I think the title sums it up nicely. Strength comparisons set aside how would they do in autocross? I'm assuming the G80 is a locker that only works at lower speeds and that the 8.8 is more of a true LSD. Is that assumption valid?
I think the title sums it up nicely. Strength comparisons set aside how would they do in autocross? I'm assuming the G80 is a locker that only works at lower speeds and that the 8.8 is more of a true LSD. Is that assumption valid?
I’d think the more variable amount of lock from a true LSD would be more manageable than the binary “on-off” of a locker.
I liked the 8.8 locker in the challenge car. Ive never had a g80 that actually worked to compare it to though.
Stuff an 8.8 under it.
Stampie said:I think the title sums it up nicely. Strength comparisons set aside how would they do in autocross? I'm assuming the G80 is a locker that only works at lower speeds and that the 8.8 is more of a true LSD. Is that assumption valid?
A locker works at all speeds and is more of a ratchet that allows one wheel to overrun the other than it is a differential. It doesn't matter how fast you are going.
I like to think of it as a spool that won't break axles.
I think you are confusing the "Gov-Lock" differential with a "locker". The Gov-Lock has some weird flyweight thing in it (the governor in the name) to make limited-slip action only happen at lower speeds because having both wheels break loose at highway speed in a pickup truck is generally a good way to find yourself in a ditch.
I really REALLY like Detroit TrueTrac in my dailys. (Torsen, Helical style)
I have one in my '77 C10, and one in my V8 Pontiac Firefly (Chevy Sprint). REALLY like them.
My understanding is that GM uses the code G80 as a generic RPO for locking or limited slip diff. Different vehicles get different units for different reasons. Trucks use a gov lock unit. This is the low speed crawl-out-of-a-mud-hole type. It won't engage at highway speeds and really isn't meant for performance driving. Camaro, V-Series Caddies, etc use clutch, torsen or active diffs suited for the track.
Please correct me if I'm wrong.
In reply to Gearheadotaku :
Thanks. I was wondering in the back of my mind if there wasn't some new rearend that Dana or whoever supplier was making, called the D80.
Also, the Gov-Lock as installed in pickup 10-bolts (8.2"? 8.5"? Whatever the pickups got) is kind of fragile. Any time I pull the cover off of one that has the Gov-Lock, there seems to be a 50/50 chance of the differential case being cracked at the diff pin. Sometimes there is even a chunk broken out. I have heard that some people modify these units to make them full time limited slips, but after seeing all those broken cases in non performance applications, I wouldn't bother.
In reply to Gearheadotaku :
That's correct from what the internet says. I guess I should have stated the G80 would come from an S10 for the gearing I want.
I got a nice surprise when we pulled the cover of the differential in my 88 Silverado. Tag in the glove box designation was for an open differential, but it had a clutch type limited slip.
I've no idea what brand, or how it ended up being there.
In reply to Floating Doc :
Have I told you lately how much I love your truck 
Don’t forget, on the ford 8.8, whether you leave the steel spring in dictates the lsd action off throttle. Drag guys take it out, most autox mustang guys leave it in.
In reply to Trackmouse :
Well that now creates a major internal dilemma for me. After the discussion today I'm thinking 8.8 unless I change my mind as I'm app to do.
I'd recommend the 8.8 just because personal experience on the street and drag strip has proven there durability. I've seen the gov lock rear ends grenade under stock trucks. If you rebuild the 8.8 using modern clutch packs and run 75-140 you can build the clutch packs to Ford extreme duty specs of you want a stronger lock with less slip. Mine did drag the inside tire for a while during break in using this method though.
I think the GM Gov locks fail due to abuse/mis-use. They must be cheaper than the clutch/torsen types most of us would rather have.
When you lose traction with a gov lock, you're supposed to ease off the throttle, let the diff lock up then roll back into it. Most folks just floor it with said results....
If I remember my 9C1 facts right, the G80 in the last b-body's 8.5 rear end were Auburn style cone limited slips. They were like MoPar's Sure Grip lsd. The problem is that they wear, and the cones eat into the case, and they are non-rebuildable.
I ended up with an Eaton clutch LSD. They are tunable by flipping the clutch plates. From super tight to barely there.
G80 is just generic GM jargon for a non-open diff. In the half ton trucks it is a Gov-lock, whose reputation has already been covered. They are great for gravel or pulling the boat up a wet ramp. They don't like launching hard. They are binary lockers though; all on or all off.
G80 in a Caprice or other Bbody, Camaro, or pretty much any GM RWD car is an Auburn cone style LSD. They were not actually made by Auburn, but the design is similar. As mentioned, they wear out over time and cannot be rebuilt, which makes finding a good junkyard one challenging. But the 10 bolt is stronger than people think and it's easy to test if it's good by spinning the wheels with the car in the air. You can "shim" the cone springs to get more life and grip, but only so much.
The 8.8 is a true clutch type LSD, can be rebuilt, and has other features depending on your goals like was mentioned earlier. The 8.8 is strong, but I doubt it's much stronger than a GM 10 bolt. I have read that the 8.8 is lighter but have never seen the data. Plenty of gear choices and aftermarket parts availabe for both. However the 8.8 was also available in IRS form, some of which had an aluminum center section in the Mark VIII I think.
In reply to maschinenbau :
Depends on which 10-bolt. The 8.8 is a hell of a lot stronger than the 7.5/7.625 10-bolt, and a fair bit stronger than the 8.5" ten bolt, although you'd have to work to do damage to one of those. I'd gauge that it is as strong as the 12-bolt.
The nice thing about the 8.8 is that it's recently common, and Ford flooded the market with 31-spline versions with thickwall axle tubes. Find a SOHC or V8 Explorer and have at it. A lot of them were 3.73 and some were 4.10.
KyAllroad (Jeremy) said:I’d think the more variable amount of lock from a true LSD would be more manageable than the binary “on-off” of a locker.
You would think so. But the in/off lunchbox locker in my 12-bolt is fun as hell. See my truck thread for vid. We were running identical times to a 5.0 fox today.
In reply to Knurled. :
Good point about the 10 bolts, I forgot about the 7.5s. I've only owned 8.5s and it was never the weakest link.
The other boon to the 8.8 is it is soooooo cheap to rebuild. A ford performance lsd clutch set is 50-75 bones. https://www.americanmuscle.com/ford-88-traclok-kit-cust-install.html
installs in four hours.
In reply to Bob the REAL oil guy. :
Kyallroad - what type of lunchbox locker do you have?
I've had 2 GM factory lockers, 1 in an Impala and 1 in a ZR2 GMC Sonoma. Both were awesome. The Impala dominated in the snow with it. The ZR2 also and off road in mud/sand/gravel etc.
I didn't have the ZR2 but 3 years and 50K (leased) but the Impala I bought with about 140K on it, sold it at 200K, and 10 years later and close to 300K and 2 more owners it was still running with a beaten drivetrain.
The G80 used in Chev trucks is a limited slip diff with governor but the governor can be easily disabled. They don't have a great reputation but I don't think it's deserved. There are millions of them on the road, it's inevitable that there will be some failures.
As far as autocross goes, I would think the smoothness of the operation would be more critical than brute strength. Where strength would come in is hard launches, shock loading/unloading etc. I have an 8.8 with the factory TracLock - and I finally fried the clutches after 7 years of autocrossing. $104 for the carbon fiber clutch rebuild kit, and I'm back on track. I also have a friend who burnt his up in about a year of autocross/open track events - about the same power level (400 rwhp ish), but he was running wider/stickier tires. I have a buddy with a ratcheting locker rear end in a Ford 9", and it has a tendency to lock up at low power levels - good if you want to rotate the car, but not so much for longer sweepers. I think the housing is less important than the selection of the differential type itself.
I have an 8.8 IRS with an Eaton Trutrac in my RX7. I highly recommend it.
also 5.14:1 gears.
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