Anyone having good results tuning a 2017 ZL1?

[Higgs Boson]

that screw is not applying any pressure on the Z06's I have tuned and they are running 9 - 9.5 psi

[lt1z350]

I haven’t messed with any vettes on it I started a thread over on camsro6 it’s pretty long now and think one car out over over 25 posted at least 2 psi gains. Mine took about 3.5-4 turns to make it hang in the air. Them when I had my throttle body off I took a flash light lid off too and saw how bad it was leaking so took the screws loose tapped it until no light shined through and then tightened the screws back up. Also if was on a stock tune you have to disconnect the vacuum line from the solenoid to the bypass leave the one from bypass to the intake. If you leave that the stock computer settings will just pull boost back out of it. All that when said and done I made 13-14 psi. I have logs with stock pulleys making 190 kpa pretty regular. Then put long tubes and a full 3 inch exhaust and was lucky to see 10 psi until I put the 9.55 lower on it.
I had one of the guys that saw no gains check his bypass butterfly and it was way off center was holding it open 1/8th of an inch with no screw. Once fixed that then saw 2 more psi if remember right. So many things play in this too the condition of the blower how tight the rotor clearance is possible belt slip. I’ve seen some say just unplugging the boost bypass solenoid pick the car up to 12 psi and not touch the screw. More so then not there is something to be found by doing this at least on the zl1 and pulley setup or more so the lower that’s in play on it vrs the corvette and the dry sump lower setup. Also anyone that knows these knows intake restrictions play a part in how much boost it can make or will make. When I did the ported nose and ported 95mm zr1 throttle body I saw around 1.5 psi gain. Ported my case I got another 1.5 psi. I actually had to put a turn in my screw after was all said and done as the boost increase had me at the time running out of fuel on ethanol. In this now hot and humid weather in Florida I can go back to how it was and only makes 14 psi but in the winter I was seeing 16-17 on it when the manifold temp was staying in the 100-110 range.
Anyway more so then not it’s worth looking into and making sure it’s sealing up all the way if wanting some free boost.

[Higgs Boson]

yeah I think I came across that camaro thread a while back which was what made me look at mine in the first place. was already backed out, was like...."Nutz!"

[8850]

I haven’t messed with any vettes on it I started a thread over on camsro6 it’s pretty long now and think one car out over over 25 posted at least 2 psi gains. Mine took about 3.5-4 turns to make it hang in the air. Them when I had my throttle body off I took a flash light lid off too and saw how bad it was leaking so took the screws loose tapped it until no light shined through and then tightened the screws back up. Also if was on a stock tune you have to disconnect the vacuum line from the solenoid to the bypass leave the one from bypass to the intake. If you leave that the stock computer settings will just pull boost back out of it. All that when said and done I made 13-14 psi. I have logs with stock pulleys making 190 kpa pretty regular. Then put long tubes and a full 3 inch exhaust and was lucky to see 10 psi until I put the 9.55 lower on it.
I had one of the guys that saw no gains check his bypass butterfly and it was way off center was holding it open 1/8th of an inch with no screw. Once fixed that then saw 2 more psi if remember right. So many things play in this too the condition of the blower how tight the rotor clearance is possible belt slip. I’ve seen some say just unplugging the boost bypass solenoid pick the car up to 12 psi and not touch the screw. More so then not there is something to be found by doing this at least on the zl1 and pulley setup or more so the lower that’s in play on it vrs the corvette and the dry sump lower setup. Also anyone that knows these knows intake restrictions play a part in how much boost it can make or will make. When I did the ported nose and ported 95mm zr1 throttle body I saw around 1.5 psi gain. Ported my case I got another 1.5 psi. I actually had to put a turn in my screw after was all said and done as the boost increase had me at the time running out of fuel on ethanol. In this now hot and humid weather in Florida I can go back to how it was and only makes 14 psi but in the winter I was seeing 16-17 on it when the manifold temp was staying in the 100-110 range.
Anyway more so then not it’s worth looking into and making sure it’s sealing up all the way if wanting some free boost.

What effect does this have on afr? Thanks Joe!

[Dixie ZL1]

Which tune parameter do you modify and to what value when you back out the limiting / opening set screw?

[GrannySShifting]

What effect does this have on afr? Thanks Joe!

It could vary depending on the calibration in the car. 1 psi isnt a huge change so doubtful it would suddenly be way lean or rich unless it already was before