Real Fiero Tech

Get the part numbers and order the shafts and gear?

Do you want it geared that high?

It would be cool if you could order that final drive setup through a GM dealership.

I have the gearing I desire at this point, at least the closest the F40 can get me with what's easily obtainable.

Just providing the internet with another possible option. I know there are those strange people that build low revving V8 engines and try to squeeze all the MPGs they can out of them, and achieve something like 25mpg.

I might have to do more digging as I would love to have a 3.0 final drive for my not-so-low revving V8 and would shoot for 30+ mpg.

I have seen the transmissions on UK ebay for around 199£

FieroWanaBe1 wrote:I have the gearing I desire at this point, at least the closest the F40 can get me with what's easily obtainable.

Just providing the internet with another possible option. I know there are those strange people that build low revving V8 engines and try to squeeze all the MPGs they can out of them, and achieve something like 25mpg.

fieroguru wrote:I might have to do more digging as I would love to have a 3.0 final drive for my not-so-low revving V8 and would shoot for 30+ mpg.

Want to go in on a group buy for a 2.50 first/1.85 second gearset?
It would have to include a custom input shaft with modded or custom 1st & 2nd gears, and a modified or custom reverse gear. Reverse will change, but I don't know what the ratio will ultimately be.

fieroguru wrote:It would be cool if you could order that final drive setup through a GM dealership.

You never know until you ask.

The Dark Side of Will wrote:

FieroWanaBe1 wrote:I have the gearing I desire at this point, at least the closest the F40 can get me with what's easily obtainable.

Just providing the internet with another possible option. I know there are those strange people that build low revving V8 engines and try to squeeze all the MPGs they can out of them, and achieve something like 25mpg.

fieroguru wrote:I might have to do more digging as I would love to have a 3.0 final drive for my not-so-low revving V8 and would shoot for 30+ mpg.

Want to go in on a group buy for a 2.50 first/1.85 second gearset?
It would have to include a custom input shaft with modded or custom 1st & 2nd gears, and a modified or custom reverse gear. Reverse will change, but I don't know what the ratio will ultimately be.

I think I would rather get the final drive as it would improve 1st and 2nd while also lowering cruise RPM. I would like to swap out the MT2 2.04 2nd gear with the MYJ 2.13 2nd to help reduce the 1st/2nd split.

The F40 also has a FX4 final drive option of 3.348, but the F84 3.091 final drive is probably better for my future turbo plans.

fieroguru wrote:

The Dark Side of Will wrote:

FieroWanaBe1 wrote:I have the gearing I desire at this point, at least the closest the F40 can get me with what's easily obtainable.

Just providing the internet with another possible option. I know there are those strange people that build low revving V8 engines and try to squeeze all the MPGs they can out of them, and achieve something like 25mpg.

fieroguru wrote:I might have to do more digging as I would love to have a 3.0 final drive for my not-so-low revving V8 and would shoot for 30+ mpg.

Want to go in on a group buy for a 2.50 first/1.85 second gearset?
It would have to include a custom input shaft with modded or custom 1st & 2nd gears, and a modified or custom reverse gear. Reverse will change, but I don't know what the ratio will ultimately be.

I think I would rather get the final drive as it would improve 1st and 2nd while also lowering cruise RPM. I would like to swap out the MT2 2.04 2nd gear with the MYJ 2.13 2nd to help reduce the 1st/2nd split.

The F40 also has a FX4 final drive option of 3.348, but the F84 3.091 final drive is probably better for my future turbo plans.

First and second are integral to the input shaft as with the 282, Isuzu, Muncie and pretty much all other FWD transmissions. You can't put together a 1-2 combo GM didn't build.

0.62 * 3.09 = 1.91
0.50 * 3.42 = 1.71

With a 3.09 and the 0.62 sixth, that would be really close to the cruise gear of an LS1 Camaro/C5 Corvette or the like. Admittedly, they run tall tires, especially compared to 285/30-18's.
Does your cam leave you with enough low end to pull a gear that tall?
Frequently when LS cars get big cams, they get gears as well.

The Dark Side of Will wrote:0.62 * 3.09 = 1.91
0.50 * 3.42 = 1.71

With a 3.09 and the 0.62 sixth, that would be really close to the cruise gear of an LS1 Camaro/C5 Corvette or the like. Admittedly, they run tall tires, especially compared to 285/30-18's.
Does your cam leave you with enough low end to pull a gear that tall?
Frequently when LS cars get big cams, they get gears as well.

Brain fart on the 1/2 being part of the input shaft... Of the 3 F40 1/2 gear ratios, the MT2 has the "least bad" split, so I will plan on keeping it.

I frequently cruise at 40-45 mph in 6th in town at 1300 rpm, which I won't be able to do anymore. However, with the 3.091 and running in 5th, the same speed will be 1390 rpm. I will likely find myself running around town in 1 gear lower than I am today.

My daily commute is about 90 miles round trip with 40 miles exit to exit on the interstate each way. Once I am on the interstate, I set the cruise at 78. So I will see the cruise RPM drop from 2350 to 2050, which won't be any issue.

As part of the future upgrades, I will be ditching the 224/232 DoD camshaft for a non-DoD 221/225 with 0.025" more lift with less overlap, which should give me more low end torque.

You still have DoD/AFM active?

The Dark Side of Will wrote:You still have DoD/AFM active?

DoD/AFM is currently Installed and wired up, but I could never get it to work with the manual.

Couldn't get it to turn on or couldn't get it to drive right when engaged?

The Dark Side of Will wrote:Couldn't get it to turn on or couldn't get it to drive right when engaged?

Couldn't get it to turn on. There are about 30 things that have to be within a specified range to work and I think I narrowed the issue down to the brake switch, as it goes through the BCM and uses the Can/Bus wires to send the signal to the ECM. I don't have a BCM installed and not really interested in adding it.

I purchased a 2009 F40 with the 3.09 final drive in the UK and should have it in couple of weeks. I could have purchased a 2013-2017 one with the 3.09, but I wanted to stay as close to the 2006 year of the MT2 to reduce the chances for a significant design change.

There are a lot of Insignias with the A20DTH diesel with the 3.55 ratio and a much smaller number with the 3.09. Since it uses both ratios, I am hoping the gear shafts to differential spacing is the same so the 3.09 final drive will fit in the MT2 F40.

If the final drive fits, then I might consider also swapping the gear side of the case as it is significantly more reinforced than the MT2, but doing so will likely require a new front transmission mount setup and will certainly require a new clutch line connector setup as well as a complete redesign of the shifter bracket.

GM says they changed the differential to a stronger unit in 2008.
Hopefully that doesnt mean the differential bearings changed too. The GMPowertrain documentation doesnt show and shaft spacing changes for any of the different ratios or years. At least thats a good sign.

I can assemble all the F40 documents i have into a zip file and google doc it if anyone is interested.

I would be interested in whatever F40 info you have.

I'm curious about it.

There is literally zero chance that GM changed the shaft centers. That would require retooling the gear lines. The whole point of designing a common architecture to use across the product line is to keep it a common architecture in order to keep costs down. Changing the shaft center defeats that purpose because it would require retooling the gear production.

The 3.09 F40 arrived from the UK finally!
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