Varied questions; RE: swaps, emissions and gearboxes

[Lacey]

Okay so to cut a long story short, those of you who\'ve met me and know me know I have mobility issues - this extends to driving. i.e. I find it difficult to use a clutch, driving over extended periods (to me an extended period is anything over 45 - 60 minutes), so I have a few questions.

Don\'t worry, the EGI is staying as it is, this is for a possible future daily driver.

I\'ve been looking around at other cars and similar things to see what\'s on the market, and preferrably as a fun daily I;d like either a fun roadster, or a cute little hot hatch.

Since the Mazdaspeed 3 MPS and the new Impreza and wayyyyyyyyyyy above price range, that\'s all the hot hatches I can think of that I actually like out of the question already, which leaves me roadsters.

There are a few I like, the main one especially being the Honda S2000 - a car I;ve always wanted. (I already have an RX-7, so I\'m not so keen having another one as a daily, though don\'t mind sticking with rotors). Only thing wrong is that Honda\'s S2000 was never made in an auto, and is also Honda\'s only longitudinally mounted engine, so there will be no auto box to fit that engine.

I was debating using a 13b T-II engine and an RX-7 modded auto gearbox on it to make it actually driveable for me, also sticking with rotors in a un little roadster that weighs (I think) less than the T-II Cab does.

My first question is whether anybody knows how possible it is (calling Hayward, hint hint :p ), to fit a decent Mazda auto box and a 13b T-II into something else.

My second question is thus, because I;ve heard a lot of conflicting arguments either way; Emissions.

Emissions regulations - Pre July 1992, you don\'t by law have to have a CAT, and you can have your car run on the older emissions test that allows for higher emissions.

Now, I\'ve heard the argument that one is wrong and the other is right, but I don\'t know which because I;ve had people arguing the toss both ways.

Do the emissions regulations go by THE ENGINE year or do they go by THE CHASSIS year?

For example, 1990 T-II 13b in a 2001 Honda S2000 - does what law applies to it? Emissions from 1990 or 2001?

Somebody clear this up for me please?

Thank you

[RobMatthews]

from engine swaps i\'ve done befor, they should test on whichever is older so if you have an engine from pre92 they wont do an emmissions test.
it may have changed since i done anything like that a few years ago now

[Prof]

Go by engine:
 
http://www.ukmot.com/6-4.asp#Text_top
 
All the MOT reg\'s are here, worth getting familiar with them if you\'ve a modded car and attract unwanted attention from poorly trained MOT guys - take the car somewhere where they know what\'s what - you know who :cheers

[Lacey]

Thanks for clearing up, I;ve heard a few people telling my that it goes by year of car and not year of running gear. That makes the S2K idea more of a go-er then!!

Was thinking about buying an S2K with a toasted engine and scrap it for a 13b T-II

Then slap on a nice Efini badge for giggles

Anybody with experience on the 7\'s auto box? good and bad points compared to other auto\'s?

[HaywardRotary]

Hi Lacey,
An auto gearbox from an FD RX7 would be a good bet,but I might be able to find one from a Turbo 2 just possibly.
Anyway yes they can run on a 13B.
Hope that helps.
Regards
Carl

[Lacey]

Thanks very much Carl! Just what I wanted to know. Trying to keep the engine and running gear pre-1992 if possible so I don\'t have to abide by the regulations of emissions and CAT\'s and stuff, I don\'t mind what auto box it is as long as it\'s a decent one, 5speed would be better than 4 but I won\'t hold my breath for one of those.

T-II engine has my preference but I\'m not completely against the engine from an early FD, I\'m just accustomed to the T-II and I\'m more familiar with it. I\'m guessing an FD auto box and a pre-FD 13b won\'t be compatible with each other without modifications to the gearbox housing or the flywheel?

Hi Lacey,
An auto gearbox from an FD RX7 would be a good bet,but I might be able to find one from a Turbo 2 just possibly.
Anyway yes they can run on a 13B.
Hope that helps.
Regards
Carl

[bumpstart]

i also have some spinal/ mobility issues that limit what i can do in one day and how far i drive

 and looked hard at auto options myself for a while there
have instead just tried to keep the HP and therefore clutch needs realistic
and thus was forced from my faithful heavy plate 8.5 inchers to a more moderate 9.5 inch clutch
my left leg is still all that not happy with a long drive though !

Anybody with experience on the 7\'s auto box? good and bad points compared to other auto\'s?

the 1st gens had a 3N71B Jatco,, which is a cheaper copy of the C4
they are also found in various forms on other mazda, and many other makers in aus
even the VL commodore uses a variant of the 3N71B and in modded forms they have run under 9 seconds with consistency

s4 rx7 use the 4N71b which is a similar box with overdrive 1:1 TQ converter

s5 and later rx7\'s use another box entirely ( think it may be an aishin RA type seen in other japs like some subi and skyline  )

in aus,, the 3N71B is weapon of choice and can be modded to handle 450KW


my experience with either in cars i have tooled for
 is that the modded manual shift 3N71B was VERY tuff and had a TQ converter that deliberately slipped to around 3500 rpm to let the turbo come up and then gripped hard

it would be a good option to replace a manual,, and is operated as a clutchless 3 spd
( there is auto and semi auto options )
when clutchless you weld a tooth onto the T bar mech and it will lock out neutral and reverse without button on the shift up

===========

with stock 4N71B and 300 rwhp,, the gearbox would drive off OK from about 1800 rpm and flare badly at and above peak TQ around 4000 -5000 rpm  

this was across two gearboxes,, and they just are at the ( stock ) limits with a simple  rf320 highflow
however the 4n71B does not have the complications and expenses of the later boxes, so is still a good candidate if worked up ( more / or better bands? )  into a daily driver

s5 box has some sort of ECU controlled cable lockout and PWM features that horribly complicate matters
while the  4N71B can go in without much of its fruit
 ( me thinks its still nice to feed them a PWM for some modulation purpose to soften the shifts but they do work without it )

[Lacey]

Thank you for the detailed post

So in short, do you think with the setup I\'m looking to go for that the 3N71B along with an import series 1 gen 3 twin-turbo 13b would probably be the best thing to go for then?

Or is the 3N71B compatible with later series FD 13b\'s?

It doesn\'t HAVE to be an FC 13b, they\'re just what I\'m used to playing with, so I\'ve no idea just how different they are to the FD 13b.

Does the 3N71B bolt straight up to other series FD 13b\'s or are all the FD series 13b\'s different in regards to bell housings and flywheel, splines etc?

Sorry, probably making myself sound like a complete noob (no change there, then!), gearing and boxes just aren\'t something I\'ve spent much time with so have no idea what\'s what and what will fit on what!

In regards to the power, I\'m not looking to get TOO much power out of it as it will be a daily drive, I\'m probably going to aim for around 300hp at the very most. The standard S2000 engine is 262, so between 262 and 300 will be ideal, suit the car, not be \'too\' thirsty compared to aiming at 400, and be easier to drive handling and power curve wise, especially in the not-so-good weather.

I\'m not too concerned about the argue between FC vs FD engines, which is better, etc etc, I know both are 13b, both are good engines, what I am concerned about is emissions regulations and the law on forced running of CAT\'s, apparently the law on imported engines extends the CAT-by-law regulations up to a 1996 cut-off rather than a 1992 one for UK market cars, so providing I can bypass the post-1992 laws of emissions since to get past an MOT with a rotary on the more extreme emissions tests without a massive amount of power stifling by CAT\'s and cans, I\'ll be quite happy.

Engine doesn\'t matter to me as long as it\'s a 13b (or 20b N/A, though somehow I highly doubt it), and as long as it can be guaranteed that it can be tested under the old emissions regulations, I\'m not too fussed about the FC-FD engine itself as I don\'t have big plans for it in terms of power, porting, etc. If FD it will be staying twin turbo, I won\'t be going single, although I might change the twins for slightly bigger ones at some stage in the very distant future.

Also one thing I would like if possible is the option of having tiptronic paddle changes - the one thing that annoys me about auto\'s is the faffing about with the accelerator to get it to change down a gear, when I\'d be happier to be able to do all the gear changes manually with the flick of a paddle (so semi-auto), is that possible as a modification to the 3N71B? I\'m not familiar with boxes so have no idea of the limitations of what can and can\'t be done with them.

Thank you ^_^

[bumpstart]

the way i see it is 3n71b and 4n71b will fit any 1974-2010 motor
but later box for FD i think requires the auto FD block and has starter motor pointing forwards
which make them a pain in the arse for anything but what its built for
s5 box is lone man out but already in the complicated bin

4n71b and 3n71b are both good options
 overdrive is good but the box isnt quite as strong or as readily worked

if its going to be a first gen with turbo
( ditch the twins idea )
then the option that will cope with modest power is a tricked 3n71b

and if required i can link you aussie builders for mild semi auto to worked ones capable of handling up to 450 kw