N14/N15 final drive compatibility

CMF_fuzzy-hair-man

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Hi All,

This idea has been stuck in my head for a while and despite a fair bit of research I can't get any further with it so I suspect it's time to ask.

OK so I know that the N14 and N15 gearboxes are a straight swap to the Micra boxes, being RS5F31A but what I'm really interested in is the final drive.

There were some diesel versions of the Almera (a 1.6 and a 2.0) that weren't available in Australia.
http://en.wikipedia.org/wiki/Nissan_CD_engine

The 2 final drive ratios I've been able to find are:
3.65:1 N15 Diesel Manual
3.4:1 N15 Diesel Automatic

The 3.65 would be handy but the 3.4 gives about the same ratio as if I kept the 13 inch wheel (it's a cg13 in a mini on 10 inch wheels). I've a spreadsheet I mapped the rpm and gears on...

So are the diesel gearboxes likely to be compatible, and if so is the final drive from an automatic diesel likely to be compatible? I guess this may be easier to answer for the UK guys?

Thanks for the patience you guys have had with my questions seeing as they are a bit left field.
 

CMF_frank2

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K11 boxes are type 30 aint they fuzzy, i seem to remember cov on AOC (almera owners club) had to change his driveshafts when going from a GA14 (which use a k11 g/box) to a GA16 engine and g/box
 

CMF_fuzzy-hair-man

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Right we have the 30's :) (Sorry, my mistake I don't remember numbers well)

The different driveshafts isn't a issue as I have to get custom drive shafts made up anyway. This info would also tie in with Cisco's experience as well.

I found this thread:
http://www.almeraownersclub.com/threads/advice-ga14de-to-ga16de-swap.26576/page-2#post-274052

Is that the one you mean?

I'm guessing if the driveshafts are different the final drive will be different and possibly the diff housing as well?

As seems to quite often be the case I got a break just after I put the question up, the Auto diff doesn't seem to be compatible, the manual diff does seem to be compatible with the GA16DE.

If the diff housing is different then I guess I am looking at whether the whole diff will swap over... Any of you tried swapping just the diffs from a N15?

After that I give up...lol
BTW: as the N15 gearbox is larger I'd rather avoid fitting the whole gearbox as I'd have to remake mounts and I'm not sure I'd fit anyway.
 

CMF_frank2

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The k11 diesel had a Peugeot engine and box iirc mate, so the n15 might have taken the same route ?
The smaller type 41 box is the better option for a mini surely ? Mine have taken loads of stick (turbo etc) and i think the k10 diffs fit those
 

CMF_nz_aj

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Only a few rare K11 had the 31, it was the viscous LSD version.
31 boxes from a GA motor will bolt onto a CG.
The CD17 & CD20 nissan diesel motors found in the N14/15 also have 31 boxes but most likely the bell housing is like the CA motors, and won't bolt to GA/CG. The diff from these or the bell housing could be swapped over.
I haven't seen any auto box diff being swapable with a manual box.

For a mini conversion I'd be most concerned about the size of box. A mini is light weight and shouldn't need a stronger box than the RS5F41A. The 41 is nice & small.
The 41 came with three different final drive ratios:
81/20 (4.05) CG10 powered K11, 1987+ 5spd MA10 K10
80/21 (3.81) 1985-87 5spd K10, 1988+ 5spd MA12 K10
79/22 (3.59) 1982-85 5spd K10
I'd suggest using the 3.59 ratio for a mini.
 

CMF_fuzzy-hair-man

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The 3.59 K10 ratio is one I knew nothing about. How'd the CG10? go with such a tall ratio?

The project already has a normal 30 5 speed box because that's what I could get easily and although tighter it fits OK. I agree the smaller box would be strong enough.

Any idea if that 3.59 K10 final drive is likely to fit in the 30 box, I'd kind of like to keep the 30 box and change the diff ratio. (My subframe has been made to fit the 30 box.) Getting a 41 box into Australia might be a bit tricky, although it's an option. I won't know if it'd fit my frame till I have one though.

http://nissan.epc-data.com/pulsar/sn15/3448-cd20/trans/381/38411Y/
Is the site I found where I could look up Nissan part numbers, it lists the final drive as for CD20, but all other bits are interchangable between the CD20 and the GA16DE so I figure that means the boxes are the same (CD20 and GA16) so the question is does that also mean it will go in the micra 30 gearbox as well?

I got to try a Micra drive shaft into a GA16 box today, seemed like the shaft diameter was the same just the splines were different, which gives me some hope that the crown wheel and pinion should fit, and Nissan changed the splines to stop the micra shafts finding thier way onto pulsars or something.
 

CMF_fuzzy-hair-man

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OK so options at this point seem continue to investigate the diff from a CD20.

I can get a GA16DE diff easily so maybe I could try that and if it fits source a CD20 from overseas.

OR

As you say source a 41 from NZ, any ideas what gear ratios the 41 with the 3.59 diff are? Are they the same as the ones listed in the CG10 specs on this site? (I'll plug them into my spreadsheet to see what comes out) Is there any distinguishing features with this gearbox?
 

CMF_frank2

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probably the same clusters eh, and they look similar to the 30 but they dont have the steel cover screwed onto the end, and the neutral/reverse switch is in a different position
 

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CMF_nz_aj

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K11 RS5F41A are easy to find & cheap in NZ. Yes the shafts are smaller.
There were not many K10s imported to NZ, so the final drive is probably best sourced from UK or possibly via your nissan dealer with the following part numbers:
RN5F41A FINAL PARTS 1988
Genuine Nissan Parts 38101-01B13 Gear Final Drive QTY1 5.910} 3.591 = 79/22
Genuine Nissan Parts 32241-05B13 Shaft Main (ℓ = 222.5) QTY1 10.100} 3.591 = 79/22

The diff from a RS5F31A won't fit in a RS5F30A box, the bearings are bigger and the speedo drive is different. The N14 CD20 uses a 31A box with 73/20 3.650 final drive. The E15ET normally uses a 31A box with 3.550 final drive.

If you want to use the RS5F30A box, there are lots of ratios as below. As I said before, the CA/CD bell housing won't bolt to the CG/GA, so either swap that or the diff. RS5F30A ratios:
71/20 3.550 B11/N12 CD17
3.650 ?
72/19 3.789 B13/N14 CD17
3.895
75/18 4.167
76/17 4.471
 

CMF_fuzzy-hair-man

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nz_aj WROTE:
"If you want to use the RS5F30A box, there are lots of ratios as below. As I said before, the CA/CD bell housing won't bolt to the CG/GA, so either swap that or the diff. RS5F30A ratios:

71/20 3.550 B11/N12 CD17
3.650 ?
72/19 3.789 B13/N14 CD17
3.895
75/18 4.167
76/17 4.471
Click to expand...

OK, so I'll look into the N12 CD17 diff, and that's a straight swap if I take just the diff right? (Just making sure I haven't confused myself) (kind of gave up on the CD17 because I couldn't find much about it).
The part number I have for this final drive is: 38101M8003 or 3810150A03. Not sure what the difference is though...

If I've got it right it sounds perfect, I can run it as is see if it's a problem, if it is I get the N12 CD17 diff and I don't have to get new drive shafts either. Thanks!
 

CMF_fuzzy-hair-man

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Nice, thanks nz_aj and everyone for your help!

Phoned up a local Nissan dealer the first of those numbers didn't seem to work, probably been replaced by the second, $363.00.

My gearbox calculator/spreadsheet has the 41 box we mentioned gaining some ground but the N12 3.55 diff is the better solution for the mini I think. ~2900 rpm @ 100km/hr and ~3200rpm @ 110km/hr in 5th seems pretty good to me.
 

CMF_fuzzy-hair-man

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Rudy WROTE:

"please dont let this thread die fuzzy, lets take it through to the end, you build a shorter box for minis and for micras set up for racing/acceleration, and I will start a taller one for highway gearing
Click to expand...

My gearbox with a 3.55 is taller, as I'm trying to make up for running 10 inch wheels, so if you wanted a highway cruiser you could try the same diff.
My spreadsheet has 2645rpm @ 100km/hr and 2909rpm @ 110 km/hr with 13" wheels with a circumference of 1.69m (the 10's are 1.52m)
1.69 is a pretty low profile 13" tire I think as it had to fit a mini.
You could also just about hit 100km/hr in 2nd gear before the rev limiter (6800 right?).

I thought making a shorter racier gearbox was easy cause you have the cg10 gearbox and diffs available:
http://www.micra.org.uk/threads/gearbox-tip-and-guide-for-k11.43321/
The later (facelift?) cg10s used the same gearbox as the CG13's with different ratios.
Of course sourcing this stuff in Australia is going to be problematic. But a Nissan dealer seems to be able to order in stuff not normally available to the Aussie market but $$$ I guess. (The last part of that link contradicts what we said before about the GA16 gearbox ratios fitting though...)

Protons made it to Australia maybe there's a more readily available solution. I'll see what I can find out...

Any good way to put my spreadsheet up so you guys can have a play?
 

CMF_Rudy

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yea sorry I got mixed up a bit fuzzy, I want the inbetween 3.789 which coupled to a mildly worked motor I'm planning should be nice for my type roads, I have a recently aquired freeby n14 sitting in my yard now ready to be poached for front brakes, central locking? and now the diff
 

CMF_fuzzy-hair-man

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Hey Rudy, the 3.789 that NZ_aj mentioned comes with a CD17 engined (Diesel 1.7lt) N14 according to his post, AFAIK these engines didn't come out to Australia so it's probably unlikely there's the right diff lurking in your N14.
 

CMF_fuzzy-hair-man

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1275 WROTE:

"I'm following this with interest, I hope to be running a CG13 in a Mini based car running 12" wheels at some point.
Click to expand...

Tell me more! Mini based...? Marcos? Midas? Am I getting warm?

12's outside diameter aren't too different to 10's so yeah I think you could use the extra gearing and if you're in something light and aerodynamic (well more than the mini) then it should make good use of it!

Unfortunately this diff swapping essentially seems to mean a gearbox rebuild so I might keep it as an option up my sleeve for the moment and maybe build up a spare box.

 

CMF_1275

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Yes it's a Midas, I've got both Mini and Metro based one's. I currently drive a K11
The engine fits quite well in a modified Metro subframe, there's certainly more room in that than a Mini subframe.

Like you say delving into the gearbox complicates things and adds considerably to the cost, although not much in the grand scheme of things.

 

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CMF_1275

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