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Discussion Starter #1
Alright.. Saturdays' plan is to install the following mods:

Headers
Vararam
T-stat..

The following weekend the car is heading over to the Vettedocs for a custom tune, but here is the problem.. Im doing the install at my friends house which is a good 30miles from my house, and the Vette Docs are another good 50miles from my house, so Im going to put a good 80miles on my car without a tune..

My question is; should I worry about the car running lean or something going wrong with the above mentioned mods on my car without a tune?? I found the writeup on doing the whole PCM relearn which I figured I would do.. But... Any thoughts or recommendations?

thanks..

-John
 

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John,

I've been told that with a basically "stock" motor, what you will be doing is actually a good thing. Allowing for the computer to "self-adjust" and learn while driving some distance will give the tuner the best baseline to work off of when he begins his LS1 edit tuning and the follow on dyno tuning. Many others here (including myself) did exactly the same thing and subsequently had very good results

Don
 

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Don scary as it seems, knows what he's talking about. Just don't ask him to get back to you with a date for Dinner.... :D :D :D
 

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Don Benson said:
John,

I've been told that with a basically "stock" motor, what you will be doing is actually a good thing. Allowing for the computer to "self-adjust" and learn while driving some distance will give the tuner the best baseline to work off of when he begins his LS1 edit tuning and the follow on dyno tuning. Many others here (including myself) did exactly the same thing and subsequently had very good results

Don
Agree with Don, driving will only help your puter adjust to the mods. Good luck on your new mods and let us know what your results are when finished. :cheers:

Jack
 

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I drove mine for a month or two with those mods prior to getting a tune. No problem. The car makes the necessary adjustments to run properly. The tune will optimize fuel and timing settings to find a few more HP.
 

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The changes you're making are well within the range of the stock PCM program. The only problem you might have is an O2 code (or two), Headers seem to be a common cause of these errors. The Check Engine light might come on, but the PCM will still be able to run the engine just fine, and you wouldn't do any damage, even if you ignored it for 100s or 1000s of miles.

The PCM is going through a continuous "learning" process, this is certainly true. But the dynamics of this process (what the PCM assumes about things like the Injector flow rate or the MAF, or the O2s, or any of a whole bunch of other things) are based on the very "factors" that get adjusted during a Tune.

Assuming the Idle Loop relearn, which takes about 30 minutes, is a good example, the PCM probably needs 30 minutes to adjust any change.

So, you change the intake or the exhaust or both, flow characteristics change. The PCM sees changes in ratios between the Long + Short Fuel Trims, MAF, and O2 sensors (maybe not very accurately, but it sees them) and it adjusts. Maybe it takes 30 minutes.

Now you get to the Tuner. He sees what the PCM thinks about how the engine is running. That provides a starting point for the adjustments that are needed.

But the moment the Tuner makes a change to the PCM, just like the mechanical changes above, the PCM sees a change in the ratios it's monitoring. It adjusts. Maybe it takes 30 minutes.

So at most, you're saving a half hour's effort at the start.
 

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You're going to void your warranty. GM will send a team of men in black ninja outfits to terrorize you and your family. The radiation given off from your untuned PCM will cause sever testicular damage (this will also cause you to find window treatments and figure skating appealing).

As Randy said you will be fine. You might get a Rear O2 code, but nothing that will cause any noticable problem other then the check engine light.

-N
 

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I also agree with Don. When I had my LG's, Corsa Tigersharks and Vararam installed at ECS. Chris gave me the car and told me to go for a long drive before he did the tune.
 

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The PCM will ReLearn by itself in 100-250 miles.

However if you do the Idle ReLearn Procedure first it will be complete in 50-100 miles and ready for the ReProgramming (sooner).
 

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Discussion Starter #14
:jammin: You guys ROCK... Unfortunately plans changed.. I talked with my friend and he decided to jump on a plane to go to miami for the weekend, so I won't be doing the install till next weekend.. :( Oh well. I think I might just install the intake tomorrow at my house along with the t-stat.. We'll see..

Thanks again guys.. Hey NY crew.. when are we going to start getting back to the track??
 

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Angry, you got us all worked up and now we have to wait another week cause of .... :zboobie: . :mah: Tell her you have priorities. :crazy: Guess we'll hear in a week. :D

Bob
 

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Discussion Starter #17
Sorry Pallas, one thing I would never question my friends on and that is... well.. look at my screen name.. :lol: I told him to have fun and don't worry.. Mods can wait BUT I better get some good strories.. Im actually pretty happy I turned out the trip.. I met some dope girl last night and had an awesome conversation with an ex.. :zboobie: Life is certainly good.. :lol:

Don... Im with you, Im sick of this weather, its down right nasty... Today it hit a high of 41 near me, and I thought... "perfect weather for the Z"... pfft.. then reality struck and I realized I need another 10 degrees.. I can't wait for 50s.. My aunt told me tonight that it was 60 in texas, and the blonde beauties were out rooming the town..

I think its time to move..
 
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