Rod Midkiff
True Classic
VERY clean looking engine bay!!!
? is that a remote start button next to the distributar access door?
? is that a remote start button next to the distributar access door?
Velocity Stacks on 40 DCNF's
- Thread starter abarth2litre
- Start date
tigeravg
True Classic
Yup. Totally worth the ugliness!
Rod Midkiff
True Classic
I installed one on mine right away and very happy that I did. Helping a freind get his running and already reached for it a few times..(His does not have one YET)
think I will in stall one on the wifes as well.
(I also put in a kill switch in the back) (just turn's off power to the coil)
think I will in stall one on the wifes as well.
(I also put in a kill switch in the back) (just turn's off power to the coil)
fiatfactory
Steve Cecchele
OK Steve and Snow White
criticize these screens... go ahead I dare you
back to back dyno testing.... on a 350SBC that makes 401hp / 402 lb/ft with open bellmouths, drops about 17hp 12 lb/ft by fitting the mesh screens
âï¸ filter screens effect on airflow
59 seconds · Clipped by Steve Cecchele · Original video "SBC EFI STACK INJECTION-DOES IT WORK? (FULL DYNO RESULTS)" by Richard Holdener
youtube.com
SteveC
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Steve Thomas
True Classic
Nobody in their right mind outside of very hardcore historics should be using screens if interested in performance - no brainer.
fiatfactory
Steve Cecchele
scroll up and read thru the thread... there are some people who would argue otherwise....
fiatfactory
Steve Cecchele
another example,
this time with DCNF pattern Borla throttle bodies, so a more direct comparison to the DCNF's.
Note the screens are below the bell-mouth, so the bell-mouth is still able to smooth the airflow into the ITB...if the screens were mounted on the outside, i.e. covering the bell-mouth, then the disruption to airflow would be even greater.
youtube.com
gaining 36hp to 512hp by removing the screens
SteveC
this time with DCNF pattern Borla throttle bodies, so a more direct comparison to the DCNF's.
Note the screens are below the bell-mouth, so the bell-mouth is still able to smooth the airflow into the ITB...if the screens were mounted on the outside, i.e. covering the bell-mouth, then the disruption to airflow would be even greater.
âï¸ wire screens limit horsepower
60 seconds · Clipped by Steve Cecchele · Original video "Carb vs EFI - Dyno Testing a Holley Double Pumper vs Custom Stack Injection" by The Horsepower Monster
youtube.com
gaining 36hp to 512hp by removing the screens
SteveC
Rupunzell
Bernice Loui
No surprise here.. screens on V stacks are an obstruction.another example,
this time with DCNF pattern Borla throttle bodies, so a more direct comparison to the DCNF's.
Note the screens are below the bell-mouth, so the bell-mouth is still able to smooth the airflow into the ITB...if the screens were mounted on the outside, i.e. covering the bell-mouth, then the disruption to airflow would be even greater.
âï¸ wire screens limit horsepower
60 seconds · Clipped by Steve Cecchele · Original video "Carb vs EFI - Dyno Testing a Holley Double Pumper vs Custom Stack Injection" by The Horsepower Monster
gaining 36hp to 512hp by removing the screens
SteveC
Idea and motivation behind screens on V stacks is much about "period correct" and what was as delivered is best. Removing the screens will impact market value.. which is why screens remain on SO many of these "vintage" motos...
V stack screens is much like low mileage.. Meh...
Bernice
fiatfactory
Steve Cecchele
The nesh screens on an old Ferrari or Ducati, are nothing like the fine mesh screens sold these days and featured in the videos or shown in the preceding threads, they are a very coarse screen, designed to keep "the big rocks" out... sure they will be detrimental to absolute flow, probably about as much as a clogged up paper filter.
If I had a million-dollar vintage Ferrari (or insert any Italian make here) race car, I'd keep it original too... for display.
I wouldn't be racing it at 10/10ths or be worried about 5% flow loss... but I would be running a "proper" filter to keep out the dust and detritus you get on a race track, and saving a small fortune on rebuilds in the process.
SteveC
fiatfactory
Steve Cecchele
Colder (denser) air will gain you more... plenty of dyno information out there to confirm it... and why most dyno numbers are corrected for temp / pressure.
Restriction in the stock air filter... some people think the snout is small and is the primary restriction, whereas in actual fact the stock element is where the restriction is at high rpm / high output... It's plenty big enough for the stock 75/85 crank Hp, it's only when you significantly raise the power level that the filter area becomes a restriction.
Cut the snout off and start pulling in hot air instead of "cool" air and it will lose more than any perceived gain... BTDT on a dyno
Plenty of much larger capacity engines pull thru the same relatively small snout openings.
Stevec
kmead
Old enough to know better
Wouldn’t it need to really only be equal to two of the venturies given only two are actually drawing at any given moment?
GregS
ProjectX
I was referring to the standard 2 barrel carb when primary and secondary are both open at the same time.
carl
True Classic
Stick your hand over the four bellmouths of twin DCNF or IDFs and you will feel a constant suck 100% at all times. Actually it probably is pulsing but so quickly it seems like a constant flow. If you reduce the snout opening the air will speed up so it's a balance of many factors. I did very poorly in Fluid Dynamics in college but I did pick up enough to know it's not intuitive to the layman and if you go supersonic things really get funky.
Steve Thomas
True Classic
It is a limitation of the DCNF that it can't have proper stacks. The bore spacing is too tight. IDFs can have but never seem to. They usualy have the cheapie sharp edge impression of a stack