RE: 4.56 or 4.30
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[div class="dcquote"][strong]Quote[/strong]... 4.10's with a good stall is plenty, and you can still drive down the highway.[/div]I've actually considered changing to 4.30s to tweak a better 60 foot time but I am hesitant due to the impact on the highway diving since I would like to continue driving the car to the track(if I didn't, I'd go with 4.56s w/ no question). BUT, I have been thinking... it would only increase my cruising RPMs by about 200 rpm, so couldn't I just have the IMRC cut-in speed changed on the chip by 200 rpm? ::uh::
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The torque and engine efficiency curves cross at 3000 rpms, so changing the IMRC cut-in only works to make the engine less efficient.
The only reason to change IMRC cut-in is with significant modification to the engine (intake, blower, etc.) - anything that would change the airflow characteristics. Headers might even warrant it, but definitely not gearing.
Cruising with the IMRCs open for long periods of time should not negatively affect the engine in anyway. I'm sure there are some guys who have done the IMRC delete that can speak to this.