Heat coating worth the bother?

[Jurgen-Jm-Imports]

Am I getting the wrong end of the stick when I think that from that report there are zero bhp gains to be had, and that "The performance of Zircotec’s coatings" relates purely to how well it protects things around the manifold?

 

this is purely why mine have been done..

 

and possibly to prolong the tubular manifolds life..

[TLicense]

reading the mira report , outer coatings made less than 5 degree shift in gas temp (the accuracy of the temp probes being +- 5 degrees - on a normal exhaust manifold - with 2 thermocouples being suspect and ignored -ie short version, bugger all gain

but the convection heat reduction was 30%+ good for your engine bay

so where did the heat go ? conducted into the material of the manifold ?

 

not exactly the test the turbo owners would want to see ,a simple measurement of turbine inlet temp is what we would need to know and probably not a great idea to repeat the 5 mins time used at full boost either -lol

 

Looking at the full report though, it's clear that at anything below full engine load (the value of which isn't defined in the report) there is a significant increase in the temperature of the exhaust gas. For example at location TC8, at 60% load during the 225Kg / hr cooling case, the EGT delta is in the region of 60 degrees. It's at these transient loads that turbine performance will be improved.

[TLicense]

Am I getting the wrong end of the stick when I think that from that report there are zero bhp gains to be had, and that "The performance of Zircotec’s coatings" relates purely to how well it protects things around the manifold?

 

I would say yes, the wrong end of the stick. The gains are two-fold.

1. The heat convected from the exhaust is less, so the cold air intake will be less saturated by the heat from the exhaust.

2. As I mentioned above, at transient conditions the EGT's are higher with a coated mainfold. This will help turbine spool. I was kind of expecting to see that at full load, the EGT's would still be much higher (which would have been a negative point) but the temperature doesn't increase as much as the uncoated manifold as the load comes on. So although the temps are hotter during spool up, at full load the temps are much the same as they would be otherwise. ++

[jevansio]

I would say yes, the wrong end of the stick. The gains are two-fold.

1. The heat convected from the exhaust is less, so the cold air intake will be less saturated by the heat from the exhaust.

2. As I mentioned above, at transient conditions the EGT's are higher with a coated mainfold. This will help turbine spool. I was kind of expecting to see that at full load, the EGT's would still be much higher (which would have been a negative point) but the temperature doesn't increase as much as the uncoated manifold as the load comes on. So although the temps are hotter during spool up, at full load the temps are much the same as they would be otherwise. ++

But in my experience, if a performance car related company puts a product into test which shows even a slight performance increase they multiply it by 10 and say it's fact. The fact that no performance claims are made or inferred says to me there are none.

 

Sorry Tony but I have a hard time believing that a coated vs non-coated manifold would have any performance effect on a moving car with a stock airbox or appropriately shielded filter (and TBH I think even an unshileded one) in the area of cold air intakes. It seems to me you are really grasping at straws if thats a reason for the coating

 

I also have a hard time believing that this has the ability to increase EGTs to a greater extent during spool up, yet not once fully spooled (if that's what the results say) How can that possibly be, surely as the temp goes up the difference in coated vs uncoated would just keep getting bigger?

[TLicense]

But in my experience, if a performance car related company puts a product into test which shows even a slight performance increase they multiply it by 10 and say it's fact. The fact that no performance claims are made or inferred says to me there are none.

 

Sorry Tony but I have a hard time believing that a coated vs non-coated manifold would have any performance effect on a moving car with a stock airbox or appropriately shielded filter (and TBH I think even an unshileded one) in the area of cold air intakes. It seems to me you are really grasping at straws if thats a reason for the coating

 

I also have a hard time believing that this has the ability to increase EGTs to a greater extent during spool up, yet not once fully spooled (if that's what the results say) How can that possibly be, surely as the temp goes up the difference in coated vs uncoated would just keep getting bigger?

 

Well it's not my job to convince you one way or the other. However I think the reason why they haven't given any performance gains is because it's a generic process that can be applied to any application. Or are you saying that you don't trust it because they didn't give an output BHP on their report? I agree that most aftermarket companies do sell a tremendous amount of BS, but when it comes to real motorsport or OEM stuff you can usually cut the BS factor of 10 down to maybe a 2.

Another way of thinking about it is do you think Zirkotek would post up a report that did actually say "our product offers no performance improvement at all"?

 

With a stock airbox, or a good shielded filter, I would agree. But as you and I well know, a well shielded filter is hardly commonplace in many modified cars.

 

When I initially saw the result I scratched my head for a few seconds as to why their is an increase in EGTs during transient loading but not at 100%. However, when you consider that the coating is holding heat into the exhaust I think it's fairly clear that what it is doing is simply retaining heat rather than generating it. The peak temperature doesn't increase because the the rate of heat transfer is proportional to the gradient of temperature between two bodies. (ie if you put a hot and cold thing together the temperature change will happen faster than if they're almost the same temperature). Put another way, it would be impossible for the temperature of the exhaust pipe to get hotter than the exhaust gas no matter what you coated or insulated it with. The extra heat has to come from somewhere.

[jagman]

The test is fundamentally flawed in that - there is no turbine !

The turbine is the largest and most rapid consumer of heat energy , and it aint there.

Its akin to a shoe test in bare feet.

There is also no/little pressure in the manifold compared to a turbo manifold

 

Data would also be needed to establish the rate of rise in the material temp (manifold)as this could impact on cyclic thermal stress within the metal and cause cracks - what it does without doubt is

1 look good

2 keep components near the hot items cooler

[TLicense]

I don't think we need to be fully spoon fed here though do we?

OK put it this way. What do you think adding a turbo to the manifold would do in terms of a delta between a coated or uncoated manifold? Or let's see if we can get to the bottom of this, what do you think makes a turbo work better, hot exhaust gas or cold exhaust gas?

[jagman]

There are people who despite owning a turbo car dont understand how a turbo works , spoon feeding as you call it makes easier reading and avoids some complex thermodynamic theorems.

Once basic concepts are understood , marketing fluff becomes more understandable .

The turbine needs large differences between inlet and exit temps to be efficient

during spool it does not have this , the engine is not producing large amounts of heat energy , " preserving" the reduced energy is not worth it .

What do I think makes a turbo work better - the other end - create more heat , timing,add fuel,improve compressor efficiency,cams,head , lots of things , but not trying to add to heat by less losses in the manifold with coatings

If this was the goal then the inner wall would be coated , better still a ceramic tube inside the manifold with aerogel interlayer on a split , air sealed manifold , - do i think this would improve spool - nope

hot gas is better than cold but the difference with coating or without at low rpm and low heat energy is not going to overcome any inertia in the turbine by any significant amount.

At high rpm and high heat energy you have bag fulls of heat energy - so much that we limit the boost and avoid overspeeding .

The original question was it worth it - if you have the money and to keep components cooler - then go on - but 1200 quid would buy a lot of heat blankets to cover components with and or Buy power making components

Edited February 18, 2011 by jagman (see edit history)

[James]

Hosting all of my lecture notes for my Industrial Plant module would be very handy just now to show turbines and heat exchanges, exhaust gases etc.

[Jellybean]

you might want to dumb it down a bit -- thermodynamic theorems ha ha love it

 

That is goin on next weeks -- status report

[Axle]

So have those who have had this done had any before and after tests conducted?

 

Or had any noticeable gains/benefits?

 

I am contemplating whether it's worth getting this done on my new 4' whiftbitz manifold/dp.

[mwilkinson]

Axle I have not had this done yet, but when I get my turbo kit from Paul I have decided to pay the cost of getting the manifold heat coated at the least. Regardless of the efficiency of this product I view it more as a labour saving exercise. Can you imagine trying to effectively wrap one of his twin wastegate manifolds with conventional wrapping. Not my idea of fun

 

It also looks a lot neater IMO

[markssupra]

Bit of a thread revival.

 

Has anyone had their manifolds, turbo housing or downpipes ceramic coated by CamCoat? I'm ready to send mine off and wonder what experiences you've had.

[Chris Wilson]

The owner of Camcoat, Peter Carter, way back when, lived quite near me in Wilmslow and I got to know him well. They are well respected and have been going donkey's years. The few things I have seen that they have heat coated looked good. But beware, tubular manifolds for turbos need all the help they can get to stop them cracking or warping. Keeping more heat in the pipes may NOT be a good idea.

[markssupra]

Thanks Chris, what would you suggest? The manifold is a tubular HKS for twin 2835's so I could possibly heat wrap the manifold and downpipe and just have the turbo housings coated.

 

Mines similar to this one, but a little more tubular towards the turbo flanges.

 

[Chris Wilson]

I would leave it uncoated, and neither wrap nor coat it, it'll make it a bit less liable to cracking. Or spray it with Sperex very high temperature paint yourself, or an equivavlent. I'd be spending money on having some support brackets made for the turbos and wastegates.

[markssupra]

Thanks Chris, that'll save me some money. Once I get it all together, I can fabricate some support brackets no problem