Woot got some numbers for my Datsun (head flow)

[280Z28]

The heads are GM L92 heads with 2.16" intake and 1.59" exhaust valves. These are baseline numbers. Numbers after some work still to come. :wall: Test was done on a SuperFlow SF600 FlowBench using the same bore I'll be running in the car (4.125).

 

Lift  Int Exh
0.100  72  55
0.200 155 115
0.300 221 115
0.350 246 122
0.400 266 124
0.450 284 125
0.500 298 126
0.550 310 127
0.600 321 128

[dr_hunt]

The heads are GM L92 heads with 2.16" intake and 1.59" exhaust valves. These are baseline numbers. Numbers after some work still to come. :wall: Test was done on a SuperFlow SF600 FlowBench using the same bore I'll be running in the car (4.125).

 

Lift  Int Exh
0.100  72  55
0.200 155 115
0.300 221 115
0.350 246 122
0.400 266 124
0.450 284 125
0.500 298 126
0.550 310 127
0.300 321 128

 

 

I assume the last row there is supposed to read .600 not .300.

 

I hope there is some more work to be done cause while the intake flows great the exhaust flows really are horrible.

[280Z28]

Doh lol. I hear the exhaust flow balances out with a wide duration split cam (like 15 degrees). Allows you to run a smaller intake duration which keeps the motor from getting too "grumpy." :dunno:

 

The exhaust will improve a bit but those valves are such different sizes...

[280Z28]

I just looked at the graph (had a pic on the cell phone) and it's obvious I wrote down the wrong numbers for the exhaust. I'll get the right ones asap, sorry.

[dr_hunt]

From what I've seen, box stock they flow like this, from LS1 Tech.com;

Intake:

.100 67

.200 150

.300 222

.400 295

.500 341

.600 368

.700 367

 

Exhaust:

.100 43

.200 111

.300 168

.400 207

.500 222

.600 227

.700 231

 

You sure you got the numbers right?

[280Z28]

From what I've seen, box stock they flow like this, from LS1 Tech.com;

Intake:

.100 67

.200 150

.300 222

.400 295

.500 341

.600 368

.700 367

 

Exhaust:

.100 43

.200 111

.300 168

.400 207

.500 222

.600 227

.700 231

 

You sure you got the numbers right?

 

Those look like LS7 numbers, these are L92.

[dr_hunt]

which part #, there are several, some of which are cnc ported from GM. I thought the l92 head and the ls7 head were the same, minus the porting.

 

Even still box stock exhaust flows are alot higher than what you posted according to ls1.com. I see you got called on the same thing on LS1.com....

[Michael]

I know nothing about LSx engines, but (1) it is very, very strange that the exhaust port flow is essentially constant beyond 0.300" lift - could there be some sort of obstruction? And (2) 368 cfm intake at 0.600" lift is on par with top-of-the-line aftermarket big block heads with 2.25" or larger valves; getting that out of the box - in a small block head - is quite phenomenal!

[280Z28]

Goodness did y'all miss post 4?

[dr_hunt]

I know nothing about LSx engines, but (1) it is very, very strange that the exhaust port flow is essentially constant beyond 0.300" lift - could there be some sort of obstruction? And (2) 368 cfm intake at 0.600" lift is on par with top-of-the-line aftermarket big block heads with 2.25" or larger valves; getting that out of the box - in a small block head - is quite phenomenal!

 

 

Yeah, but they have 11 degree valve angle, raised ports, so some sbc heads similar in construction flow very nicely too!