sr20 with a supra 5 speed ????

[syco86]

Guys i have a question ... does anyone know anyone who has put a supra 5 speed behind an sr20 ... i have just blown my sr20 5 speed and have been told that its very common as the box isnt very strong ... i was thinking of putting in a supra 5 speed as i know they are very strong.

Any information or alternatives will all be greatly appreciated .... the sr20 is in my spriner :greenbounce:

thanks in advance

[slide86]

retain the sr20 bellhousing and get an RB box and bolt it onto the SR bellhousing.

you will need a custom bellhousing to fit a supra box on an SR

[hatzo]

What exactly blew in the box?

[floody31]

Which supra box?

If you're talking W-box, meh, RB boxes cheap, plentiful alternative.

If you're talking R154, the strength thing is all hype, may as well go RB25 or Z32 box.

[Benno]

not point in fitting a RB20det box to an sr, it isn't any stronger the the SR box
rb25det and vg30 gearbox is alot stronger and is a common upgrade for high powerd SR's but it isn't a bolt up job.
you'll need your sr front case/bellhousing and a RB25det box and find someone with a jig to cut and weld it up.

[Brendo]

rb20 g/box on and sr20 in a ke70/ae86 lines straight up with the shifter position or so ive heard, thats why people do it...

[syco86]

<div class='quotetop'>QUOTE (Brendo @ Feb 17 2008, 04:53 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=487608)</div>
rb20 g/box on and sr20 in a ke70/ae86 lines straight up with the shifter position or so ive heard, thats why people do it...[/b]


so to fit an rb25 box i will need to make a custom bell housing then .?? so essentially its no easier to fit than say a supra 5 speed as thats what i would need to do as well ..??

hmmm surely someone is making something to put behind the sr's ... !! this is the first box ive blown in this car and i only ust bought it not long ago so who knows what paunishment it got before me .... but i know if i out another sr box in it wont take long before i blow another one..... what to do :(

[floody31]

Well the bellhousings and such for RB25 box behind SR are already available. As are ones for the Z32 box. I have no idea about shifter position.

RB20 box has double synchros on the lower gears, unlike SR box, but yes is a fairly standard 71C box as used in practically every medium performance rwd Nissan from about 1978-late 90s.
Advantage is of course that they are cheap as chips and easily available.

I believe that the Nissan boxes would just be a simpler path than Toyota box to Nissan engine.

Also unrelated example but wtnessed a fresh R154 last 2 meetings behind an RB30ET, RB25 box has lasted 2 seasons since.

[Tyrie]

Nissan gearbox info on SAU (http://www.skylinesaustralia.com/forums/Gearbox-Specifications-I-t132433.html&hl=twin+synchro)

[syco86]

<div class='quotetop'>QUOTE (floody31 @ Feb 17 2008, 08:19 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=487751)</div>
Well the bellhousings and such for RB25 box behind SR are already available. As are ones for the Z32 box. I have no idea about shifter position.

RB20 box has double synchros on the lower gears, unlike SR box, but yes is a fairly standard 71C box as used in practically every medium performance rwd Nissan from about 1978-late 90s.
Advantage is of course that they are cheap as chips and easily available.

I believe that the Nissan boxes would just be a simpler path than Toyota box to Nissan engine.

Also unrelated example but wtnessed a fresh R154 last 2 meetings behind an RB30ET, RB25 box has lasted 2 seasons since.[/b]

Do you know how makes the bell housing for the rb25 to an sr .?? this is going in my sprinter is the box physically bigger as well .?? as in will i have to modify any tunnels or anything like that ??

Whats an rb25 box worth roughly and where is the best place to source one .??

[Gunner]

there is no bolt on bellhousing for an rb25 box to any motor, as the bell housing is part of the actual gbox case, the bell housing has to be shut and cut, which can be quite hard to do and not cheap.

the boxes themselves can be sourced for anywhere between 1000-1500 depending on availability at the time, and any jap import wrecker will have them.

as i said its not as easy as some people think and alot of engineering does go into it, there are shops that do the conversion, and are quite successful, and aren't to expensive, but the supra box is a far cheaper alternative, as parts can just be bolted on and in.

as for the size of the box they arent long but they are fat. and u will have a hard time finding enough clearance in an 86 tunnel, u have trouble getting them in commodores if that gives u an idea.

expect to pay upwards of 3000 to get it done, supra box will cost anywhere between 2000-2500.

rb25 is tough, ive put over 500hp atw thru them and only munched syncros, but it is not an easy conversion nor is it cheap.

but it is the a good upgrade and worth doing, if ur shifting technique is to harsh. a very cheap alternative and one i would look into is to change the way u r shifting, also the qaulity of ur clutch. i used to break alot of gbox's, i mean alot, i changed my technique and have only been blowing diffs since, b ut i like high rpm revdumps