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npdw

ceramic coating stainless headers

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Hi all,

I bought the stainless header from walloth & nesch (link). When I was testfitting the header it was very close to the brake line exit through the body. My idea was:

  • Bring the brake lines forward away from the header to avoid heat in the brake lines (drilling new holes in the body)
  • Put ceramic coating on the headers to avoid heat in the engine bay / brake lines

 

Then I started reading about ceramic coating, and now I have 3 questions:

  • I found out it is mostly done on headers made of steel, but mine are from stainless steel. What are your thoughts about this? 
  • There are also many types of ceramic coating with different maximum temperatures. Any ideas about the maximum temperature of a header?
  • You can coat the outside of the header but also the inside. What would be your recommendation for stainless headers?

 

Any other advice is welcome too. Thanks!

 

Niels

 

 

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Any pictures of the proximity of the exhaust to the brake line?

 

Your brake pipe is unlikely to heat up *that much* that it causes a problem with the performance of the brakes (assuming your brake fluid is in good condition). The fluid is subjected to pretty high temperatures within the brake calipers if you use them hard. I would have thought you would be damaging your paint in the engine compartment before it did anything to the brakes. People run some fairly outlandish turbos and I have not hear of this causing, or contributing to, any brake fade. Also, while a coating may cut down heat radiation from the exhaust, is it likely to be enough to justify the cost (if this is the only reason that you are doing it)?

 

A secondary heat shield that cuts down radiated heat and allows air to flow over both sides would work too. You could form one out of a sheet of stainless steel and ‘band it’ to the header using locking stainless steel ties. 

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I'm planning to use SwainTech to coat my headers.  They have a terrific reputation, and their ceramic coating is thick enough that it might really block temps.  I'm going to leave the inside uncoated to maximize exhaust velocity.

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7 hours ago, npdw said:

Bring the brake lines forward away from the header to avoid heat in the brake lines (drilling new holes in the body)
Put ceramic coating on the headers to avoid heat in the engine bay / brake line
 

 

You might also consider insulated sleeving for the brake lines; many types / sizes available, something like this:

https://www.summitracing.com/parts/hsp-204002

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3 hours ago, Ian said:

I'm planning to use SwainTech to coat my headers.

 

I used Swain Tech on my E30 M3 daily driver stainless S14 manifold. It looked great when it was new, but the white faded as the years and miles progressed. Then, at the hot spots the "outer" white coating flaked off revealing the "inner" dull coating. I spoke with Swain Tech about it and they said "sorry about that" but that is what it does. They did note that the heat containing properties of the coating were still intact; I am not convinced however.

 

So, if you don't drive too much, then it shouldn't be an issue.

 

Alternatively, you can install a heat shield sleeve over the two lines to keep them "cooler". I intend to do this on the Turbo even though I have never had a problem. Shown is what I have done on the A/C lines on the M3. I got mine at the Hot Rod shop across the street.

 

Eastwood makes an internal coating but I have no experience with that.

 

In the case of an '02 with a header, I never had a problem with heated brakes........

PB103813 (Medium).JPG

P6064188 (Medium).JPG

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13 minutes ago, Einspritz said:

 

I used Swain Tech on my E30 M3 daily driver stainless S14 manifold. It looked great when it was new, but the white faded as the years and miles progressed. Then, at the hot spots the "outer" white coating flaked off revealing the "inner" dull coating. I spoke with Swain Tech about it and they said "sorry about that" but that is what it does. They did note that the heat containing properties of the coating were still intact; I am not convinced however.

 

Interesting observation.  I gave Swain a call this morning, and they told me the flaking was from expansion of the pipe.  Their coating goes on in layers, and the outer coating is the most brittle, leaving the middle layers intact.  They suggested that conditions that cause their coating to crack would likely crack the thinner shiny coatings, but YMMV.  I'm going to give them a try since I live near them, and will see how their coating works for a track car.

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You might also find this interesting.

 

On my S14, Cylinders 1 & 4 run lean while 2 & 3 run rich relative to the average, hence the soot shown.

 

Perhaps the mixture is burning "down there" due to the scavenging effect of the header where the two pipes meet. I haven't measured the length nor volume to see if that is the case.

 

Since you have a 4 into 1 you may not have this happen, where one part is much hotter than others.

PC133914 (Medium).JPG

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14 minutes ago, Einspritz said:

On my S14, Cylinders 1 & 4 run lean while 2 & 3 run rich relative to the average, hence the soot shown.

Do the spark plugs also indicate the same rich/lean?

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Yes. Also, you can see that I have installed two bungs for each of the downpipes. Sensors revealed that. In addition, and separately, I probed each of the individual cylinders at the ports but not under load; high and low idle. Same thing. Occurs at WOT, and partial throttle upon acceleration and steady state.

 

Here's the rub: while the 2 & 3 are rich, the 1 & 4 are lean, the injection system squirts (twice per cycle) in ports 1 & 2 then 3 & 4 simultaneously. Given that the intake side TBs are all equal, my only explanation is that the scavenging is causing the effect because the same mount of fuel and air is being delivered. Yes, I had the injectors checked......as well as all the Helmholtz and "pipe organ" calculations.

 

Of course you would never detect it if you use the port that the ECU sees as it is averaged due to the crossover placement.

 

I haven't been able to get other S14 owners to put in the ports and take readings.........but would be interested to find if "they all do that" or it is just me. No one else in the E30 M3 gruppe seems to care, and S14 members don't get it.

 

So, there you go. Mystery.

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I use the stock S14 header in my M2, so I'll check my header when I pull it off the engine for coating.  

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Just got my Try-Y from I.E,  Ceramic coating is nice so far.  I don't know if it will crack over time. But it beats having it all rusty.  My experience is that the stainless header will start to rainbow after a while.  Ceramic does keep the heat down under the hood.  I will pull out my FLIR next time I come back for a ride and snap some pics.

 

Regards

 

 

  

 

 

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Quote

A secondary heat shield

Simeon nailed it.  A shield, attached to the header where the brake line passes is by far the most effective.

I have made them out of stainless tubing, and you can clamp them to the header tube if you don't want to weld

to it.  If you can keep the shield as far from the brake line as possible, attached to the body will also work.

 

Moving the line is also a really good idea- but sometimes, that can cause other problems, so that

becomes a 'whichever works best' scenario.

 

Any sort of blanket is a distant second- the blankets don't usually allow airflow under them,

like the shields do, and that's what makes the shield so effective.  And why 2 shields do better than 1. 

 

I can't imagine a coating would help enough to make it worth the expense and hassle.

 

t

 

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(edited)

On the S14 header, what was the original use for the factory ports at each port.

 

I made a feeble attempt at inserting Haltech exhaust thermocouples in those ports, but the thermocouple probes have a 90 deg bend with a straight section to the thermocouple.  The probes could not extend far enough into 2 of the header pipes to get proper readings.  So I kissed it off as an experiment and have an EGT kit paperweight on the bench.  I is supposed to have weld on bungs that use Swagelok fittings, but I didn't want to pursue it.

Edited by jimk

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Exhaust thermocouples do a great job of getting temperature, but no so good at %CO.

 

the FLIR sounds great, but how do you get temperatures under full throttle / full load?

 

I might add, but since I don't know the S14 / 2002, that it might be a good thing to have a heat shield above the steering idler bushings a - la - Turbo. IIRC it is still available from BMW. What I DO know, is that without it, the proximity to the down pipe causes the bushings to melt.

 

In addition, the Turbo has a cooling duct right in the spoiler; it's not an air intake for the engine as some have said, but points to the center of the turbocharger. It still gets mighty hot under there....the perfect place for a roadkill BBQ.

 

I put about 50K miles on the M3 before I did the coating, but never saw a "rainbow" effect in the stainless steel......

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