Increase the lockup of your 320is LSD!

[Guest Anonymous]

This is a great tip I got from Carl Nelson at CNPR:

Fill the differential with synthetic (e.g. Redline MTL), I used Castrol Synthetic gear oil. Then add about 1/2 bottle of Ford "Additive Fricton Modifier", Ford Part # C8AZ-19BS46-A.

I measured the torque to break a wheel loose at 44 lb-ft!!! With 100 lb-ft as a rough measure of the original torque, this has moved the 25% lockup to ~44%. Yahoo!!! Perfect for a street machine.

I'd encourage more of you out there to try this. The additive is cheap ~$5.00.

Cheers!!

John N.

[Guest Anonymous]

We'll put this in the FAQ section!!!

[Guest Anonymous]

Can I get it at the local Kragen or do I need to go to a Ford dealership?

-Hamish

[Guest Anonymous]

oil I put in tranny's or diff's. I just fill them till it backs out the fill hole.

Cheers!

John N.

[Guest Anonymous]

Hey, great idea!! I use 320 LSD's in my 2002's up here in snow country (Anchorage, in the hills) but this will be even better. I normally save the '02's by driving an '82(wife's) and '83 320iS, already with LSD. Any long term problems anyone predicts with this additive?

Eric.

[Guest Anonymous]

Oh then the grin factor would be huge!!

[Guest Anonymous]

I hope you stick around on this forum.

Just out of curiosity, where did you learn what you know? Did you go to a particular tech. school or college? Maybe it's not to late for me to reinvent myself!

Gil

72 Tii

[Guest Anonymous]

(sold 3 of them) and none of the measured breakaway torque was over about 18 ftlbs. I guess that might be attributable to wear? I think the figure should be 25 ftlbs. to according to definition, but I've never seen published spec's anywhere.

I've also got a 3.64 ratio E21 LSD which is supposed to be 40% slip, but measures somewhere around 16 ftlbs. as I recall. I guess it needs an overhaul (or that magic fluid).

Gil

72 Tii

[Guest Anonymous]

John N.,

I'm glad to hear your diff is working well, but it seems like folks are going to get the impression that the friction modifier helped increase the LOCK UP.

That's not how it works. The friction modifier actually increases the SLIP! Friction modifier for LS diffs is available in 4 oz bottles from GM, Ford, Red Line, etc., but it all works the same way, it lets clutches slip to prevent chatter.

Most lubes made for LS already have the additive in the formula. If you have chatter, you can add extra friction modifier.

The normal amount of friction modifier already included most Red Line gear lubes is 4% by volume (any Red Line gear lube that says it's suitable for LS diffs.) Other manufacturers are similar.

If you have 4% in the fluid already, and have no chatter complaint, adding more will cause INCREASED slippage.

The trick to using friction modifier is to get a gear lube that contains NONE, and add a very small amount at a time until the chatter goes away. Red Line 75W90NS contains no friction modifier (NS), and is a good choice for fine tuning the friction modifier percentage. Remember that 4% of a one quart bottle is only 1.28 oz, so be careful throwing in too much!

// John

[Guest Anonymous]

No idea. This was a block stock 320is differential out of a car with >170K miles. Thank goodness it doesn't make any nasty whining or rumbling noises. Based on all literature I've ever seen, I would expect the break-torque to be ~25 lb-ft.

I took my measurements with one wheel jacked up, the e-brake off, the car out of gear by putting my clicker torque wrench on the nut on the stub-axle and seeing where it would start turning. The results I got were very repeatable.

Sure would be interesting if someone else verified this, but I'm happy with what I have.

Cheers!

John N