hey does anyone know what the proper size bolt is for the stud replacement on the down pipe. i tried a M10x1.50X25 and it didnt seem to fit properly thanks
jeff

 

Here's the Part Numbers (Qty.of 5 for everything - I wanted an extra set just in case):

P/N: 4519 - Metric Washers, Flat, Stainless A-2 (18-8), 10mm - Total: $0.60
P/N: 4816 - Metric Washers, Lock, Stainless A-2 (18-8), 10mm - Total: $0.60
P/N: 6465 - Metric Socket Head Cap Screw - Stainless A-2 (18-8), 10mm x 1.5, 25mm (length) - Total: $5.00

Total Cost Including Shipping (UPS Second Day Air) was $20.13

Ordered right off their website at www.boltdepot.com

Posted a few years back
From: 93silverbullet
Here: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/downpipe-nut-201768/

 

It's M10x1.5

But I'll warn you I've tried bolts from boltdepot, mc-master-carr, etc and they all rust in a hurry and don't fit very well. Even stainless, which might last better than carbon steel but it's a lot weaker. The OEM hardware is expensive but they fit better and last far better than anything else. The OEM studs&nuts are inconel or monel or something exotic, which is something you can't get from a bolt distributor.

Dave

 

For peace of mind i would replace only with Mazda hardware. Part#'s are:

JE10-40-355B nut $5.94 a piece (you need 4)
NF01-13-708A stud $9.36 a piece (you need 4)

N3B7-13-491A downpipe to turbo gasket i payed like $55.00 for mine

All these parts you can get from Ray Crowe 1(888) 533-3400 and they ship for free.

From: 2-Rotor

 

Ray charges $5 for shipping now.

 

Go with OEM Mazda bolts. The Mazda one's I believe are locking bolts and hold better. If you go with the others your liable to blow a gasket (as I did) and you'll be stuck with a lawnmower as a lesson learned.