanks giving. I just want to tune it a bit before then. Wont be putting the 3.0 pulley on until tuner gets it. Was 84 degrees here today ! Crazy.

Didnt I read you saying you prob wouldnt do meth again ? Were you still getting up to 150 IAT spraying ? I guess the main thing would be for the increased octane especially for me here in Ca with our 91 and 10% ethanol.

realcanuk

I don't recall saying I wouldn't do it again. I ran meth with the eforce and with my YSI. What I said is your wont know the actual drop in iats because the sensor is at the back of the eforce and I would bet very little meth actually reaches there.

dllhg

I recall hearing recently that spraying 50/50 with meth is better for 1/4 mile and pure meth was better for dyno ......

dllhg

Oops sorry ! I spent about 10 hours reading up yesterday and I'm sorry I mixed you up with someone else. Might have been Coolhand .....

realcanuk

I always ran a mix, but most disagree. Not getting into that conversation again. There are plenty of threads on all these topics... you need to do a lot of reading and searching.

dllhg

10 hours on my Sunday wasnt enough ? lol Spent about two hours reading about just that tonight and I still couldn't decide. Personally I like the idea of it being less flammable and giving better cooling. Did you go 50/50 or ? I like to mirror what others have done on the same platform successfully. You certainly qualify with your times and no cam even.

BIGMAC

I don't think Julio of Alky Control fame would agree with you .

luka2sb

i personally would spend more effort lowering the charge temperatures, and a lot less effort on your opinion of spark.

you don't have in-cylinder pressure transducers, you don't have "knock ears", you dont know your cylinder pressures (or the cylinder pressures that the LS3 pistons can support), you just have an opinion that the spark is not advanced enough; based on other peoples experience on other engines. soooooo you're either the ultimate engine whisperer or you're risking the health of your engine on a guess.

I did it too (completely different engines), thinking spark was too retarded, tried advancing it 1 degree or 2, and it went from absolutely no knock to a little knock here and there. backed off, tried it in a different operating zone, advanced a degree or 2, started knocking again. Over time i learned more about engines, eventually i got some real education on combustion theory then things started making more sense.

Point is just because spark is low while IATs are high, doesn't necessarily mean the spark is incorrect. sure you can test adding spark, and it might work, but you are reducing your safety margin. For instance, if you get it tuned in december, make sure you log data at the drag strip in the summer, it may very well knock, even though it never knocked on the dyno.