How are people liking 4.09 gears in the MT82?

[silverbullet85]

I was thinking of going with 3.91 vs the 4.09 I think the 4.09 is to aggressive and I'm boosted. I basically have a 3 speed cause with my gearing in the 19 d4 I'm at 120+mph at 7500 ramps in 3rd, which means I'm not at the optimum rpms for alot of play. On the highway I'm at the top of second at 75 so around 60 its almost an instant shift to 3rd then I'm at to low an rpm. I prefer to have 3rd gear go from 70ish to 110 in 3rd which is ideal for me. I have a 19 gt mt procharged stg 2 3.55 car btw

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[GreenS550]

I was thinking of going with 3.91 vs the 4.09 I think the 4.09 is to aggressive and I'm boosted. I basically have a 3 speed cause with my gearing in the 19 d4 I'm at 120+mph at 7500 ramps in 3rd, which means I'm not at the optimum rpms for alot of play. On the highway I'm at the top of second at 75 so around 60 its almost an instant shift to 3rd then I'm at to low an rpm. I prefer to have 3rd gear go from 70ish to 110 in 3rd which is ideal for me. I have a 19 gt mt procharged stg 2 3.55 car btw

I Whippled my '19 Bullitt with the same transmission you have. And though the power is there, the long gearing is there as well. I am convinced that had I put a 456 in the Bullitt I never would have supercharged it. I was shifting at the end of the 1/4 mile into 4th. Ridiculous.

The only comparison I can give you is the 2011 Brembo (373 axel) with the MT-82 old gearing and a 600 rwhp Roush. I loved it. To get that comparison you need a 4.21:1 axle ratio. in your car.

My Bullitt clutch was slipping on the 2-3 shift at the dragstrip because of that ridiculous gearing. Never had that issue with the stock Brembo GT clutch.

 

[silverbullet85]

The plan is 750 whp so I figure id be ok cause 7500 rpm in 3rd is 109mph and 4th at 7500 would be 155mph which I would guess I would not be at recline but even at 6000 rpm I would be at 124. With 750 whp I should be going through the traps at 135+ or I'm doing something wrong. Thats my thinking anyway

 

[Angrey]

Planning 1/4 out with a manual transmission can be problematic if you're trying to do it with just the rear gears. You might solve one issue (but create another).

Optimally, you want to take the power, estimate the trap speed, then select the gear you want to finish in at redline.

However, if you find yourself in a tweener, where you're in between shifts at that power level, it's problematic because there's only so much you can adjust the tire size and if you increase the rear ratio to pull you back to trapping at redline in the higher gear, then you might create a problem with blowing the tires off in the first couple of gears and making it very hard to drive out of the hole without getting sideways. This is easier if you have a turbo where you can do boost by gear. Your controller can soak up some of the over-torque by limiting boost in lower gears.

I'm setting my car up to be a street car so 60-130 and 60-160 is most important to me. With 27.6" (drag radials) tall tires, my setup is PERFECT. I can rip 60-160 all in one gear (3000 rpm to 8000 rpm) OR I can start out in 3rd (4000 rpm) run to redline at 131 mph and rip one shift straight back and finish to 160 in 4th. I can rip 60-130 all in 3rd (4000-8000)

However, on track radials (26.7"), it's much more problematic. 60-160 still works. However, 60-130 I won't be able to stay in 3rd unless I limit at 8700 rpms, which is beyond what I'd like to limit (for a car lifetime of repeated runs). That 3-4 shift at the very end will kill dragy times.

 

[Trap]

Naturally aspirated, I rate my "seat of the pants" dyno and performance upgrades in the following order:

The way you measure this is by comparing to identical cars (except for that one mod), one with the mod and one without and how noticeable it would be driving one car immediately after another.

1) E-85
2) Tune
3) Rear Gears
4) Lighter wheels
5) Headers/exhaust

Thanks for the upgrade list. Unfortunately around here E-85 is non existent. 2 & 3 seem to be the way to go with this.

 

[Angrey]

Thanks for the upgrade list. Unfortunately around here E-85 is non existent. 2 & 3 seem to be the way to go with this.

Was posting it more for reference of how significant it will feel (than a recommendation). It won't "feel" as drastic as E85 swap/tune, but it'll steel feel pretty noticeable, then again, I was coming from 3.73 so for someone coming all the way from 3.55 or even 3.15's it might feel way more impactful.

 

[Bullittrich]

So I just fell into the rabbit hole last night and read through all 17 pages lol got a 19 pp1 tuned on e85 with an SCT, are you guys still having issues the car not picking up the gears properly, also what kind of mph is top of 4th gear now and which set of 4.09 are you guys running? Thanks

 

[Trap]

I have the 3.73 gears now, so while switching to 4.09's would not be huge, I'm betting the FR tune and the gear swap would make a very noticeable difference

 

[TnWHTMARE]

Naturally aspirated, I rate my "seat of the pants" dyno and performance upgrades in the following order:

The way you measure this is by comparing to identical cars (except for that one mod), one with the mod and one without and how noticeable it would be driving one car immediately after another.

1) E-85
2) Tune
3) Rear Gears
4) Lighter wheels
5) Headers/exhaust

Sorry to drag this up....but I couldn't resist.

I have to admit that I am a bit surprised that gears would not be at the top. Are you speaking from a GT350 perspective? Even so, I would still have thought that the gears would have been more impactful than a tune and E. A NON E tune on my 2 5.0's really didn't net anything. The E certainly did make a difference.

 

[Angrey]

Sorry to drag this up....but I couldn't resist.

I have to admit that I am a bit surprised that gears would not be at the top. Are you speaking from a GT350 perspective? Even so, I would still have thought that the gears would have been more impactful than a tune and E. A NON E tune on my 2 5.0's really didn't net anything. The E certainly did make a difference.

I was just going by how much each mod "felt" in difference before and after.

The biggest noticeable difference for me was the added timing and torque from E-85. Next was the first tune. Next was gears. Gears definitely pepped it up.

 

[Superspirit]

Gears are definitely the biggest bang for the buck.

 

[krishelnino]

I have a spare Torsen 3.73 diff laying around since last year. After talking to few people on here, I've decided to get 4.09 gears before swapping the differential.

I ordered the 4.09 gears for $210 and install kit for $120 shipped yesterday. Also found a place that will do the gears for $325 if I drop the differential at their place. Also, reached out to Lund and they're asking 150 for a tune revision for the new gears.

Will the BG 75W90 with additive be sufficient for the 4.09 gears. My main concern is if these gears are good for road course usage? Has anyone tracked with 4.09 gears ? I plan on swapping to 75W140 when I track the car.

 

[TnWHTMARE]

I am not qualified to answer your question from an experience standpoint. But based upon the chart listed several pages back, 4.09's simply get you close to what a 15-17 with 3.73's gives you at the tire. So I cant imagine that they would be a bad choice for the track.

 

[TnWHTMARE]

And btw, I am seriously considering the swap also, to the point that Brandon has already sent me a "tune" for them.... and I dont even have the gears yet. I LOVE this car but the it really takes time to get through the gears.

 

[ctandc72]

So I just fell into the rabbit hole last night and read through all 17 pages lol got a 19 pp1 tuned on e85 with an SCT, are you guys still having issues the car not picking up the gears properly, also what kind of mph is top of 4th gear now and which set of 4.09 are you guys running? Thanks

Your tune has to be adjusted. It's a max gear ratio setting inside the tune.

2019 PP1 3.73 gears MT82:

7000RPM in 4th gear is 154mph with a 275/40/19 tire

With 4.09 gears:

140 mph

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