Thread: Who would be interested in a Quaife differential

I think a market exists, possibly in the tens to few hundreds over time (with proper marketing, etc.). Combine that with a fresh chain option, again, and builds wouldn't surpass the trans capacity as easily.

I literally bought my Regal from the guy I built it for, because I wanted to have the transmission build, including GM Racing Torsen, 1" chain set, and Raybestos Blue Plates... all of which are now unicorns in the 4T65e market.

Yeah there appears to be some interest in this according to Facebook. A chain would be great, but isn't really possible for this price. If we could find something stronger than the gxp chains for cheap that's already manufactured, that would be perfect.

Even a vendor buying up a few spare 4t60 sprockets to machine for decent 7/8" options is better than nothing. Things will wind up just getting rarer, and maybe it'll be fun to hear about the occasional JY find of upgrades.

I'd rather pursue dual chains. That appears to be quite a bit stronger than the 7/8 chain. Especially with the absence of a stator support on the sprocket end.

I think the market has gotten too soft to support much more than what you see ZZP putting effort into (slight IC re-design, etc.). It sux to deal with as our chosen platform to tinker with, but for the sake of not spending the money to transition to a more-supported platform, it is what it is.

Yeah you're right. It's tough to spend a couple thousand on it when new mustangs and Camaros are running 10's with a few mods.

Originally Posted by GTPpower

Yeah you're right. It's tough to spend a couple thousand on it when new mustangs and Camaros are running 10's with a few mods.

I wouldn't say that, so much, since the couple thousand spent on a 3800 car, coupled with the price of the car, is about 25% of the cost of those vehicles, let alone the thousands more spent on upgrades to mod them into 10's. Markets are going to last for certain platforms based on mass appeal, and that unfortunately dictates where offerings will develop and last. Hondas somehow break the mold, on the backs of a few dozen extreme builds, while we didn't get the word out about the 8-9sec ZZP/Intense shop cars enough to sustain market share beyond the recession as production ended.

I was just looking for differential options the other day. I found 2 readily available, and they appear to be variations on the same concept, being the Phantom grip, and that Engineered Performance, and while I don't have experience with either, the reviews I've read don't instill confidence...
I acknowledge that I am about 10 years too late on looking for this stuff, but as plentiful as 3800 variants are, you'd think there would still be options. I'd pay a grand for an essentially bolt- in torque biasing diff, as long as it was quality. Easier to stomach than the going price for a GMP chain set, if the prices I've seen are accurate.

EP was a better clutch design than the Intense LSD, from what I heard, but still not a great solution. Never heard of Phantom.

The engines are plentiful, but the small modding market is one where most buyers are on a tighter budget than what can support robust mods for 400+whp builds. You see plenty of near-stock bolt-on guys, and 300-350whp setups still buying up things sporadically, that they don't actually need... That, however, didn't support the manufacturing of more trans upgrades or engine items beyond they heyday of the 3800's. People get frustrated if there's not a simpler path to "parking lot pimpin" their car, because regardless of performance, if the car doesn't also draw looks and sound great, it doesn't meet the need of majority of the "car crowd." (Enter the 14-15sec Mustang GT market doninance of the past 40yrs, riding the coat-tails of the few who put in the time/money to make some absolute monsters that built a brand name.)

I ran an EP limited slip diff for years in my 350ish hp car with great results.

I'm not doubting anyone has, or even folks didn't grenade an Intense, or the thousands who didn't have trouble with a stock diff. My stock diff lasted in a 333whp GenV setup for years, then got more fun with an I/C'd MP112 pushing it even harder for a few more years at street racing and commuting, before rust did that car in. Still sits as a viable 175k spare in my garage.

The question is for a gear-based setup that is factory hard-built to specifically address the issue, and why the market may or may not support the effort to build & sell more. People mod slower cars for much more money. It's a fickle thing, and vendors constantly chase the demands.

I do think the EP's are decent. Definitely the best out there. But it's still just a limited slip, which doesn't seem like much of an upgrade over our stock diff. He also doesn't warranty them either, which is too bad.

Originally Posted by BrandonHall10

Not to derail the original intent of this thread, but I'm genuinely curious...

Isn't the 4T80e a viable alternative to a 4T65e filled with unicorn parts? Granted it isn't a direct swap, but cheaper in the long run, no?

Cheaper, yes. But unproven. And it's a swap that most people don't have the skill to complete.

It's been done a few times, and not rocket surgery. Turbo400sbc did one, I believe, among his many creations.

The issue would be hitting the limit of that trans, but having no upgrades as compared to what places built for the 65.

Originally Posted by GTPpower

He also doesn't warranty them either, which is too bad.

This. It doesn't promote confidence. That is the main thing that rings in my head about the EP LSD's

Originally Posted by ThatOldCarSmell

This. It doesn't promote confidence. That is the main thing that rings in my head about the EP LSD's

I don't understand that either. How do you sell something and not stand behind it? Quaife warranties theirs for life.

Hello GTPpower, I just joined the forum when I found your Quaife post. I’m definetly interested in buying one. I have a good HP Riviera. Built engine, trans myself. Former GM tech. LMK