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Have you?

But it's your project so you don't have to justify what you want. But you will have to accept the fact that the auto will drain more power than a manual, and being a small 4 it will be more affected than a larger capacity mildly worked 6 or so.

Dare to be different. And you are. But so am I.

I'm just different...,., some say special

I'd say for a cruiser and burnout machine use auto. Drift and track manual.

Never seen or heard of positive feedback from drifters or circuit racers from a auto-

Just do it d, put it in d and then down to 1-2 smile em up and have fun

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no D, I haven't. But in a normal Datsun manual box there is a big 'hole' between 2nd and 3rd that noticeably hurts performance. With a 3spd auto, that gap is enormous and the 1st to 2nd shift will absolutely kill the performance of such a low powered car. I've seen the effect of a 196rwbhp Datsun converting from manual to the exact 3spd Jatco you're talking about and even just for drag racing with stall speeds and diff ratios optimised to make the auto as good as possible for accellerating over 400m, it still hurt its performance pretty badly. For drift with various radius corners requiring various entry and mid corner speeds, 3 gears just isn't going to cut it with a low power/torque car. It just won't offer the flexibility you'll need. Even if it was a manual 3spd, rather than a power robbing auto. That's not rocket science. Hell, a 6% gearing change (ie the 0.2 which you say is squat) has made my 270rwbhp track car half a second a lap faster on a short track (QR Clubman) that takes just over 60sec to complete! Gearing is a massive factor for a car's performance. And the less power/torque you have, the more important gearing is.

We will see then as ae86 with 150hp atw has one moer than one world drfit championship even today still embarrassing other drifters with same hp 4age.
A vb10 has 300kg less to lug around but If I was building a drifter track
weapon it would be a Sunny b310 with a vh or vk v8 not a rare thouee.

Its not being different just looking at a box I can work on myself and
easy enough for parts, I have 4 of them atm have given away for free.
Never once did I say it will be more efficient just feel that a well
setup auto matched to torque band and storing energy in the converter
can take off much better 56,60,T50 manual without moving left foof or
getting your foot off the accelerator.

150rwbhp AE86 has about 50% more power than you're hoping for. I went from 116rwbhp with my junker L16/18 stroker to 146rwbhp with the SWR L18/20 stroker and it was an entirely different machine with only 25% more power. So that AE86 will have absolutely nothing to do with your 1000 in my experience. And I bet that AE86 didn't use a widely spaced 3spd gearbox for fairly obvious reasons...

For the heck of it, let's play this out a little bit

If you can get a bw35 for it, then the ratios are:

2.39:1
1.45:1
1:1

Not only is first pretty tall (for this application at least), if you do the math, the ratios also ARE NOT evenly spaced.

If we assume a redline of perhaps 6000rpm (because you'll run out of blower efficiency/flow by then, unless you run very low boost which sort of defeats the purpose) - anyhoo - if you upshift at 6000rpm That'll pull you down to 3640rpm when you shift from 1-2 - that's close to a 2500rpm drop.
If you shift from 2-3 at 6000rpm, then it'll be yanked down to 4150rpm or about a 1800rpm drop. That's certainly more liveable.

With a 3.9 diff you'd be hitting the redline in top gear at about 160km/h. Well, that is to say, you 'would' be if you were runnin 185/60 r13 tyres AND a manual. But this is an auto, and the convertor slippage (and this is slippage, so it doesn't 'really' count as torque multiplication) - you're probably looking at more like 145-150km/h at 6000rpm in top.

If you ran a 3.7 diff (good luck getting one, it took me a few years to get one. More than a few said they had one 'ju7st needed to grab it outta the shed' sort of thing, but none got back to me, Then I got very lucky and a bloke from here sent me the gears) - anyway with 3.7 gears you'd get close to 155-160km/h in top at 6000rpm, But with those 3.7s you lose about 5% torque multiplication (so ballpark, potentially 5% less acceleration, assuming traction never came into play in a big way.) If you were making about double the planned figures (say approx 250bhp and 200 ft lbs) then you'd be fine, but methinks you'll end up disappointed.

You might even find you need to run a looser convertor than stock to get things happening. Which means more slippage at higher rpm (it's not drastically more, but even with zero, there's still not an ideal setup to be had given the ratio spread etc). That's not necessarily a bad thing, unless you do a heck of a lot of normal driving in it, and you'll start to get a little peeved at the higher rpm needed to get up a driveway at low speeds and stuff like that. Don't get me wrong, I've driven (considerable distances) in setups with 3000rpm torque convertor stall speeds, but they just aren't as nice for the low speed stuff.

I'd add the further complication that you might not even 'get' 6000rpm upshifts, because the amr charger would have to be spun at what - more than double crank rpms - maybe even 3 times, to make enough boost at all, and then it'd be rpm limited because it would just heat things up too much. So then you can end up with something that actually performs no better than an NA a15 street setup. And it'd be further hampered by the shortcomings of the 3 speed auto..

So with the very real possibility of the blower limiting the peak rpms, lets take another look at the upshift points. Let's say you have to make them closer to 5400rpm (It might even be lower)

rounded to the nearest 50

1-2 upshift, it's yanked down to 3300 - over 2000rpm lower, and possibly low enough that it's out of a decent boost range.
2-3 upshift it's yanked down to to 3700 about 1700 rpm drop. It'll probably handle that one ok.

At peak rpm in top gear and a 3.7 diff about 150km/h (or more like 140km/h after accounting for convertor slippage) and with a 3.9 diff about 145km/h - or 135km/h accounting for convertor slippage.

I have to say 130-140km/h from a boosted a15 isn't going to make a lot of people happy. Even if it did get there a little quicker than a stock a12 or probably not far off a stock a15 both of which hypothetically had 'regular' 4 speed manuals and 3.9 diff gears

It's just my opinion (so take it or leave it, I won't lose much sleep) - but I hope I'm putting forward enough info to at least explain what lead me to it, but anyhoo - it's my opinion that to get this sort of setup to work at all well, you're going to need an a15 and one with an sc14, so that it won't be overheating the charge whilst still managing decent boost levels, It'd likely have to be driven quicker than the crank - around 1.5 times crank speed, to get high enough boost levels to make it work. Even then it is very likely it'll be borrowing from peter to pay back paul - that is to say that the auto will take back a lot of the gains the supercharged a15 made in the first place..

Now having said that - if you can verify that it IS indeed a bw35 that was fitted to them, AND you can find one (you'll need to to get a compatible bellhousing and convertor) show me any manuals you have, and the trans in question, I'll rebuild/upgrade it as much as is possible, for the cost of the parts. At least that way you can experiment with it without having to spend thousands. Very early bw35s (afaik) also had a rear oil pump. This means they could be push started, among other things, but it also might affect parts interchange with later bw models (thereby limiting the amount of parts can be swapped in from more recent versions). Very very early ones apparently also had no external cooling pipe lines - instead the convertor itself had fins on the outside, and the bellhousing had passages/windows in and out and it was effectively air cooled.

Assuming the early datsun ones weren't either of those setups, it should be fine.

Technically speaking, yes you can setup the valvebody of a bw35 to be fully manualised. But I'd strongly advise against it. As mentioned one of the things that breaks them is the low/reverse band (which is engaged any time you manually select 1st and floor it, if the roadspeed isn't too high). The stock valvebody (with the mild shift kit thing I've detailed elsewhere for the valiants) will downshift at a higher rpm if you manually select first and floor it than it will in drive. And with the shift kit, it will still allow the downshift at slightly higher rpm again. but at a certain road speed, the valve body over-rides things and just won't down shift. AND that, is ABSOLUTELY a good thing. It's no earthly good 'allowing' the downshift if it leads to a broken trans (and it will, and easier than you think - if you want I'll show you some pics of trans cases that have their centre lo/reverse servo attachment points ripped apart, and also damage to planetary gear 'cages' that just won't take the stress.

In a very light car, you'll get away with a bit more. But the thing to do there is pretty simple, go ahead with the 'mild' shiftkit that will increase allowable downshift rpms, and then slightly tweak the governor to 'fool' the valvebody into thinking it is not spinning as hard as it is. With a combo of those two, you'll be able to downshift at a reasonable rpm, but it will still safeguard you against any accidental (or deliberate) attempted to downshift at too high a road speed or rpm level...

I did a bit of googling, but it appears that of the very few datsuns that utilised the bw35 auto, as far as I can tell, NONE of them were a-series engines. They were the maybe the c series, the 'first type' of e series (i.e, NOT the one that was based around an a series block with new ohc/head), the h series (possibly aka the R series, as the different names referred to engines that were of the same basic design/family) and possibly the L series. Which means you'd need to make/adapt a bellhousing to suit, so not any cheaper (purely the price of adapting I'm talking about here, not the total cost) than adapting a 71b manual box, and it's no contest as to which will provide the best potential performance and economy.

Now if it turns out i've missed some info out there somewhere, and there was in fact a bw35 behind a nissan A series engine, my offer stands, I'll happily build/tweak a bw auto for you for nix (you just cover the parts costs themselves) and can have it done practically any weekend you like (i.e. if I get a trans to reco on friday night, it'll be good to go by sunday, possibly even saturday arvo depending on motivation levels ! :) )

a14 force - I'll send you an email tonight, but I'd like to send a second one this weekend (when I have more time to spare) to detail some of the other stuff that goes hand in hand with it to help make it survive (most of which doesn't involve much money - just a little time)

Email received, thanks!

Sorry to dig up an old post but thought ide add a little food for thought!

I have a 92 rodeo ute , running a forged rb30t , I went from a rb25 manual box to a manualized 33/34 box , and a 3500 stall

I went from running a 13.4 with the manual box to an 11.6 with the auto

In the process of building my 1200 sedan and paul from keas (top bloke cant recommend him any higher ) is building me a bluey auto box for my a series

Im currently doing a turbo a series , am starting on the manifold , but am still up in the air about what I wanna do , either efi or blow through carb with e85 , but im leaninv towards an ems stinger

Anyways will be interesting and if its gay ill put my 60a back in , I love the jatco in my ute and itll run a 10 soon (new injectors and tune) so ide love to test it out on a mid 100s hp a series

12 second a12 would be cool as too!