Don Terrill’s Speed-Talk

I have posted images of this in the past. I doubt that I still have them but could make new ones. Could you? Sure, here you go. As you can see, the air circulates around in a toroidal path. It changes at various piston levels quite differently. CFD flow follows piston.png Makes one wonder if other ...

Darin was previously showing burn marks and carbon deposits of a ran head, which matched almost identically to his Dykem testin on flowbench. Some think fuel washes the surfaces, when an alternative view could be that the fuel on wetted surfaces burns poorly (rich) during combustion leaving carbon ...

Learning to use the Pipemax (latest version pro 4.7) and getting these lines in airflow calcs. Wondering if I have something wrong in my data input that could cause it. Mach Z-Factor Valve Lift = Level=10 Cam calculated Speed of Sound velocity thru Valve Curtain Areas Pumping Choke Valve Lift = Leve...

Widen where it's red. It will slow down the high speed areas and even out the pressure in the tube, using the area better. It will also reduce secondary flow which is a result of having unequal pressures across the port.

If you look at the typical low loss venturi shapes, the contraction can be much more abrupt than the expansion without flow loss. Nicely rounded entry to right size pipe would not lose much and it would flow poorly backwards.

Nut124 wrote: ↑Wed Jun 24, 2020 2:54 pm

Calypso wrote: ↑Wed Jun 24, 2020 1:36 pm

Nut124 wrote: ↑Wed Jun 24, 2020 8:50 am For manifold, I have a nice IR with 44 IDFs.

Many Twincam IR-manifolds have an abrupt 90deg bend right at the carb flange...

That is correct. Mine came from Pierce Manifolds and is as good as the space allows.

Would bike carbs fit in?

That is certainly part of the equation. I know each different pipe had a different optimal curve. The fun part came when we found that a two stroke at constant throttle and rpm, would increase EGT with time. Now it was time for the really sharp tuners to go have a beer. :lol: Well, EGT sensors are ...

Nut124 wrote: ↑Wed Jun 24, 2020 8:50 am For manifold, I have a nice IR with 44 IDFs.

Many Twincam IR-manifolds have an abrupt 90deg bend right at the carb flange...

In our two stroke shifterkart engines, the curve for best wide open power was very advanced down low and got progressively more retarded through the rev range. Probably due to some form of the same phenomenon. 2-strokes retard at high rpm to put more heat into pipe, which changes the speed of sound...

Vapour blasting seems to give nice results. Several youtube videos about that and nice pictures from google search. A local guy built his own setup picking features from different videos and gets nice results. He uses glass "crush" as media mixed with water. Although not sure if it's a sol...

PCV into the rear of the carb?

1972ho wrote: ↑Mon May 11, 2020 4:05 pm Check the mustangtec sight you have a replacement 289/302 HIPO aftermarket head from ford 1970 casting date just like a replacement Cj holley carburetor that you could buy if you lost your original.

Those look like the same casting, but without the plugged thermactor holes.

IIRC, 351C stock rods also have a piston oil squirter channel in the big end cap parting line and a small notch in the rod bearing. By my understanding, those are for wrist pin and bore wall oiling, not for piston cooling. Piston cooling requires a different nozzle and flow volume. Not sure what th...

Makes sense, but it did seem different enough to be cast differently. Can't claim expertise however.

It's C8ZE
Google search on the crane Fireball head shows a same head. Didn't notice Crane stamping on these though. May have just missed it, or it wasn't there...