Car modification kit--exhaust flange

What are Exhaust Flanges?

An Exhaust Flange consists of a pair of metal sections that join your exhaust pipe together. They are used with an exhaust gasket and a set of bolts. The most common options for exhaust flanges are the 2-bolt or 3-bolt type but 4-bolt are also available. Generally, you would use an m10 bolt with the 2-bolt option and an m8 bolt for the 3-bolt. The grade of bolts we recommend is 8.8 tensile or higher so they can be tightened without breaking or stretching the bolts. We also use spring washers, Loctite, or a locking nut to help prevent the nuts from vibrating loose.

How do Exhaust Flanges work?

Exhaust flanges work by using a gasket and a set of bolts to join them together. When setting up an exhaust or waste gate pipe for ease of fitment it is recommended that you use exhaust flanges or v bands to enable sections to be pulled off and re-fitted for access.

You can use exhaust flanges without gaskets, you will need to use an automotive-grade silicon

The gasket in the picture has a copper ring pressed on the inside to help prevent the gasket from blowing out from the heat of the exhaust.

Welding Exhaust Flanges

Welding exhaust flanges is much the same as welding v-band flanges.

The main factors to start with are tack welds every 20-30mm, to help prevent distortion stitch weld the flange and let the flange cool down between welding (if time is an issue then try bolting the flange to a heat sink to pull away the heat from the flange when welding).

Exhaust Flange vs V band Flange

Both of these options serve the same purpose, to connect exhaust or waste gate tubes. They both have different effects on your installation.

We have listed these below:

Exhaust Flange

PROS:

The bolts to join the flanges together are easily replaceable if threads strip from over-tightening

These are more forgiving with distortion when welding (will still bolt up and seal if slightly distorted)

CONS:

The gaskets can be affected by heat and blow out over time, these can also blow out if your flange is heavily distorted

V band Flange

PROS:

V bands do not require gaskets so there is one less thing to fail

CONS:

When your exhaust and wastegate setup are all made up of v bands then there is no set alignment, this can cause issues when bolting things together if they are not sitting in the correct orientation

The v-band clamp thread can strip easily because of the small thread size, when tightened or bolting/unbolting when hot these can bind and seize. Another main reason for the thread and nut to take is if they are both stainless steel