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Spyderman · Alfasud Joined: 04 Sep 2003 Posts: 48 Location: Hampshire

Hi Guys (and gals)

A question have you any iea how much power you can chuck through a Sud/33 gearbox.
From what I have been told the 2nd gear syncro is meant to be a weak point, and the 4speed stronger than a 5speed.
Anything else you know about them. I heard the the area around the diff O/P shafts/axles is meant to be a little weak. Might I be able to strengthen that with a custom made billet ali sump cover.

Is there a best box to use ? Given I'm looking at the idea of centrifugally supercharging a 1.7 16v, past 200bhp.

The only alternative I can see is to use an Adaptor plate onto a VW buggy box. You can get the adaptors and you can get heavy duty vw boxes.
Unlike most of you guys I don't need to fit the box into a sud/33/145 etc
its going ino a kit car.

ZeNiTh-PbArM · Posted: Sun Dec 05, 2004 9:39 pm Post subject:

hi,

i wouldn't replace a sud or 33 box with a VW one, since you would get 5 reverse gears and only a very short forward one!

regards,
zp

paddy granger · Alfa Sprint Joined: 12 Aug 2003 Posts: 248

An interesting link for you.

http://www.hbpsystemsplc.co.uk/engine.htm

Alan · Guest

Hi,

I've currently got 160bhp going through my box, on tarmac rallying which puts a lot of load thro on standing starts. Bit of a hybrid box though .... it's a 33 casing, with internals from a 1350cc Sud 5 spd, fitted onto a 5.3:1 Crown wheel / pinion and a plate LSD. So far it hasn't failed.

Some of the race cars I've seen over the years put over 200 bhp thro the box - I've been informed in the past that up to 200 - 210 bhp is okay, above 210 bhp failures will start to occur. That's a five speed box in a 1700 16v 33.

If you want more info, AH Motorsport might be worth a try - do a lot of boxer race prep. Tel 01252 845717.

Cheers,

Alan

Matt Stolton · Posted: Tue Dec 07, 2004 4:23 pm Post subject: Gearbox Strength

I don't think the actual box is very weak. Far from it, the actual gears are very good.

The weakness is in the Synchros, which appear to be made from glass.

I am currently working on a 1.7 box which will use the "sychros" from a 145/6 boxer box, which are completely revised, compared with a sud/33 derived box. They use some sort of torsion device to mesh the gears onto the driven shaft, rather than the glass synchro rings of earlier variations.

If you can live with the noise, a straight cut box would obviously be stronger, but you would need to change the synchros as well as they are the major problem.
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

Peter D · Alfasud Joined: 15 Aug 2003 Posts: 60 Location: Denmark

It is the torque and not the power that kills the gearbox and clutch.

I have run for 10 years with a 33 16V gearbox and a supercharged 1.5 engine with 220 Nm torque (0,9 bar).

The gearbox has raised no problem.

The clutch is a Fichtel & Sachs group A aluminium-clutch, which has lasted 16 years!

If you boost the 1.7 16V with max. 0,45 bar, it will (approx.) give 45% more power and torque than the original 137 bhp and 150 Nm meaning about 200 bhp and 220 Nm.

That should be possible without destroying the gearbox.

But remember if you fit too tough a clutch (sintermetallic without springs) it will transfer bigger loads to the gearbox and then you can not rely on my experience.

Peter (DK)

Matt Stolton · Posted: Wed Dec 08, 2004 9:38 am Post subject: Clutch

On my P4 project we actually used the standard clutch in the end, as we wanted to create a 'fuse' between engine and box.

Over 4 months, 4000 miles, and some serious abuse, it never really slipped, and didn't appear to have worn very much at all. Admitedly it wont have the torque of a blown car, but I'm certain it has (had) around 180BHP.

I did manage to break the box though, which ended up being dead synchros on second. That was three months after it was "professionally" rebuilt, and was at a track day.
_________________
Regards

Matt

Ex Alfa 33 'GTA' (P4 with Knobs On)
Now cruising in a 166 3.2 Ti!!

Peter D · Alfasud Joined: 15 Aug 2003 Posts: 60 Location: Denmark

Gearbox strength and destroying synchros have nothing to do with each other.

If you are not kind when changing gear (especially downwards) you would also destroy the synchros even if your Alfa 33 was only a 1.3 with 90 bhp.

Peter (DK)

paddy granger · Alfa Sprint Joined: 12 Aug 2003 Posts: 248

Spyderman · Alfasud Joined: 04 Sep 2003 Posts: 48 Location: Hampshire

Cheers Zp, You can actually use a VW box you just need to flip the ring gear for mid engine use, main disadvantage is they are 4 speed boxes.
Had one in my kit when it had VW beetle motor and box. Before I got to swap in the 1.5 sprint engine and box.

Thanks for the advice of AH motorsport Paddy, I may pop in to see them
I know where they are, fortunately about 10 mins from where I work. Have been in before.

Out of interest is there any external differences between a 145/146 box and a 33 box?

Thanks for help so far Guys

Guy

paddy granger · Alfa Sprint Joined: 12 Aug 2003 Posts: 248

Peter D · Alfasud Joined: 15 Aug 2003 Posts: 60 Location: Denmark

It is not enough to match the revs properly when downshifting.

You will have to double de-clutch, because if you only push up the revs when the clutch is down, you will not spin the gear axle to the right speed.

The alternativ is to be a little more gentle and wait a little so that you do not try to engage e.g. 2. gear when still going 100 km/h.

Peter

paddy granger · Alfa Sprint Joined: 12 Aug 2003 Posts: 248

Thanks Peter.

I just wanted to check - you will be glad to know that I always double-de-clutch on the downshifts.

I obvioussly don't downshift to 2nd gear when doing 100 km/h...that is just insane!

The only problem is that I can't heel and toe with the standard pedal setup.

sportston · Posted: Sun Apr 09, 2006 10:34 am Post subject: make an organ pedal

try making an organ pedal to fit over the top of existing one. You need a hinge at the bottom and a flat straight piece of ally smooth on the underside. This will help to heel and toe. 2nd at 100 clicks is doable.... just. but it works better at 90. At least with my standard 1.7ie box it does.

Horizontally Opposed · Alfasud Joined: 29 Aug 2004 Posts: 44 Location: Greece

I am curious...
I see 70s cars still going with no gearbox problems at all!

Isn't there ANY way at all you can fix your 33 gearbox so that it will never bother you again?? You know... as it was supposed to be...

Is it that difficult? I hate the idea of having to use a vw box...

Edward · Alfa 33 Joined: 21 Sep 2003 Posts: 307 Location: Bristol

Well from my point of view - the combination I run is 170 hp through a Sud 1.2 box. This works fine and it is in my regularly used track car. It would seem that 5th and reverse are a little difficult to find recently - but this is a selector problem I guess - not a power / torque one. Just be kind to your box and it should be good back.

Edward.
_________________
The faster the better.

paulhide · Posted: Thu Apr 13, 2006 10:10 pm Post subject:

Yeah, just change/tighten up the linkage bushes; normally makes a big difference with gear selection if your having difficulties finding 5th and reverse or 1st/2nd. (Won't help worn syncromesh on 2nd of course.)
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Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188

Guest

how difficult a job is it to do? do you need to take the gearbox out? i often find 1st and 4th dont want to go in - yet theres no crunching...

paulhide · Posted: Sat Apr 15, 2006 8:12 am Post subject:

Changing the gearstick/bushes is easy, but only tends to affect lateral extremity changes. (ie 1st/2nd or 5th/reverse) Gearbox end bushes are a little harder to reach and I'm not sure how they affect things. Might be rather hard to get at if you've got a P4?
_________________
Owner's Club 33 Registrar. Now from P4 & S2 1.7 QV
http://www.alfa-pages.co.uk/viewtopic.php?t=5188