AMSOIL now offers Series 500 High-Performance DOT 3 and Series 600 DOT 4 Racing Brake Fluid. I recently sold some to a couple members of the local 350z club, but since this is a new product I don't have any feedback on it. I have edited my post in the Group Deals section providing additional information and pricing.

 

I think I am going to try it when I put in a proportioning valve on my truck. Got the flyer in the mail but didn't see anything about compatibility. Do you know if the system needs to be purged to run the DOT 4 fluid when changing over from stock? The specs are pretty close on the 3 and 4 but the price looks like a much better deal on the DOT 3.

 

They are compatible and will work fine.

 

I've sent a note to AMSOIL tech services to verify and should have a response within the next day or so. As 00SEMAX19 points out, you should not have a compatibility issue; but in order to get the most benefit from the DOT-4 (should you go that route) it would be best to replace all the fluid in your brake system with the new product. You essentially do that anyway when you bleed your brakes. I'll get back with you soon with confirmation.