L35 Flow Numbers

[GAShan]

I just got back my heads. Mild porting and cleanup of bowls, 2.02/1.60's.
Lift Int Exh %Exh/Int
.100 64.5 54.1 83.8
.200 121.7 101.8 83.7
.300 164.2 138.7 84.5
.400 196.7 165.7 84.2
.500 217.3 180.6 83.1
.600 218.0 185.1 84.9
.700 219.0 188.4 86.1
velocities are much improved, we were looking for that more than ultimate flow numbers

 

[Christian Dionne]

That's kinda neat that they don't stall above .500" lift, gotta love those wiz kids!

Now all you need is a short duration .700" lift cam

 

[Buster]

Any idea what they flowed before the work?

 

[GAShan]

I'm going to stay with the stock cam for ease of tuning and use Crane Gold 1.6 roller rockers to get a little more flow. No idea what they flowed stock, but I think if you do a search on the bb you can find some stock numbers.

 

[the Sandman]

I have some stock intake flow numbers on my L35's (before porting/polishing):

LIFT/CFM
.050/30.1
.100/60.2
.150/81.3
.200/100.5
.250/122.5
.300/142.7
.350/158.6
.400/171.6
.450/181.6
.500/189.0
.550/194.1
.600/194.1
.650/198.7
.700/201.1

 

[V6 Kompressor]

As you can see with the numbers.... Flow does not increase much at all above .500 lift. But just remember, these flow numbers, as with most flow benches... the figures are derived from lifts and flows under a vacuum condition and not BOOST. I am working on a bench that can measure flow under boost conditions, but the blower unit that was donated is trashed and not worth rebuilding. I want/ am trying to build a flow bench that can measure flow on the positive side and also be accurate with the pitot tube installed in a cylinder of a 4.3 block.... I think the positive pressure flow numbers may surprise a few people, but mostly would be a better "real world" guide for turbo engines.... The software has already been developed and is windows compatible... Thanks to Bill Gates, anything is windows compatible now.... But don't give up on the normally aspirated flow numbers because they are a benchmark... but there is a better way of measurement...

 

[Buster]

I'm going to stay with the stock cam for ease of tuning and use Crane Gold 1.6 roller rockers to get a little more flow. No idea what they flowed stock, but I think if you do a search on the bb you can find some stock numbers.

Not sure what your goals are with your truck, but I'd put a cam in the truck. The stock cam makes too much torque, practically unusable power down low (hint: Digs looking for slicks). The power band just needs to be lifted a bit and then your flying.

 

[myclone]

As you can see with the numbers.... Flow does not increase much at all above .500 lift. But just remember, these flow numbers, as with most flow benches... the figures are derived from lifts and flows under a vacuum condition and not BOOST. I am working on a bench that can measure flow under boost conditions, but the blower unit that was donated is trashed and not worth rebuilding. I want/ am trying to build a flow bench that can measure flow on the positive side and also be accurate with the pitot tube installed in a cylinder of a 4.3 block.... I think the positive pressure flow numbers may surprise a few people, but mostly would be a better "real world" guide for turbo engines.... The software has already been developed and is windows compatible... Thanks to Bill Gates, anything is windows compatible now.... But don't give up on the normally aspirated flow numbers because they are a benchmark... but there is a better way of measurement...

OH YESSS!! TELL ME MORE. TELL ME MORE!!! How is this bench built? Hows it work? Ooh yeah!! At least share the flow info once the bench is running.

I have SO wanted to see some positive pressure flow numbers to see what forced induction stuff is doing. Ive had the idea in the back of my mind for years but lack the know how to attempt it(at one time I was looking REAL close at a leaf blower.. LOL). I agree that the flow numbers "under boost" will be suprising.

 

[kbbeckius]

It was mentioned that flow doesn't increase much after .500" lift. Do you know why?? Because peak flow efficiency occurs at a lift that is approximately 1/4 the valve diameter. For example 2.02" valves = .505" lift, 1.6"=.400". Sure more lift will provide more flow to a point, after that it levels off, no matter how much more you open the valve it simply wont flow any more, sometimes it actually decreases. Undercut valve stems will help some, I'd be curious how much though, as they cost more, and weaken the valve. You ever see what a loose valve head does to a combustion chamber, it ain't pretty.

Thx Brad

 

[canadian]

sounds like we now have a real use for those electric turbos on ebay! you can use them in a flow bench! :roll:

 

[10secTy]

I have a guy reverse flowing my heads right now. They are 96+ vortecs.
He did the regular port and flow on them.
Stock numbers where 210 his is up to 250 so far and will now reverse flow them. I will be posting info on the results when he is done.

Thanks

Nolan