Stupid gearbox question
Turbo Mini Forums

Need to have a box refreshed for the van. I've only got one from a 998 lying round. Will that go straight on with the 1275 drops or do I need to do anything else??

all A+ boxes are the same bar final drive iirc

Yes i moved to the darkside

Instagram @jdm_brett

not , ratios are not the same , 1275 have a taller first gear.

Would a shorter first gear be a problem with a turboed 1275 running about 10 psi and 3.2 final drive??

Edited by apbellamy on 11th Aug, 2009.

probably not,

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10 psi with a 3.44 final drive on mine and running 10's, i feel i have to change to second too soon. as it revs out very quickly and cant build up much boost.

for me a taller first would be great.

fit a taller diff then.

3.1 diff with 13" wheels and a tall 1st is a decent setup

10" wheels and a 3.44 diff must be a real screamer ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

It will be on the Metro Van, so it's 13" wheels and 3.1/3.2 CWP depending on what we can get at the right price.

look for a 1275 gt gearbox!

It's a budget build from bits we have lieing round or picked up on the cheep.

You've seen the van, it's not worth spending thousands on a descent engine/box...

a 998 box may well have a 3.1 in it

It came out of the van originally. Low comp 998, with IIRC a 3.44 unfortunatly.

Not that there's anything stopping me counting the teeth on the Crown wheel....

Schrödinger's cat - so which one am I ???

Yes i moved to the darkside

Instagram @jdm_brett

My idea was divide the crown wheel number by 3.44, 3.2, 3.1 etc and see if I get a whole number...

But yes if I can see both gears my ageing brain will need to do less

On 11th Aug, 2009 Rod S said:

On 11th Aug, 2009 apbellamy said:
Not that there's anything stopping me counting the teeth on the Crown wheel....

Probably worth counting the ones on the pinion too.... otherwise you will get a "divide by zero" error message in your maths

I see your point - there's a table here that might help

http://www.ime.org.uk/ime/f/final_drive.html

For the ratios your looking at it should work but, as you can see from the table, at lower ratios, the crownwheel teeth numbers are replicated but the pinion is different, ie, the 3.6 crownwheel is the same number of teeth as the 3.4

EDIT - and sometimes it's easier to read the part number than count the teeth accurately which is why I like that table, it has all the part numbers too. It all depends whether the number is covered by the tab washer....

Edited by Rod S on 12th Aug, 2009.

Schrödinger's cat - so which one am I ???

That's usefull. Thanks Rod.

I'll dig my box out and have a poke tomorrow...

phnarr phnarr

I would avoid a 3.44 and an A+ box on 10" wheels. 1st was useless and it was unbearable at about 80.

A spread ratio box with a chunky engine and a very long legged final drive will make a good engine. My old bird's 998 E had lovely gear ratios in comparison.

Bugger off, I'm getting there.

its a bit of a screamer alright, and in stereo with the missus in the passenger seat off the lights!

it was all i had at time and just wanted it built

how does the 998E box differ ratio wise?

On 12th Aug, 2009 1972-ANGUS said:
its a bit of a screamer alright, and in stereo with the missus in the passenger seat off the lights!

it was all i had at time and just wanted it built

how does the 998E box differ ratio wise?

In boost we trust

its exciting ill say that, but with s/c drops the noise takes some getting used to!!!

with the torque, i just cruise around in 3rd or top, its great chav slappin stuff off the lights, i tell ya.

is this not a good thing? it running like an n/a in first with less wheelspin?

Drives
-Ford S-max Mk2 Ecoboost
-Rover 100 VVC #2 - track project

Searching is all you need on TurboMinis

Doesnt the 998E have a 2.95?

indeed for that it works a treat, but its always a compromise as 80mph comes at something silly like 6000+ in top. and as its a daily drive, economy is out the window.