Cusco Rear Diff. Jewelry

[Blaaaack-BRZ]

http://www.facebook.com/#!/media/set...8312172&type=1

[old greg]

[ESBjiujitsu]

me likey the cusco blue!!!!!

[70NYD]

I don't get it? What is it supposed to do?

[MattR]

Originally Posted by 70NYD

I don't get it? What is it supposed to do?

From what I can gather via a poor Google translation, it is supposed to help dissipate heat generated by the diff better (heatsink fins) and possibly hold more fluid.

From http://minkara.carview.co.jp/userid/...blog/26435400/

"Up Def cover capacity differential oil effective for sports driving, such as ① Circuit! 　500cc up the capacity of the oil 　　(from the Service Manual) 0.05 l 1.15 l ± genuine 　± 0.05 l 1.7 l capacity after installing the cover-up def → cooling capacity up by air-cooling fin"

[OrbitalEllipses]

Originally Posted by 70NYD

I don't get it? What is it supposed to do?

Bling.

[old greg]

Originally Posted by 70NYD

I don't get it? What is it supposed to do?

Something completely unnecessary.

Rear end ring and pinion gear sets are what are known as Hypoid gears, which involve quite a bit of sliding between the faces of the meshing teeth. This creates heat from friction which raises the temperature of the gear oil. The more power you're putting through the diff the more heat is created, and the hotter the oil gets the less it lubricates which leads to more heat, wear and premature failures. That's why you'll see differential oil coolers on high horsepower race cars. The fins on this diff cover increase the surface area which would mean improved cooling and by extension lower diff temps and less wear.

The thing is, though, the stock diff is totally overbuilt for the meager 200hp the car is making. Diff temp will not even remotely be an issue, even if you were racing at the 25 hours of Thunderhill. If you were to turbo your car and regularly take it to track it might be a worthwhile mod. Otherwise, it's just a shiny blue bauble.

[Ryephile]

Originally Posted by old greg

The thing is, though, the stock diff is totally overbuilt for the meager 200hp the car is making. Diff temp will not even remotely be an issue, even if you were racing at the 25 hours of Thunderhill. If you were to turbo your car and regularly take it to track it might be a worthwhile mod. Otherwise, it's just a shiny blue bauble.

The diff was designed for a heavier car with more power. Diff temps shouldn't even be on the radar yet, though good dataloggers will record it anyway to find out at which power and race duration level it'll be relevant to regulate the temp.

[70NYD]

Originally Posted by old greg

Something completely unnecessary.

Rear end ring and pinion gear sets are what are known as Hypoid gears, which involve quite a bit of sliding between the faces of the meshing teeth. This creates heat from friction which raises the temperature of the gear oil. The more power you're putting through the diff the more heat is created, and the hotter the oil gets the less it lubricates which leads to more heat, wear and premature failures. That's why you'll see differential oil coolers on high horsepower race cars. The fins on this diff cover increase the surface area which would mean improved cooling and by extension lower diff temps and less wear.

The thing is, though, the stock diff is totally overbuilt for the meager 200hp the car is making. Diff temp will not even remotely be an issue, even if you were racing at the 25 hours of Thunderhill. If you were to turbo your car and regularly take it to track it might be a worthwhile mod. Otherwise, it's just a shiny blue bauble.

Sorry I meant what the hell is the purpose of this? I get how diffs work, And am fairly familiar with tribology, what I don't get is how they can just manufacture something like this which obviously needs extensive testing to make properly. If anything, this can, on a daily application, overcool the lubricant leading to premature failures

[Ryephile]

^^This is why so many aftermarket products are "buyer beware". IME you should only be changing component specification for items that need improvement, otherwise you risk creating problems for yourself.

[djdnz]

You'll have more headaches with this than anything. This is similar to decorative valve covers, my friend installed some on his Mustang and they have been leaking slightly ever since. What a pain.

Pass on this.

[jkonquer]

i wonder how hard it is to torque down the top bolt.

[Godzilla35]

Originally Posted by Ryephile

^^This is why so many aftermarket products are "buyer beware". IME you should only be changing component specification for items that need improvement, otherwise you risk creating problems for yourself.

^^This is what is kind of scaring me about the FRS / BRZ / GT86 tuning parts done so far. A lot of it seems a bit... rushed? I really hope these big name companies are actually doing the R&D on a new car like this, especially with suspension geometry... and NOT just doing "what they normally do" or "what's worked in the past". I have friends in the engineering field, and a lot of them say that if it's true most of the time, this case is probably no different... but I just get the feeling this car isn't as "inexpensive" as it seems in the long run.

[SkullWorks]

how long do you think it takes to design a diff cover and produce it?

I make 1 off Oil pans and Trans Pans all the time, if you want cooling you simply add surface area, how much is usually limited by design not desire. you are not going to "over cool" diff fluid, it doesn't have to get pumped so the system pressure never comes into play.

is this a necessary product for the car on this date? um negative, I can only think of about 3 cars I have seen that need this and I'm fairly sure none are running the stock diff, however, as soon as someone wants to put this car on the track with R-Comps (as cusco has been doing for months) they are going to start seeing diff fluid come out of the overflow tube, especially with longer than 20-30 minute sessions.

If you happen to be running the Cusco Clutch type LSD, and are tracking your car this will become quite necessary

however...haters gonna hate, so continue on without thinking please

[ESBjiujitsu]

couldnt agree more godzilla35!

[SkullWorks]

oh yeah and as far as it leaking goes....give me a damn break, shitty stamped or crapily cast domestic valve covers and what is obviously a CNC machined (finished if nothing else) differential cover is just telling the whole world you have no idea how anything works and or you have no business installing parts on your own car.

[jkonquer]

Originally Posted by Godzilla35

^^This is what is kind of scaring me about the FRS / BRZ / GT86 tuning parts done so far. A lot of it seems a bit... rushed? I really hope these big name companies are actually doing the R&D on a new car like this, especially with suspension geometry... and NOT just doing "what they normally do" or "what's worked in the past". I have friends in the engineering field, and a lot of them say that if it's true most of the time, this case is probably no different... but I just get the feeling this car isn't as "inexpensive" as it seems in the long run.

That is why 90% aftermarket parts never improve the performance. Real r&d'ed parts come out 2 years down the road. And many companies dont do real life tests, they pretty much design the parts through numbers

As far as cusco, they are asethetic part company. Yeah make awesome lookibg strut bar, but nothing more.

[Brian S]

Its a differential cover for christ sakes, I understand tribiology quite well also but systems should also be looked at in cases such as these. What is a cover's purpose? Due to centripical force in the diff. the fluid in the enclosing gets forced outwards in various velocities which ultimately causes the fluid to change thermally due to making contact with the casing. You really think this has a dramatic effect in how effective and reliable the differential will perform. Hardly if not at all. If the purpose was to change the thermal properties due to heat you would cool it in different ways. This part is for show and thats it just like an aftermarket valve cover thats maybe powdercoated.

[fatoni]

Originally Posted by Brian S

Its a differential cover for christ sakes, I understand tribiology quite well also but systems should also be looked at in cases such as these. What is a cover's purpose? Due to centripical force in the diff. the fluid in the enclosing gets forced outwards in various velocities which ultimately causes the fluid to change thermally due to making contact with the casing. You really think this has a dramatic effect in how effective and reliable the differential will perform. Hardly if not at all. If the purpose was to change the thermal properties due to heat you would cool it in different ways. This part is for show and thats it just like an aftermarket valve cover thats maybe powdercoated.

I think you mean centrifugal force

[old greg]

Originally Posted by Brian S

...centripical force...

Originally Posted by fatoni

I think you mean centrifugal force

You're both wrong.

[fatoni]

Originally Posted by old greg

You're both wrong.

Im not saying thats where the heat is generated

[Turbowned]

Centripetal force, maybe? lol

This is clearly a race-only part. Anyone who buys this and doesn't track their car extensively is wasting money.

What I don't understand is why the fins don't extend lower than the bottom of the diff. How is air supposed to cool those fins?

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