Speed-Talk is running on www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Dimpling a LS port

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Posts: 2175
Joined: Wed Apr 21, 2010 4:35 am
Location: Fresno, CA

Re: Dimpling a LS port

Post by In-Tech »

Plenty of overthinking/underthinking can go into an air/fuel injection event. The exit coming from the injector? Stream/4hole/5hole and the repulsion from the valve closing...and if you have a plenum or not for it to "recognize" the "mixture". We could talk about this for hours and there is no simple answer the OP is looking for. Conversations like this are stupid unless more variables are answered, then logical people with experience could help. Sorry :D
Heat is energy, energy is horsepower...but you gotta control the heat.
Posts: 1884
Joined: Tue Aug 18, 2009 2:53 pm

Re: Dimpling a LS port

Post by levisnteeshirt »

hoffman900 wrote: Mon Sep 27, 2021 12:01 pm
levisnteeshirt wrote: Mon Sep 27, 2021 11:48 am I wonder if keeping the dimples in a straight line , and a gap between the lines would act like a vane that's getting popular
What do you think that would accomplish?

I’m not asking in a mocking tone, just trying to make you think about what is happening and what that would accomplish.

Bryan Maloney outline what the “Glidden fin” does in another recent post.
Bryan Maloney wrote: Sun Sep 19, 2021 2:43 pm
hysteric wrote: Sun Sep 19, 2021 7:52 am

Did you see a net gain in performance by improving swirl?
No, our goal was to prevent the swirl from ramping up so highly at high lift. When the goal is cylinder filling, we wanted the air column helix to chase the piston down the bore and not sling the fuel into the cylinder walls.
Street engines with low valve lift may benefit at low RPM from additional swirl; the valve L/D never gets high enough to where the swirl naturally spikes.
The often maligned reverse-swirl "Elkins fin" behind the intake guides can be beneficial in moderation. Some OEM's take this feature to the extreme.
A "Glidden fin" along the centerline of the floor of the intake port can add flow stability and help limit high lift swirl.
I suspect only a small few who use the “Glidden fin” understand it to that effect. It does look cool though, so I think there is a lot of that going around.

Since ports aren’t just straight tubes, people should be concerned with and understand Dean’s Vortices. It’s only been mentioned by one person on ST, and he is a friend of mine, so we have a lot of sidebars about this stuff.
if you go back and look at the Joe Sherman 215 RI AFR heads he won an engine masters with ,, he did use some dimpling , in certain areas ,,, not the whole port ,, I wish he was still here
Post Reply