glamabilly

So I'm half way through my D17A engine build. I'm using mostly stock parts, except for a cam and a limited slip differential as the rules of the class i'm going to be using this engine in don't let me do much. I'm hopeing I'll be able to slide the cam through inspection, and the diff. I've got to the cylinder head part of the build. I am having a valve job done on the head this week, and I know the importance of a good valve job.

-Does anyone have any specific data on the gains of a 3 or 5 angle valve job over stock?
-I plan on port matching the head to both the intake manifold and the exhaust. Will doing either on this head be of any benifit, or will it slow down the flow on this head? I'll be using a DC sports 4 to 2 to 1 header. It has way bigger tubing than the exhaust port.
-I don't have access to a flow bench, so I'm not going to be doing any porting, but does anyone have some photos of what they have done to clean up the ports?
-Is there any benifit to reshaping the back of the valves?
-I'm really thinking about the d16Y8 intake swap, but can not find any realiable info on weather it actually delivers any benefit other than looking better in the engine bay. I found one at the junk yard last weekend so I took it. is it worth anything in putting it on.
-Does anyone have any dyno charts with the work they have done to show what head work is of any benefit? I've tried to find dyno charts for a D17a2 with a detailed list of work done and have not had much luck.
-Lastly, how much can be taken off the head before it starts to affect valve timing, or clearance issues between piston and valves? I'll be using a crower stage 1 cam.

I know this engine has been described as the worst Honda ever built, but some basic head work should produce some gains, it can't be as bad as people say, is it? I'm not looking for a monster, I'm really just trying to get a realiable engine for my club rally car, with maybe a bit more midrange power to pull me out of corners a bit better.
thanks.

mac25

-For N/A I doubt the y8 manifold makes any gains on it's own.

-The reason it makes gains is that it has bolt spacing to fit larger throttle bodies, such as the k20 or j30 throttle bodies. You can then port match the intake by removing material to the throttle body.

It may even, net even N/A, because it looks to me (since I own both) that the stock D17 intake manifold has larger runners than the y8, diameter wise.




-The fundamental reason the y8 manifolds are uses is because with the throttle body being side mounted there is way more space to run larger injectors; which are needed for boost.

xRiCeBoYx

iTrader: (22)

That, and it's metal and can theoretically handle more pressure

mac25

Good point, I forgot about that.

glamabilly

So don't bother with the Y8 manifold then. what are your opinions on light porting and polishing of the combusion chamber? This engine I'm building is an extra one, I've got a good one in the car, so this is going to be an experiment. I've got the means to be able to do some work to it, and I'm not quite convinced the D17a2 engine is a total dud. All the numbers for everything have come back as an almost blueprinted engine from the machine shop, there was zero wear in it, all it had was a head gasket leaking oil down the back of the block, and the small holes behind the oil control rings were plugged so it consumed about a liter of oil every 2000 km, I was expecting worse.
I'm trying to find flow numbers now for the head, I'm having a hard time with that one. They have to exist somewhere, and I don't want to have to send mine out to find them.

mac25

All I can tell you is that I/H/E do work well to increase hp when equiped with an aftermarket camshaft, which no one will know you have.

It would stand to reason that larger exhaust port should also increase power, but I do not know of anyone who has dynoed the d17 with P&P, in order to calculate the P&P alone.