Anyone got a LS9 cam in NA?

[BigDaddyCool]

Hoping there are a few with a LS9 cam in NA.

So we can all discuss its characteristics.

Wanna see if others have lean spikes mid wot run, what timing, what the cyclinder airflow is at each rpm interval to map out what works better in etc.

So far I've managed to pull 290kw at the engine in a 6.0 v8 LS3 MAF L92 Heads Shorty Headers 200 Cell Cats X Pipe Stock Rear Mufflers and Diff on 19's.

[GHuggins]

This isn't possibly the lean spike after so many seconds into PE is it? Does it happen at a specific rpm or specific time after being floored out? Present in open loop only?

[BigDaddyCool]

Don't believe so...... Attached a scan of my latest run...... right at the start of the scan stand still 0-100km/h. You can see it leans out, the wideband and o2's report slightly different RPM? Maybe due to being logged at a different interval eg. 100ms vs 200ms possibly.

Either way it's always around the same spot........ tried to level timing and fueling around the area so keep it flat to make sure the results arnt flawed in any way...... I put together a VE/MAF mix tune to try and cover the basis which is what this run is..... it looks slightly better then my maf only.

[GHuggins]

If you stomp it later - does it happen at a different rpm? In other words from a roll and stomp at a higher rpm vs stopped and stomp at the same lower rpm?

[GHuggins]

If you don't mind do a closed loop pull and see if the result is the same and add fuel trim cell to your channels... It appears to still be commanding 12.55 but leans out the what appears to be stoichio at 14.68 even though it's obviously in open loop... You fueling appears to also be off below this point - air fuel is up and down until after the lean out then stays somewhat close to 12.55... I assume you've tried adding to the MAF to see if anything changed?

[Brice]

post your tune.
For testing purpose, have you tried to disable VE (run MAF only) ?

27 degrees timing @2000 rpm seems high, can you lower it to high 10' and see what's going on

[BigDaddyCool]

post your tune.
For testing purpose, have you tried to disable VE (run MAF only) ?

27 degrees timing @2000 rpm seems high, can you lower it to high 10' and see what's going on

I originally ran MAF only. I tuned the VE and ran mixed to try and double up on some fueling accuracy. That said I don't like spikes on my MAF curve as well. I'm one for finding better ways to make sure things run smooth then to spike the maf in a spot. But I do agree 27 degree's at 2000rpm does seem excessive and may be hindering airflow. I used to run around 14-19 I guess same spot on the stock cam.... still trying to adjust the spark table to suit, my old stock cam used to run 72/g roughly at 2000rpm, this ls9 runs 55/g sec..... So it's hard to both get power and not run timing....

I ran a test this morning, I'm thinking perhaps my lean spot is due to timing...... too much timing. Maybe it's causing a vacuum leak due to cylinder pressure or something. Took out a degree in the area.... was better, only 10% lean as opposed to 15% yesterday spike (no fueling changes at all just timing). Across my logs it seems taking out timing has helped.

I'm going to lower timing in my WOT area's back to a reasonable level and see how it responds. I probably have a partial leak on the intake... maybe the exhaust, i'm checking them as I get time. It's looking like under WOT it's best not to exceed around 27 degree's in that trouble spot.

My logs too big to post up as I have a fair drive to work of a day and HP Tuners has their upload limit so.....

I might look to use the TPS Multi for the VE in that spot perhaps as well.... I'll keep at it, I don't think it should take too long to work it out. I'll hold off posting further until I work it out a bit better.

GHuggins: I'm thinking your hinting at looking towards my transients being an issue perhaps? ..... You might be onto something but I haven't a method to detect it and know how it works fully. I have messed around with it to suit startup and drivability but thats it. I could add more to the impact tables.... or adjust evap so it spreads it out longer...... In an automatic I find it messes with things/drivability too much sometimes. So right now I'm not looking too much at it. I did try the corvette ZR1 transients (2006 C06 Corvette transients to match my setup 56/2.0 etc) just to 'double check' that idea........ didn't make any difference.

Fueling: I have an AEM, it's first gear..... that mostly is always out... I try not to pay too much attention to it, it's a full load take off..... if you add what it asks for 1st gear you overshoot on my car. 2nd gear or higher is only accurate with the AFR fully.

I think adding alot of timing with the LS9 cam isn't the answer..... idle, part throttle sure...... but full throttle.... just because it doesn't knock doesn't mean you should keep adding timing I think.

Anyway...... I'll hold off posting further until I nail a few more things down. I think I'm just starting to get an idea on what the cam wants.....

PS. I have a nice excel table I throw my engine torque into to instantly show a dyno graph I built..... saves time and simplifies it. May not be accurate on cam change due to the cars torque calculations but still.... Its cool to have.

[GHuggins]

Like I've said before I think the lean spike your seeing is a misfire due to timing whether it's too much or too little... You told me taking timing out didn't help, so we tried adding some which also apparently didn't help... Don't take out or add 1 or 2 degrees - try taking out 5 - if it's better start dialing things in...

As you said - just because it's not knocking doesn't mean that more timing is helping... You can also try ramping timing in like a stock CTSV does and see if that helps things any...

[BigDaddyCool]

Like I've said before I think the lean spike your seeing is a misfire due to timing whether it's too much or too little... You told me taking timing out didn't help, so we tried adding some which also apparently didn't help... Don't take out or add 1 or 2 degrees - try taking out 5 - if it's better start dialing things in...

As you said - just because it's not knocking doesn't mean that more timing is helping... You can also try ramping timing in like a stock CTSV does and see if that helps things any...

Thanks for the input. The LS9 cam does seem to take time to spin up... a better diff ratio would certainly help. My plan at this point is to establish a rough timing limit under WOT...... and then i'll look at how to bring in more timing if possible once it gets going. It's an interesting cam thats for sure. I might yet keep it as I've already flattened out my torque curve under 3500-4000rpm which was my first aim.

Lots of trial and errors to go.

[minytrker]

I had a LS9 cam in my G8 for a couple years. It made zero more hp over stock until around 3200 rpm and came alive at 3500 rpm. It wasnt a bad cam but there are much better choices out there. It ran and drove like stock except was faster.

[BigDaddyCool]

I had a LS9 cam in my G8 for a couple years. It made zero more hp over stock until around 3200 rpm and came alive at 3500 rpm. It wasnt a bad cam but there are much better choices out there. It ran and drove like stock except was faster.

Logged today, took our a fair bit of timing in the trouble spot...... still no deal, still leans out. I have two concerns with this, one is a manifold vacuum leak (1 bolt is broken on the intake - waiting on the replacement set of bolts to pull it back off and bolt it down fully) and the intake gaskets I don't trust so I'm replacing those..... but second worry is a head gasket leak... short of doing a compression test...... I figure I'll wait til I fix the manifold then I'll see if it's still there, if so I'll have to do a compression test...... to make sure the head gaskets are bolted down good enough.

Frustrating. If it's the intake manifold having a vacuum leak I'm probably giving up power. I'll leave my tune how it is until I get the parts and redo that intake manifold. Long story, obviously there was something in the hole and I over tightened one of the intake bolts.... broke one. Such is life.

[andrew1988]

when i was tuning my ls9 cam in i had a lean spike wot and it went away after zeroing out the prediction coefficients and i also made the alcohol PE table the same as the regular PE table.
I only changed the alcohol PE table after i suspected Bp 98 had ethanol in it because the stoich is 14.4.1 but i dont think it has ethanol in it at all now.

side note: wot became easier to tune after i went to a card style ls9 maf in a decently long 4 inch tube.

i am maf only but i have tuned blended but i found the car drives no different blended or maf only.

i also have a 1900 magnuson blower but these are things i encountered after i went from stock l76 AFM cam to the ls9 cam.

[GHuggins]

Prediction coefficients is a good point - did not think of that one So is a changing calculated stoichio value - will throw all fuel adjustments and transient fueling tables off...

[BigDaddyCool]

Sorry to say started off with a maf only zeroed out dynamic gear....... same deal. Don't have E85 or a ethanol sensor......... so stoich is the same. Before I did the cam I had a 6% lean issue right on 4500rpm at peak torque..... with the new cam it leans out 10-15% at around 3100-3700rpm depending on what timing running... and 4500 has no issue. So I'm stumped really. Hopefully it just turns out to be the intake not being down properly and a gasket issue.

I feel like I can run more timing through that spot but somethings off there....

[BigDaddyCool]

Arg PLEASE HELP.

I thought ah stuff it I'll increase the maf in the bad spot that spikes lean ......... what happens, it moves clearly to me depending on how fast PE hits etc. So now I think what am I missing, is this some sort of Injector End of Injection Target? .......... It has a pattern that seems to repeat...... I've never held WOT long enough to see a pattern.......... but it seems to repeat from start to finish.

Look at my scan...... it aint transients or maf or ve ........ HELP

[5FDP]

Post the most recent tune file too, maybe someone see's something.

[GHuggins]

Running ID 850s? Sounds like you have the lean after so many seconds into PE issue. I don't know of a fix for this, but know that there's a thread about it.

[BigDaddyCool]

Latest Tune File.

I fixed my intake today, double checked things........ it's sealed up tight. So it's definitely a tune issue because it's still there. Yes x amount of seconds into PE it shoots lean doesn't matter where, what gear or rpm now I've done some more testing. It looks like a transient issue, like it transients does it's thing, then it expires and repeats but no amount of fiddling changes anything.

I have tried adding 30% to transient impact, tried messing with EVAP, timing, more fuel, fuel injector boundaries.... It's doing my head in.

Vacuum drops to 0, is that triggering reversion? I'm trying to think of what the LS9 cam's fundamentals have changed to cause it to drop fuel like this. It's frustrating.

Oh GHuggins, I also just had new injectors fitted a year or so ago, and I got new o-rings at the time as well, so there should be no issue there. Injectors fitted were P/N:12576341

[GHuggins]

Files tuner locked...

[BigDaddyCool]

Files tuner locked...

Bad habbit..... file attached is unlocked. I think HPT should have like a locked or unlocked status on the main bar for this...... so people know when they are working on a tune straight away if its locked to save posts like this.