Larry, all of our testing was with gasoline.maxracesoftware wrote: ↑Sun Sep 19, 2021 4:41 pmwas that on Race Gasoline ??by Bryan Maloney » Sun Sep 19, 2021 2:53 pm
I observed almost the same thing years ago after adding reverse swirl fins to a pair of 18 degree Chevy heads on an open ARCA engine. Picked up 8-13 cfm on the bench, but no power increase on the Dyno.
any Dyno Tests with Methanol w/Bowl Swirl Fin ??
here's Pics of ProAction 14 deg SBC Heads on 406cid
Looses 90+ HP @ 9400 RPM with Bowl-Swirl Fin only on "Methanol"
makes 1005 HP @ 9400 RPM "without" any Bowl Swirl Fins
and without anyother trick Fins
Runs quickest down the Dragstrip "without" any Trick Fins !
You can get away with "Trick Fins" with Gasoline
but Methanol is a different story !!!
On Year 2020 NHRA Comp Eliminator Champion Craig Bourgeois's A/ND 14deg=1024HP and B/ND 23deg=1005.2 HP Heads
( highest Tq and HP Curve is with 4.7 to 4.85:1 Air/Fuel Ratio on both 14deg and 23deg )
with Methanol ....there are no "Trick Fins" ... just straight forward Porting !
Note : the Chrysler ProStock Truck Heads Bowl Swirl-Fin were even a little more drastic than these Pics ... but were only run on Race Gas , no Methanol tests !
a Bowl Swirl-Fin is "worthless" on Methanol ,
also i always gain HP , as much as 40 HP so far ,
grinding away Swirl-Fins in various LS-type Heads + reworking Short turn Curve -to- Floor Apex area
to compliment me removing that Bowl-Fin !
pretty drastic when you see Piston's Gas-Port hole combustion so deep inside the Chamber
( on the Deck surface , yes, but so deep into the Chamber , no ! )
i doubt anyone seen anything like this before ???
"How to Lose 90+ HP on Methanol"
Hi_Vortex_Bowl_Fin_18.jpg
Hi_Vortex_Bowl_Fin_17.jpg
Hi_Vortex_Bowl_Fin_15.jpg
Hi_Vortex_Bowl_Fin_13.jpg
Hi_Vortex_Bowl_Fin_5.jpg
The fins that are in your heads in the photos are really extreme. The siamese port wedge heads don't seem to run well with extreme fin trickery. I think any fin needs to be a smooth continuation of the port; not an extreme dam.