Flow development...

[WPH]

[color=#000000]Our

[86rocco1]

I remeber seeing something about a Peuguot head over at recently, it might be worth browsing the forums over there.

[WPH]

Yes, an exellent source on european 16V heads. He publishes a lot of info on his flowtesting and engine development.

[larrycavan]

Any air speeds recorded for that head yet?

[WPH]

Not yet, I don't have a pitot available. The whistling noise didn't show up with the valves in, just a nice sound of air flowing.

[WPH]

Did some probing with a simple 180deg pitot without static pref. I have an idea where the flow is fastest and some of those points
seemed pretty obvious. What kind of pressures should I be seeing with 10" or 15" test pressure if the port speed is in acceptable range?
I'm expecting a delivery from a hobbyshop and possibly I'll have a real pitot before next weekend.

[larrycavan]

[WPH]

Just finished my pitot and measured port velocities. Stock head and my "EVO" measured almost the same numbers:

Pitot Velocity Calculations Helper
Inches-Test Velocity FPS Convert To Converted
Pressure At Test Prssure Pressure Velocity FPS
15 256 28 350
Set Pressure for testing in A4 - Convert to new pressure in C4

Enter observed Pitot Readings - Velocity is calculated on right
Observed Velocity FPS Velocity FPS Converted
Pitot Pressure At Test Pressure At Conv. Press Pitot Pressure
18.8 287 392 31.35

Highest port velocity was recorded near port splitter entry, reading was dependet of pitot angle in the port.
Lowest FPS measured at the same spot was 15" = 256, 28"=350.

[WPH]

Time for a update. Flow improvement described above was done to a scrap head. Our actual head on engine was fitted with a single plenum
EFI manifold (DIY) and the #'s on that combo were 126.7cfm@10"

After some headwork flow went up to 141.3cfm@10" (360fps) w/o manifold but w manifold it dropped back to 128 cfm. Obviously it was time for a new intake system.
I fabricated a short runner ITB setup with 4x46mm snowmobile TB's which had to be heavily modified to match bore-to-bore width of 90mm.
Total length was limited to 178mm due to chassis clearance and intake flow is 136.6cfm@10" with TB's & manifold.

Next stop is chassis dyno:

170.2 lb/ft@5830rpm, 221.1 hp@7420-8000rpm. 94 R+M octane unleaded pump gas.
Available torque@4000rpm is 147.5lb/ft and it doesn't drop below until 8000rpm. There is a small dip in curve @ 4500rpm but hopefully we can fix that.

[CraigAPD]

Have you tried playing about with the areas around the head of the valve in the combustion chamber (shrouding)?

[WPH]

Combustion chamber in this head is fully deshrouded, unfortunately no pictures available. Scrap head in the previous pictures shows the areas needing attention pretty well and they have been dealt with. I made a set of valves to protect the seat rings while deshrouding areas around valves. I have checked the "burn pattern" on this head and it shows no marks of fuel wash or anything else related to bad combustion or fuel separation. I did get some reversion on the previous ex/intake manifold combo but managed to cure that with a modification to collector length. Our dyno run suggests that we currently have an issue with too short ex primaries which causes the dip in torque curve@4500rpm. I have run some sim testing which shows that we would benefit from using primaries 2" longer than what we have now. I didn't want to modify too many things at once and that's why we ran original header on dyno.

[WPH]

"170.2 lb/ft@5830rpm, 221.1 hp@7420-8000rpm. 94 R+M octane unleaded pump gas.
Available torque@4000rpm is 147.5lb/ft and it doesn't drop below until 8000rpm. There is a small dip in curve @ 4500rpm but hopefully we can fix that."

This is the dynorun of the engine I've been playing with. Mapped on rollers at our nearest dynoshop. Megasquirt V2.2 DIY ECU,
wasted spark system with Ford EDIS coil, 440cc injectors. I'll try to get some pictures of the engine with all the recent parts.

[106-1194218389]

That is almost 2 hp per cubic inch, not too shabby!

John

[WPH]

It's almost as good as it is going to be without opening the ports at divider wall. Port dia @ divider is 25mm, which is too small. Pipemax suggested 1.817 to 1.889 port CSA for 7420rpm, might go even slightly higher since we are going to turn the engine to 8000 rpm.

[larrycavan]