4.778 Final Drive For $296
12-07-2005, 02:45 AM
#151
Stuck in a love triangle
Originally Posted by Slick8
Like to stay away from FI for now, just seems like a more reliable way to go especially with the warantee.
12-07-2005, 08:48 PM
#153
Originally Posted by kw1k
my guess is that it MIGHT void it. I mean there going to really have to look at it to figure out that some1 put a new FD RATIO correct?
If the service department is already suspicious because of mods done or if they happen to test drive it which they will and happen to notice the difference in gear ratios then they might look at it.
The way it sounds it would make a considerable difference.
Not too sure about the Kia gears though.
12-07-2005, 09:27 PM
#154
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HUH?? wtf are you saying man? a New Final Drive is not going to give you "25 - 30 whp"
New FD is goign to make your Gears Shorter which is going to make you accel faster. Thats it , not add you HP.
oh and if 66hp HP was made with the mods you listed your 1/4 would be much lower and your 0-60 would be lower also.
New FD is goign to make your Gears Shorter which is going to make you accel faster. Thats it , not add you HP.
oh and if 66hp HP was made with the mods you listed your 1/4 would be much lower and your 0-60 would be lower also.
12-07-2005, 11:27 PM
#156
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Originally Posted by Slick8
The lower gear will multiply the hp and torque, mechanical advantage at the wheel with a trade for rpm. More hp and torque, faster car.
Originally Posted by JeRKy 8 Owner
Will this mod greatly affect the lifespan of the transmission? More wear?
12-08-2005, 12:54 AM
#157
Originally Posted by BaronVonBigmeat
On the freeway, a little. Ditto for the engine. But most any mod will be that way to some extent. Actually, it's probably easier on the transmission when you're taking off from a dead stop, and aggressive launches won't take quite the gazillion-RPM clutch bomb they do now.
it won't make a difference.
I do it every stop light
All kidding aside, starting from first gear won't need much gas if any.
12-08-2005, 09:08 AM
#158
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Originally Posted by Slick8
The lower gear will multiply the hp and torque, mechanical advantage at the wheel with a trade for rpm. More hp and torque, faster car.
12-08-2005, 09:11 AM
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Originally Posted by 4 years to Supercharge
Good point.
If the service department is already suspicious because of mods done or if they happen to test drive it which they will and happen to notice the difference in gear ratios then they might look at it.
The way it sounds it would make a considerable difference.
If the service department is already suspicious because of mods done or if they happen to test drive it which they will and happen to notice the difference in gear ratios then they might look at it.
The way it sounds it would make a considerable difference.
12-08-2005, 11:39 AM
#161
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It would be REALLY REALLY hard to void the warranty on the tranny from changing the final drive. That would be like trying to void someone's warrenty because they always drive 10mph over the speed limit.
I'm guessing that the most they could void would be LSD and Halfshafts. Anything other than that would be one heck of a stretch.
I'm guessing that the most they could void would be LSD and Halfshafts. Anything other than that would be one heck of a stretch.
Originally Posted by JeRKy 8 Owner
I'm pretty sure doing this mod would void the warranty on your tranny if it came down to it. But I guess as long as you still have the engine under warranty it's okay.
12-08-2005, 03:50 PM
#164
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Originally Posted by MadDog
Definitly will NOT add any HP. Why do you think that the measured whp does not change (ignoring losses) with the different gears you dyno in?
12-08-2005, 04:26 PM
#166
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More research on the final drive. There are 3 different R&P gearsets available from Mazda with a 7" ring gear.
1) Short Pinion: S2000, Kia, 1st gen RX-7, pickup 4x4 M/T 87-88, Miata
2) Long Pinion: 2nd gen RX-7,
3) Turbo Pinion (8" ring, but smaller than Long Pinion, Medium Pinion???): 2nd gen TurboII RX-7, Twin Turbo RX-7 3rd gen
1) Short Pinion: S2000, Kia, 1st gen RX-7, pickup 4x4 M/T 87-88, Miata
2) Long Pinion: 2nd gen RX-7,
3) Turbo Pinion (8" ring, but smaller than Long Pinion, Medium Pinion???): 2nd gen TurboII RX-7, Twin Turbo RX-7 3rd gen
NOTE: Mazda also made what I call the "hybrid" 7.5 inch rear. It was installed on most '84-93 trucks and was also later used on the rear of the Sportage. They basically took the 7" pinion housing and pinion and mated it with a larger ring gear. - Miata Drivetrain Interchange Guide
12-08-2005, 04:31 PM
#167
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More pieces to the puzzle:
The pinion shaft [long pinion] is approximately 2-3/8" longer than the “short pinion” shaft version.There are two (2) alternate gear sets available from the factory that will fit the “long pinion” differential case. Please call for information about these ring and pinion sets. - mazdamotorsports catalog diff & axle
12-08-2005, 04:50 PM
#168
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Last but not least, a possible 4.875 fitment:
Hmmmm, this makes me think about that extra part in the FEED 4.777 R&P set pic, the ring 10-bolt spacer. Will call MazdaMotorSport to verify. 
AND even more compelling from the Miata Drivetrain Interchange Guide,
differential shaft diameters and splines:
7" small axle = 25mm x 24 spline (808, RX-3, 79-83 RX-7)
7" large axle = 27mm x 26 spline
7" S2000 = 29mm x 28 spline
7.5" small axle = 27mm x 26 spline '84-03 B2000/B2200 & early 95-97 Sportage
7.5" large axle = 29mm x 28 spline ('98-05 Sportage)
8" = 31mm x 30 spline. TT/TII/929
Purchase an adapter kit that allows you to fit a short pinion gear set to the 1986-91 RX7 [into a long pinion pumpkin]. This is more expensive than the modification explained above but does provide the ability to install a different pinion shaft later, if you need an alternate ratio. - mazdamotorsport catalog diff & axle
AND even more compelling from the Miata Drivetrain Interchange Guide,
differential shaft diameters and splines:
7" small axle = 25mm x 24 spline (808, RX-3, 79-83 RX-7)
7" large axle = 27mm x 26 spline
7" S2000 = 29mm x 28 spline
7.5" small axle = 27mm x 26 spline '84-03 B2000/B2200 & early 95-97 Sportage
7.5" large axle = 29mm x 28 spline ('98-05 Sportage)
8" = 31mm x 30 spline. TT/TII/929
Last edited by Slick8; 12-08-2005 at 04:54 PM.
12-08-2005, 05:25 PM
#170
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Originally Posted by Nemesis8
Nice work Detective Slick8
The rep said that they only have one upgrade
for the RX-8, the 5.125 for $1,116.00.I hope this works out, I put some time into this, been a real fun waste of time.
12-08-2005, 06:12 PM
#171
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Originally Posted by Slick8
Last but not least, a possible 4.875 fitment:
Hmmmm, this makes me think about that extra part in the FEED 4.777 R&P set pic, the ring 10-bolt spacer. Will call MazdaMotorSport to verify.
AND even more compelling from the Miata Drivetrain Interchange Guide,
differential shaft diameters and splines:
7" small axle = 25mm x 24 spline (808, RX-3, 79-83 RX-7)
7" large axle = 27mm x 26 spline
7" S2000 = 29mm x 28 spline
7.5" small axle = 27mm x 26 spline '84-03 B2000/B2200 & early 95-97 Sportage
7.5" large axle = 29mm x 28 spline ('98-05 Sportage)
8" = 31mm x 30 spline. TT/TII/929
Hmmmm, this makes me think about that extra part in the FEED 4.777 R&P set pic, the ring 10-bolt spacer. Will call MazdaMotorSport to verify.
AND even more compelling from the Miata Drivetrain Interchange Guide,
differential shaft diameters and splines:
7" small axle = 25mm x 24 spline (808, RX-3, 79-83 RX-7)
7" large axle = 27mm x 26 spline
7" S2000 = 29mm x 28 spline
7.5" small axle = 27mm x 26 spline '84-03 B2000/B2200 & early 95-97 Sportage
7.5" large axle = 29mm x 28 spline ('98-05 Sportage)
8" = 31mm x 30 spline. TT/TII/929
12-08-2005, 08:37 PM
#173
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Originally Posted by Slick8
Hmmmm, this makes me think about that extra part in the FEED 4.777 R&P set pic, the ring 10-bolt spacer. Will call MazdaMotorSport to verify.
See the 2nd Pic.
https://www.rx8club.com/showpost.php...54&postcount=1
12-08-2005, 10:53 PM
#174
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Originally Posted by QBallz
Thanks for all this info Slick 8. I think there is already a spacer between the Ring Gear and Gear case or at least that what it looks like I've been staring at the pics in Need for Speeds thread. Also from looking at it, it appears that that is the standard diff and not the LSD. So maybe that spacer is just used if you dont have the LSD?
See the 2nd Pic.
https://www.rx8club.com/showpost.php...54&postcount=1
See the 2nd Pic.
https://www.rx8club.com/showpost.php...54&postcount=1
Last edited by Slick8; 12-08-2005 at 10:55 PM.
12-08-2005, 11:13 PM
#175
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Originally Posted by cas2themoe
Theres all this talk but has anyone actually had it done to their 8 yet?