6MT to 5MT swap or 6MT to AT swap.
Hi everybody,
We are thinking to swap 5MT on a 4port to 6MT. Do you think that the car will gain from such a change? Just to remind you that the low power 4port comes in Europe with 5MT What do you think about a drag race between 4port-5MT and 4port-6MT? Who will be the winner. Is it enough the data below to draw such a conclusion ? Here is an .xls that a member of www.rx8forum.gr prepared. http://img340.imageshack.us/img340/5526/6mttb9.jpg |
change the rear before the tranny unless the tranny is broken
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Originally Posted by zoom44
(Post 2812614)
change the rear before the tranny unless the tranny is broken
i would think there was a reason the 4-port manuals are mated to a 5mt instead of the 6, altho it could just be for cost. the ratios are obviously different and the 5mt's ratios must be optimized for the 4-port motor. you might end up making it slightly more of a slug off the line. why do you want to do that? why not spend the $ on the motor or something else instead |
I think he's hoping to avoid a shift.
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I dont see the benefit for the money here.......
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how much cost it cost to change this? And how much does it cost to go from AT to MT? Just curious.
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No one knows, it's never been done. It's way easier and probably cheaper to just trade to an 8 built with a 6MT.
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That's what I was thinking
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Originally Posted by ZachLegend
(Post 2812901)
how much cost it cost to change this? And how much does it cost to go from AT to MT? Just curious.
Ken |
for the money spent will not gain enough either way it's still a 4 port!
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i want to say that the shorter gears with the 6MT will allow the 4port rx8 accelerate quicker.
however.. lets say they are in the 1/4 mile, the 5MT may allow the 4port rx8 to cross the line without shifting into 4th, so that may save a bit of time and allow it to win. in reality: it will be a such a small distance that the better shifter will win each time. my advice: if you have a 6MT transmission laying around. go for it. otherwise i'd follow what zoom said. change the rear diff first. that will make a big difference. |
^exactly
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hey everybody, thanks for your remarks !!
a lot of European owners may be interested in this swap !! the European 5MT has the 4 port engine BUT the rear diff is the same as the 6 port in the States, i.e 4.44 and not 4.1 as the auto has ... therefore a simple conversion for Europe is the 6 speed transmission swap. zoom, are you reffering to a 4.77 diff ? the posted .xls from my friend rotaryPilot is in kilometers, sorry its hard for everybody to easily understand .... just a few more info: the 5MT 4port already needs to be in 4th gear for the 1/4 mile run... and the 4th gear has the same ratio as the 5th gear in the 6speed MT... cost wise, we can obtain a used 6 speed tranny for € 1000 installed or the Feed 4,77 rear diff for € 800 installed what i understand from the gear ratios is that due to the fact that in reality the 6speed has an overdrive 6th, when a 5MT is converted to a 6 speed MT, it will gain an extra gear between the old 4th on the 5MT (which is equivalent to the new 5th on the 6speed MT) theory is always confusing.... :eyetwitch |
The cost for dropping 6MT is the same with dropping a 4.77 final gear , here in Greece. We are just wondering which solution will give us better times in 0-400m drag race.
Keep in mind that we are dealing with a 4-port, 5MT, 4.44 European specs RX-8 with 192BHP. So the target is a better time at 0-400m. Do you think that either 6MT or 4.77 will provide worst times in 0-400m when dropped in an RX-8 4port, 5MT , 4.44 ???? |
I think that with the money you are going to put into this, you are better off trading in.
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Originally Posted by Rootski
(Post 2812971)
No one knows, it's never been done. It's way easier and probably cheaper to just trade to an 8 built with a 6MT.
Obviously it did not cost me that much however. |
the OP is in Europe and has a 5mt already on a 4 port motor. dollar for dollar- or make that euro for euro, he will make a better gain thru swapping the rear gears than he will swapping the tranny.
this isnt about making an AT into an MT. |
Slap a Greddy turbo on it - that will make a huge difference for not a lot more in cost .
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Originally Posted by zoom44
(Post 2814599)
the OP is in Europe and has a 5mt already on a 4 port motor. dollar for dollar- or make that euro for euro, he will make a better gain thru swapping the rear gears than he will swapping the tranny.
this isnt about making an AT into an MT. So why is dollar for dollar a better choice the 4.77 for my case? I just mentioned that in Greece 6MT or 4.77 cost the same. So you are telling me that 4.77 will make my car better concerning performance than the 6MT. why? |
with the 6MT, you will need the 6P engine (someone correct me if Im wrong). So youd prob be better off with the 4.77.
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Originally Posted by Renesis07
(Post 2815896)
with the 6MT, you will need the 6P engine (someone correct me if Im wrong). So youd prob be better off with the 4.77.
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There is no reason that the 6MT could not go behind a 4P engine...it would just make less power output than a 6P engine.
Now, as for whether or not they are directly interchangeable as far as shifter/PPF mount/sensors, I cannot say...but logic would say that they should be. |
Why would you do it though? There's probably no place the 8 is more expensive than here, and even here it would only be about 5000-7000 euro difference to get a high power :)
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Many people asked why I would buy an early build 04 4P AT with cloth interior and then trouble myself to convert it to 6P MT with power heated leather interior, rather than simply buying an MT "GT" from the beginning. The answer was that I would not have had the funds to buy a higher priced MT outright, while the car I bought was for sale VERY cheap. And then I could tinker with the car as time allowed, and invest more funds gradually to make it an MT.
Further I have learned a lot from doing it this way and as well I know 100% how the car is put together, rather than relying on dealerships to do it for me and being left to wonder. His case may be the same...perhaps that extra 5-7k euro would have been out of his budget at the time, yet over a period of time he can save up more for further modifications, and learn valuable information for all of our benefit in the meantime. |
Originally Posted by RotaryResurrection
(Post 2817612)
There is no reason that the 6MT could not go behind a 4P engine...it would just make less power output than a 6P engine.
Now, as for whether or not they are directly interchangeable as far as shifter/PPF mount/sensors, I cannot say...but logic would say that they should be. 1) 6MT in 4port engine will it have better performance than my RX-8 Euro specs? (RX-8 euro specs =5MT-4port engine-4.44) 2) What is better in terms of performance? 6MT in my RX-8 euro specs or 4.77 in my RX-8 euro specs. (RX-8 euro specs =5MT-4port engine-4.44) If someone can help me in those questions 1-2 and leave the cost outside. Thanks |
Old thread ressurection, sorry......but since it has some info about Euro spec, i will just add few more related :
4 port engines with 5speed MT do have different flywheel and 225mm clutch 6 port engines with 6 speed MT uses 240mm clutch (same disc as FC turbo and FD, same pressure plate as FC turbo) however, 225 mm clutch has center (splines) same as 240mm clutch, so technically 6 speed might work on 5 speed cluch..... And quite interestingly, 5 speed trans seems to be pretty much same as FC turbo/ FD trans, atleast main parts of it...... I have not compared 5 speed (4 port) and 6 speed (6 port) front counterweights, but if they are same, you can most likely put 6 speed flywheel (and 240mm clutch) on the 4 port engines.... |
Originally Posted by hIGGI
(Post 4326011)
And quite interestingly, 5 speed trans seems to be pretty much same as FC turbo/ FD trans, atleast main parts of it......
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Originally Posted by dznutzuk
(Post 4326803)
It's the basically the same r5m tranny as the fd. The actual gearing is different though, and the bell housing is the same style as the FC. There are swappable parts to make a nice transmission to fit in the 8.
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i have done this swap on my car.i have a 5 speed 4 port JDM rx8,and had another one 6 speed car for parts,so...i changed the gear-box and that gave me more acceleration,but i have bigger fuel consumption on the highway at cruise speeds as the motor needs to have arround 3700 rpm for 120 km per hour,via 3200 witch i had with the five speed.anyway i am not concerned about fuel consumption as my car is turboed also,i have changed the rear differential but did not notice any difference,in the end i have changed the suspension witch is more better and little lower.why i did not buyed a 6 speed?i had one before and sold it,after some time i have found the five speed in really good condition and buyed it.Now is turboed and has gearbox,rear diff,ECU,clutch and flywheel,crankshaft,rotors,counterweight,shocks and rims from a 6 speed,so is not a five speed any more:)why i did not put a 6 port engine.I have one layng in the garrage but the programming for this one and all the money and soul i have put on it where perfect so i preferred to rebuild mine,and to be honestly 300 hp for me is more than enough....
P.S.i am not sure about the fd,but the 5 speed tranny is EXACTLY the same in the mx5 miata 1.8 liters,and another observation,i have been SOOOOO bad with my 5 speed but never had issues,on the 6 speed i managed to fuck up synchros 3 times,and the lay gear bearing is whiiring all f....n time......so now i am thinking to go back to 5 speed |
GEARING EU MANUALS 5 Speed - 6 Speed
Originally Posted by hIGGI
(Post 4326806)
Do you have gearing specs for 5 speed from RX8?
GEARING RX-8 - EUROPEAN Manuals - 5Speed and 6Speed Comparison of gearing specs for 5 and 6 speed (European 4Port Manual, 6Port Manual) 5-speed gearbox Standard Power 6-speed gearbox High Power I. 3,48 3,76 II. 2,02 2,27 III. 1,48 1,65 IV. 1,0 1,19 V. 0,76 1,0 VI. – 0,84 R 3,29 3,56 Final Drive Ratio 4,44 4,44 Ať to jde :-) Interesting fact is that on the Highway the 5 speed drives with lower RPM, it is also slightly better driveable in city driving or more unpleasant conditions (there are some positives of 5 speed - but there are no special oem fit kits for it - like Stage II or III EXEDY etc.)... |
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