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We are always looking for factual data to help us determine the weak points in any motor and a flow bench is a great tool to help us figure out where their might be a flow restriction. We did extensive research into this for the MZR platform and we are just starting to get into it for the EB.
For comparison purposes here are the flow numbers of the stock IM on the MZR platform (all numbers in CFM):
Stock OEM MZR Intake Manifold:
Runner 1) 199
Runner 2) 235
Runner 3) 233
Runner 4) 192
214.75 average CFM
859 total CFM
~20% flow imbalance
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Gasket Match Porting of Stock MZR Intake Manifold:
Runner 1) 212
Runner 2) 239
Runner 3) 233
Runner 4) 207
222.75 average CFM
891 total CFM
~14% flow imbalance
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JM Fabrications Sheet Metal Intake Manifold:
Runner 1) 379
Runner 2) 356
Runner 3) 350
Runner 4) 379
366 average CFM
1464 total CFM
~7% flow imbalance
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As you can see theres a pretty large difference between the stock OEM and the upgraded JMF sheet metal one. The JMF manifold far out flows the stock head which saturates around 225CFM. The ported stock manifold is a decent upgrade but the real difference is in the improvement in flow imbalance between runners. The OEM manifold has a 20% flow imbalance from the factory (mostly due to the huge bulge in runner #1 for the VTCS flapper rod) which can be improved slightly with the gasket match porting to 14%. The JMF manifold deletes the single runner between the ports and evens out the flow to roughly 7%. Remember that all this testing is done at 28inWC and boost will have a large impact on cylinder filling but as long as we compare all the manifolds at this same 28inWC then it should give us some useful results.
So we started our testing with the OEM EB intake manifold. Because it has single ports instead of the divided ports like on the head, we expected it to flow more because it was very similar to what the JMF intake manifold does by deleting the divider between ports. Here are the numbers that we found:
Stock OEM EB Intake Manifold:
Runner 1) 331
Runner 2) 336
Runner 3) 329
Runner 4) 337
333 average CFM
1333 total CFM
~2% flow imbalance
![Auto part Vehicle]()
The numbers are truly astonishing. This manifold should be good for 700WHP worth of flow easy as long as it doesn't fail due to too much boost pressure. The extremely low flow imbalance is most likely due to the throttle body being located in the middle of the plenum vs the 90 deg bend it has to make with the MZR. We are really excited by this because it gives us a great head start to making clean, efficient power. There are probably some benefits to increasing plenum size and changing runner length but for the average owner this manifold should suffice.
We plan to make many more posts like this as we do our testing to keep you guys informed. We are in the process of getting the head flow benched and having some comparative numbers after porting/valve upgrades/cams to show you guys what kinds of gains can be had. Our initial impressions and data show us that there is a lot of room for improvement!
For comparison purposes here are the flow numbers of the stock IM on the MZR platform (all numbers in CFM):
Stock OEM MZR Intake Manifold:
Runner 1) 199
Runner 2) 235
Runner 3) 233
Runner 4) 192
214.75 average CFM
859 total CFM
~20% flow imbalance
Gasket Match Porting of Stock MZR Intake Manifold:
Runner 1) 212
Runner 2) 239
Runner 3) 233
Runner 4) 207
222.75 average CFM
891 total CFM
~14% flow imbalance
JM Fabrications Sheet Metal Intake Manifold:
Runner 1) 379
Runner 2) 356
Runner 3) 350
Runner 4) 379
366 average CFM
1464 total CFM
~7% flow imbalance
As you can see theres a pretty large difference between the stock OEM and the upgraded JMF sheet metal one. The JMF manifold far out flows the stock head which saturates around 225CFM. The ported stock manifold is a decent upgrade but the real difference is in the improvement in flow imbalance between runners. The OEM manifold has a 20% flow imbalance from the factory (mostly due to the huge bulge in runner #1 for the VTCS flapper rod) which can be improved slightly with the gasket match porting to 14%. The JMF manifold deletes the single runner between the ports and evens out the flow to roughly 7%. Remember that all this testing is done at 28inWC and boost will have a large impact on cylinder filling but as long as we compare all the manifolds at this same 28inWC then it should give us some useful results.
So we started our testing with the OEM EB intake manifold. Because it has single ports instead of the divided ports like on the head, we expected it to flow more because it was very similar to what the JMF intake manifold does by deleting the divider between ports. Here are the numbers that we found:
Stock OEM EB Intake Manifold:
Runner 1) 331
Runner 2) 336
Runner 3) 329
Runner 4) 337
333 average CFM
1333 total CFM
~2% flow imbalance
The numbers are truly astonishing. This manifold should be good for 700WHP worth of flow easy as long as it doesn't fail due to too much boost pressure. The extremely low flow imbalance is most likely due to the throttle body being located in the middle of the plenum vs the 90 deg bend it has to make with the MZR. We are really excited by this because it gives us a great head start to making clean, efficient power. There are probably some benefits to increasing plenum size and changing runner length but for the average owner this manifold should suffice.
We plan to make many more posts like this as we do our testing to keep you guys informed. We are in the process of getting the head flow benched and having some comparative numbers after porting/valve upgrades/cams to show you guys what kinds of gains can be had. Our initial impressions and data show us that there is a lot of room for improvement!
