4.09 vs. 3.73 opinions wanted

[BlueDevil2016]

I currently have my DD driver 2016 manual GT. Looking for a little more acceleration from my GT (3.31 gear) but keeping it N/A - never going Power Adder route. Already have the Power Pack 2 but maybe I've grown used to it and as always want a little more without breaking my budget. Just asking if I went gear change, would 3.73's be enough or go all out to 4.09's. Anybody out there with 4.09's please chime in

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[SVT-DADDY]

4.09 is a lot of gear you'll be cruising around 2500 at 70mph off the top of my head.

First would probably be useless because of the way the trans is geared.

I'd go 3.73

 

[BlueDevil2016]

Thanks, I guess I've heard one too many times to never fear the gear lol!

 

[SVT-DADDY]

I think that moto started when Ford first introduced the mod motor. I had 4.30's in my 1997 Cobra and that was moderate, lots of guys ran 4.56's.

These cars have a little more low and and better tranny gearing.

 

[2-tone]

I think 3.73 is all you would want for a street car. First gear is pretty steep in the mt82 compared to earlier mod motor manual transmissions.

 

[BlueDevil2016]

Now starting to lean more toward the 3.73's. Was just curious if anyone out there had done the 4.09's and regretted it. I do know the gearing for the MT-82 trans (15-17 GTs) is more aggressive than the 18+ GTs so it does seem 3.73s would suffice. Thanks guys!

 

[Cobra Jet]

I think that moto started when Ford first introduced the mod motor. I had 4.30's in my 1997 Cobra and that was moderate, lots of guys ran 4.56's.

These cars have a little more low and and better tranny gearing.

Same here, had 4.30’s in my prior 1996 Cobra - awesome gearing and really woke up that DOHC! 4.30’s were the rage back then, with some guys going with 4.56’s. I could never understand why Ford opted to go with 3.08’s with that POS T45 trans...

I actually got better mpg’s after installing the 4.30’s!

 

[whatsup62]

The 3.657 first gear is almost worthless with the 3.73's. When I was NA first to second comes way to soon...cant imagine what it would be like with the 4.09's. Now with the TR6060 and being boosted, the 4.09's are perfect.

 

[jabrax]

Hey Blue, how many miles on your car? Any interest in swapping pumkins. I have 3.73's and thinking seriously about 3.31

I currently have my DD driver 2016 manual GT. Looking for a little more acceleration from my GT (3.31 gear) but keeping it N/A - never going Power Adder route. Already have the Power Pack 2 but maybe I've grown used to it and as always want a little more without breaking my budget. Just asking if I went gear change, would 3.73's be enough or go all out to 4.09's. Anybody out there with 4.09's please chime in

If you are interested in swapping for 373, let me know. I might be interested in swapping pumpkins

 

[TheLion]

The 3.657 first gear is almost worthless with the 3.73's. When I was NA first to second comes way to soon...cant imagine what it would be like with the 4.09's. Now with the TR6060 and being boosted, the 4.09's are perfect.

Not if you have a higher rev limit. Most after market calibrations will allow for a higher rev limit. Power Pack 2 from Ford Performance gives you another 350 RPM which the OP has. Power Pack 3 gives you another 650 RPM. I run 3.73's with a Power Pack 2 and it's a really good combination. Power Pack 3 would be best with 3.73's, the two are made for each other! However that extra 350 RPM of Power Pack 2 gives me a pretty decent speed range in 2nd, 3rd and 4th gear.

3.73's with a Power Pack 2 is a very potent combination for NA street cars. Braski ran an 11.86 with a Power Pack 2, Big / little's and an IRS re-work and cat back exhaust. That's moving pretty good for just a Power Pack 2 as the only power adder.

Take a look at Tremec's ratio sets for the 6060 as well if you want a comparrison: http://www.tremec.com/anexos/TREMEC_TR-6060_1017.pdf

Now here is the MT-82's speed ranges with the different rev limits and 3.73 final drive:

3.73 Final Ratio Speed (6800 RPM stock Rev Limit)
3.657 13.641 41.10 MPH
2.430 9.064 61.85 MPH
1.686 6.289 89.14 MPH
1.315 4.905 114.29 MPH
1.000 3.730 150.29 MPH
0.651 2.428 230.87 MPH

3.73 Final Ratio Speed Engine RPM (7150 RPM Power Pack 2 Rev Limit)
3.657 13.641 43.21 MPH
2.430 9.064 65.03 MPH
1.686 6.289 93.73 MPH
1.315 4.905 120.17 MPH
1.000 3.730 158.03 MPH
0.651 2.428 242.75 MPH

3.73 Final Ratio Speed Engine RPM (7450 RPM Power Pack 3 Rev Limit)
3.657 13.641 45.03 MPH
2.430 9.064 67.76 MPH
1.686 6.289 97.66 MPH
1.315 4.905 125.22 MPH
1.000 3.730 164.66 MPH
0.651 2.428 252.93 MPH

With stock rev limit, I agree that 3.73's a bit short. But the extra 350 RPM of Power Pack 2 makes it just right. It doesn't feel like your running out of gearing instantly. It may not be a huge difference, but it's definitely noticeable and has pretty good punch. About as much as your going to get on 93 pump gas and NA without doing more exotic NA mods like Long Tube headers and E85 which I don't believe the OP is interested in at all.

 

[BlueDevil2016]

Yes to TheLion, My goal is just to have a little more grunt when I get on it. No PA or flex fuel planned here. Pretty satisfied with the mods I have. Just would like to get in the power band faster. I don't do any highway driving so I don't think I can go too short a gear.

 

[w3rkn]

3.73 would not be so bad, if the 6M had better gear ratios for the D4.

 

[BlueDevil2016]

Just another question, how hard are the gears to swap on S550s anyway? I had a place quote me $1200 in labor alone - 6-8 hours needed. I had my cousin who has since moved away do a swap in 3 hours on my 88LX. Otherwise I'd ask him. Just wondering if the IRS are that much harder to work on than the old solid rear.

 

[Grintch]

Same here, had 4.30’s in my prior 1996 Cobra - awesome gearing and really woke up that DOHC! 4.30’s were the rage back then, with some guys going with 4.56’s. I could never understand why Ford opted to go with 3.08’s with that POS T45 trans...

I actually got better mpg’s after installing the 4.30’s!

The rear gear ratio is meaningless without the transmission ratios. What was 1st gear like in those cars? A 2015-17 GT MT82 with 3.31 gears has lower overall gearing in 1st than a Shelby with 3.73's, a 2018 with 3.73's, or even a 1969 Drag pack car with 4.30's..

 

[SVT-DADDY]

3.37 if I remember correctly. The bigger issue is that those early mod motors made no torque, needed the help to get going.

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