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Thread: DE head package - on a budget - infotainement

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Posts: 31-40 of 111
2014-10-12 21:08:34
#31
First.... thank you all for joining in...


The HLA is 17 mm in diameter, making the HLA hole 17.0something in diameter, but surely under 17.1mm... so subtracting 17.1 from 24.5, that leaves us about 7.3mm of unnecessary splitter width. What we don't know is how evenly set the HLA bore is in relation to the two bow-legged intake ports.

Exact HLA placement inside the splitter is as yet not fully determined by me, or a photo or some other evidence I've been able to find. The cut away shown a number of posts above doesn't include the HLA The view below kind of shows it, and yet it isn't specific. What you can tell in the view below is the HLA does interfere on the intake side, while it appears to not be an issue on the exhaust side.




So, by mathematics there is SOME room along the splitter for removing some material to help "straighten" the port, and remove some of the bow-leg the ports follow. This will help, but my little home made calipers found another problem....

no guessing on this one.... we know the valve is 34mm, the bowl/seat @ 29mm, and now....

Originally Posted by ost
A stock intake port is approximately 27mm (+ or - .25mm) and 100mm long @ that diameter


Think about that for a moment... the port = the throat for nearly 4" of length. The "throat" in an intake port is the narrowest point inside the port, it is designed to help speed up airflow a short distance from the valve. This narrowing also limits reversion(the air/fuel charge "bouncing" off the closing valve and moving back up the manifold). Often times, especially in performance engines, the throat is preceded by a gradually tapering section that goes out to the flange, and it either connects to an intake plenum, or an ITB. The tapering section is similar in principle to a velocity stack. The SR20, having a "throat" 4" long only chokes down the air volume by having a set diameter through this part instead of a tapered diameter. So if, along with straightening out the air passage we can add a taper to each port, in theory, we should be able to see noticeable gains in volume, with minimal loss in velocity.


So lets move on to what all this means.... Intake port - 4 panel as it transitions from stock to "within the lines" = inside "stock" openings - note I have not increased the opening size, I've worked within the original casting, and at no time have worked beyond that. The outermost green dotted crescent highlights that the area just inside the ports edge got the majority of the work, and not the edge itself




Look carefully... in the 2nd view down I diagram what I'm doing. Note the orange dotted line, it shows where I worked the splitter at its widest point. It shows I changed the shape, that I removed a bit more material from the roof and floor of the splitter while taken only a minimal amount from the splitter wall. Remember our measurement of 24,4mm, that is at the narrowest point at the center of the splitter, but do to the extreme arc of the port, the splitter at the roof and floor are closer to 40mm, and with care offer up a LOT of material that can be removed if done carefully... as shown by the time you get to the bottom view.



The other green dotted line/arc show additional areas of material removal. They also begin to highlight the narrowing, and shaping of the splitters leading edge.


So... why did I leave a large section of the port walls untouched?


more to come......



PS - over the next couple of weeks I'll be trying to keep up here, but I have a family issue I need to pay the most attention too... so if I'm not on for a day... 2 or gosh darn even 3... I'm just handling family issues.... I'll be back shortly
Last edited by oldeskewltoy on 2014-10-12 at 21-31-39.
2014-10-12 21:19:57
#32
Originally Posted by ebinkerd
Would love to see something like this done with the ve head.


Get me a VE head.....

Most of what I'm doing on this head should be transferable in some way.... especially when I cover working valves short radius, and the exhaust side of the head.
2014-10-12 21:51:07
#33
Way beyond my knowledge but subscribed. Very interesting.
2014-10-12 21:55:06
#34
No worries family comes first.
2014-10-13 17:49:46
#35
GTi-R (54C) check out that nice valve angle



VE



I am happy to see someone massaging cylinder heads with the ability to measure the differences made. Thank you for this.

The highport head you are flowing is the worse for flowing air and this should be a great starting point. The above two photos are a few more of the different offerings Nissan made for the SR20 family. I hope they help you get ideas.

Here is a thread from a few years ago with numbers obtained from a flowbench. Maybe they can be used to compare? http://www.sr20-forum.com/all-motor/15394-gtir-54c-head-flow-data.html Posts 1 and 3.
Last edited by Kyle on 2014-10-13 at 17-57-53.
2014-10-13 19:23:57
#36
The intake port on the VE looks superb!
So it seams, that we just need to develop the right cam-package for road racing - and it would be a killer combo!

@Dan: smallport 4age .
2014-10-13 19:35:41
#37
Originally Posted by Kyle

Here is a thread from a few years ago with numbers obtained from a flowbench. Maybe they can be used to compare? http://www.sr20-forum.com/all-motor/15394-gtir-54c-head-flow-data.html Posts 1 and 3.


very interesting information... although the intake side tends to vary... the exhaust side.... is, "pretty crappy"
Originally Posted by snickers

The exhaust flowed the same as all the other DET's out there... pretty crappy.

Exhaust only flows 170 @ .500"


I have some thoughts on the exhaust side as well........... .... but for now I'll stick to the intake side.....



A unique view... 3 slightly different angles on my port work. Cylinder #2, my control, on the left, cylinder #1(within the lines) on the right...



... these views help to show how I've worked the top and bottom of the splitter, it also shows how I've shaped the bowls to blend into the seats. The top view shows the splitter roof, the center view shows the center work, and the bottom has more of a focus on the splitter floor. Also the short radius blending is plainly visible.


This photo also shows I left a large portion of the port walls untouched... so I ask again... Why did I leave sections of the port wall untouched?







more to come......



PS -
Originally Posted by MartinS
The intake port on the VE looks superb!
So it seams, that we just need to develop the right cam-package for road racing - and it would be a killer combo!

@Dan: smallport 4age .


I was thinking the same thing....

2014-10-13 19:41:36
#38
Originally Posted by oldeskewltoy
Originally Posted by ebinkerd
Would love to see something like this done with the ve head.


Get me a VE head.....

Most of what I'm doing on this head should be transferable in some way.... especially when I cover working valves short radius, and the exhaust side of the head.


I have a ve head I won't be using anymore that I will be selling at some point. Shoot me a pm and we will see if we can get it sent out to you.
2014-10-13 20:01:50
#39
Lets make a fundraising for this VE head :P
I am out - coz have to finance our DE knowledge-raising .

Who would like to help Dan by investing money into a VE head?
2014-10-13 20:22:56
#40
Originally Posted by oldeskewltoy
So... why did I leave a large section of the port walls untouched?



...to discourage fuel puddling on the runner walls?
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