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

that makes sense to me

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.

I dont see the benefit for the money here.......

how much cost it cost to change this? And how much does it cost to go from AT to MT? Just curious.

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.

That's what I was thinking

As far as anyone in this group knows, there has only been one successful swap from AT to MT. Look for Rotary Ressurection's thread on how he did it. For most people (maybe everyone except RR) rootski's opinion is right - trade the AT for one with an MT.

Ken

for the money spent will not gain enough either way it's still a 4 port!

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

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.

Yes sir it has...I daily drive the first and only known successful, fully functional 4P AT to 6P MT swap done using factory engine and components. For the average person who might pay to get all of the parts from a partscar, then swap it in, cost would be in the $2500-3500 range; more if that person chooses to get the engine or trans rebuilt prior to use (as I did).

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 .

Thanks for the clarification.

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.

why is that? I can drop an 6MT to my 4port engine. Do not forget that I already have a 5MT

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 :)

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.

Yes just the 6MT in my 4port engine costs 800 euros ! My question is the following and I just put it in points:

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