Gearbox Advice

[josh-sri]

Afternoon all, I'm looking for some advice on what gearbox to use in my nova turbo build. I understand an f28 is seen as the best bet but at the moment they seem to be fetching pretty good money for the ones that are available.

My first thought was an f20, means I can keep the original mount, not too expensive and readily available so I can crack on and get it complete. I know it may not last long but if it means I can get the car finished and use it a bit that would be helpful as I'm finding motivation is getting smaller and smaller at the moment!

So whilst looking for an f20 I have come across f16 and f23. F23 seem readily available and cheap, would I be able to use the bigblock conversion shafts in an f23? Also as far as I'm aware they are cable shift and hydraulic clutch, am I going to come across problems in this area? F16 I have no knowledge on at all.

Any advice would be brilliant and if anybody has any of these boxes local to East Yorkshire that would be great too.

Thanks

Josh

[mk1nova_rich]

I have very little knowledge about the F23 other than knowing they have been used in turbo builds before. Obviously the hydraulic clutch and cable shift will give you something to think about...although it wouldnt be a surprise if you can swap the shifter turret to run a traditional rod linkage

F16 is very similar to F20 I believe

[Will F]

F16 are old and weaker than the f20, so won't last long if you put more than std torque through them..
f23 aren't really cheap? They are 150 ish but that said, the f20s are commanding 130£ plus now!
youll need a hydro clutch, cable shift and new mounts fabricating so a bit of a ball ache, but worth it for the aforementioned modern touches...

[DaveMarshall]

Remember that many F23 gearboxes are engine/car specific so you would need to watch which you choose if you do go down that route.

Dave

[josh-sri]

Thanks for the replies, I'm swaying more towards an f20 at the moment if I can find one local, just so I can progress the build a bit quicker, f23 might be an upgrade next winter :roll:

[Stuart]

There are two fundamental versions of the F23, the basic change is the starter is on different sides... You will want the one from a Turbo car (or to make life easier, NOT one from a Z22SE vehicle)
Some of the castings dont have all the mounting holes machined out either so that is one to look out for.

They are great boxes though and if looked after (regular oil changes, overfilling to 2.25L and a breather system to catch the excess), they will take bonkers power, just look on the Cobalt SS forum in the USA as an example lol

[josh-sri]

Thanks for that information Stuart, I am running a z20leh in my nova so whilst I am looking for an easy solution as far as fitting goes, I'm also looking for something to cope with the torque these engines produce. This was one reason for including the f23 in my options, I think the best bet will be to purchase both and have a good think about it before deciding on what I'll use.

Thanks again

[Iain]

You can retrofit cable shift to F20s, so I imagine it goes the other way and you could convert an F23 to rod.

[DaveMarshall]

If if its going in a Nova which I'm guessing it is then a turbo F23 box will not be the easiest as it mounts on the top. I would guess a 2.0 Vectra B F23 would be the easiest to fit as it has the engine mount to the front.


You can retrofit cable shift to F20s, so I imagine it goes the other way and you could convert an F23 to rod.

To convert an F20 to cable you use the parts from a F17, F23 is a different type of box so would probably be harder to convert the other way.

Dave.

[josh-sri]

Thanks for that information Dave very helpful, I shall update my build thread soon to show my progress.