G80 locker, a few questions for those who have modded one.

The problem is that of the two locking wedges, one is the side gear and the other side is a glorified washer with a set of wedges on it that are not locked to the case in any way except for the spinning counterweight shaft. As soon as the spinning counterweights are allowed to spin again, the whole locking wedge piece disengages and is allowed to spin relative to the case, completely disabling any lockup.
There was talk of two types of G80--maybe yours (@kildea) is another type that does not unlock at high speed? I'm sure this is the type mine is, as well as anyone else whose diff unlocks above 25mph.

Doherty_340 said:

do not want !!

tbh, i take 99.9% of the stuff posted on here as scripture.

are you refering to me and my car? if so, i plan on keeping, maintaining and driving the complete balls off it for as long as possible....

if not, you would cut the weight rather than weld??

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Sorry--I was referring to what exactly my car does.
I would probably weld the weights to the carrier. You will have to completely disassemble the diff (I think) to get at the pawl to cut it. It really wouldn't be a good idea to try to cut the pawl while it is still in the car--too many metal shavings and such.
But that is my opinion. Maybe those with more experience disassembling/reassembling these diffs would comment?

some very helpful/informitive replies...thank you all.

tho, some new questions have arised....

i've watched a computer generated video on youtube of this diff, how it works, and it in 'exploded' views. ( i guess its the video posted? i haven't tried it as the media player on this laptop is rubbish. plays videos in robotic/ strobelight type jumps.)

if i go the welded weights route, and i suffer slip and a hot housing, can i still get it split to replace my clutchpacks??

could it be possible to install a single extra 'disc' to the worn pack to tighten them up? or best replacing all of the pack? i'd guess even with the extra 'disc' in the worn pack, the worn discs could still slip against one another but grip the single new 1, thus still giving slip/possibly more heat??

if the weights are welded, they still have to rotate to generate the lock-up, right? and if i just weld the pawl to the casing, the weights would still expand and...lock-up?? or bust into pieces?? lol.

at first, i'd thought about shaving/champhering the weights at each end, increasing the centrifugal force needed to expand them out...then i thought that would just heighten the difference in speed needed between the wheels to achieve the lock-up?? am i understanding this correctly??

sstory: i'd prefer to do this mod right, ie dissamble/cut the pawl/reassemble. tho only if its a better option. if welding the weights has the exact same outcome and is obv the quicker/easier option, then i'l do that...

also to clarify, the complete axle is out. i bought it on its own as my 940 is non locking. after upping the boost to 0.8 bar its funny, but not much 'fun' leaving 70ft long 1 wheeler lines. i like 11's and arse out achshun.

sstory0626 said:

You will have to completely disassemble the diff (I think) to get at the pawl to cut it. It really wouldn't be a good idea to try to cut the pawl while it is still in the car--too many metal shavings and such.

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absolutely.
there really is no way to get at a narrow section of that weight, and it takes a while to cut through with a cut-off wheel anyways. if you don't want to open it (a hassle from my perspective) then cutting the weight is not an option, in this case welding is the way to go.

i ruined one of mine by (after cutting the weight) replacing the spring with a hefty wave spring and grinding off the nubs on the ramps in an effort to turn it into something of a limited slip - i failed miserably, though it worked well for a couple of weeks, the clutches were worn completely smooth eventually and i was back to an open diff.

Doherty - You are not welding the small flyweights, just the one large weight. Look at the operation again and work through the stages with the video and you'll see why. You'd just bridge that gap between the weight and the case with a small chunk of metal and weld it at both sides - don't go crazy and you'll be able to grind it off if you need to get into the diff.

Doherty_340 said:

some very helpful/informitive replies...thank you all.

tho, some new questions have arised....

i've watched a computer generated video on youtube of this diff, how it works, and it in 'exploded' views. ( i guess its the video posted? i haven't tried it as the media player on this laptop is rubbish. plays videos in robotic/ strobelight type jumps.)

if i go the welded weights route, and i suffer slip and a hot housing, can i still get it split to replace my clutchpacks??

could it be possible to install a single extra 'disc' to the worn pack to tighten them up? or best replacing all of the pack? i'd guess even with the extra 'disc' in the worn pack, the worn discs could still slip against one another but grip the single new 1, thus still giving slip/possibly more heat??

if the weights are welded, they still have to rotate to generate the lock-up, right? and if i just weld the pawl to the casing, the weights would still expand and...lock-up?? or bust into pieces?? lol.

Click to expand...

When the weights are spinning, the diff is unlocked. Weights stopped=diff locked. You want to try to find a way to keep the weights from spinning.

at first, i'd thought about shaving/champhering the weights at each end, increasing the centrifugal force needed to expand them out...then i thought that would just heighten the difference in speed needed between the wheels to achieve the lock-up?? am i understanding this correctly??

Click to expand...

Your second thought is correct.

sstory: i'd prefer to do this mod right, ie dissamble/cut the pawl/reassemble. tho only if its a better option. if welding the weights has the exact same outcome and is obv the quicker/easier option, then i'l do that...

also to clarify, the complete axle is out. i bought it on its own as my 940 is non locking. after upping the boost to 0.8 bar its funny, but not much 'fun' leaving 70ft long 1 wheeler lines. i like 11's and arse out achshun.

Click to expand...

The more I think about it, the more disassembling/cutting off the pawl counterweight would be the best way to go. THe complete original function of the diff is retained, and the only thing you are changing is you are deleting the high-speed unlock. I think if you weld the spinning counterweights to the carrier, there will always be a lot more preload on the clutch packs than they were designed for, and they will wear prematurely.

sstory0626 said:

I think if you weld the spinning counterweights to the carrier, there will always be a lot more preload on the clutch packs than they were designed for, and they will wear prematurely.

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This is correct, but nobody is suggesting he do this.

The piece to weld is the large counterweight - welding that does the exact same thing as cutting it off, absolutely no change in the operation between the two methods - the operation of the bits inside are left completely untouched since the hooks simply stay in one place either way.
In each case the diff will unlock if the wheel that originally had traction looses traction - no matter what you do, if the flyweight axle changes rotation direction (traction goes from one wheel to the other) it will tend to back off.

I've already looked into it, there's no way to make this pile work like a real clutch-type LSD.

If you weld the pawl to the spinning counterweights, the spinning weights will no longer spin. Yeah, I see what you're talking about there. But where I disagree is in the difference between welding and cutting. If you cut the pawl counterweight, the spinning weights will still be able to spin and the diff will be able to function as an open diff. If you weld the pawl to the spinning weights, there will be no unlocking action and it will function as a standard clutch-type diff with a significant amount of preload, or at least a really touchy engagement. I think that will be the difference here--ability to function as an open diff until a certain axle speed difference is reached vs. only a torque difference required for lockup. Maybe the welded pawl is better for all-out performance applications where a progressive lockup is required, and the cut pawl better for daily drivability and longevity?

If you weld the pawl to the spinning counterweights, the spinning weights will no longer spin. Yeah, I see what you're talking about there. But where I disagree is in the difference between welding and cutting. If you cut the pawl counterweight, the spinning weights will still be able to spin and the diff will be able to function as an open diff. If you weld the pawl to the spinning weights, there will be no unlocking action and it will function as a standard clutch-type diff with a significant amount of preload, or at least a really touchy engagement. I think that will be the difference here--ability to function as an open diff until a certain axle speed difference is reached vs. only a torque difference required for lockup. Maybe the welded pawl is better for all-out performance applications where a progressive lockup is required, and the cut pawl better for daily drivability and longevity?

Disassembly is not difficult. Cutting the weight was not difficult with a 4.5" grinder w/cutoff wheel. A little smokey, as the metal seemed to bleed gear oil as it was cut, making the familiar hot differential smell. But I wouldn't necessarily say it was easier or harder than welding the big weight into place. You'd want to do some clean and prep before welding, so that would take some time too.

I could have probably cut off more, and I might when we pull the diff to inspect the plates

again, thank you all for the informitive replies!

to clear up some of the confusion that has arised.

the place to weld is here:



this is pawl-casing gap to be bridged and welded, yes?


not:



or the gap from the pawl to the weight?

jus' so everyone ( myself included ) understands.

again tho, if i weld the pawl as per the pic. what effect will the weights still expanding have??

sstory0626 said:

If you weld the pawl to the spinning counterweights, the spinning weights will no longer spin. Yeah, I see what you're talking about there. But where I disagree is in the difference between welding and cutting. If you cut the pawl counterweight, the spinning weights will still be able to spin and the diff will be able to function as an open diff. If you weld the pawl to the spinning weights, there will be no unlocking action and it will function as a standard clutch-type diff with a significant amount of preload, or at least a really touchy engagement. I think that will be the difference here--ability to function as an open diff until a certain axle speed difference is reached vs. only a torque difference required for lockup. Maybe the welded pawl is better for all-out performance applications where a progressive lockup is required, and the cut pawl better for daily drivability and longevity?

Click to expand...

No, nobody is suggesting welding anything to the spinning weights.

The only welding would be at one point - the outside of the larg weight, welded at its tip to then outside case.
the spinning counterweights will still spin, they will still catch the pawl hooks in either direction.

Nobody has suggested welding ANYTHING to the spinning counterweights.

Doherty_340 said:

again, thank you all for the informitive replies!

to clear up some of the confusion that has arised.

the place to weld is here:

this is pawl-casing gap to be bridged and welded, yes?

Click to expand...

yes

excellent, thank you.

2 wheeling here i come..... provided my clutchpacks aint toast.

You weld the counter weight to the case, not the pawls.

sdturbo said:

You weld the counter weight to the case, not the pawls.

Click to expand...

could you highlight the area you mean?? or is that the end inside the casing, that you can't see in that pic.

kildea said:

This is correct, but nobody is suggesting he do this.

The piece to weld is the large counterweight - welding that does the exact same thing as cutting it off, absolutely no change in the operation between the two methods - the operation of the bits inside are left completely untouched since the hooks simply stay in one place either way.
In each case the diff will unlock if the wheel that originally had traction looses traction - no matter what you do, if the flyweight axle changes rotation direction (traction goes from one wheel to the other) it will tend to back off.

Click to expand...

OK, gotcha. Sorry about the confusion--I'm not sure where I got the idea that you were saying to weld the large counterweight to the spinning weights.
Need more coffee.

What I recon we could do with is more detail on how the disengagement speed increases with different incremental cutting of the main disengagement centrifugal mass.

These diffs are really just designed to provide improved traction on very slippery surfaces, and take approximately 1/2 of a revolation of the slipping tyre before the small rotating centrifugal weights kick in. Primarily just to get the car moving when on snow, ice, etc.

Once on the move, the big more visible weight is designed to move outwards against spring pressure above around 25mph and disengages the lockup function. The reason for this is safety, to avoid any push-on understeer issues on road cars. There is a good video explanation of how exactly the same thing is done and for the same reason but by electronic control instead of mechanically on the Porsche 928.

The G80 system suits my own needs well on my car, but the disengagement speed is just a little low for my purpose as its early disengagement allows the more lightly loaded inside wheel to spin up in some corners in use. I'm keen to retain this diff, but increase the disengagement speed to around 50mph, but still allow it to disengage above this point.


The big mass only effects the cut-off speed, and has no bearing on the engagement speed or even if the unit engages at all. If there is no speed differential between the half shafts the diff will not lock up at ANY speed.

Either welding the unit up to the diff housing or cutting out the whole of the mass will effectively prevent disengagement if that is the goal, but it still won't engage at first until the same speed difference is detected between the half shafts by the small rotating weights.

This works very well with big rear slicks to avoid putting large scrub friction loads through the axle when the diff isn't needed.

Before altering my own diff in combination with a possible ratio change, I'm curious if anyone has information from cutting off only PART of the big disengagement mass?

As the mass closer to the end will have a greater centrifugal effect than that nearer the pivot, perhaps removing the first 1.5" might increase cut-off to 50mph, and removing 2.25" raise disengagement to 70mph....??

I believe these diffs are actually capable of quite high torque transmission, with the clutch discs actually there mostly to provide initial friction and to smooth the engagement action a little. It is the loading of the ramps that provides the lock-up effect, and this is related to the torque that is being transmitted therough them with increased torque producing an increase in locking pressure.


I know many people modding these units just want them to stay locked up at any speed for drifting etc, but note that they still require the half shaft speed difference to lock up initially, so they are not really the same as a plate type LSD or locker in action at all.

Just wondering if anyone has info from experimenting or R+D on these units before I make my own first experimental cut on the big mass.

It is of course a major pain to have to keep removing and dismantling the unit to slice another little bit off every time if the disengagement speed is still too low, so any info on results from cutting off smaller amounts of the big mass would be very helpful.

I'm not sure if any of you guys will have bothered trying to remove only part of the disengagement mass for what you will want to use the cars for?

Turbeam said:

The big mass only effects the cut-off speed, and has no bearing on the engagement speed or even if the unit engages at all. If there is no speed differential between the half shafts the diff will not lock up at ANY speed.

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Watch the video again, when the large outer weight swings out the hooks that catch the flyweights (stopping the spinning of the countershaft, and engaging the ramp mechanism) are out of reach - above a certain speed the ENGAGEMENT is disabled.