Question guys. I've tuned the z06 i've been talking about in SD mode (01 z06, stock heads, lg long tubes, borla stingers with no cats, ati 10% underdriven ballencer, 30lb SVO injectors 37ish with ls1 fuel pressure, lg motorsports 90mm throttle body with fast 90 intake, vara ram, spec 3 clutch, 239/242 .651/.612 110lsa 110icl cam and all apropriate valve train stuff, comp adjustable timing set, ported ls6 oil pump). The car still has the maf plugged in but is disabled via fail frequencies set to 0 and 1 for low and high frequency fail respectively. Have to leave plugged in because this car has it's IAT sensor in the maf. Now that being said i've set this car up according to the directions of the EFI Live SD tuning tutorial, that is above 70kpa and above 4000 (or close to) rpm the car will be at 13 to 1 a/f and below those figures at 14.7 to 1. I've left the pe table values at 1 so all my wot tuning occurs in the appropriate cell values of the ve table as well. The car hold an idle just fine and the commanded a/f values seem to be in line with what i'm seeing on the wide band.

This car has always been run in open loop as the car has always been stronger this way every since he put on the headers and forgot to bolt up his oxygen sensors. When logging it looked great so I just told him to not put them back on.

That being said this guy is complaining of the car smelling like gas and pipes turning black now that we've done the cam and i've done the speed density tuning. The car runs real strong and drives just fine and he's perfectly happy with that. Now, for the questions.

The reason this car is in speed density mode is that during driving with the maf the low activity code will set and usually sets when the car starts loading up (his cruz a/f would go from 14.7 ish to 12-11 to 1 while the bucking occured). This being said it would seem that the maf is getting reversion caused by the big cam with lots of overlap. I don't think there is anyway to tune this out, except for physically modifying the intake tract. Am I wrong on this? I'm trying to decide that since i've got the ve table taken care of should I go ahead and try to re-implement the maf?

Second, do you think more timing will clear up some of this smell?

I'm getting the car this weekend or soon after if the weather doesn't cooperate so i'm going to try some of these things with it then. In the mean time feel free to make any suggestions. Thanks.

 

I'm interested in seeing what the outcome is on this. I have a 03 Z06 that has very similar issues, but it's tuned with LS1edit. I'll be bringing the car back to the tuner next week to see if he fix the issues.

 

But how's the car drive and feel? Does it run well or sluggish? This car i'm working on drives very well for a cam this big, but it's just the smell and the pipe color. I'm starting to lean to the side of customer expecting too much and maybe just have him put cats on but we'll see after I do a double take on the current setting. I'll post my results for sure.

 

The car runs real strong up top, I don't really have an issue except when the revs drops below 1500rpm. That's when the car starts to buck and surge. My car also smells like gas, the pipes haven't turned color yet but I've only put on about 200miles after the H/C. I can def. feel the lost of power down low, like under 3000 rpm, but as long as the car is over 1500rpm it doesn't buck or surge. And I have no issue with idling except for trying to drive the car when it's still cold.

My setup is PRC LS6 stg1 heads, TSP MS3, Kooks 1 3/4 with no cats, halltech stinger, stock TI exhaust, ASP pulley, 36lb FAST injectors, and ported Ls6 oil pump. Maybe there's more fine tuning that could be done on the fuel setting.