looking for big help with tuning an extremely large cam in my ls1

[01blkss]

hello guys i have a similar post in the SD section but this seems to be the place to really dind my information.

hello gentleman...

I will be installing a TREX cam in my 2001 ls1 and i currently have a SD tune in the car but with boltons only.

i am looking for great information about how i am going to tune the car for this cam. what are the major things i am going to look at and what are the things i am going to change.

What are these things going to do, and how is changing them going to affect my motor?

PLEASE help me out

Thanks
Louie

[white2001s10]

These are all my opinions here:

The hardest part will be getting a decently smooth idle, so of course all the idle tables apply, including idle speed & spark, etc...

A cam like that generally moves more air through the system, but traps less in the cylinder... meaning lower cylinder pressure and more misfires.
To an extent, the idle speed can be raised to counter-act this, but keep in mind that simply raising the idle speed way up is actually the LAST thing you want to do.
When you use other means to smooth and strengthen the idle, you don't have to raise the idle up as much, and all is better this way.

Running closed loop will make fueling at idle very difficult to get right. Stoich according to your narrow-band O2's is not going to be what the engine wants at idle. A wideband is more helpful, but here still it's not 14.6:1 AFR that is going to give you the best/strongest idle with a cam like this.

Open-loop (OLSD) tunes are best suited for taming camshafts like this, because you're not fighting against a fueling correction system that's trying to get 14.6:1 AFR in the exhaust... without actually knowing the AFR in the chambers.

Generally the idle will want to be leaner than 14.6:1 on your wideband... maybe even as lean as 15.5:1 (every engine is a little different).
Generally the spark at idle will want to be increased by quite a lot.
Where 16* works well for a stock or small cam, this cam may want 26* or more at idle.

Even in open-loop, there is an idle control & learning routine that you'll have to work around. This routine isn't expecting big fluctuations in idle speed to be normally happening, so keep that in mind. The routine tries to compensate for fluctuations in idle speed, and in doing so there is often overcompensation that make the fluctuations even worse.

One way to reduce this is to reduce the amount of change this routine can excercise.
Less IAC movement is better than more.
Less degrees of spark correction (overshoot & undershoot) is better than more.

The fewer changes that the software is able to make, the smoother the idle will be.

The MAP (vacuum) reading will not be steady with this camshaft, and this will aggravate the idle fluctuation due to the changing fuel delivered.
If fueling values are changing from 35 to 45 to 50 back to 35, then your fueling is obviously not very steady and will cause idle problems.
Find out which load (VE/fueling) cells that you're hitting during idle. Scanning/datalogging will show you this.
You'll need to work on this area to smooth the fueling out.
Some people make all the numbers the same and others just reduce the difference in nearby cells.

This should get you started.

[01blkss]

These are all my opinions here:

The hardest part will be getting a decently smooth idle, so of course all the idle tables apply, including idle speed & spark, etc...

A cam like that generally moves more air through the system, but traps less in the cylinder... meaning lower cylinder pressure and more misfires.
To an extent, the idle speed can be raised to counter-act this, but keep in mind that simply raising the idle speed way up is actually the LAST thing you want to do.
When you use other means to smooth and strengthen the idle, you don't have to raise the idle up as much, and all is better this way.

Running closed loop will make fueling at idle very difficult to get right. Stoich according to your narrow-band O2's is not going to be what the engine wants at idle. A wideband is more helpful, but here still it's not 14.6:1 AFR that is going to give you the best/strongest idle with a cam like this.

Open-loop (OLSD) tunes are best suited for taming camshafts like this, because you're not fighting against a fueling correction system that's trying to get 14.6:1 AFR in the exhaust... without actually knowing the AFR in the chambers.

Generally the idle will want to be leaner than 14.6:1 on your wideband... maybe even as lean as 15.5:1 (every engine is a little different).
Generally the spark at idle will want to be increased by quite a lot.
Where 16* works well for a stock or small cam, this cam may want 26* or more at idle.

Even in open-loop, there is an idle control & learning routine that you'll have to work around. This routine isn't expecting big fluctuations in idle speed to be normally happening, so keep that in mind. The routine tries to compensate for fluctuations in idle speed, and in doing so there is often overcompensation that make the fluctuations even worse.

One way to reduce this is to reduce the amount of change this routine can excercise.
Less IAC movement is better than more.
Less degrees of spark correction (overshoot & undershoot) is better than more.

The fewer changes that the software is able to make, the smoother the idle will be.

The MAP (vacuum) reading will not be steady with this camshaft, and this will aggravate the idle fluctuation due to the changing fuel delivered.
If fueling values are changing from 35 to 45 to 50 back to 35, then your fueling is obviously not very steady and will cause idle problems.
Find out which load (VE/fueling) cells that you're hitting during idle. Scanning/datalogging will show you this.
You'll need to work on this area to smooth the fueling out.
Some people make all the numbers the same and others just reduce the difference in nearby cells.

This should get you started.

Awesome man i appreciate you taking the time to write that detailed response. the cam will probably going in in like 6 days so i will definately take a look at all the things that you mentioned and when i start getting closer but not perfect i will be able to post exact symptoms and results.

Thanks
Louie Panayi

[minytrker]

That was a pretty good reply. I just went through all that a few weeks ago after installing the MS3 (237/242 .603/.609) cam in my z06. I lucked out and had a very tuner here for the weekend that walked me through the whole process. With my cam and a really great custom os tune I still have stock idle and my car drives like stock still unless you get on it.

[01blkss]

That was a pretty good reply. I just went through all that a few weeks ago after installing the MS3 (237/242 .603/.609) cam in my z06. I lucked out and had a very tuner here for the weekend that walked me through the whole process. With my cam and a really great custom os tune I still have stock idle and my car drives like stock still unless you get on it.

awesome i am hoping for the same...and then if i ever want a real choppy idle i will just lower the idle a little:devil:

[minytrker]

you wont have to worry about lowering your idle it will be pretty choppy on its own

[oztracktuning]

add lots of idle timing, add running air flow and if possible tune a little rich - is my bet

[01blkss]

you wont have to worry about lowering your idle it will be pretty choppy on its own

lol i bet!

add lots of idle timing, add running air flow and if possible tune a little rich - is my bet

how to add running airflow? which parameter?

thanks guys

Louie

[oztracktuning]

G0108

Give it more than enough and then work downward. More than enough should be something like 11.000g/s - others may have a set of values for you.

Too much and it will pull itself along when not idling.

Too little and it will stall when coming to a stop.

Choose an idle of 1000rpm or so initially and work downward to as low as you can - aim to get to 800?

I have a much smaller cam - but it likes 30 deg advance at idle and likes to idle at 14.0:1 much better than at 14.629

[01blkss]

G0108

Give it more than enough and then work downward. More than enough should be something like 11.000g/s - others may have a set of values for you.

Too much and it will pull itself along when not idling.

Too little and it will stall when coming to a stop.

Choose an idle of 1000rpm or so initially and work downward to as low as you can - aim to get to 800?

I have a much smaller cam - but it likes 30 deg advance at idle and likes to idle at 14.0:1 much better than at 14.629

G0108 is A/C torque loss...

B0108 is max throttle for idle mode...


Did you possibly mean...B4307 Desired Air flow?

But thanks for the info...


And setting my idle would be...B4603 correct?
And then i want to set it for In gear AC off for an M6 correct?

thanks
Louie