Flow Performance
High performance, low cost air flow metering products
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Flow Performance FA (Flow Adapter) series Cylinder Bore Adapter plates facilitate the mounting of cylinder heads to the Flow Performance FR4 flow receptacle. The FA series adaptors allow precise location of cylinder heads for realistic and repeatable flow testing time after time.
Cylinder Bore Adapters
for internal combustion engine cylinder heads
We can make just about any size up to 4.385" (111mm).
Contact us for your size.
The FA series Cylinder Bore Adaptor plates fit into the FR4 flow receptacle to locate cylinder heads onto the FR4
Flow Performance cylinder adapters provide an easy means of clamping adapter and test piece into place on an open style bench surface.
The original head bolts are usually too small in diameter to be effective at locating the head on the adapter, so you may need to use the shank of a larger diameter bolt for a dowel pin. You want to use soft bolts, not grade 8. Another good source for dowel pin material are the shanks of cheap drill bits. Soft bolts and cheap drill bits are usually easy to cut with a hack saw fitted with a fine tooth blade.
While most cylinder heads are located on the engine block with 2 or more dowl pins, the size and location of the original dowel pins are not always convenient for a flow bench adapter. Using the head bolt holes are the next best solution for locating a head onto a cylinder adapter.
Flow Bench Adapters
for other test items
Other items can also be tested on Flow Performance flow bench kits, like carburetors, manifolds, mufflers. Flow Performance only supplies cylinder bore adapters for our flow bench kits. While our cylinder bore adapters can be used to fabricate special adapters, the customer will need to perform the design and fabrication of special adapters. Following are some general guide lines for designing and building flow bench adapters.
Cylinder bore adapters simulate the cylinder of an internal combustion engine. They help locate a cylinder head on a flow bench, and form the boundaries that the intake and exhaust ports of the cylinder head will experience.
The Flow Performance FR4 flow bench receptacle is designed for testing internal combustion cylinder heads using our cylinder head adapters.
Related links...
                     Click here for Cylinder Bore Adapter pricing...
                     Click here for your vehical bore sizes
The Flow Performance bench receptacle (FR4) has a 4.51" diameter opening. Using a locating collar or studs on the adapter plate provides a precise method of locating the adapter onto the receptacle.
An example of an adapter plate for a test item that has a flange. Lag studs (studs that are half lag bolt, half machine thread) can be used in soft plate material like melamine.
Example adapter for test items that have a pipe slip coupling, like mufflers and exhaust pipes.
Notes on designing, building and flow testing a special adapter:

Always flow your test piece using vacuum if possible (even cylinder head exhaust ports if practical). There are many advantages to pulling ambient room air through the test piece into the flow bench, as opposed to pushing air from the flow bench through the test piece into the atmosphere. With the prior, only the test piece and adapter are components of the test. With the latter, the whole flow bench including air source, along with adapter and test piece, become components of the test. That is  a lot of variables. Also consider that not all flow benches can produce positive pressure, and many that can have limited capacity when producing positive pressure.

Using a short section of tubing on your adapters that will be used by the application of vacuum pressure will help standardize your adapters for use on other flow benches in two ways. One is that it will reduce the effects of vena contracta on your test piece, providing maximum flow.  The other reason is that it will help reduce the effects of using different thickness adapter plates. Your test piece will give similar flow rates on a 1/8" thick plate as well as a 1" thick plate when a short section of tubing is used.

Flow Performance is not aware of any hard and fast rules regaring the design of flow bench adapters. In some cases, an adapter design that you may be fabricating may become the default standard for that test piece. So always design your adapter so that it can be easily reproduced by others, and document it in detail.

When designing an adapter, consider what your goal. Is it to see the maximum flow that can be realized by the test piece, or what the realistic flow can be when the test piece is installed in it's working environment. These goals should be considered when designing your adapter.

Always record the current atmospheric conditions, including humidity, especialy for items that have porous or fibrous materials like air filters and mufflers. With these parameters recorded, your flow rates can be converted to mass flow if desired.

Dowel pins can be drilled by clamping the adapter to the cylinder head, using the cylinder head bolt holes as a drill guide.
Adapter gasket material

1/16" sheet rubber can be used as a gasket material for your adapter. It can be glued in place using contact cement or E6000 glue. 1/16" sheet rubber can be found at some home center plumbing departments as gasket material or packing material.
Flow bench adapters are part of your test piece. They are not part of the flow bench. They are a component of the test and should be documented in detail.
Available from Flow Performance    up to 4.385" (111mm)
Not available from Flow Performance