Got around to doing some head flow testing this weekend. Shown below is a mildly ported LS1 head, an LS1, LS6, and LS2 Intake. The head was mounted to a 3.9" bore adapter, and all flows were performed at 28" of water:


LS1 head w/ 2.02 Intake Valve, Stock Exhaust Valve


3.9" Bore Adapter


Head w/out Manifold = A


Head w/ LS1 Intake = B


Head w/ LS6 Intake = C


Head w/ LS2 Intake = D

Results:
Flow (CFM)
Lift A B C D

.050 32 33 32 33
.100 67 67 67 67
.150 104 102 103 102
.200 141 136 139 138
.250 177 165 170 168
.300 201 188 195 192
.350 225 205 215 209
.400 245 219 231 225
.450 263 230 246 238
.500 274 235 252 244
.550 265 238 252 244
.600 265 238 252 242

Notice how the port stalls over .500" lift. This is due to the port design and short side radius not allowing the air to turn the corner. The air windows across the valve and the energy is translated into swirl.

The LS6 head offers a better short side radius and higher lift flow capability. Interesting to note that the LS6 Manifold outflows the LS2 intake at the upper end.

Hopefully I will be testing an AFR 205 Head with these manifolds soon.

Enjoy!

Paul

 

Thanks for the test results Paul. I guess my LS1 will get the LS6 intake manifold after all!

 

Yet another example of why I like this forum. Thanks for the hard work that went into gathering this data.

More bad results for the LS2 intake. Makes me wonder what went wrong with this intake. Perhaps it is designed specifically for the LS6 head.

 

Great thread, thanks for the info!

 

Great info. It will be interesting to see how the LS2 intake performs on the LS6 heads.

 

Great post, thanks. The LS6 heads will be interesting too.

 

Thanks. Did you seal off the other ports on the intake? Why no radius on the intake opening? Try porting the LS2..... Plenty of power to be found.

 

All ports remained open on all intakes. I was looking at the LS2 intake ports and noticed that they seemed narrow with some parting line flash and steps. This intake is made differently than the LS1,and LS6 Intake. My next step is to widen and smooth the LS2 intake ports then re-test.

Paul

 

Ed

 

Using the data above...

 

Thanks for the info! Thats a great hobbie you have there,if it is a hobbie. Where do you get your expertise?

 

For some additional information, here are a couple of tests we performed a while back

LS6 vs LS2 vs FAST on a 5.7L engine

and

LS2 vs LS6 on a 6.0L engine

 

This is just a hobby that I have been playing around with for the last 30 years. Started out with Lawnmowers, building my own overhead valve head, grinding my own cams, etc, then progressed to cars in the late 70's/early 80's. I bought the flowbench about 5 years ago to learn more about airflow. It has been an eye opener to say the least!

I also restore old Musclecars and currently have an original 69 Camaro SS L-78 and 1970 Z-28 LT-1. Between these hobbies, I stay pretty busy.


L-78 w/Original Paint


70 Z-28

Paul

 

Paul

The LS6 head was knows to flow better then the LS2 head. Thanks for reconferming this.

Any plans to test the AFR 225 and LS7 heads too?

 

The LS6 and LS2 heads are identical other than the fact the ls6 iues lighter valves. Both are 243 castings.

 

If any forum members would like to donate an AFR 205 or 225 head for testing, I would be glad to do a comparison with the above test using the same manifold combination. For a valid test, I would prefer to use the 3.9" bore adapter to keep all tests on an even level. Is the AFR 225 compatible with a stock bore LS1/LS6?

Paul