Rx8 Tranny on FC
10-25-07, 07:53 PM
#4
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I need to change my tranny and the RX8 tranny is like new with 6 speed with short speed....sorry I dont know what is the name for this in english.
Can I install the RX-8 6 speed transmission into my 2nd Gen RX-7?
5th gear on the FE tranny is the same as the 4th on FC trannys anyway, so there is no real advantage of using the RX-8 tranny, and 6th on the FE tranny is actually taller (.83 vs .71) than the FC, resulting in lower gas mileage at highway speeds.
Using a RX-8 tranny would be like adding a extra gear between 2nd and 3rd to a standard 2nd gen RX-7 M or R type transmission.
Add in, that the RX-8 6 speed transmission is also about 4 inches too short, forcing you either to relocate the shifter 4 inches forward in the car, or move the engine 4 inches backward (towards the firewall) to make it fit in the stock shifter location.
Can I install the RX-8 6 speed transmission into my 2nd Gen RX-7?
5th gear on the FE tranny is the same as the 4th on FC trannys anyway, so there is no real advantage of using the RX-8 tranny, and 6th on the FE tranny is actually taller (.83 vs .71) than the FC, resulting in lower gas mileage at highway speeds.
Using a RX-8 tranny would be like adding a extra gear between 2nd and 3rd to a standard 2nd gen RX-7 M or R type transmission.
Add in, that the RX-8 6 speed transmission is also about 4 inches too short, forcing you either to relocate the shifter 4 inches forward in the car, or move the engine 4 inches backward (towards the firewall) to make it fit in the stock shifter location.
Last edited by Aaron Cake; 10-30-07 at 08:36 AM. Reason: Merge two posts
10-25-07, 08:23 PM
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from what i can remember there is no real benefit in upgrading to the RX-8 6 Speed. The gearing in gear 5 and 6 is practically the same as gear 5 in a T2 tranny. Just get your T2 tranny rebuilt.
EDIT* OP beat me to it...by answering his own question??
EDIT* OP beat me to it...by answering his own question??
10-25-07, 09:07 PM
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Can I install the RX-8 6 speed transmission into my 2nd Gen RX-7?
5th gear on the FE tranny is the same as the 4th on FC trannys anyway, so there is no real advantage of using the RX-8 tranny, and 6th on the FE tranny is actually taller (.83 vs .71) than the FC, resulting in lower gas mileage at highway speeds.
Using a RX-8 tranny would be like adding a extra gear between 2nd and 3rd to a standard 2nd gen RX-7 M or R type transmission.
Add in, that the RX-8 6 speed transmission is also about 4 inches too short, forcing you either to relocate the shifter 4 inches forward in the car, or move the engine 4 inches backward (towards the firewall) to make it fit in the stock shifter location.
5th gear on the FE tranny is the same as the 4th on FC trannys anyway, so there is no real advantage of using the RX-8 tranny, and 6th on the FE tranny is actually taller (.83 vs .71) than the FC, resulting in lower gas mileage at highway speeds.
Using a RX-8 tranny would be like adding a extra gear between 2nd and 3rd to a standard 2nd gen RX-7 M or R type transmission.
Add in, that the RX-8 6 speed transmission is also about 4 inches too short, forcing you either to relocate the shifter 4 inches forward in the car, or move the engine 4 inches backward (towards the firewall) to make it fit in the stock shifter location.
5th gear on the FC tranny is the same or near 6th on an RX8.. 4th is 1:1 same as the RX8's 5th gear.... The only thing they did was split 2nd or 3rd into 2 gears (I can't remember which).
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10-25-07, 09:43 PM
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10-25-07, 11:03 PM
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10-25-07, 11:13 PM
#16
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This is usually not the case.
This is the current specs off the Mazda USA website...
http://www.mazdausa.com/MusaWeb/disp...ode=RX8&bhcp=1
3.760
2.269
1.645
1.187
1.000
0.843
Notice the 1.000 ratio is the *5th gear* of the 6-speed transmission.
On all FC turbo (and non-turbo) transmissions, the 4th gear is 1.000.
Zenki FC turbo 5th gear ratio is 0.762.
Kouki FC turbo 5th gear ratio is 0.719.
Non-turbo 5th gear ratios are even taller - 0.70x?
So technically, ANY of the FC transmissions will give you a higher top speed versus the RX-8 6-speed trans.
Most 6-speed transmissions just add an extra gear in the middle...
1st gear for both 5-speed and 6-speed
---->6-speed 2nd gear
5-speed 2nd gear
---->6-speed 3rd gear
5-speed 3rd gear
---->6-speed 4th gear
4th gear for 5-speed and 5th gear for 6-speed - usually 1.000 ratio
5th gear for 5-speed and 6th gear for 6-speed - overdrive ratio
Does that makes sense?
-Ted
10-30-07, 06:43 AM
#17
Banned. I got OWNED!!!
No - becuase it's wrong
There is so much bullshit in this thread I don't know where to start so lets pick it apart one at a time
It does bolt to the back of the motor but thats it. You need the RX8 starter, a turbo flywheel & clutch and an adapter plate to mate an FB slave and have it all work properly
The driveshaft will not work
The shift is 3.5 inches forward and there are 3 options
1) Move the motor back 3.5 inches
2) Hack your interior to hell
3) Do what I'm going to do.
The trans will handle the power of an RX8, the trans will handle the power of a modded TII @ the trans will handle the power of a 310hp 9,000 RPM P-Port on the race track with a slight modification to the internals of the trans intself. What the trans WON'T handle is speed shifting, jamming gears and driving like an idiot. But than again NO trans will tolerate that for very long. Yes it is true that the FE trans has a bad rep and it does break easier than most. DO a little research on RX8club.com and you'll find that trans behind a drag race 600hp 20B - weak trans my ***.
You'll need a custom mount as well.
Now the best for last - here is a comparision of the FE trans VS a USDM S5 TII trans - STOP SAYING ALL THEY DID IS STICK ONE GEAR BETWEEN TWO OTHERS!!!! TOTALLY AND COMPLETELY WRONG!!!!!
There is so much bullshit in this thread I don't know where to start so lets pick it apart one at a time
It does bolt to the back of the motor but thats it. You need the RX8 starter, a turbo flywheel & clutch and an adapter plate to mate an FB slave and have it all work properly
The driveshaft will not work
The shift is 3.5 inches forward and there are 3 options
1) Move the motor back 3.5 inches
2) Hack your interior to hell
3) Do what I'm going to do.
The trans will handle the power of an RX8, the trans will handle the power of a modded TII @ the trans will handle the power of a 310hp 9,000 RPM P-Port on the race track with a slight modification to the internals of the trans intself. What the trans WON'T handle is speed shifting, jamming gears and driving like an idiot. But than again NO trans will tolerate that for very long. Yes it is true that the FE trans has a bad rep and it does break easier than most. DO a little research on RX8club.com and you'll find that trans behind a drag race 600hp 20B - weak trans my ***.
You'll need a custom mount as well.
Now the best for last - here is a comparision of the FE trans VS a USDM S5 TII trans - STOP SAYING ALL THEY DID IS STICK ONE GEAR BETWEEN TWO OTHERS!!!! TOTALLY AND COMPLETELY WRONG!!!!!
10-30-07, 05:36 PM
#19
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The trans will handle the power of an RX8, the trans will handle the power of a modded TII @ the trans will handle the power of a 310hp 9,000 RPM P-Port on the race track with a slight modification to the internals of the trans intself. What the trans WON'T handle is speed shifting, jamming gears and driving like an idiot. But than again NO trans will tolerate that for very long. Yes it is true that the FE trans has a bad rep and it does break easier than most. DO a little research on RX8club.com and you'll find that trans behind a drag race 600hp 20B - weak trans my ***.
We built two identical "high power" motors...
One runs an SE3P (drop the stupid "FE" ****, cause MAZDA calls it an SE3P) trans and the other runs an FC turbo trans...
Which trans is going to blow up first?
I put money on the SE3P trans blowing up first...
Now the best for last - here is a comparision of the FE trans VS a USDM S5 TII trans - STOP SAYING ALL THEY DID IS STICK ONE GEAR BETWEEN TWO OTHERS!!!! TOTALLY AND COMPLETELY WRONG!!!!!
1st gear is basically the same for both transmissions.
6-speed 2nd, 3rd, and 4th gears are almost exactly IN BETWEEN the 5-speed 2nd and 3rd gears...
Your graph shows the truth.
You don't know what the **** you're talking about...
-Ted
10-30-07, 07:34 PM
#20
Banned. I got OWNED!!!
I never said the TII trans wasn't stronger, I just said the the FE 6spd isn't as weak as people bitch and moan about.
And please don't get all bent out of shape & butt-hurt becuase someone goes ahead and provides fact that proves you wrong or disagrees with your OPINION. God forbid someone should disagree with the great Ted of many avatars. My graph shows that they didn't just stick a gear in between two existing ones which you and a few other high post count people on this forum seem to stick by as fact.
Do you see the bolded red? Does the graph support that? My graph proves that ALL the gears are tighter. Should I draw you a picture to what you are discribing? Almost the same and the same are different by definition. "Almost exactely" huh? I wouldn't depend on one of your engines in a race. It takes a man to admit when he's wrong - can you do that?
Ask a few people that actually RACE these things and they'll agree that while the box needs some work, the ratios are much better.
You don't know what the **** you're talking about regarding this subject and when someone disagrees with the "great" Ted, you start calling people names and change your avatar.
And please don't get all bent out of shape & butt-hurt becuase someone goes ahead and provides fact that proves you wrong or disagrees with your OPINION. God forbid someone should disagree with the great Ted of many avatars. My graph shows that they didn't just stick a gear in between two existing ones which you and a few other high post count people on this forum seem to stick by as fact.
Originally Posted by Ted
1st gear for both 5-speed and 6-speed
---->6-speed 2nd gear
5-speed 2nd gear
---->6-speed 3rd gear
5-speed 3rd gear
---->6-speed 4th gear4th gear for 5-speed and 5th gear for 6-speed - usually 1.000 ratio
5th gear for 5-speed and 6th gear for 6-speed - overdrive ratio
---->6-speed 2nd gear
5-speed 2nd gear
---->6-speed 3rd gear
5-speed 3rd gear
---->6-speed 4th gear4th gear for 5-speed and 5th gear for 6-speed - usually 1.000 ratio
5th gear for 5-speed and 6th gear for 6-speed - overdrive ratio
Ask a few people that actually RACE these things and they'll agree that while the box needs some work, the ratios are much better.
You don't know what the **** you're talking about regarding this subject and when someone disagrees with the "great" Ted, you start calling people names and change your avatar.
10-30-07, 07:37 PM
#21
Former Moderator. RIP Icemark.
Why are the shift points so low on the FE (because that is what Mazda has on the VIN-Ted) in the graph? 9000 rpm redline... not 7000 (and of course the 13BT from the FC really runs out of power at 6500 anyway, due to ignition and breathing issues), so top speed in a gear should be 6500 in the FC, not 7800.
And that graph shows a clear extra gear shoved in between 2rd and 3rd...kinda like Ted said.
Then toss in that the Reni and FE tranny combo is designed to run the motor at 3000 rpm at 60 MPH (not just above 2000 like the FC/FD) for optimum gas efficiency at freeway speeds. How do you get around that? Drop rear end gearing so that the car really doesn't have ***** at the stoplight?
So TitaniumTT seems you are having a hard sell to justify the RX-8 tranny into anything but a Miata and an RX-8. I have thought long and hard about putting the FE tranny into a Turbo FC as well, but came to the conclusion that due to the 5th and 6th gear ratios on the FE, that there is no real advantage when comparing it too a FC R type tranny. Now if 6th gear was at .615 or something like that... then I can see an advantage... but it is not.
So what sort of advantage is there to make this swap on a FC or FD...other than being a ricer to have the extra 3rd gear?
After all you were the one that posted this:
about a blown FE tranny that the guy wanted to put into his RX-7.
getting awfully close to flaming in your reply... better watch it. Keep it on track of the subject.
Not on attacking someone who's opinion you may not agree with.
And that graph shows a clear extra gear shoved in between 2rd and 3rd...kinda like Ted said.
Then toss in that the Reni and FE tranny combo is designed to run the motor at 3000 rpm at 60 MPH (not just above 2000 like the FC/FD) for optimum gas efficiency at freeway speeds. How do you get around that? Drop rear end gearing so that the car really doesn't have ***** at the stoplight?
So TitaniumTT seems you are having a hard sell to justify the RX-8 tranny into anything but a Miata and an RX-8. I have thought long and hard about putting the FE tranny into a Turbo FC as well, but came to the conclusion that due to the 5th and 6th gear ratios on the FE, that there is no real advantage when comparing it too a FC R type tranny. Now if 6th gear was at .615 or something like that... then I can see an advantage... but it is not.
So what sort of advantage is there to make this swap on a FC or FD...other than being a ricer to have the extra 3rd gear?
After all you were the one that posted this:
Originally Posted by TitaniumTT
How much you want for the blown tranny? It won't fit without a shitton of work and hacking your interior BTW
Not on attacking someone who's opinion you may not agree with.
10-30-07, 07:50 PM
#22
Banned. I got OWNED!!!
Yes I did post that becuase I do plan on dropping that trans in my car for reasons mentioned below. I can do the work and I have an idea how to make the shifter fit and retain my interior. I wanted the trans because buying a blown one dirt cheap and having it rebuilt and modded is cheaper than buying it already rebuilt and modded. If I can save a few $$, why not? I spoke the truth did I not? It is bunch of work, some tools that the average person doesn't have are needed, & unless you're creative, you need to butcher your interior. What's 3.5" forward of a stock FC shifter.
My setup should be good to ~7500rpms and it would also be beneficial in my setup to keep rpms above 4500 when upshifting so really tight gears are to my benefit.
My commute is 53 miles and not one foot of it is on the highway so cruising speeds is really not of a concern to me. I did the math and yes it is something around a 10% drop in effiecency. But that's what I have my 22mpg Cherokee for. I didn't buy or build this car for effiecency - I built it for fun. I'd like to keep the rpms above 4500 during upshifts and not spiking of the revlimiter ALL the time would be nice during some spirited driving.
Even if the overdrive was just on-par with the Type R tranny it would be an almost perfect trans. Yes I agree getting it even closer to a .615-.7 would be better but like I said - my commute doesn't take me on the highway so for ME, for a fun commute car/auto-x/track car the FE trans would be advantageous to any FC trans.
Why are the shift points so low on the FE (because that is what Mazda has on the VIN-Ted) in the graph? 9000 rpm redline... not 7000 (and of course the 13BT from the FC really runs out of power at 6500 anyway, due to ignition and breathing issues), so top speed in a gear should be 6500 in the FC, not 7800.
Then toss in that the Reni and FE tranny combo is designed to run the motor at 3000 rpm at 60 MPH (not just above 2000 like the FC/FD) for optimum gas efficiency at freeway speeds. How do you get around that? Drop rear end gearing so that the car really doesn't have ***** at the stoplight?
So TitaniumTT seems you are having a hard sell to justify the RX-8 tranny into anything but a Miata and an RX-8. I have thought long and hard about putting the FE tranny into a Turbo FC as well, but came to the conclusion that due to the 5th and 6th gear ratios on the FE, that there is no real advantage when comparing it too a FC R type tranny. Now if 6th gear was at .615 or something like that... then I can see an advantage... but it is not.
Last edited by TitaniumTT; 10-30-07 at 07:55 PM.
10-30-07, 08:07 PM
#23
Former Moderator. RIP Icemark.
Yes I did post that becuase I do plan on dropping that trans in my car for reasons mentioned below. I can do the work and I have an idea how to make the shifter fit and retain my interior. I wanted the trans because buying a blown one dirt cheap and having it rebuilt and modded is cheaper than buying it already rebuilt and modded. If I can save a few $$, why not? I spoke the truth did I not? It is bunch of work, some tools that the average person doesn't have are needed, & unless you're creative, you need to butcher your interior. What's 3.5" forward of a stock FC shifter.
My setup should be good to ~7500rpms and it would also be beneficial in my setup to keep rpms above 4500 when upshifting so really tight gears are to my benefit.
My commute is 53 miles and not one foot of it is on the highway so cruising speeds is really not of a concern to me. I did the math and yes it is something around a 10% drop in effiecency. But that's what I have my 22mpg Cherokee for. I didn't buy or build this car for effiecency - I built it for fun. I'd like to keep the rpms above 4500 during upshifts and not spiking of the revlimiter ALL the time would be nice during some spirited driving.
Even if the overdrive was just on-par with the Type R tranny it would be an almost perfect trans. Yes I agree getting it even closer to a .615-.7 would be better but like I said - my commute doesn't take me on the highway so for ME, for a fun commute car/auto-x/track car the FE trans would be advantageous to any FC trans.
My setup should be good to ~7500rpms and it would also be beneficial in my setup to keep rpms above 4500 when upshifting so really tight gears are to my benefit.
My commute is 53 miles and not one foot of it is on the highway so cruising speeds is really not of a concern to me. I did the math and yes it is something around a 10% drop in effiecency. But that's what I have my 22mpg Cherokee for. I didn't buy or build this car for effiecency - I built it for fun. I'd like to keep the rpms above 4500 during upshifts and not spiking of the revlimiter ALL the time would be nice during some spirited driving.
Even if the overdrive was just on-par with the Type R tranny it would be an almost perfect trans. Yes I agree getting it even closer to a .615-.7 would be better but like I said - my commute doesn't take me on the highway so for ME, for a fun commute car/auto-x/track car the FE trans would be advantageous to any FC trans.
10-30-07, 08:46 PM
#24
The 3.46 final drive ratio option was to give the same rpm in high gear, to make things fair. As you can see the RX-8 tranny is almost exactly the same as the FC tranny, except for one extra gear between 4th and 5th (not between 2nd and 3rd!).
EDIT: This graph shows average rpm vs. mph. The graph starts right after the shift from 1st to 2nd. i.e., the first "step" on the staircase is your average rpm in 2nd gear. As you can see a direct swap to the RX-8 tranny does let you keep your rpms about 200-300 higher on average, which isn't bad. But the higher drive ratio will also hurt fuel economy. Once we equalize things in high gear (for unchanged freeway mileage), you get 100rpm in 2nd and 4th and that's about it (assuming you even redline in 4th). Where the RX-8 tranny really shines is that narrow change in ratios from 5th to 6th... which is entirely useless for anything except economy. It gives you a more economical gear to downshift into instead of 4th when going over hills.
Sources:
tire size: http://www.teamfc3s.org/main/tips.php
figuring out tire diameter from tire size: http://www.1010tires.com/TireSizeCalculator.asp
stock tranny (NA) gear ratios: http://howto.globalvicinity.com/gv_w...i=87&co=1&vi=1
RX-8 tranny gear ratios: http://www.rx8club.com/archive/index.php/t-21206.html
Last edited by ericgrau; 10-30-07 at 09:15 PM.
10-30-07, 08:50 PM
#25
While it may work for the few that don't have highway commutes, I just want to point out that, all else being equal, the SE's 6th gear will have less gas efficiency than the FC's 5th gear. I've been told be many that it's not the case, but based on my own experiments with a NA and a GTUs, the one with the higher gearing is less gas efficient at cruising speeds.