what would be achieved by combining a gsr motor w/a type r head? how would that compare to just buying a jdm type r motor?
thanks!
thanks!
Originally posted by Joe Alaniz said:What I have noticed is that the B16A head has a different bowl shape to it ( compared to the B18C1). If shaped correctly you see really good high lift CFM gains. If you don’t well…. let's just say you gave someone money to just make it look pretty while overlooking this area. Over the years, many porters and head shops say bowls are for low lift, short side for mid lift and runner for high lift. This is where you target to change the flow characteristics at certain lifts. I am sure this applies to many heads but it just goes to show you that Honda heads are finicky. Where you think something shouldn’t work actually works!
one more thing that I have noticed is that on a lot of production multi valve heads, high ports seem to flows better in low to mid lift numbers while ports with a tighter radius tend to flow better at high lifts. I noticed this a lot with motorcycle heads also. They don’t lift very high. on the average they see about 0.300-0.350 in. (7.6 - 8.9mm) of valve lift only. A high port would work extremely well on this type of lift.
I would also like to comment that all of this testing was done a Superflow flow bench. There was no guess work done hear or “I don’t need a flow bench to tell me I’m correct” type attitude.
Quote: Originally posted by Endyn
The GSR head has a larger ID to the intake seat than the B16 head which is intended to feed a 1.8 liter engine...We don't see the differences that some seem to believe exist, with the B16 head being more swirl oriented and the GSR leaning more toward tumble.
on the all-out killer heads, our best head based on a B16 casing will outflow an equivalently prepared GSR by perhaps 5 cfm at .500 lift and that's not enough to cause one to out perform the other in the real world.
The inside diameter of the seat (of an 00-01 ITR head) is also larger than that of a stock B16 head, allowing higher flow rates necessary to feed a 1.8 liter combination.
bstrin5150 on Nov/07/02 said:what effect does the 45 degree vs the 60 degree valve seats have?
he best way to kill reversion on the intake valve is to simply put a 90 degree angle on the side of the valve head. (flat with sharp edge margin to chamber side) We've never seen any worthwhile results from trenching the chamber side of the intake valve.
Valve shapes were the first place most of us began looking for reduction in reverse flow.
Intake valves like to have "square" edges...with the corner defining the break from the chamber side of the head to the margin being 90 degrees (or less) with a sharp edge (no radius) and the corner defining the break from the margin to the face angle being equally sharp.
Joe Alaniz trials different margin thicknesses in addition to altering the back cut.
Quote:
According to Alaniz, up to 50 percent of flow increases from head work can come from a proper valve job. Many believe that a thin 45-degree face on the valve is the way to go, and it does help at a specific valve lift. But by keeping the face a certain thickness, overall performance is improved. Alaniz also says that valve widths are equally important to maximizing flow.
Another pointer he gives us for intake valves relates to the thickness of the margins, which affect the way air passes by the valve. A correct thickness will allow air to flow smoothly past the valve, while an incorrect width will cause passing air to tumble as it comes off the edge, making for inefficient flow.
In a Straight Shot port, the design allows for a line of sight from the inlet directly to the front opening of the intake valve. Sometimes this design gives a lower flow value but because it is straight, we attain higher velocity of fuel/air entering chamber. It also creates a turbulent spin or swirling in the combustion chamber, yielding a more efficient and more complete burn.
A High Approach port is where a turn is necessary in the port design. The term "high approach" comes from angle of the last section of the port relative to the valve - it is more in-line with the valve stem.
Mike Kojima said:The best valve jobs are done on a Serdi machine. The Serdi is very high precision which insures that all the valve angles and depths come out equal. Most low price shops use stones. Stones can give a good valve job but the stones must be dressed frequently and dial indicators must be used to insure that the seating surface remains concentric. Stones require a highly skilled person who is conscientious of doing a good job. A butcher can make a big mess with stones.