Question about computer tune

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Sep 3, 2007 | 10:56 PM

NEVERL8C5

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Pro

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From: SpringHill Florida

Question about computer tune

I am changing rears from 3:15 to 3:42 and have read threads where some people have had their computers adjusted to compensate for the changes. I also read where some have mentioned your computer being locked after this procedure.What does this mean?
The rear is almost complete as I am writing this.

Sep 3, 2007 | 11:56 PM

Humanoid 2.0

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From: .... NJ

Cruise-In VII Veteran

St. Jude Donor '05 thru '19

Do you have an auto? If so you would want the shift points adjusted, otherwise I don't think you need to do anything else.
Some tuners lock the compute and some don't. If it is locked then another tuner or GM can't change things on the computer, it is basically a password that the tuner only knows. If you don't want it locked check with the tuner and ask before they do the work.

Sep 4, 2007 | 01:08 AM

tblu92

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Joined: Aug 2005

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From: CA.

St. Jude Donor '13-'14-'15

Yes--you don't have to adjust the speedo on a Corvette when making a rear diff change---The reason being --that the speedo pick-up sensor is on the output shaft of the diff on a corvette rather than the output shaft of the trans as on most vehicles-----HOWEVER if you have an A4 (automatic) you will have to adjust your shift points a
-8 % to compensate for the change--

Sep 4, 2007 | 05:41 AM

NEVERL8C5

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From: SpringHill Florida

thanks it is an automatic and I will ask the guy doing the adjustment not to lock it. I sure am glad to be a member of this forum.Everyone here is always so helpful.

Sep 4, 2007 | 11:26 AM

Mike Mercury

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From: S.W. Ohio. . . . . . NRA Life Member

Quote:

Originally Posted by tblu92

-----HOWEVER if you have an A4 (automatic) you will have to adjust your shift points a
-8 % to compensate for the change--

actually, that's a nifty rule-of-thumb for the A4's when changing rear axle ratios.

Would you use 25% for the 2.73 to 3.42 ?

Last edited by Mike Mercury; Sep 4, 2007 at 12:30 PM.

Sep 4, 2007 | 12:38 PM

Corvette_Brett

Instructor

Joined: Apr 2007

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From: MCMINNVILLE TN

tsp has a really good special going on or it was last week its like $125 for their mail order tune or somthing like that and they do free retunes for a year if u further mod it between now and then. good luck

Sep 4, 2007 | 12:51 PM

Bill Curlee

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From: Anthony TX

CI 6,7,8,9,11 Vet

St. Jude Donor '08

If your going to get the PCM tuned to compensate for gears, you might as well get a complete mail order tune. They will adjust your fan settings (you will need to change the thermostat to 178 or 160 deg) adjust trans shift points and operating pressures, change the necessary fuel and timing tables, etc etc. I had ECS do a tune for me at Carlisle and WOW! I got 2-3 more MPG, better throttle response, cooler operating temps, and a for sure seat of the pants performance increase. They had a $99 tuning special at Carlisle!

Cant beat that with a stick!

Do all the little bolt on MODs that you want, provide that info to the tuner and have the PCM tuned! You will NOT be sorry.

BC

Sep 4, 2007 | 02:47 PM

Corvette_Brett

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From: MCMINNVILLE TN

just incase i was unclear that price was for all that. i think that is the cheapest ive seen in awhile. heck tuners arund here want over a grand for a tuner and tune. but that being said most of the supporters on here are cheaper than that. mid tn sucks when it comes to tuners.