2004 6.0 NV4500 Tahoe

[Dantheman1540]

Tonight was my first time really getting on it since I did the heads and although it has an exhaust leak and isn’t really done being tuned, it feels much better midrange and definitely up top! The maf fueling looks great +/-3% and it seems to love 23* of timing. After I finish fuel tuning I can’t wait to sprinkle a little more timing and see what it does.

It actually spun on the 1-2 shift long enough I peddled it which it’s never done on dry pavement.

 

[iamdub]

Tonight was my first time really getting on it since I did the heads and although it has an exhaust leak and isn’t really done being tuned, it feels much better midrange and definitely up top! The maf fueling looks great +/-3% and it seems to love 23* of timing. After I finish fuel tuning I can’t wait to sprinkle a little more timing and see what it does.

It actually spun on the 1-2 shift long enough I peddled it which it’s never done on dry pavement.

Mine's at 24° (on 93, 10.25 SCR)

 

[Dantheman1540]

Mine's at 24° (on 93, 10.25 SCR)

Before at 10.9cr & 21-22* it had what I thought was false KR in weird spots including right at the top but I thought it was related to the shifts. I did a bunch of spark table smoothing and upped it to now 23* with 10.5cr and it has absolutely zero KR anywhere and genuinely feels more lively. I’ve seen some people seeing 26-28* making Mac power with somewhat similar cams in ls2s so I’ll try to sneak a little more in there later and see how it feels.

 

[Dantheman1540]

I make sure to keep the low octane table 4* or more below the high in case it does sense KR.

 

[iamdub]

Before at 10.9cr & 21-22* it had what I thought was false KR in weird spots including right at the top but I thought it was related to the shifts. I did a bunch of spark table smoothing and upped it to now 23* with 10.5cr and it has absolutely zero KR anywhere and genuinely feels more lively. I’ve seen some people seeing 26-28* making Mac power with somewhat similar cams in ls2s so I’ll try to sneak a little more in there later and see how it feels.

I'm kinda feeling that my 24° might be safer than I thought. Instead of trying to max out the timing to the ragged edge on 93, I'm gonna try 90 octane (50/50 mix of 89 and 91) and work down from there.

 

[Dantheman1540]

I'm kinda feeling that my 24° might be safer than I thought. Instead of trying to max out the timing to the ragged edge on 93, I'm gonna try 90 octane (50/50 mix of 89 and 91) and work down from there.

Do you know what your low octane spark table is set to? I ran 87 with the previous setup but only during a long road trip that was a steady cruise for two tanks.

 

[iamdub]

Do you know what your low octane spark table is set to? I ran 87 with the previous setup but only during a long road trip that was a steady cruise for two tanks.

24°. Just ramps up more sharply on high octane. Unless we're looking at two different things.

I could probably run 87 on a road trip if I could ensure that I wouldn't go WOT.

 

[Dantheman1540]

24°. Just ramps up more sharply on high octane. Unless we're looking at two different things.

I could probably run 87 on a road trip if I could ensure that I wouldn't go WOT.

There's a high octane table which is what the truck will start with and stick with unless KR is recorded then it will pull timing and possibly revert to the low octane table of the KR is consistent. Typically a good tuner will take the high octane table paste it onto the low table and then subtract X amount of timing across the board to keep stuff safe in the event you get KR or decide you want to run cheaper fuel which I will be doing after I get the tune sorted.

 

[Dantheman1540]

Very frustrated with this idle surging, sometimes it idles flawless then other times it drops into this crazy sawtooth pattern where timing can jump from 29* to 15* I've already made fairly large changes to the overspeed/underspeed tables trying to keep the spark from over correcting itself and the spark table is very smooth and gentle, especially in those areas and the surrounding cells.

I'm gonna go back to adjusting base idle airflow and see if that's part of the problem. The white sawtooth pattern is the spark advance.

 

[Dantheman1540]

I think I partially figured the idle out, the base idle airflow need about a 50% increase which seems crazy when keeping the same cam. Guess these heads really flow a ton.

 

[pwtr02ss]

I think I partially figured the idle out, the base idle airflow need about a 50% increase which seems crazy when keeping the same cam. Guess these heads really flow a ton.

Glad you're making some head way. I've been watching GRG here and there. When the weather gets figured out, I think I'll be ready to start messing up. It's nice to read something and have a slight idea of what you're saying!

 

[iamdub]

Glad you're making some head way. I've been watching GRG here and there. When the weather gets figured out, I think I'll be ready to start messing up. It's nice to read something and have a slight idea of what you're saying!

The things I've watched vids for, my HPT doesn't have. It's like I have a different version. For one, I can't find the idle over/underspeed thing in mine.

 

[pwtr02ss]

The things I've watched vids for, my HPT doesn't have. It's like I have a different version. For one, I can't find the idle over/underspeed thing in mine.

Not sure about that either lol.

I'll send you the link for what I've been watching in the morning. I haven't put the rubber to the road yet but I feel like I'm understanding it a little better. Basics. Very bottom of the list basics

 

[randeez]

are you in the basic mode? should be under engine>idle>rpm

but dont adjust those tables how you think...if anything just "soften" them up from stock if you think they correct too much

 

[Dantheman1540]

Glad you're making some head way. I've been watching GRG here and there. When the weather gets figured out, I think I'll be ready to start messing up. It's nice to read something and have a slight idea of what you're saying!

Get on it!

The things I've watched vids for, my HPT doesn't have. It's like I have a different version. For one, I can't find the idle over/underspeed thing in mine.

That’s odd, I’ll screen shot where it’s at next time I’m on my laptop.

are you in the basic mode? should be under engine>idle>rpm

but dont adjust those tables how you think...if anything just "soften" them up from stock if you think they correct too much

Yeah I just softened it up across the board keeping it progressive but trying to keep it from making 25* swings. Now that it’s idling a little better I may reverse some of it closer to stock.

It just seems so weird to me that it’s wanting 11.5g/176* of airflow at idle when before it only wanted 8.4g/176*. Does that seem like a crazy jump just from some ported heads? My buddies 408 with a huge cam and even better heads doesn’t need that much BIA. Although, he is in a stock truck intake, TB, and even filter and tube. Maybe those restrictions make a difference at idle.

 

[iamdub]

are you in the basic mode? should be under engine>idle>rpm

but dont adjust those tables how you think...if anything just "soften" them up from stock if you think they correct too much

I never knew there were other modes. I just double-click on the "VCM Editor" icon and go with whatever pops up. I'm not looking to make changes so much, at least, not yet. I've just been comparing the stock tune to what my tuner did to try to get an understanding. I asked him to not tune out the lope/chop at idle and, if he could, exaggerate it. He said he put it as much as he felt comfortable. I've read that adjusting the over/underspeed is how this is done.

 

[iamdub]

WellI'llbedamned.

After a 3-second search: Edit>View>Advanced

 

[pwtr02ss]

I never knew there were other modes. I just double-click on the "VCM Editor" icon and go with whatever pops up. I'm not looking to make changes so much, at least, not yet. I've just been comparing the stock tune to what my tuner did to try to get an understanding. I asked him to not tune out the lope/chop at idle and, if he could, exaggerate it. He said he put it as much as he felt comfortable I've read that adjusting the over/underspeed is how this is done.

I never knew this either. I've got the ol trusty hp on the charger. When she comes up to temp, I'll see what mine says

 

[randeez]

Get on it!

That’s odd, I’ll screen shot where it’s at next time I’m on my laptop.

Yeah I just softened it up across the board keeping it progressive but trying to keep it from making 25* swings. Now that it’s idling a little better I may reverse some of it closer to stock.

It just seems so weird to me that it’s wanting 11.5g/176* of airflow at idle when before it only wanted 8.4g/176*. Does that seem like a crazy jump just from some ported heads? My buddies 408 with a huge cam and even better heads doesn’t need that much BIA. Although, he is in a stock truck intake, TB, and even filter and tube. Maybe those restrictions make a difference at idle.

Give it what it wants.
Also that's not the final say in tb position. His table may show a lower value but some of the adder tables may be way different, tb parameters different, etc. And even tho huge cam, overlap may be way different and it pulls a lot of vacuum at idle

Mines at like 16.9gs

 

[Dantheman1540]

Give it what it wants.
Also that's not the final say in tb position. His table may show a lower value but some of the adder tables may be way different, tb parameters different, etc. And even tho huge cam, overlap may be way different and it pulls a lot of vacuum at idle

Mines at like 16.9gs

Its happy now with the AC off, with the AC on it struggles and surges at idle still. I added 10% to the Torque model>loss>vs AC pressure table, should I adjust the Idle> proportional tables?