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Discussion Starter #1
Aim: a super Grand Tourer for the road ...and a bit of circuit/track performance driving.

I'm enjoying modifying my CBA '59 GT-R Black Edition to gradually improve on the very good base platform, particularly for efficiency, handling and performance.
Performance wise the car is currently a LM stage 4.25 with EcuTek phase 4 motorsport, frankly it is astounding what Iain has achieved using EcuTek development of the factory ECU.

The most recent modification is to port, profile and polish the stock intake manifold, a nice little project for over the Christmas break. ok, here's the starting point, the factory intake manifold from front, (cylinder) bank 1 and bank 2 perspective.
 

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Discussion Starter #2 (Edited)
For disassembly, the Engine Mechanical: Intake Manifold Collector exploded view and Removal and Installation section was used as a reference. Interesting how much attention there is to correct tightening and removal sequence for the fasteners!

First, disconnect the battery. It can take quite a bit of time to complete the porting process, so you may want to put the battery on charge while you're busy (more on that later)!
Remove all vacuum hoses and electrical connectors from the manifold collector, throttle bodies, map sensor and inlet pipes. The connectors (ref. throttle body connector image) come apart relatively easily when squeezed quite firmly between finger and thumb at the marked point.
The brake booster hose was pretty well gummed on, so I eased the end of the hose back and applied a few drops of washing up liquid as shown in the last attached image - it makes removing and refitting all hoses much easier.
Remove the bolts from the EVAP solenoid and tube as shown below, disconnecting the vacuum pipe only on the right side provides enough freedom to move it safely out of the way.
I diverged from the manual's removal sequence in that I did not remove the throttle bodies from the manifold collector before removing the collector from the engine; there's no need if you undo the intake pipe clamps, unplug the MAP sensors and release the pipes from the throttle bodies by pulling them back towards the front of the car.
 

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Discussion Starter #3
The MAP sensor, PCV, vacuum and brake booster hoses are shown below and in the last two images the harness cable tidies that need to be released from the manifold collector. Gently presssing a flat bladed screwdriver in to the zip tie where indicated will release it.
The large harness needs the spigot released in the rectangular hole, the harness is pretty tight on the bracket.
 

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Discussion Starter #4 (Edited)
With everything disconnected, undo the intake collector bolts in the given sequence.
Lift the collector off carefully and have a suitable surface ready to place it while you deal with the intake manifold (in the image I've already jumped ahead and removed bank 2 throttle body, it's just for reference).
The second image shows the EVAP solenoid and tube tucked out of the way on the left.
Now undo the manifold bolts in the given sequence. Bolt 6 (third and red arrow fourth image) is obscured by the wiring harness, undoing the four cable tidies from the fuel rail (image five) provides enough slack to move it out of the way.
Just press the sides of the cable tidy together and push down to release it from the fuel rail.
Remove the fuel assembly mounting bolt (marked green) in image four.

Be careful to ensure the injector looms are out of the way, even once everything is released it's still a bit of a pain to 'thread' the intake manifold through the fuel rail in order to remove it as there isn't much clearance.
Have a cup of tea or swear, either works.
 

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Discussion Starter #6
Efficiency.
...and something I could do myself; more on that later.
There appear to be quite a few areas where cost and mass production have taken priority over design, which is a pity given the Takumi's attention to detail during assembly and yes, absolutely, as shown by the guys at Gotboost Performance (gtrboost.com) in the US it is a proven process.
I'm grateful as Frank was kind enough to provide advice on the process.

Before continuing it's worth having a closer look at the profile and finish on the existing manifold. If you reference the areas highlight orange in the first image you can clearly see flow marks, imperfections in the finish and the top left arrow that shows misalignment between manifold and cylinder head intake port.
The red arrows indicate how complicated the transition between the circular runner section and oval cylinder intake is. At the location of the large red arrow there is a pronounced 'tongue' in the throat of each runner and the sides are pinched in at the location of thin red arrows, preventing a nice smooth transition. The second image showing cylinder 3's intake shows this nicely, though it applies equally to all.

Those intake ports are crying out for profile work, as done in the sport engines for example.
 

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Didn't realise you we're this handy with a spanner mate!

As well as being stage 4.25 ( stage 4 + downpipes) don't you have ported MY11 turbo inlet pipes as well?
 

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Discussion Starter #8
With the manifold completely removed, use some masking take to protect the cylinder head intakes from foreign bodies while you work.

Disassembly of the intake manifold collector:

remove both throttle bodies (the manual excerpt below is JDM, there are no water lines to remove on UK cars) undoing the bolts in the order prescribed and once again have an area prepared where you can store them safely out of the way while you work. As you can see, removal of the allen head bolts is straightforward using simple hand tools.
I should have mentioned earlier that I used penetrating oil on all the bolts prior to disassembly (20min edit limit is a pain for stuff you forget!)

The second image shows removal of the bank balance tube and wiring harness bracket. The two zip cable tidies just unscrew from the bosses on the tube.

The map sensor was well gummed in to its mounting point on the collector (it is just a push fit with an 'o' ring retainer), a few drops of the magic well known washing up liquid and a couple of turns had it out in a jiffy though.
 

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Discussion Starter #9
Looking at the (bank 2) throttle body mounting flange, we can see the aperture is 60mm diameter and a match for the throttle body, albeit somewhat smaller than the mounting gasket.
During disassembly, with the bolts loosened you'll notice that the throttle body has ~2mm of free play, which means that unless you get lucky during assembly then the body and mounting flange hole will not align.
If the mounting flange hole is ported (opened up) by 2mm to 64mm (the inside diameter of the gasket) then alignment will be guaranteed. If you look carefully you can see that I have already scribed the mounting flange ready for porting.

For porting and profiling, I used the metal cutting bit for rough and a Dremel with 115 high speed metal cutter. The 134 and 144 bits would have been very useful too, but I couldn't obtain them locally.
I also had a good supply of sanding wheels in 60 and 120 grit and for finishing, abrasive buffs of all grades which work really well.
I think the flapwheels would have made for more rapid progress with roughing, but couldn't get any suitable for the Dremel; although I did obtain a 120 grit for the drill, albeit too large diameter to use in many places.

I carefully assembled the intake manifold collector and manifold to have a look at factory alignment.
 

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Discussion Starter #10
Here's the view from the engine back up the intake runners. Bearing in mind I had the luxury of assembling this inverted with a view up the runners, we clearly see how poor the alignment actually is. In the third image, looking at cylinder 5's intake runner we can clearly see the 'tongue' profile at the base of the runner.
The small ports and holes you can see in the roof of the runner are for exhaust gas recirculation to reduce emissions.

The manual excerpt demonstrates the recommended alignment process, in the best possible case we can see this is at best a compromise.
 

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Once again there is a lot of free play between the intake manifold and the collector, easily 1mm in each direction. To make port matching worthwhile I took a(nother) leaf out of Dave of Gotboost's book and pinned the two sections of the manifold together using M4x15 bolts.
The second image shows the position for the 4mm blind hole. I used a compass to draw a radius out from the centre of the boss, half the width of the M4 bolt head. Once drilled, I used an 8mm drill bit to carefully countersink the boss to allow the bolt to sit all the way down flush to the manifold flange.
I also countersunk the entry to the 4mm blind hole in the intake collector by about 0.5mm to allow the bolt to find the hole more easily during assembly as it is quite a precise fit. You can just see this in image three.
Note: the gasket has to be fitted during the dry assembly, as you want each of the three components to align perfectly.

Image three shows the two 4mm blind holes (at either end of the manifold collector flange) which accept the two 4mm bolts, now epoxied in to the manifold in image four and five.
 

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Discussion Starter #13 (Edited)
Using the cutting tool I roughed out the profile of each port, to the point where the junction is quite seamless, the second and third images show this quite nicely.
 

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Discussion Starter #14 (Edited)
The collector runners were then polished using 260

then 320 abrasive buffs.
The metal is soft and works quite easily, however it is still time consuming as you are constantly working/checking to ensure smooth progression. Good lighting is very important as with my fat fingers and a drill bit stuck up there, there was room for nowt. While doing the work, I though a head torch would have been very helpful, which I didn't have...
The finish is pretty good, the slight roughness you can see depends on the incident light, some of which is actually the imperfections in the casting - it can't be felt and I didn't think it necessary or worthwhile to do anything beyond finishing with wire wool.
You can see the lines I've scribed on the collector flange from when the manifold was attached, indicating where additional port matching is required but wasn't possible with the manifold in position.
 

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Discussion Starter #15
On to the manifold itself. As it's so small, access is great to work on it.
Actually, it may not look like it, but there's a lot of work to be done to smooth the profile. If you compare the images to those posted earlier, hopefully you'll be able to see that I was able to smooth the 'tongue in the throat' of each port I referred to earlier almost completely. Pay particular attention to the casting at the neck of the runners, there's a definite constraint around the flange at the runner entry.
Looks like I didn't photograph the finished collector and manifold when dry assembled.
 

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Excellent work mate, thanks for sharing :smokin: What sort of gains/improvements are the guys in the US seeing from this process?
 

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Discussion Starter #17 (Edited)
Next up the throttle body mounting flanges.
I ported each to 64mm using the Dremel 115 metal cutter, as referred to earlier in the thread. This worked very precisely and produced an excellent finish.
I used the large flap wheel to smooth out the 'tanks' of the collector, mainly to smooth the entry from the throttle bodies.
In image one you can see I was able to polish out almost the complete length of the intake runners. If you look at the top right of the collector in the first image you can see a web that runs from the throttle mount back to cylinders five and six on the other side. At first look I thought it just a strengthening web, but the channel runs all the way to the cylinder runners. Perhaps it is just the way they produce the casting.

The gunk you can see inside is just 3-in-1 degreaser. You can see it's pretty well gummed up in there and requires a thorough clean down before assembly proper. The degreaser worked ok in conjunction with an old small wheel cleaning brush, I expect the more powerful the better for this task.
 

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Discussion Starter #18
The intake collector has perfectly milled 23mm diameter holes for the bank balance tube. The (Hitachi) manufactured bank balance tube has 20mm diameter cast holes:
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In the second image below, the connector on the left is the brake boost feed.

I centred the gaskets and scribed the mounting flanges, then ported the balance tube inlets to match the 23mm collector holes. I also smoothed the inside of the casting around the hole to aid flow as both sides were pretty rough.
To aid assembly, I put a dot of glue on the gasket then centred it ready to mount up to the intake collector.
 

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After another thorough clean, I dry fitted everything together and masked it up to paint. It actually came up so well I was in two minds whether to bother; but crackle black intake manifolds do it for me, so I persevered...
 

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The recommended three coats produced the following.
It's manky stuff and sticks to your skin like the proverbial. You need gloves, eye protection and basic respiration for spraying ...eye protection you'll of had to hand from all the metal work, but you won't necessarily have needed gloves to this point.
I let it dry overnight, gave it a light overcoat, let it dry for a further two hours then baked it for an hour in the oven at the recommended 93c.
 

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