lq9 timing table copied to lq4 tune

[ullose272]

so i know that most of the power difference between the lq9 and the lq4 6.0s is the tune. now i havent messed with tuning the timing, but im fairly familiar with tuning the air/fuel. so if i wanted to put the lq9 timing tables on my lq4 i would basicly compare my file against a lq9 stock file and change everything that is different to the lq9 tune? id imagine id want to do everything under the spark tab (advance, retard, dwell, and knock sensors?) then retune my fuel tables?

[gagliano7]

Your high and low octane tables in advance is what you will want to change. After you make the changes log spark knock to see how it is. The LQ9 has higher compression than you LQ4. You could still add more timing in your tune than the LQ9 tables in your WOT areas. When you do a WOT run see where your timing is being used from your table (cylinder airmass). I have a 5.3 in a 1992 chevy pickup 2wd and I used the 2004 ZO6 timing table which worked great for me. I am in the .76-.84 range for my WOT timing.

[Jon S.]

... most of the power difference between the lq9 and the lq4 6.0s is the tune ... i wanted to put the lq9 timing tables on my lq4 ...

A stock LQ4 and LQ9 tune are nearly identical. In fact, the LQ9 uses LESS spark advance in the Low Octane table - due to its higher compression ratio.

The modest difference in rated power output is a function of the difference in compression ratio, and refinements to the LQ9's cylinder heads.

[askkmb]

I would adjust timing after i did fine tuning on the air fuel.

[ullose272]

I have allready done a ve tune and pe tune. Id imagine it would change with the timing? So retune? The lq9 tune i was looking which is supposed to be a stock tune file, had more advance coming in earlier and 1-2 degrees more through the top end. Reason i ask about the other tables is they are different than mine for air intake temp and coolant, ect. So i didnt want it to add or subtract timing if i left my stock tune when it should have with the lq9 tune. Get what im saying. im used to distributors where you had a initial and total timing how fast it came on, and thats it. So these 3d maps are a little different. But im catching on

[MikeOD]

and refinements to the LQ9's cylinder heads.

The 2001+ LQ4 and LQ9 both have the same 317 heads. 1999-2000 LQ4's have iron heads which are different, but to say the LQ9 has refined heads over the LQ4 isn't true as the LQ9 didn't even exist when the LQ4 had iron heads...I think the first LQ9 was 2002.

The only significant difference is the compression ratio...an LQ9 has flat tops and floating pins instead of dished pistons and pressed pins like an LQ4.

[Jon S.]

The 2001+ LQ4 and LQ9 both have the same 317 heads. 1999-2000 LQ4's have iron heads which are different, but to say the LQ9 has refined heads over the LQ4 isn't true as the LQ9 didn't even exist when the LQ4 had iron heads...I think the first LQ9 was 2002.

The only significant difference is the compression ratio...an LQ9 has flat tops and floating pins instead of dished pistons and pressed pins like an LQ4.

When GM was marketing the LQ9 in the Cadillac Escalade, one of the "technical" points was that the LQ9 cylinder head used the LS6 runner design. This distinguished it from LQ4. The cylinder head casting numbers were the same, but the GM part numbers (at the time) were different. The LQ9 cylinder head is long since out of production. The more common LQ4 cylinder heads are often used as a direct replacement part, but these are not identical.

In "GM LS-Series Cylinder Head Guide" by David Grasso, regarding the difference between LQ4 and LQ9 cylinder heads, he makes similar comments as above.

[mecanicman]

When GM was marketing the LQ9 in the Cadillac Escalade, one of the "technical" points was that the LQ9 cylinder head used the LS6 runner design. This distinguished it from LQ4. The cylinder head casting numbers were the same, part the GM part numbers (at the time) were different. The LQ9 cylinder head is long since out of production. The more common LQ4 cylinder heads are often used as a direct replacement part, but these are not identical.

In "GM LS-Series Cylinder Head Guide" by David Grasso, regarding the difference between LQ4 and LQ9 cylinder heads, he makes similar comments as above.

Maybe in comparison to 1999-2000 lq4 models with iron heads, but 2001-2007 lq4 and lq9 have identical heads.

[Jon S.]

Maybe in comparison to 1999-2000 lq4 models with iron heads, but 2001-2007 lq4 and lq9 have identical heads.

They have the same casting number ... but that doesn't make them the same cylinder heads. I didn't write the GM marketing literature, nor did I author a book on the subject - just sharing available information - you are welcome to take it, or leave it.

[ullose272]

ive always read the lq4 and lq9 heads were the same and both share the ls6 style runner. ive heard it was more of a marketing ploy.

[2xLS1]

I'll leave it. Heads with the same casting number have the same ports unless modified after casting them not taking into account manufacturing tolerances.

[askkmb]

I have allready done a ve tune and pe tune. Id imagine it would change with the timing? So retune? The lq9 tune i was looking which is supposed to be a stock tune file, had more advance coming in earlier and 1-2 degrees more through the top end. Reason i ask about the other tables is they are different than mine for air intake temp and coolant, ect. So i didnt want it to add or subtract timing if i left my stock tune when it should have with the lq9 tune. Get what im saying. im used to distributors where you had a initial and total timing how fast it came on, and thats it. So these 3d maps are a little different. But im catching on

It might change slightly. Basically what i was trying to say is that if the air fuel is not set correctly, lets say you're too lean, you might get knock retard even if the timing is good. So what i always do is set the timing at reasonable degrees(around 5 degrees lower from what the final timing should be) and then tune the fueling and later increase the timing. Then re-tune the fueling if necessary. I know there are more ways to skin the cat but this is my method of doing it.

[gagliano7]

The heads are the same on both. The only difference is the LQ9 has flat top pistons which ups the compression ratio.

[MikeOD]

They have the same casting number ... but that doesn't make them the same cylinder heads. I didn't write the GM marketing literature, nor did I author a book on the subject - just sharing available information - you are welcome to take it, or leave it.

I've got a set of LQ4 iron heads I removed from a stock engine myself, and I've got a couple sets of 317 heads that I've also removed myself...the set on my 370 came from an LQ4 (the pistons were dished when I pulled it), and the other set, much to my surprise came from an LQ9...I'd paid for an LQ4, and when I pulled the motor apart I found flat pistons and floating wrist pins...I guess someone lost track of what it came from at the salvage yard and had I been planning to use the bottom end, I would have made out on the deal, but I didn't care as I was tearing it apart anyways...I put the set from the LQ4 on my 370 because they looked a little cleaner...the set from the LQ9 had some scratches and scuffs on them, probably from the accident that put the donor vehicle in the salvage yard.

Either way, the heads are exactly the same. Casting numbers are the same, and all ports and chambers are as cast, there was no machine work done differently to either set. The LQ9 is as I already said, an engine that didn't come to production until 2002, and at the time, when it was not yet on the showroom floors, yes, the 317 heads on it were an improvement (significantly less weight) over the iron heads on the original LQ4, so marketing absolutely could have rightfully said that...however, the day the first LQ9 was built, the heads were pulled from the same bin as the LQ4's being built that day.

There is 100% without a doubt nothing different between 2001+ LQ4 and LQ9 heads.