Been watching a few car shows... Wheeler Dealers... Car SOS ... Gas Monkeys etc ...

I have heard that this is one of the best and most efficient ways of improving engine performance without fiddling with the ECU or adding extra performance parts and not putting any extra strain on existing parts...

It makes sense, by taking away heat from the engine the cooler air will make it perform better.

Has anyone had this done on their Jag?

Are the benefits worth the cost?

I think it is about 200 quid per manifold.. then you have the cost of removal and re install and recalibration of the ECU (not sure)..?

On the face of it it seems like a very good way of improving the cool air flow without adding a load of new parts?
Thanks

Smitty

 

Smitty, I will jump in on this as I think it is a lot more hype than actual improvement (other than cosmetic). At part throttle, the air maybe spends 3 seconds in the intake. That is not a lot of time for the air to warm up. But, lets play with some numbers. Lets say in that 3 seconds, you are getting 10F warmer air into the engine (probably doesn't warm up that much, but I will give you this much just for the sake of the argument). 10F change in air temp is good for 1% change in power. So, assuming you are starting with a 400 hp motor, even at a moderate "part throttle" where you are getting 300 hp out of the engine, with this mod and making everything identical again, now you are making 303 hp. I doubt you would see that difference. Keep in mind that I am giving you a lot to make the numbers come out in your favor. Even under full throttle, the air wil spend less time in the intake (absorbing that much less heat), but you would only see maybe 4 hp change. Does the ceramic insulate well enough to make outside air temp equal the temp going into the cylinder?

If you look at the exhaust, a ceramic coating is not going to provide that much heat transfer resistance. So, again, I am going to try and give you everything possible. Lets say that the ceramic coating drops the under hood temps by 20F. This change is only going to help reduce the amount of heating that the intake is going to experience. This really would only be a gain if you are sucking underhood air (which most modern cars do not do). But ,I will give you all 20F change. The motor will experience a 2% change. So, on a 400 hp motor at full throttle, you are going to see 408 hp. Yes, a gain, but in the scale of things, not anything that you will really feel.

So, in short, you can see a max gain of 12 hp on a 400 hp motor (only seen when at full throttle really) that would end up costing you 600 quid (400 for the exhaust manifolds, 200 for the intake). Awefully expensive power gains if you ask me.

If you are wondering why I am talking about this, I have done a lot to my truck to try and gain as much power as possible through cold air and figuring out the effects. One of the things I did with my truck was put it on a dyno and measure the difference between a stock intake and my modified intake (which really was cutting off the restrictive cone over the air filter, the rest was more than adequate for the motor). Removing a major restriction to the intake and therefore sucking under hood air in the process, I gained 1 hp and 10 ft-lbs of torque (per the dyno) on a 235 hp motor. Because the intake sucks in behind the headlight, the under hood temps are not going to rise from outside temps when moving and if you are sitting still, not much power is needed from the engine.

Now, you want to gain something, take those exhaust headers and use a die grinder and round some of the sharp edges. Get into the intake and round out some of those corners to make them flow better. Now, this is where you can start to see some gains. This is another one of the things I did with my truck. It was a lot of time and effort, but the cost was minimal. But ,I pulled the heads and did a mild port and polish on the heads and intake to make a moderate change (say 15 hp, granted, that is more of a butt dyno number as I never had the motor dyno'ed after that mod, but I could feel a little bit of a change). The fact of simply smoothing out the intake reduces what is called the laminar boundary layer (where the air "sticks" to the surface, restricting overall flow, normally about 1/8" thickness for air) because you don't have the air tumbling over the cast surface which is rough. By smoothing it out, you reduce the laminar boundary from around 1/8" to under a 1/16". Ok, this doesn't sound like much, but take a 2" intake pipe. With the laminar boundary figured in, really you are using a 1-3/4" tube with no sidewall restrictions for a total tube area of 2.40 square inches. Where, if you smooth the walls, get the laminar boundary down to say 1/32", now your effective tube size is 1-7/8", or a tube area of 2.76 square inches. While it is not mcuh, that is a gain of roughly 15% in area. You will see a lot more power change with that than the ceramic coating.

So, can you get some benefit from the coating like the shows say. Sure. I think where they are getting the most gains is spending some time doing a mild polish on the intake/exhaust headers to smooth out the surfaces to get their gains there.

 

Very good detailed answer from Thermo.
It does look cool too.
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