BBK LT's.. chrome or polished ceramic

[spyder210]

hello all. i will be getting bbk lt's and their off road h pipe

wat type of lt's should i get? the chrome ones or the polished ceramic ones?

wat is the difference between them besides the excess 100 bucks of the pol. ceramic

wat do the polished ceramic offer more so then the chrome? any more performance out of them???

or just looks or what???

thanks

[429mustang]

I'd get the ceramic coated, the coating's supposed to insulate the pipe more keeping under the hood cooler, and they'll look good for a while. The chrome usually discolors after a while.

[fiveohpatrol]

Other than the lower underhood temperature, its really a manner of aesthetics.

The ceramic coated ones will look much nicer for a much longer time, and the chrome ones will turn a blueish color the first time you drive it.
I had chrome shorties on my car, and after about 2.5-3 years of use, they had barely rusted, and looked pretty much the same (blue) as the day I installed them (after they discolored)

Unless you have huge plans for the car, I don't think the underhood heat loss will justify the extra cash, but thats just my opinion.

[Technick]

It is more than just a issue of underhood heat. If the heat is less under the hood, WHY? Because more of the heat stays in the header tube, the hotter the exhaust gasses, the faster it moves, more velocity, more velocity equal better scavenging of the exhaust, which results in better cylinder filling of the engine, which makes more power. How much power depends on your particular combo. It is defenatly worth the extra bucks in my opinion.

[fiveohpatrol]

I've never seen velocity given as a function of temperature, what makes you think that?

[Technick]

Basically when you heat something up it expands, when it cools down it contracts, with the exception of water. So the further down the exhaust pipe the exhaust goes the slower the exhaust goes, that is why most stock exhaust systems have the pipe diameter reduced the farther it gets from the engine, to keep the velocity up , which helps the scavenging effect of the exhaust. Why do you think that turbo's are as close to the exhaust manifold as possible? If it was back at the tailpipe it would produce little if any boost! That is another reason why turbo's have a lag issue. It takes "time" for the expanding hot exhaust gasses to get the impeller moving.The hotter the exhaust gases are the faster the turbo impeller spins! Basic physics!
Now close to the cylinder head, where the exhaust is the hottest, and fastest, you can get away with a "stepped" header which also helps scavenge the exhaust. By creating a change in header diameter (slightly larger, usually by 1/16") one can cause a "low pressure" area at that point that will help pull the exhaust down the header pipe. This does not work at the tail pipe or elsewere as the velosity and heat are not enough to sustain the effect.