Gearbox
Turbo Mini Forums

Hi there . it's the local pain in the arse again .... with this engine that Benross is building for me ... will produce around 160bhp ... now av been told that if i run more than 10 psi i will destroy my standard grearbox ,, is there a cost effective way of limiting the boost to 8 - 9 psi ,,? if how do i go about doing it

yea, you just turn the boost down to save the gearbox, although then it won't make the power.

Sadly, if you want the power, you NEED the gearbox to take it.

Mr. Prawn, the friendly Crustacean- slowly making steps towards forced induction.

manual boost controler they are on ebay for about £20.

or get straight cut drop gears.

could use a adustible actuator then set it to 8 psi, think avonbar sell them..

yer i was intraduced to a challenge set of drop sccr gears .. but there like 350 plus fitting .. .. i am happy to run @ 9psi although be it shit .. at least im in my mini

If you can get hold of a set of SC drops they will help and are easy to fit while you are building your engine back up.

If something is worth doing, it's worth doing half of.

So whats the point of building a good turbo engine if you want to limit it? you'll probably still break the box anyway - diff or drops

Paul

I seriously doubt it!

you can get them new from minispares for about £160

It's call not get a bottomless money pit ! .. i built what i could with the funds i had ..

Do you have a spec for you engine once it is finished?

If you have a modded head and a decent intercooler at 10psi you are looking at 120bhp maybe more I would say as a minimum that you need a x-pin diff and sc drop gears. With a little mechanical sympathy the standard helical box should cope.

If something is worth doing, it's worth doing half of.

A 4 pin diff should be on your list for when you do have some spare cash. That should be do able with the engine fitted, but I would try and put s/c drops in it while you have it apart.

1312 T
omega 10cc dished race pistons
Avonbar Phase 2 turbo cam
head ported polished , chambers opend up double valve springs
Crank lightend balenced
South african block ..

You should be capable of quite a bit more than 10psi with that sort of setup if you have an efficient intercooler.

Definately go for the x-pin and sc drops. I would also look into getting a megajolt setup on there.

I take it the 123 dizzy you have is the one with 16 selectable advance curves? If so you could probably sell that for more than what it would cost you to get a megajolt kit together.

If you were running a dizzy you may as just weld a standard one than have a £200 item on there.

If something is worth doing, it's worth doing half of.

yes has pre selectable curves ... megajolt not a tube a glue what ur on about .. is this dizzy no good ..?

I wouldn't say no good but not ideally suited.

Have a search on here for megajolt and you should find a few good threads about it.

If something is worth doing, it's worth doing half of.

i would bin the 123 asap ( not actualy bin it just replace it) the curve is unsuitable for even a std metro turbo

Yes i moved to the darkside

Instagram @jdm_brett

Curve 0 set at 6degrees at idle should be safe but not ideal.

If something is worth doing, it's worth doing half of.

i know spooner from many years ago
he hunted me out and came to me with a dud engine, basicaly some one put togeater a decent ..... ish .... engine with phase 2 cam balance crank etc but.... with shite pistons which shit the ring lands i believe before spooner got the the car ... anyway, been the chap i am i told him to drop the engine out and bring me the short block upon looking found the above with helical gears etc...
the cr ratio was in the 10s

hes on a budget, so i have place him 28 cc in the combustion chambers and replace the inlet valves as these were goosed on the stem collets, some one place single valve springs in there and valve bounce did the rest,
i have bored and honed the block +0.040" to 5 microns. 10cc omegas, building this up over the weekend.

now! with the cr down in the 8s and togeater with the good guy bits i have advised him to run this car at 8 psi and no more untill he can afford the drops and diff ect at a later date at least the short engine is ok the crank and shell were fine, cam etc

there is a two stage boost controloler in the cab standard 4 psi and the second 8 psi..... as we know with the cr and that boost the engine will survive for a later date untill he can rebuild the bottom end etc ........this is spooners daily drive so a compramise between funds and time for him to get back on the road asap

i have made him aware of all the pit falls with the fueling timing and boost...... i am helping lee out so to speak.

He's in good hands

If something is worth doing, it's worth doing half of.

Hes a top man ...

in case it helps , im running helical STANDARD drop gears at over 190 bhp with no problems .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

well thats a new one on me robert, well suprized
STANDARD you say, if the standard helical idler was supported with the stubshaft and timkin bearing setup in the MS version, i cant see a problem

iam on to this route before chrimbo if i get time.

robert i know your on borrowd time,if they are Standard

Im running a complete standard gear train other than a cross pin diff, with 50hp fixed hit nitrous. Admittedly the engine doesnt see the full torque all the time, but with the instant 50hp increase in second gear, im just waiting for something to break. I now have my grubby mits on a progressive controller, which should help, as long as I dont increase the hp; much

On 6th Nov, 2009 BENROSS said:
well thats a new one on me robert, well suprized
STANDARD you say, if the standard helical idler was supported with the stubshaft and timkin bearing setup in the MS version, i cant see a problem

iam on to this route before chrimbo if i get time.

robert i know your on borrowd time,if they are Standard

Edited by robert on 9th Nov, 2009.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

robert, i got a little confused and did not read right what you put,
i thought you meant the drop gears,were standard.

yes the helical box, gear train is stronger than the SC setup

what do you think if the standard helical idler was supported with the stubshaft and timkin bearing setup in the MS SC version. ?