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Discussion Starter #1
I'm wondering if any of you with stock intake have modified your shift point? I have an auto that currently shifts at stock RPM. My mods are in my signature. I have some 265 18 Mickey Thompson drag radials that are a bit shorter than stock. I believe the diameter difference is causing me to shift just before I cross the line in the quarter mile, and I'm considering added a couple hundred RPM's to see if that carries me across in 4th. What I don't want to do is fall out of the power curve so much that I'll lose anything that way. I plan to do some trial and error with my sct, but in the meantime, I thought I'd seek out input here.

I know I can reserve a dyno session, but there are good resources here that I can look to until I get to that point.
 

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I shift at 7000 rpm with the coyote intake manifold, kooks long tubes, cold air, and a boss rotating assembly. Just wind it out a little more. Like you said, you really have to look at your dyno sheet to know when your power drops off.
 

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With the stock manifold you start to loose the powerband around 6-7k, Boss Manifold will help you make better power higher in the RPM band but you can always wind out 4th only if you're looking to save a shift from 4th to 5th.
 

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A proper solution would be a cobra jet intake manifold, I can't wait for that mod... you'll never have to worry about that curve turning town at 7000 rpms ever again! 😉
 

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Discussion Starter #5
Thanks for the comments. I plan to get a line lock soon, installed at a shop that has a dyno. I'll run it there, see what's a good point for me. Until then, I'll try adjustments with my Bama tune.
 

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Stock intake is done after 6500 rpms. So 67-6800 ideal. If you need to make it through the traps just rev it out instead of shifting. Look at any stock intake dyno sheets.
 

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Discussion Starter #7
it's an auto and I don't "manually" shift it. I don't trust myself that much! So I'm looking for alternatives.
 

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Please do not do "trial and error" with the SCT if you plan on running sustained or repeated high revs. The Coyote blocks weakness are the rod bolts and oil pump. Both of which do not like high rpm. There should be an adjustment for your tires, the 18" MT you discussed using in the SCT X4 programmer. Go to the tire size, select revs per mile, for the 18" tire its around 1200. Then see what rpms you go thru the traps with.
 

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Please do not do "trial and error" with the SCT if you plan on running sustained or repeated high revs. The Coyote blocks weakness are the rod bolts and oil pump. Both of which do not like high rpm. There should be an adjustment for your tires, the 18" MT you discussed using in the SCT X4 programmer. Go to the tire size, select revs per mile, for the 18" tire its around 1200. Then see what rpms you go thru the traps with.
I have no idea where you got that 1200 revs per mile for any 18" tire, but they're wrong (18" is a wheel measurement at the bead seat, not the tire diameter, and not even the wheel's maximum diameter to the outer edges of the flanges).

A 265/40-18 tire (suggested by an 18" tire a little shorter than stock)
only turns about 790 revs per mile. I have a full set in this size for my "3-season" driving . . .


Norm
 

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I had my auto with the stock intake shifting @ 7300 rpm.
 

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I play it safe with 7K...
 
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