M6 & 4.10's inside please..
 

I just went from 3:42's to 4.10's and I havent got my spedo recalibrated yet. Can anyone give me a rough estimate how far off it might be..Also should I buy a programmer to do this or take it to a shop? Thanks for your help....

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2002 Z28 M6, 4.10's, Lid & K&N, Borla, many more to come..

it gets farther off the faster you go

i just put 4.11's in mine and 38ish seems to be about an actuall 30mph and 85 seems to be about 70 mph, someone else will have to correct me.



edit: i'd take it to a shop and have them do it, and also get rid of your emissions & rear O2 sensors, and skip shift, and whatever else you can think of. it shouldnt cost as much as a full tone. MTI did mine for 75$

from what i remember. when i would do 70 it showed 85-90..and put miles on the odo alot faster than it should have.

Minw read right at 11 mph off. I trun right around 2100 at 80 mph. Before calibration it woul read 1800 or so at an indicated 80 mph. I was getting passed by everybody. When I would do 2100 rpms it would read 90.

About 25% 40 = 50 & 60 = 75 etc...

Thanks for the responses!!!