Alex's white NA8 build.

[Alex 2550]

Black is better for radiant but the paint provides a tiny amount of insulation for convection which is how an air to air really works, it obviously will absorb heat from sunlight and the road easier through radiation but again it’s a small amount.
Engineering explained did a video debunking MCMs video.
I’ll only be spraying the parts visible from the front and trying not to soak the core.
Last time I taped up the rear when painting to discourage air and paint to flow through the core.

If this was a full race car chasing every tenth I wouldn’t paint it, I also would of gone the low mount Manifold instead of top mount


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[greenMachine]

Yes, vive la difference!

[Lokiel]

I never understood why a painted intercooler could be better than an unpainted one as claimed by MCM.

It's essentially adding a layer of insulation to the aluminium intercooler.

Thermal dynamics with regard to air cooling basically means that surfaces are always moving to the ambient temperature:
* if the ambient is hotter they heat up to it
* if cooler, they cool down toward it.
The greater the delta between ambient air temperature and the material, the greater the heating/shedding of temperature by the material.

Aluminium absorbs heat/cold quicker than paint so sheds/gains heat faster than paint too.

The paint layer is slowing down the aluminium's ability to shed/gain heat, it's only changing at the rate of the paint layer, not the aluminium which will be MUCH hotter.

If you want a black intercooler, get an anodised one, not painted.
Even then, anodising changes the properties of aluminium so double check if it affects its temperature too.

As ManiacLachy pointed out too, painting an intercooler black isn't a great idea, it's subject to receiving a lot hits from debris/stones that will chip the paint and look ratty very quickly. Even full of bugs and with lots of bent fins from stone impacts, a raw aluminium intercooler looks OK/good.

[bruce]

MCM are 'not the Messiah but just a bunch of naughty boys'.

[KevGoat]

... or rather than paint, fit a grille.... Stealth, plus protects the intercooler (I've removed stones, dead birds and other stuff that could have damaged the IC) and doesn't restrict airflow radically.

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[The Zork]

There is a reason why manufacturers paint the radiators black. Clue: it's not to save money

[Lokiel]

There is a reason why manufacturers paint the radiators black. Clue: it's not to save money

... so that they look shitty within a year or two and fastidious owners buy a new one?

[StillIC]

I believe manufacturers coat aluminium heat exchangers black to help prevent corrosion, which improves long term performance. That is, a corroded heat exchanger works less well than a black coated non-corroded radiator. But I am sure a shiny new uncoated aluminium heat exchanger works best.

[Alex 2550]

Something for everyone to enjoy,
Shows that painting an intercooler black does reduce efficiency slightly.
It’s negligible, I’ll be painting just the front face of mine still but if I was going after as much Power as possible or tracking it I would not.

https://m.youtube.com/watch?v=z_mmmXTbLP0


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[Alex 2550]

So had a chance on the weekend to do a little porting on the manifold and turbo, basically just a gasket match in manifold and turbo then ported the wastegate a little and gave it a little valley to guide gasses, with a 3” exhaust behind it people have talked of boost creep issues due to how free flowing the exhaust is and how restrictive the wastegate port is.
People overcome this to a degree with what I have done, my thought. do it now and not later.

I started with a carbide and worked down to 160 grit.
I actually continued on from these photos tidying it all up a little, these pics are only after the first round with carbide.
Watched a few videos and I know I could of take more out of the wastegate but I got scared of it not sealing.
First up the manifold.





Now the turbo, you will notice much more came off the turbo than the manifold so I would of essentially had a step all around the turbo flange, also you can see the large bumps from casting where the studs go, I measured and these are about 12mm thick so I removed them.








Manifold, elbow and dump pipe get picked up today to go get ceramic coated.
Still looking at options for turbo heat shielding and not sure if I will make a turbo mounted shield or something similar to Flyin Miata.
I’m considering painting the compressor housing the same as my valve cover as I have left over paint that has high enough heat rating. Just a cosmetic thing but hey why not?


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[Lokiel]

Nice job with the porting. It seems a scary job but if you take your time, use light, short circular strokes, you wont take off too much material with each stroke.

I'd be wary too of taking too much material from the bolt points - in some photos it looks like the wall is thick enough to remove more material but if it's near a bolt, you want to keep it thicker for added strength (otherwise you can thin it out a little).

I find you get the best results if you do it over a couple of days.

After day one, you've done most of the work, it's taken a while and you'll think "That's good enough!"".
The next day you'll be refreshed and can see those little areas were it can be improved upon and shouldn't take long to clean up - after taking longer than you expected because now you're good at this and your critique levels have been raised, it'll be ready.

[Alex 2550]

Nice job with the porting. It seems a scary job but if you take your time, use light, short circular strokes, you wont take off too much material with each stroke.

I'd be wary too of taking too much material from the bolt points - in some photos it looks like the wall is thick enough to remove more material but if it's near a bolt, you want to keep it thicker for added strength (otherwise you can thin it out a little).

I find you get the best results if you do it over a couple of days.

After day one, you've done most of the work, it's taken a while and you'll think "That's good enough!"".
The next day you'll be refreshed and can see those little areas were it can be improved upon and shouldn't take long to clean up - after taking longer than you expected because now you're good at this and your critique levels have been raised, it'll be ready.

Spot on,
The photos here are after the first go.
I left them and went and did some other things, came back and thought “yep can do better”


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[greenMachine]

It looks like you have matched the ports to the gasket, and that is logical. But, as you mentioned, and as is clear from the 'before' photos, the gasket opening is larger than both the manifold and the turbo entry, with the turbo entry being the smallest of the three.

I think the way to handle the porting task is to forget about the manifold (unless there are dags to be cleaned up), and transfer the manifold exit opening to the turbo entry opening, and port that to smooth the gas flow transition from the manifold cross-section to that of the turbo port.



Enlarging the exit of the manifold, then constricting the exhaust gas down to the turbo port size will only make the gas do more as it makes two transitions rather than one. Whether that makes any material (sorry ) difference to turbo performance I seriously doubt, but as someone who doesn't want to do any more work than I have to, halving the porting task (to the turbo side in this instance) seems like a win

I have to say, for a first pass, you seem to have done a great job with the grinding Any recommendations for a good carbide bit?!?

[Alex 2550]

It looks like you have matched the ports to the gasket, and that is logical. But, as you mentioned, and as is clear from the 'before' photos, the gasket opening is larger than both the manifold and the turbo entry, with the turbo entry being the smallest of the three.

I think the way to handle the porting task is to forget about the manifold (unless there are dags to be cleaned up), and transfer the manifold exit opening to the turbo entry opening, and port that to smooth the gas flow transition from the manifold cross-section to that of the turbo port.



Enlarging the exit of the manifold, then constricting the exhaust gas down to the turbo port size will only make the gas do more as it makes two transitions rather than one. Whether that makes any material (sorry ) difference to turbo performance I seriously doubt, but as someone who doesn't want to do any more work than I have to, halving the porting task (to the turbo side in this instance) seems like a win

I have to say, for a first pass, you seem to have done a great job with the grinding Any recommendations for a good carbide bit?!?

Thanks very much mate,
I did take them out to the gasket size with the same orientation on gasket when marking so it’s now a smooth transition from the manifold to the charger without steps, I am also unsure if there will be any benefits to this.
I have read things like boost being reached faster but I’m bot sure if it would be noticeable, what I hope is it just makes it a little better flowing, I had thoughts before starting along similar lines of the BP head, Will taking these out increase flow but reduce velocity and therefore actually make things worse?
Anyway I came to the conclusion that the difference will be minor in either direction, surely a step can’t be good and to not port in close to the turbine wheel.
My thought here is that I won’t be changing the neck of the bottle but the body will be larger if that makes sense….. and in my head step was bad.

As for the Carbide bit.
Well I had a very slim choice to pick from locally but needed that day so I got a P&N workshop series flame bit, at $75 it was more than I wanted to spend but I must say it did do a much better job than my cheap ones that are quite small.

If I had the BP4W here I’m going to use I would of matched up the ports to the turbo manifold with some dye, I’m not sure how it goes grinding a ceramic coating but I believe the face of the manifold remains bare so I’ll ask when it all comes back.
I did properly bolt the dump elbow to the turbo to make sure everything bolted up nicely before going to be coated and I took a very small amount of material away from where the bolt head sits, all the areas with nuts was fine but I will need to take a couple mm of 2 studs.

I have read a bit about doing away with turbo gaskets and using a smear of grease that burns off and forms a carbon seal, if anyone has thoughts on this or has done it I would be interested in hearing about it.
It would be for manifold to turbo and turbo to 5 bolt elbow.


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[greenMachine]

Thanks, I got a Bunnings one when I did the clearancing of the suspension arms, it seemed to make heavy weather of the job but I had zero experience with them at that point. I will look around a bit more this time.

I hadn't heard about the gasketless joining, so can't comment.