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Discussion Starter #1
Jesse,

I have the 3.73 gear sets in my auto trans, as you know.

I have a question related to my shift points.

The shift point is set at 6200 and I am actually shifting around 6,150 or so, per my HP logs
I need to double check the sport mode to see if this is taking place in sport mode.
I am fairly sure this is the case. However, I will do another log and make damn sure it is in sport mode when I log.


I checked the mph and it is as follows:

3-4 shift 81mph
4-5 shift 110 mph

Would it benefit my application to raise the shift point? If so, to what and avoid slip?
Would that increase my MPH?


Remember my only concern is covering the 1/4 mile faster.
 

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Discussion Starter #3
faster than the 3.23 ever felt. But, that is expected......

My only concern is up top acceleration Shifting into 5th @ 110mph makes me wonder where I will be as I cross the trap.

With the 3.23, I was at the top of 4th doing 135mph when I crossed the trap.

I have yet to see where I am @ the top of 5th gear with the 3.73
 

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It's easy to calc using the gear ratios, rpm and tire size.

RPM*60/final gear ratio/tranny gear ratio*circumference of tire/5280=MPH

I think that's correct.
 

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Discussion Starter #5
Can I count that on my fingers?

I do not know the tranny gear ratio.


I'll wait til I get to the track this fall.
 

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Auto is as follows (from a pdf of a brochure someone posted):
1st - 4.02
2nd - 2.36
3rd - 1.53
4th - 1.15
5th - 0.85
6th - 0.67

I can do the calcs for you. Just give me your tire size, RPM and gear you want it calculated in.

DRs? 305/35/18?
6150 rpm with 3.73
4th = 112.63 mph
5th = 152.38 mph

6200 rpm with 3.73
4th = 113.54 mph
5th = 153.62 mph

6150 rpm with 3.23
4th = 130.06 mph
5th = 175.97 mph

6200 rpm with 3.23
4th = 131.12 mph
5th = 177.40 mph
 

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Discussion Starter #8 (Edited)
I would like the caluclation based uppon the diameter of the 305/35/18 MTs which is 26.39 an 6200 rpm

I know Jesse had previously stated that one should not go above a certain speed without reinforcing some parts.
Not sure what that speed was but, if I recall, I would be safe in the 1/4 mile.

After all, I did the swap in an effort to improve the 1/4 and he knows this.

I know there are members who feel the 3.73 will not inprove my 1/4. In fact, there have been comments that
the 3.73 will be in betweem shifts or may be shifting as I trap.

When I saw my car with the 26.9 diameter PS2s shifting into 5th @ 110, I thought, OH OH.

I will definately test the 3.73 gears this fall and wondering if increasing the shift point will help increase my MPH or if it is even
a good thing.

Junkie,
Thanks for your help in this....
 
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