this is an EXCELLENT point.... i never thought about this...

i suppose wrapping PRE turbocharger exhaust is a good idea, to keep heat in, as 80 or so percent of turbocharger spool up is based on heat, and the rest is exhaust flow...

but wrapping after the turbo might be useless, as you might want to get all the heat out ASAP, as well as exhaust gas....

this hopefully gets interesting now

 

I do not recomend wraping the headers not only on turbo cars but any header. yes it holds the heat in, and keeps it there. The Idea behind it is to keep the exhaust gasses hot longer for a faster flow, and on a turbo helps the turbo spool a little faster, or that is the idea anyways. I noticed absolutley no difference on spool time in my car vs wrapped or not. But that heat that is held in litterally cooks the header, Mild steel is worse but it will do the same to stainless, it actually crystilizes the metal making it very very brittle and weak. The end result is a header that is very prone to cracking at welds and just exhaust gasses litterally blowing thru the header on bends. I know this first hand as it did it to my headers.

Scott do not wrap your turbo headers unless you like building them.

Steve

 

Good info.

 

well we know what wrapping does...

that heat stays inside the exhaust, where its SUPPOSED to be. If your exhaust components deteriorate due to the heat staying INSIDE the exhaust... it sounds to me like there is a problem w/ the material that the exhaust is made of.

Its better to keep the heat inside cuz the exhast can flow better. when it cools, it becomes denser and harder to push out the pipe. the exhaust isnt a heatsink... its not designed to radiate heat. if it was, they would have engineered fins into the pipe along time ago. there is no benefit to allowing the heat to escape the exhaust while its inside the pipe, tube or manifold.

all that does is make the exhaust colder and denser and harder to push out the exhaust, heats up your engine bay and causes your wire harness plugs to get brittle and break, youre coolant hoses to get brittle and rupture (Z32 anyone?) makes your IAT higher than it has to be... just not good...

 

i put the The header wrap and the reflective wrap on that mr2, for one reason. not to keep the heat in the header for spool up, as it would make little or no diffrence. but to keep the heat out of the hot pipe going to the intercooler to keep the intercooler as affeciant as possable. knotice how close they are. this was only done for track night. on one run we sprayed the intercooler with C02, and it made the car quite a bit more powerful, but due to tracktion and transmission problems we decided we would call it quits on the co2 sence all it did was make the car spin more and harder to shift. tho that run the car pulled the fastest trap speed of the night at about 5mph faster then all of the rest.

Turbos work purly on how much heat makes it though the turbo.

example: take a baloon, and fill it just a little bit with air. heat it up and it will expand. so it seems like there is more air in the baloon when its hot. so the air going into and engine seems less then whats comming out. so much to the point that the pressure on the turbine wheel is so much that it can spin the compressor hard enough to fight the resistance of the pressure in the intake. there is accaully the same amount of air comming out of the engine as going in (not accounting for fuel added and ring blow by) the air is just more spread out taking up more space. so if there was no heat, the turbo would just spin with the air flow passing it but not accaully make any pressure.

 

Heating steel makes it stronger, not weaker. That is what forging is about. Aluminum foil will not work as it conducst heat.

 

i would wrap a turbo manifold but not a header.N/A=400 degree EGT and Turbo=1,600 degreeEGT. I want to keep all the heat in i can. To each there own.

 

Yes it will. its proven. My friend did it on his MKIII supra. He crumpled some Reynold's wrap around his manifold and his turbine housnig and the reinstalled his stock heat sheilds... and whoa... it made it NOT-as-hot under the hood.

check this out.

im not one to call a person a liar, especially when all the other info he's supplied me with has been legit, to date.

 

the foil will block a lot of heat. it does this two ways. one the radiant heat gets reflected by the foil, secondly the air pockets between the layers act to trap heat, much like insulation in the walls in your home does.