Ok, I do a fair amount of driving for work, and it would be really nice to have a 6th gear to bring the revs down at higher speeds.
@ 80mph the car is sitting at around 4k

Is there a 6 speed gearbox that would bolt on, or is it possible to modify the existing box to a better ratio?

*sighs* I wish there was, I believe the bellhousing is the same in the fs as the v6, give me a couple of hours and I will post up some info, its all on my computer at home, Im leaving work now anyway because i'm bored and cold. . . . .

the bell housing is very different between the KL/KF/KJ and FS. There is a 6 speed gearbox used in the mazda3 that shares some of the same parts as our gearboxes, but the box won't fit

OK, so it looks like you can't do a 6spd upgrade. How about changing the ratio of 5th? It seems a little high revving for me. Do you reckon this is somthing that can be done at home, or get a pro to have a look?

It can be done at home, but one has to be very careful not breaking the fluid diverter funnel that goes into the 5th gear area. The 5th gear is in a separate compartment. This is that black steel cover you see right next to the frame rail.

A 5th gear from the 93 onwards 626 fits. So does the mazda3, 5, and 6's (1.8/2.0/2.3l engines only) gears
The turbo diesel 5th gear also fits, but it is a very tall ratio (you will have to be going pretty fast to benefit from it, or you will have complete lack of power at 70mph). Look through my website for the different ratios.

This is what I need, Not bothered about lack of power at 70 just need the rpm to drop as it costs too much in fuel already !!

With regards to the mazda 3/6 6speed box, could a new bellhousing be made up or a hybrid one made or is the box physically not compatible with the car i.e driveshafts etc.

Sorry but can you clear one thing up for me, Would the 2.3 mps engine physically fit and bolt to the BJ chassis or would new engine mounts have to be made ?

Sorry for all the questions.

Stu

a new bell housing will have to be made... I'm not sure if it's possible to modify our stock ones to fit the 6 speed box even though they are the same family of boxes... even then, it is not worth the trouble as the 3/6 uses cable shifters, whereas the BJ (FWD) uses a rod linkage... it will be a lot of trouble to make it work! you're better off adapting a toyota 6 speed to fit the car... either way it won't be cheap!

none of the new motors will directly bolt in... yes it will clear the bonnet, but it won't bolt in, the mounting points are completely different and the exhaust faces the wrong way! besides that, those (ford) motors aren't as great as mazda wants you to believe, parts are expensive and they are difficult to work on... not to mention the wiring nightmare involved getting it to even work.... even if you cleared all of those problems, you have to deal with how hard it is to modify those engines... you're better off putting a turbo in the FS like what I did and have plenty of fun... on a good day I have about 200hp to the wheels and it puts me into the seat enough! the FS is a much easier and simpler to work on motor, and can be made reliably strong... the new engines are aluminium and there is very little margins for error... aluminium is best saved for coke cans, not engines!

Thanks for that, I didn't think they would but I heard somewhere that they would

I am currently doing (albeit very slowly) a V6 conversion on the BJ, Do you know anyone in the states who has documented the wiring ? It's not a problem for me to do it will just make everything flow easier and I will have less head scratching I have tried searching a few us sites but I never seem to come up with anything of use ?

if you're going to source wiring locally (which you should because of LHD/RHD differences), then there's going to be quite a few differences, especially since many UK mazdas didn't have true OBD2 till 2001 or so

there's a rare 4WD automatic V6 GW 626 estate in japan... it is probably the most ideal donor car to do the swap as many electrics are similar to the BJ and the chassis is mostly the same... many things bolt up! they never came with manual gearboxes, so a conversion is necessary regardless since you can't use any 4WD gearbox

realistically, you should try sourcing wiring from a Xedos 9... they came with KLs... MX-6s should have KLs too

I got engine box and loom from a Probe, I was just wondering if there is anyone who has an actual wiring diagram ?