My LS1 tuning journal

[silverTA2002]

Oh yeah, and another question.

I accerate a LOT at 1000 to 2500 rpm during normal driving (duh, who doesn't).

Will it help part throttle acceleration (30% throttle) by messing with timing down there, or should I only worry about WOT timing?

[Plums]

I gave the whole table an extra 7 degrees and it certainly livens up the part throttle response.
Some of my mates call me Miss Daisy, (I guess I do drive rather sedately) but the extra timing down low makes the Ute so
much more drivable, with the added bonus of improving fuel economy, (about 23 MPG around town).

Yelo, did I miss-read your post or do you run 32 deg @ WOT? Does anyone else run up over 30 @ WOT?

Cheers, Plums...

[silverTA2002]

I gave the whole table an extra 7 degrees and it certainly livens up the part throttle response.
Some of my mates call me Miss Daisy, (I guess I do drive rather sedately) but the extra timing down low makes the Ute so
much more drivable, with the added bonus of improving fuel economy, (about 23 MPG around town).

Yelo, did I miss-read your post or do you run 32 deg @ WOT? Does anyone else run up over 30 @ WOT?

Cheers, Plums...

No, I was running between 21 and 29 degrees with an average of 25.

I'm still trying to get the timing down correctly, but first I'm trying to see what's wrong with my passenger front o2 sensor. There's nothing visually wrong with the wires or anything, so I don't know why it isn't reading correctly. And my fuel economy on this tank seems to have gone to crap (go figure with an o2 not working).

[Yelo]

Plums: You read it right....I run 32º @WOT (9.9:CR) on 91 octane without a problem (at least this week.....I change my tunes so frequently it not funny) It's kinda high for an F-body or Corvette to run but the 6.0 truck heads with the lower compression can get away with alot more timing (especially with mirrror polished chambers and valves)....I also run a TR220 cam so cylinder pressures are different from stock too

silverTA2002: YES...increased timing at part-throttle will make your car SO much more fun to drive....Like Plums said: you can add ALOT down low and FEEL the results

[silverTA2002]

Awesome!, I'm gonna have to add some more timing down low.

Does timing down low follow the same rules (i.e. keep adding it till you get KR?)

I just added 2* from 1k-2k to see what happens, and no KR I also decreased timing up top in the cells where I was getting knock with the 95% PE setting, after that, I have close to no KR.

I get the feeling I'm just gonna keep changing and changing till it's just about perfect.

Also, as for the o2 that I had a problem with. I read that the front and rear are the same, just have different cable lengths, so I switched them on the passenger side, and NO PROBLEM. So it was an o2 going bad. Oh well, at least I have a backup.

What's kinda wierd now though is that my LTFTs have gone quite a bit more negative compared to a few days ago. Now they're averaging -8 where they were -3 on average before my o2 went bad.

Is this some "safety feature" that will go back to normal after a little driving? If so, I don't want to mess with things if the computer will "fix itself."

[silverTA2002]

Also, for part throttle timing tuning, which cells do you modify?

For full throttle, I've been doing .52 and up and 2000rpm and up. Is it just "everything else" for part throttle?

[Yelo]

Does timing down low follow the same rules (i.e. keep adding it till you get KR?)

Yep....

I get the feeling I'm just gonna keep changing and changing till it's just about perfect.

Probably so....That seems to be what I have doe (and am still doing)

What's kinda wierd now though is that my LTFTs have gone quite a bit more negative compared to a few days ago. Now they're averaging -8 where they were -3 on average before my o2 went bad.

Is this some "safety feature" that will go back to normal after a little driving? If so, I don't want to mess with things if the computer will "fix itself."

Weather and other variables can make a BIG difference in LTFT's...if it stays that high you can start to change things....but give it 2-3 days

[silverTA2002]

Well, I did two more logs tonight. One part throttle (33% or less) another mid throttle (50% or less).

My LTFTs for both averaged -3 and -5, I'd consider that ok for now. This afternoon (right after the o2 switch) it was closer to -10.

I also used these logs to see which cells I'm in for part throttle and to look for KR.

The only time I had KR was in 5th gear at 2k rpm. But, it's still KR, so I decreased timing in those cells by 1* and increased by 2* in all the cells I didn't have KR. This is getting fun.

I'm starting to understand the log data, etc. and how to change stuff.

One thing I'm curious about though is WHAT ELSE SHOULD I MESS WITH?

There are a bunch of other tables and things in HPtuner, but are you supposed to change any of that other stuff to make more power and/or better fuel economy and/or make the car run better? I haven't read ANYTHING about stuff other than IFR, MAF, PE, and high octane timing vs. RPM.

Also, do you have any suggestions for whether or not to mess with the KR decay rate? I've heard it mentioned, but I dunno.

Thanks again.

[Yelo]

Most of the other tables hardly ever get played with.....they are useful for SOMETHING but most of us don't really know what that SOMETHING is ???

Us A4 guys have alot more to play with than the M6 guys because we have a computer-controlled transmission to play with as well


To answer your question: KR decay rate is how fast the the computer pulls timing....and how fast it brings it back in, to be truthful I don't know the scaling that VCM Suite uses (I'm an old-school LS1Edit guy....but VCM Suite is on it's way here as we speak ) but you want it to pull timing as slowly as possible and bring it back in as quickly as possible (to prevent power loss due to extended periods of lowered timing)

[raptorman02]

Where is the "IFR" table?? I feel like an idiot asking but I see nothing called IFR.

Thanks in advance

Ok, I understood your first paragraph, but as for the rest..... :huh2:


I'm just trying to follow what I've read about tuning for your LTFTs during partial throttle by chaning the IFR table.

Is this not the best way to go?

I have a stock MAF, stock injectors.

My mods are FRA, Holley filter, SLP lid, Jet hot headers and catted Y, dynomax muffler, NGK TR55s, and HP tuners.

[Yelo]

"Injector Flow Rate" table...it's under "Fuel"

[silverTA2002]

Today I did a bunch of playing with the PE ratio just to see if my o2s were accurate or not.

I went to 90% PE and had a little knock (1-2* for about 10% of the WOT cells), then I went to 85% and only had 3* for 10% of the cells.

My o2s went to 930 and 920 at 85%. BUT, my car didn't feel any faster, and part throttle seemed a bit slower, and after a little reading, I found that with long tube headers, you'll get higher o2 readings than actual due to the placement of the sensors compared to stock. So my o2 readings are useless (but very consistent between logs :huh2: )

Long story short, I just ended up going back to 95% PE and messing with timing some more.

[mustbbrent]

SilverTA2002,

Just wanted to say thanks for doing the journal. I found it really helpful to listen to your journey to tuning. The HPT product arrives here in a day or two. Can't wait.

[silverTA2002]

SilverTA2002,

Just wanted to say thanks for doing the journal. I found it really helpful to listen to your journey to tuning. The HPT product arrives here in a day or two. Can't wait.

Hey, not a problem at all, I hoped it would be helpful.

Oh and as an update, I went to the drag strip last thursday.

I ran a best of a 13.4 at 105mph with a 2.0 60'.

It was kinda disappointing since that's exactly what I ran BEFORE tuning, only with better weather. Before it was 70 degrees and less humid. Las week it was around 80 and quite humid.

Either way, the car seems quite a bit slower than what it SHOULD be with my mods (lid, FRA, filter, headers, and muffler. Many people are running that STOCK. And I should be at least 40-55hp above stock.

The only thing that should be slowing me down is my speaker box and other crap I had in the car at the time (computer, etc.) But that should only make up about .1 second or 10hp.

Before headers, with a lid, FRA, filter and muffler swap, I ran a 13.8 at 104mph with a 2.2 60' (FWD cars kept going through the water pit) weather was ok like 75 degrees out and mid humidity.

I'm just kinda frustrated after spending $1500 in mods and only gaining 1mph.

My timing is good (26-28 at WOT). I have zero KR at WOT. My LTFTs are around -2. The only thing I'm unsure of is my Air/Fuel ratio.

But I've gone anywhere from 100% PE to 85% PE and haven't felt any SOTP change.

Any suggestions?? I just don't feel like spending more $$ to dyno and get no results.

[mustbbrent]

Just my .02. I have been following and seen the saga. All I can tell you is.. I am in Austin, Tx area where it gets muggy and hot and I am running full timing advance >30* with no knock retard through 5700rpm or so. But I am a 6.0liter truck with a few bolt ons currently (though not for long,) nothing like you guys. in a non boosted, NA motor, timing and A/F make the ponies.

I do agree with the other guys, add as much timing as you can down low and slowly step up through the rpm adding as much timing as you can at each rpm till you get KR... then get those A/F ratios inline and go back and see if there is extra timing again. A bit painstaking, but works. I don't have a wide band either, but will be putting in a bung so others can attach and see.

[silverTA2002]

Did a few changes for the first time in a while.

I went with 93% PE to see if I'm still rich.

I have no KR, and an average of 28* of timing at 100% throttle.

My o2s are 940 and 920 average now.

The timing seems pretty close to ideal, so I may just keep leaning it out till I get KR.

[tiggerfan]

I tuned my GTO tonight. At WOT it took 3 pulls to get the air/fuel perfect but I did. From 3300 RPM up it looks as flat as it gets and is right on.

Its worth it to get the wideband o2 on the dyno to tune the air flow.

From here on out its timing tables, to the limits and then I'll see where I'm at.

Did a few changes for the first time in a while.

I went with 93% PE to see if I'm still rich.

I have no KR, and an average of 28* of timing at 100% throttle.

My o2s are 940 and 920 average now.

The timing seems pretty close to ideal, so I may just keep leaning it out till I get KR.

[silverTA2002]

I tuned my GTO tonight. At WOT it took 3 pulls to get the air/fuel perfect but I did. From 3300 RPM up it looks as flat as it gets and is right on.

Its worth it to get the wideband o2 on the dyno to tune the air flow.

From here on out its timing tables, to the limits and then I'll see where I'm at.

Now that your A/F is dead on by wideband, what do your o2 sensors read? (i.e. were they accurate?)


Today I went to 91% PE. I had to retard timing 1* in a few places to have zero KR. But, my average timing is still 26-27*

My o2s are about 920-930 on average.

[tiggerfan]

Now that your A/F is dead on by wideband, what do your o2 sensors read? (i.e. were they accurate?)


Today I went to 91% PE. I had to retard timing 1* in a few places to have zero KR. But, my average timing is still 26-27*

My o2s are about 920-930 on average.

At WOT they averaged around 860. So I'm not sure if they are completely accurate, but I trust the dyno wideband a LOT more then the stock sensors.

[silverTA2002]

Well, today I went to 89% PE, logged, decreased timing where there was KR, logged again.

And I have an average of 1* of KR at WOT with 89% PE. And my timing only averaged 25*.

I went back to the previous 91% PE where I have no KR, and more timing. That's probably it for my A/F ratio. Even though my o2s read 940 and 915.