Differential Modifications

[rob83ke70]

I recall a discussion some time ago on here about differentials, I think it was in a thread relating to rules for racing a class of corollas.... the basic gist of what I was interested in is as follows:

 

:D, you said that you could make an open centre diff behave like a limited slip, yet upon scrutineering behave like an open centre diff.... I'm having a guess here that you are tightening the differential gears inside the carrier via means of shims or other adjustments, so although it can act like an open centre, it is reluctant to do so, and so acts more like a limited slip. Is that right or am I barking up the wrong tree?

 

What I had in mind was a poor man's LSD, basically I have a 4.3 BW diff that I'd love to behave like a limited slip for a tarmac hillclimb (there is no rules that say I can't have an LSD, its just money and finding the parts). I don't want to weld it up because its still a road going registered car, and I'd rather not break stuff (and its my only 4.3 ratio at the moment).

 

Anyone with ideas feel free to contribute. I've searched for mods like this but all I get is pages explaining how LSD's and differentials work..... very frustrating....

 

 

Robert.

[Felix]

"Phantom Grip" might be what you are after.

[rob83ke70]

very interesting..... I thought I hadn't heard of that, but as it is in the FAQ I'd obviously dismissed it as "limited slip" whereas I was looking for "bodgy diff modifications" or something lol.

 

I will be putting one of those in both the corollas (ke30 rally car and ke20 street/race car)...

 

Maybe a mini-spool would be the go for the hillclimb? but that's a bother because I'd have to take it out soon after or else Kylie would get done over for drifting everywhere lol.

 

Anyone got a sensible opinion on what a ke corolla is like to drive on public roads (both sensibly and non-sensibly) with a locked diff centre?

 

Robert.

Edited April 3, 2010 by rob83ke70

[MRMOPARMAN]

yeah 'phantom grip' is what you'd be after.. seen quite a few of them at race meets fail. and when they fail, they take the rest of the diff with it. and that was on dirt..

 

sounds like its time for a diff conversion. ive never heard of LSD's for baby borgwarners.

[rob83ke70]

Thats interesting about the phantom grip..... what sort of cars were they in when they failed? how did they fail? I'm very curious about them, but not curious enough to spend $350 or so to buy one.

 

Why didn't I get a job as a fitter/machinist at a place with lots of CNC gear? Think of the things I could make!!

 

I did install some shims into the diff carrier behind the differential gears and this tightened it up a fair bit, which seemed to do what I wanted it to do (it would spin both wheels on dirt evenly) but I think something has worn a bit and its not as tight anymore. I'm thinking at this stage I should pull it apart and install some thicker shims so its nice and tight again...

 

Robert.

[Doogs]

The other option you have is a "spring locker" setup that a place called Tayell Automotive do in Melbourne.

3 Griffith Ave, Bentleigh East, VIC

 

p: (03) 95795529

 

Old discussion thread

 

Cheers,

Dougal

[Dropz]

I'm going to assume that by spring locker you mean a cone type lsd as cone type LSDs have springs inside which allow them to operate. i would advise against these lsds as they are very unreliable. the r31 skyline silhouette came out with a cone type lsd from factory, they tend to become open wheelers very quickly. and even after shimming 9/10 will be open wheeling after one decent burnout.

 

i am just curious, why do you want an lsd for track and open wheeler for the streets?

why not just have an lsd thats always an lsd, you do realise that lsds don't lock up all the time, only under the pressures they are designed to operate in. lsds are not illegal, many many cars have come out with them from factory so a car with an lsd should have no issues when being scrutineered.

[rob83ke70]

I'm under the impression that I don't want a cone type lsd lol.

 

I want something that would make power go to both wheels and I don't want a locked diff on the street. an LSD would be ideal, but I want something that is going to go in a standard BW diff as thats what I have fitted.... I'm being difficult.

 

I'm planning on running a jap diff in the rally car at this stage (ke30) and I'm under the impression that you can get LSD centres (very rare/expensive but possible to get) so thats probably what I'll do.

 

As I'm running a modified 4k every kilo counts, and I'm trying to keep weight to a minimum...

 

Robert.

[TRD ke70]

yip you are going down the right path, shim the spider gears, best way is to heat the housing and freeze the gears, then quickly put it together, hitting in the biggest shims that will fit, so when the housing cools and the spider gears warm up it locks everything up.

 

We have done this to Banjo diff's but not a BW.

good luck

[Doogs]

No one said it's a perfect solution, more a cheap option between an LSD and an open diff.

Sure if you want something better, install another diff with a proper LSD centre.

LSD centres for Corolla diffs are either rare as hens teeth or quite costly, so most people who upgrade choose another diff.

[rob83ke70]

Thankyou TRD KE70, thats what I was wanting to hear, I will be doing so at some point before the hillclimb.

 

I'd be up for trying one of those Tayell Automotive LSD kits in the rally car. I can't see any problems for the sort of events we'd be competing in, we aren't too serious or we'd be throwing lots of money around lol.

 

Robert.

[MRMOPARMAN]

Thats interesting about the phantom grip..... what sort of cars were they in when they failed? how did they fail? I'm very curious about them, but not curious enough to spend $350 or so to buy one.

 

they've all been on datsuns that ive seen (my club was heavily datsun based). springs would break and go through the diff, spiders and pins would pop out aswell (last 2 may or may not be related to the phantom grip).. however this was all on dirt.

 

I'm going to assume that by spring locker you mean a cone type lsd as cone type LSDs have springs inside which allow them to operate. i would advise against these lsds as they are very unreliable. the r31 skyline silhouette came out with a cone type lsd from factory, they tend to become open wheelers very quickly. and even after shimming 9/10 will be open wheeling after one decent burnout.

 

i am just curious, why do you want an lsd for track and open wheeler for the streets?

why not just have an lsd thats always an lsd, you do realise that lsds don't lock up all the time, only under the pressures they are designed to operate in. lsds are not illegal, many many cars have come out with them from factory so a car with an lsd should have no issues when being scrutineered.

 

in this case, the spring locker is completely different to the cone type LSD's used on borg warners. if you read the link to the tread provided above, you'd see their a different sort of 'phantom grip'.

 

and while we're on cone lsds. they're not all shit like everyone seems to think they are. they work well, provided they arent thrashed constantly, the oils changed regularly - with the right type ofcourse. they can be easily adjusted too. only problem is you can only get them for borgwarner 75/78's. corollas use a smaller type aptly named the 'baby borgwarner', and hence, they don't fit.

 

the problem with all these phantom grip type additions, they work well for a little while, but due to their inherent design (ie metal on metal, rubbing under pressure) they wear out much quicker than a normal LSD. the more you can get them to LSD, the longer then will suvive. this is why they wear out so quickly on the street. high levels of grip, and no burnouts etc allowed. so they are wearing with every turn. this is also why they last much longer on dirt racing.

 

to be honest, i think the best and cheapest option until you can afford a proper diff conversion is to either

1. have a 2nd welded diff, and just swap it over the day before the race meet. you will get so good at it the more you do it, you'll be able to swap diffs in 1/2 an hour or less.

2. weld the diff and put up with it.

3. make your car race only and weld it.

 

locking the diff properly is worth a fair bit of time imo. very good bang for buck mod!

[oh what a nissan feeling!]

and while we're on cone lsds. they're not all shit like everyone seems to think they are. they work well, provided they arent thrashed constantly, the oils changed regularly - with the right type ofcourse. they can be easily adjusted too. only problem is you can only get them for borgwarner 75/78's. corollas use a smaller type aptly named the 'baby borgwarner', and hence, they don't fit.

 

 

Agreed, all of my burnout vids on youtube were done with the same shimmed up cone type lsd, and the thing still worked flawlessly last time the car was going. On the other hand obese type vehicles seem to kill them real quick if driven wrong.

[MRMOPARMAN]

On the other hand obese type vehicles seem to kill them real quick if driven wrong.

 

yep thats right, heavy cars alone don't usually kill them, nor really light cars that are thrashed. its only when you combine the 2 that they flog out real quick.

 

my favorite place to get LSD's from is fairlanes :thumbsup: the old farts never drive above 50kmh so their usually in top nick even after 300,000+km