Tuning larger LT-5 cams

[XfireZ51]

You know you have a good tune when:

1. If you have a SM FW, there is little or no clatter from ZF-6 at idle.

2. When cruising down the road, you only hear the exhaust note and no motor noise.

3. At steady cruise you hear a steady exhaust note, no oscillation.

[HAWAIIZR-1]

Thanks for the info and I'll shoot for that good tune. When Marc H sent me this last tune a few weeks ago for the Stage 1 cams, it did make a night a day difference versus his standard 500HP package tune. He upped the idle a bit too so that is probably why I don't have the Fidanza aluminum SM rattle now; I have not confirmed the exact idle speed, but analog tach shows a little under 1K range. Not as lopey sounding, but much better than the rattle.

[XfireZ51]

I have the motor idling between 775 and 825 based on
my scans.

[XfireZ51]

Pretty much putting a fine point on the calibration. I've been playing with AE(Acceleration Enrichment) for throttle response. Nice at this point. You can feel a direct connection to the pedal effort and the response. Also, adjusted Min Air for getting the IAC counts to mid teens. I played with RPM Deadband at Idle and went from +/- 50 to +/- 25. Seemed to like that also. Quiets the SM flywheel a bit more. Overall Left BLMs are higher than Right but that difference becomes minimal at cruise. Its exaggerated more at idle and when Coolant Temps go up.
But Overall Left Avg. BLM is 132, Right Avg. 125. Close enough, IMO.
Motor is quiet at cruise with a lope at idle. All you hear is the exhaust note and its a mellow purr. Not harsh or loud. No drone in the cabin even at 1600rpm or so. Tuning is soooo much easier using the Ostrich and =Jeff='s VeTuner. You can have a new set of VE tables calc'd in about 3 min and then ready to download.
Next is installing the WB O2.

[Paul Workman]

Originally Posted by XfireZ51

Pretty much putting a fine point on the calibration. I've been playing with AE(Acceleration Enrichment) for throttle response. Nice at this point. You can feel a direct connection to the pedal effort and the response. Also, adjusted Min Air for getting the IAC counts to mid teens. I played with RPM Deadband at Idle and went from +/- 50 to +/- 25. Seemed to like that also. Quiets the SM flywheel a bit more. Overall Left BLMs are higher than Right but that difference becomes minimal at cruise. Its exaggerated more at idle and when Coolant Temps go up.
But Overall Left Avg. BLM is 132, Right Avg. 125. Close enough, IMO.
Motor is quiet at cruise with a lope at idle. All you hear is the exhaust note and its a mellow purr. Not harsh or loud. No drone in the cabin even at 1600rpm or so. Tuning is soooo much easier using the Ostrich and =Jeff='s VeTuner. You can have a new set of VE tables calc'd in about 3 min and then ready to download.
Next is installing the WB O2.

Like a moth to a flame. Fascinating.

Maybe you should do a demonstration/presentation at BG next spring, Dom! Think about it...

P.

[XfireZ51]

Paul,

Glad someone finds this useful. I'm no tuning guru but I could probably discuss it from the perspective of someone who wants to get involved in their own tuning. The evolution of tools for tuning has been pretty rapid in the last 10 years even for OBD1 stuff thanks to guys like Craig Moates, Mark Mansur, Rob Rauscher and Grumpy. They started out hacking GM stuff and have moved on to Ford, Honda etc.
As a point of clarification, the tuning I have done is on a
stock block LT-5, Fidanza wheel, ported top end and GVD heads w 236d/.425" lift single pattern intake cams & stock exhaust cams. 63mm TB, 1 7/8" Watson headers. Now that Part Throttle is pretty well dialed in, I'm hoping to get to dyno for work on WOT. Results so far show little to no knock retard which tells me top end fueling and timing isn't too far off.

[HAWAIIZR-1]

Dom,

I'm all ears and want to learn this stuff. With the exception of the difference in cams and header tube size having .430 lift with 230 deg @ .050 and 2" primary tubes, I have almost the identical set up. Thanks for sharing all the technical data and I'll try to be a sponge and retain.

[mike100]

Originally Posted by XfireZ51

...
But Overall Left Avg. BLM is 132, Right Avg. 125. Close enough, IMO.
Motor is quiet at cruise with a lope at idle. All you hear is the exhaust note and its a mellow purr. Not harsh or loud. No drone in the cabin even at 1600rpm or so. Tuning is soooo much easier using the Ostrich and =Jeff='s VeTuner. You can have a new set of VE tables calc'd in about 3 min and then ready to download.
Next is installing the WB O2.

Tell me about the VE tuner function...does it make a base map off of STFT values or does it use a strategy to tune each cell based on a target air/fuel ratio using a wideband or even the O2 sensor?

[XfireZ51]

Originally Posted by mike100

Tell me about the VE tuner function...does it make a base map off of STFT values or does it use a strategy to tune each cell based on a target air/fuel ratio using a wideband or even the O2 sensor?

=Jeff= built it and I did some testing for him. It's pretty flexible. Can use either WB O2 scan or BLMs for Open or Closed Loop tuning. You can set the "windows" for the data you want to use. For example, I use data with Learn ON, C/L, +/- 2.5kPa, +/- 50rpm. You can do same for using AFR instead.
Also has provision for datalogger being used and whether you're in
Port Throttle Open or Closed mode. you can also set target BLM or AFR for the calc. Neat if you want to run a bit rich or lean. Be cool if that could be done by RPM range so cruise could be on the lean side, while upper RPM richer.
Basically it takes average of L/R BLM and compares to target BLM.
Calcs % adjustment and applies it to current VE tables, then creates new bin file. You can also apply "smoothing".
Something you want to do with tuning us turn OFF
DFCO, CCP, and EGR so you're not chasing your tail initially. Once you have tune set then you can turn them
back on and tweak a bit. Also spend some time on SA tables to optimize along with ancillary parameters.

[tomtom72]

Dom, I would like to add my Thank You also. No, I don't understand much of this. I haven't yet to plow thru the corvette FI book by Mr. Probst. I got side tracked with night courses for my job.

I am going to ask what could be a really novice Q. This fine tuning that you are doing would only benefit an LT5 that has it's cams timed correctly, right?

TIA

Tom