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| 3.6 liter High Feature I a Fiero (Page 12/15) |
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Rickady88GT
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DEC 18, 01:00 PM
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| quote | Originally posted by fieroguru:
You could stick with the stock VSS sensor and just find a simple sprocket with the proper ID to press onto the axle/Tripot
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What is the RPM at 65mph with the custom ratio?
My understanding is that the first gear is to low, witch works well for a low power engine but worthless for the LS4. And that the final is to high, basically a freeway gear for fuel economy and not usable for anything else. But changing the final gear on the differential will change all 6 gears. So if I understand this modification correctly, how compatible are the 6 gears after the modification?
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msweldon
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DEC 18, 01:57 PM
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Guru,
Can the lower differential ring gear be swapped out only or do you have to swap the diff ring gear AND pinion?
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fieroguru
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DEC 18, 02:15 PM
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| quote | Originally posted by Rickady88GT:
What is the RPM at 65mph with the custom ratio?
My understanding is that the first gear is to low, witch works well for a low power engine but worthless for the LS4. And that the final is to high, basically a freeway gear for fuel economy and not usable for anything else. But changing the final gear on the differential will change all 6 gears. So if I understand this modification correctly, how compatible are the 6 gears after the modification? |
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It depends on your tire diameter. My 285/30/18 rear wheels are 24.8" in diameter, which is close to stock Fiero. The change to the 3.09 final drive really gives the car a factory V8 feel vs. feeling like it is way over geared (all gears too short), which is what it feels like with the Fiero getrag.
1st gear is now like a C5 ZO6 with a T56 with a 3.90 final drive and 6th gear is like a C5 ZO6 with a 3.45 final drive... both feel very close to stock for a V8 performance car. There are some differences in the gear spreads because the F40 is a wide ratio and the T56 is more of a close ratio. There are other gear options for 3rd, 4th, 5th & 6th if you feel like tearing down the input shaft as well. There is also a 3.348 final drive for those that want something in between the 3.55 and the 3.09.
code:
TRANSMISSION GEAR RATIOS
1st 2nd 3rd 4th 5th 6th FD 1st * FD 6th * FD
Fiero Getrag 3.50 2.05 1.38 0.94 0.72 3.61 12.64 2.60
F40 w/ 3.55 3.77 2.04 1.32 0.95 0.76 0.62 3.55 13.38 2.20
F40 w/ 3.09 3.77 2.04 1.32 0.95 0.76 0.62 3.09 11.65 1.92
MAXIMUM MPH BY GEAR
Dia RPM 1st 2nd 3rd 4th 5th 6th
Fiero Getrag 24.8 7000 40.9 69.8 103.6 152.1 198.6 N/A
F40 w/ 3.55 24.8 7000 38.6 71.3 110.2 153.1 191.3 234.5
F40 w/ 3.09 24.8 7000 44.3 81.9 126.6 175.8 219.8 269.4
Cruise RPM At 65 Cruise RPM At 85
Dia RPM MPH Dia RPM MPH
Fiero Getrag 24.8 2291 65.00 24.8 2996 85.00
F40 w/ 3.55 24.8 1940 65.00 24.8 2537 85.00
F40 w/ 3.09 24.8 1689 65.01 24.8 2208 84.99
 [This message has been edited by fieroguru (edited 12-18-2018).]
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fieroguru
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DEC 18, 02:18 PM
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| quote | Originally posted by msweldon:
Guru,
Can the lower differential ring gear be swapped out only or do you have to swap the diff ring gear AND pinion? |
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You have to swap the ring gear and the two main shafts (the 3 parts in the center). The overall diameter of the ring gear gets smaller, but the distance between the main shaft and differential remains the same, so the "pinion" gear on the main shafts is larger on the 3.09 gear set.
 [This message has been edited by fieroguru (edited 12-18-2018).]
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Daryl M
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JAN 01, 03:15 AM
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Attempting to post a few photos from my phone.
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Daryl M
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JAN 03, 12:39 AM
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Dennis LaGrua
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JAN 07, 04:50 PM
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Following this post with great interest. The 3.6L with the F40 is the perfect powertrain combo for the stick trans fans. I hope to do the 3.6L 6T70/75 swap one day and I'm researching how to make it work. Most of these swaps that I've come across use the Bosch e9 PCM with the Camaro code or use an aftermarket unit. If it can be done with the OEM PCM then thats a plus. ------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "
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Rickady88GT
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JAN 07, 09:17 PM
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| quote | Originally posted by Dennis LaGrua:
Following this post with great interest. The 3.6L with the F40 is the perfect powertrain combo for the stick trans fans. I hope to do the 3.6L 6T70/75 swap one day and I'm researching how to make it work. Most of these swaps that I've come across use the Bosch e9 PCM with the Camaro code or use an aftermarket unit. If it can be done with the OEM PCM then thats a plus.
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I could be wrong but I thought that the 2.8HF was avaliable with the 6 speed manual. Just use that PCM.
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Daryl M
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JAN 07, 09:19 PM
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I am doing the harness now. You may want to chat with Ryan at GM tuners. I just got my ECM back from him and am looking forward to getting far enough along to turn the key.
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Daryl M
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JAN 07, 11:06 PM
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Rickady88GT the 2.8 is a much earlier model than the LFX. The LFX requires a different ECM. Besides, the LFX came in Camaros with manual tranny's. [This message has been edited by Daryl M (edited 01-07-2019).]
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