Z1 Performance

iTrader: (564)

please do not drill holes in your throttle body...this is the definition of a "hack repair"

there is something fundamentally wrong with the car if your car does not sustain an idle under ALL conditions....you would be best off solving that problem as it should be solved

To the OP - did you have your Unichip tuned, or did you just use their baseline map? If it was tuned, you should bring it back to whomever tuned you and work with them to resove the issue, as that is clearly where your problem is (as evidenced by your previous post of the car working fine with the Unichip out of the loop). If you have reservations about that tuner, contact PF, or one of the many other Florida based shops on here and get it taken care of in the proper manner.

05Z33

iTrader: (11)

I am running one of the unichip tunes from them which accounts for headers, CAI, and true dual exhaust. The plenum spacer and test pipes are not accounted for with this tune, which I'm sure could bump both my idle and power. I'm just hesitant about paying a few hundred dollars for a tune on the unichip; when I plan on upgrading to a better system such as utec, HKS, or Osiris. I was really just hoping to get my idle bumped for now via a consult, but some people say it can or can't be done on an 05. So which is it?

Z1 Performance

iTrader: (564)

I think Jeremy answered the question of the idle bump. But bumping the idle is absolutely NOT needed with your mods.....no two ways about it. Again, IMHO its a band aid for the underlying issue.

My question to you is this: is it worth running around with a setup that is not optimized? Is that worth driveability issues? You've already spent considerable money on the car given your mod list, and even though the unichip leaves alot to be desired, it should not be causing ANY such issues whatsoever, and will work just fine for your current mods. I am quite sure than with a proper tune, which could be done in a manner of about an hour or so on the dyno, followed by a 10-15 road session, you could have the best of all worlds - a setup that is now precisely tuned FOR your mods,without any driveability issues at all. Seems to me that would be worth the relatively small additional cost, especially relative to what you've spent so far.

Neither test pipes nor a plenum spacer will affect your idle qualities whatsoever. The only way the plenum spacer could, is if there is an intake leak, which is a fairly common thing when the spacers are installed unless exact care it taken. Not to say you don't know what you're doing on the install side, but it has happened to many people before and can easily happen to even the best mechanics.

My parting words are this. Cars are like fingerprints - no 2 are exactly the same. Many cars will react differently, sometimes significantly differently, to identical mods. This is why base maps are great to get you started, but they are not the be all and end all. The ONLY way to properly tune your car with your level of mods, is to have the tune done on your car. A base map will work reasonably well...as is evidenced by your exact scenario. The car starts, drives, but has the hiccup when it comes to this one idle issue. Not only would a proper tune, done on the car, likely solve this issue, it would allow you to run a specified map designed around your exact car and exact mods, vs a generic off the shelf map.

If it were my car, I'd contact Jeremy at PF, or the guys at Japtrix. Both have significant Unichip experience, and will get you sorted out for a relatively small cost, without a bunch of hassle. If I were in your position, with this being my car, and I didn't have the ability to do the tune myself,
this is exactly what I would do.

Anyway, that's my advice...do with it what you will.

reno56

I realize this thread is ancient but just to put some info out there for the next person searching for solutions related to stalling on decel, increasing idle, or throttle body drilling.

Since I've put in C8 revup cams in I too obviously had stalling on decel and a hard time idling low. Because I have a few more things to do before I get the car tuned on a haltech standalone (will be using different throttle body's) I drilled a 1/8 inch hole in the throttle plate and the car idles at around 950-1050 rpm now with no decel stalling or service engine light.

I originally tried to bump the idle via the screw inside the throttle body compartment. While this did bump the idle to what ever I wanted it also put triggered a limp mode and the service light. I'm assuming from the ECM recognizing a resting throttle position out of spec..

So while drilling a hole in the throttle plate may not be the correct way to bump idle it certainly works.

rcdash

iTrader: (18)

Good feedback ... but not really necessary with Osiris or a Haltech pro plug in. Both can set the idle up higher and you can have it come off decel in a way that precludes cutting out... You will not need that hole when you are retuned, but it can be tuned around too... The throttle plate is never really closed so it's all good.