Just bought upper and lower typhoon intakes and was wondering if any one where I could get some info on porting polishing , inside of runners a little rough
From what I've heard polishing intake ports is not a good idea. There needs to be some velocity to an intake charge to get the fuel mixture right.....or something
I used a cartridge roll kit and some porting carbide bits I got from Summit, its pretty easy just time consuming. Make sure you get the longest mandrels you can find to reach all the way in the runners. Also, one of the runners in the lower has a bad kink in at the bottom, I used my carbide bits to reshape it by removing a some material. Thats about all the port work it needs, then just polish the runners to your level of satisfaction. I dont remember which runner had the kink in it, but its pretty obvious when you're examining it. I also did a lot of work on the TB opening becuase I bought a 75mm TB to go along with the manifold. Overall, works great!
From what I've heard polishing intake ports is not a good idea. There needs to be some velocity to an intake charge to get the fuel mixture right.....or something
seems like I heard that for carb intakes because the fuel and air travel through the intake together, so you want it to tumble around a bit and get mixed together. In an EFI manifold, the fuel isn't introduced until right where it meets the heads. I would think smoother is better for airflow.
Also, I don't think the smooth walls would have a great effect on velocity(aside from turbulent vs. laminar airflow; that could be a bigger difference than I thought), that has more to do with the actual size of the runners, yes?
seems like I heard that for carb intakes because the fuel and air travel through the intake together, so you want it to tumble around a bit and get mixed together. In an EFI manifold, the fuel isn't introduced until right where it meets the heads. I would think smoother is better for airflow.
Also, I don't think the smooth walls would have a great effect on velocity(aside from turbulent vs. laminar airflow; that could be a bigger difference than I thought), that has more to do with the actual size of the runners, yes?
You alos don't want the wet carb airlfow to encounter much obstruction as that tends to cause the fuel to puddle out of the airflow - i.e. when using a smaller carb (600-650cfm) on a 347 and an open or dual plane intake - use a open spacer under the carb to give the air/fuel a larger turning radius to avoid the air/fuel from hitting the intake bottom causing fuel puddling. If using larger carbs, the velocity throught he venturies is less and the issue is reduced.