..........can you do these BIG mods (i.e. SC'ers, cams, heads, headers, etc) without tuning the car? How the heck does the car run, idle, A/F...lean conditions, etc????????

What am I missing?

 

Some people do get lucky with mods and no tuning, but the majority do not. As for the C6 specifically, I think Andy at A&A is going to be a very good showcase for this. He is a very respected tuner, has put AF heads and a cam on his C6 and his dyno numbers are very poor at best. He cannot tune the new C6, but he is one of the best C5 tuners. It will be interesting to see his findings as he gets access to a tuner for the C6.

MAF systems are a little more forgiving of modest mods than speed density systems. However, they still only have the ability to change parameters within a set window, so large mods will see deminishing gains without tuning.

Todd

 

Anyone have word on LS2Edit software yet? Or something similar from another company?

 

For tuning ANY car you can use the two units MAFT and the timing tuner to vary the BASE spark and fuel curves. This would allow you to adjust ony the base curve and not vary it by rpm the way ls1-edit does it but if you are running pig-rich the way the cars come stock....11.3-11.9 as the tuners are seeing, then you can adjust the entire fuel curve up or down to the 12.9 area. The MAFT uses separate adjustments to get long term fuel trends and WOT adjusted separately.

The MAFT can't adjust for variations from the average for those looking to adjust down the fuel ratio towards rich for power adders such as using 13:1 up to 3000rpm then dropping to 12.2-12.5 for nitrous up to redline.

The timing tuner works the same way and goes in the crank position sensor harness which allows adjustment of the spark according to base-line only. Once again you can't get +5 degrees at a certain rpm and load take out 2 at another and add 11 degrees up top like you can with edit. You can increase timing until you get knock retard then back off and this is where most guys saw 6-7 degress everywhere.

The timing tuner worked great after I got edit too. When using nitrous it turns on with a trigger switch when you turn on the nitrous arm switch pulling timing for your nitrous shot without having a permanant timing curve for N/A aplications when driving on the street. Using Auto-tap, I was able to get the 3-5 degree pull verified.

While you will never match a full dyno tune with edit you can get in the ball park and see 75% of the gains with auto-tap and a wideband such as the innovate unit.

As far as how tuners can mod without tuning altogether, adding a supercharger is quite different from adding a huge head/cam package where idle quality is an issue. A supercharger with a decent amount of boost wants to loose 3 degrees timing for every 100hp added (1 degree for each pound of boost ?....one of you forced induction guys can verify if I'm off) and it likes the pig-rich stock fuel curve. The stock curve still isnt optimum but it is safe for forced induction applications.

The other mods we have seen still dont require tuning but Andy's head and cam package is definitly going to see a big gain from it.

 

If you read all the tuner posts carefully, you'll find that most just accept the results they get, pending availability of LS2Edit. Lou at LGM said his was running rich after headers. Andy at A & A said he used a real mild cam to mitigate the tuning issue. He has only test fitted a SC, not got it running. The only huge HP car came from OpticZ's NO2 installation, which can be tuned via the added fuel shot, instead of the PCM.