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Cam and I built one of these David Vizard budget flow benches

If I had tig skills and a tig, this would be a done deal. Also, the projects we have going now require OE reliability: Cam's got to be able to drive his 944 daily, and my buddy's 244 has to have probably 4-5 days a week out of it, 3 seasons, and be able to go a couple hundred miles from home without a hitch. That means that ALL the stuff that goes along with the performance aspect has to be bulletproof. You could almost say that the performance aspect is among the last things to consider. Sounds goofy, I know, but it's self-imposed restrictions like this that force us to think harder. When I was a kid we had cars that had wires running everywhere and exhaust leaks and stuff like that, but we had time to mess with them all the time and never went more than 30 miles from the house.
 
I'm not sure what you have for a welder, but you can do decent work with a spool gun and a mig with aluminum. It definitely takes practice, but it's a much lower barrier to enter with.

There's not a lot of material in the stock b230f intake runners, and the injector boss area is a big (the biggest?) restriction there. Even the cheap welded KL Racing intake is 2mm larger in diameter at the port flange (40.5mm vs 38.5mm with the intakes I have here).
 
Intake manifold swap seems outside of the scope of this (my) project. I like the cast KL one, the work and expense required is probably not worthwhile at this power level.

Depends on how in the weeds a ported B230F manifold still is, I suppose.

Either way you still have a Volvo 8V head.
 
Just for what it's worth, your power ceiling without a turbo will be about 160 whp.

I'm assuming this is NA for some reason.
 
There are a few project cars this here flowbench research applies to, one of which is NA.

My 940 - this is just my normal car that I use to get places
Racecar - for lemons racing
Dad's friend's 244 - fast weekend car

Different solutions make sense for each.
 
Intake manifold swap seems outside of the scope of this (my) project. I like the cast KL one, the work and expense required is probably not worthwhile at this power level.

Depends on how in the weeds a ported B230F manifold still is, I suppose.

Either way you still have a Volvo 8V head.

So klr142s General Leif makes like 155whp (so assuming about 180 crank) with a modified k-jet intake (bigger tb, and some smoothing I believe).

That same engine, head, and camshaft combo will usually make 220 crank hp with ITBs or DCOEs. So that's a significant amount of power on the table with just the induction side.

A well warmed over 8v head can still do 260+ crank hp...
 
My project = my car. Oops. Highly doubt I'll be touching 160 whp suction engine power (as they say) in the 940. In addition, welded up modded B230 intake is much less objectionable on a race car.
 
Do as you wish, but bothering with that intake manifold is an abject waste of time and consumables.
 
Dude I wish I could tell you that we have the means to do that. Unfortunately we would have to send the head out to have that done. It's now extremely clear to me that it's the intake side, not the exhaust, that needs all the help it can get, because of the manifold.

I'd think you'd be able to spend some time there with a dremel continously checking as you go to get it done. The big problem would be the new pistons you need to get it to work.

As for the intake barring finding a suitable 2.0-2.5L stock manifold from another brand, the b21f setup appears to be the way to go.
 
Interesting stuff. Nice job.
I built my own flow bench a few years ago too. What surprised me is that it was really simple to do and it can be really accurate too. You've done the hard work. All you would need to do to measure actual flow rates is add a orifice of a known size between the head and the vacuum source with another manometer across it. You can either calculate the flow rate of the orifice, or get it measured on a known bench, then every pressure drop you measure across your head can be related to that orifice using a simple equation.
An AMM is a nice idea, but really difficult to calibrate. Manometers are very accurate. They are what would be used in a lab to calibrate flow devices anyway, so they only lose out in terms of user friendliness.

I think you did the right thing to reposition the manometer to the bore adaptor. The spark plug hole will be experiencing air flow across it, but you really need the manometer to be in relatively still air, to measure the pressure drop across the head as a whole. The larger you can make the chamber immediately under the bore adaptor the better. I used a 1m length of 4" soil pipe which seemed work well, but a large diameter drum of some sort would be better.

I can back up your findings about inlet manifolds. On a B230 530 head at 12mm valve lift I got about 138 CFM@28"H2O with a plasticine flow smoother on the inlet to give the best case scenario for that type of head. With the standard B230 inlet manifold added on that dropped to 120 CFM@28"H2O.
 
Do as you wish, but bothering with that intake manifold is an abject waste of time and consumables.

Here are the results of an abject waste of time and consumables:

First, the racecar head came back and we had a better way to calibrate the flow bench instead of assuming all the stock ports flowed the same. This revealed that all the prior numbers were fairly optimistic, which I believe because it all seemed a little too easy.

Next we flow tested the B230 and B21 manifolds on a stock port. No restriction noted for either.

What gives? Turns out it'd probably help if you plugged all the ports on the manifold...

After this our stock port and stock B230F manifold threw down these absolutely putrid numbers:

.050" 19.6
.100" 51.7
.150" 80.3
.200" 105.1
.250" 118.4
.300" 126.3
.350" 130.4
.400" 124.7
.450" 124.7
.500" 124.7
.550" 126.3
.600" 127.1

So, not much more flow than the exhaust port. Awesome.

Esmth donated this B230F manifold which got cut up and eventually ported in the name of science:

ebkpovIl.jpg


First thing to note is all the nasty bosses in the plenum area. Those got cut off and the runner entry got smoothed particularly on the short side. Cylinder 1 and cylinder 3 are especially impacted by the throttle body stud bosses, one of which was good for some 8 cfm at peak on its own (I forget which, I think #1)

b5Uq9ncl.jpg


The injector bosses on the B230F manifold can be slimmed down considerably although this made only a small difference in our tests.

UuIKh24l.jpg


The big ticket seemed to be in widening the runner near the port entry, particularly on the long side.

DPBtaVnl.jpg


Fortunately for me my dad took good notes of what the final product ended up being, in the name of repeatability:

3AHCGVCl.jpg


And I made this little tool, which you can have the STL file for if you ask nicely (or tell me where I should upload it):

rDX9N2Kl.jpg


The narrow end goes in the injector boss area once porting is complete, and the wide end goes into the widest part of the runner until the notch is no longer visible. Here it is, not going, plus the first few layers got too squashed:

UuIKh24l.jpg


and of course the final results, before and after:

.050" 20.4 20.8
.100" 50.7 51.2
.150" 79.1 79.7
.200" 103.0 104.4
.250" 120.7 121.5
.300" 134.6 135.5
.350" 144.4 147.1 +1.9% (gainz not worth noting up to this point)
.400" 147.1 154.7 +5.2%
.450" 149.0 160.7 +7.8%
.500" 149.9 163.7 +9.2%
.550" 149.9 157.7 +5.2%
.600" 150.9 157.7 +4.5%
 
Oh, and the port with no manifold:

.050" 21.6
.100" 53.7
.150" 84.6
.200" 112.4
.250" 135.5
.300" 152.8
.350" 166.9
.400" 166.9
.450" 166.9
.500" 171.1
.550" 173.3
.600" 175.5

The smart folks on speed-talk.com seem to suggest an expected loss of around 1% per tenth of an inch of valve lift with the intake system installed no matter what. We didn't test the B21 manifold on this port but on a stock port it came in around a 10% loss at worst. Significant improvement over the B230 manifold

Also worth reading:
https://www.motortrend.com/how-to/hrdp-0802-chevy-intake-manifold-porting/
 
Glad you?re generating data-backed insights on the topic! Genuinely interesting couple of posts.

Still sticking to my hot take on the B230 manifold being poo, however :-P
 
If I am reading this right, there doesn't seem to be much of a benefit porting the manifold with any of the stock smaller cams below like 10.5mm intake lift? M, T, A, B?
 
If I am reading this right, there doesn't seem to be much of a benefit porting the manifold with any of the stock smaller cams below like 10.5mm intake lift? M, T, A, B?

My conclusion here is: if you have to keep it, porting it does not hurt at all.
 
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