stainless steel exhaust headers: to wrap or not

dark_knight

dark_knight

Member +
some of you may have been following my td04 build.. and know that i got a toyosports ss exhaust header. i've heard of and read several posts of users complaining that they crack a lot. my question is, why do they crack..? what is the real reason..?

a) is it that the tubing expands/contracts faster than the flange during normal use so the difference in rate causes the cracks..? would heat-wrapping the headers then prevent this..?
or
b) is it that the weight of the turbo and mani weighs down on the flange (if not braced) and the engine wiggling about during routine use causes the cracks..? would bracing them then prevent this..?

can someone clarify and give convincing reasons to the same..?
 
dac69er

dac69er

Super Moderator
ive not had any cracking issues yet, but the damn think leaks from the flange as its all distorted from the heat of the welding. i have had the flange skimmed and it helped mildly.
 
dac69er

dac69er

Super Moderator
Mine is braced at the downpipe. I have heatwrapped it for the simple fact that it stops so much radiant heat in the engine bay, and most importantly near my fmic
 
dark_knight

dark_knight

Member +
how big is your fmic dac69er for you to worry about radiant heat from the headers..? i'm more worried about my hood paint.. as the headers do boil quite a bit..
 
S

Skalabala

Member +
Heat wrap will give you better fuel consumption, better turbo spool and wont heat everything in the engine bay to a million degrees.
Do not remember the brand but it was "Titanium" 2500 deg F works great!
Brace and wrap it will help a lot!
 
dark_knight

dark_knight

Member +
good one Skalabala. i've heard nothing but bad things about the cheapo wrap we have available on eBay and the likes.. so i've been a little hesitant. how much worse off is the turbo spool without the wrap..? is it really anything noticeable..? like do i have to rev to 8k to get boost..? lol
 
dac69er

dac69er

Super Moderator
dark_knight said:
how big is your fmic dac69er for you to worry about radiant heat from the headers..? i'm more worried about my hood paint.. as the headers do boil quite a bit..
Click to expand...

its not big, its a renault 5 turbo intercooler. it sits in front of the manifold.
 
thefalls

thefalls

Member +
The general opinion is to wrap mild steel and leave stainless steel alone. Did the research long time ago and thats what everyone said.
 
dark_knight

dark_knight

Member +
mild vs. stainless wrap

thefalls said:
The general opinion is to wrap mild steel and leave stainless steel alone. Did the research long time ago and thats what everyone said.
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i think you meant it the other way around thefalls.. mild steel is the one that is more prone to the elements so you'd rather not wrap it as the wrap would actually keep moisture in, speeding up degradation.. or am i twisted in thought on this..?
 
wildchild

wildchild

Member +
mild steel or stainless steel, the heat wrap keeps the heat in the pipes until it leaves the manifold. else engine temp and turbocharher temp will soar high and will affect performance.
once the hood is closed. it cannot be prone to elements unless through the grill. that too just 5mins after start up will evaporate any moisture in the wrap.
 
dark_knight

dark_knight

Member +
allow me to disagree with you wildchild, on account of the fact that if the manifold is not wrapped then the engine and turbo temps will rise. how..? if heat is escaping, then how will it again be that the engine+turbo temp will rise..?
once the hood is closed, yes, there is a chance that it will cook the bay temps. i have a vented hood and no air-con so i have better flow into and out of the bay..
 
S

Skalabala

Member +
Have seen 300rpm gain with wrapped mani and dp.
And remember that you must put the wrap in water before applying it :)
Stainless must be wrapped, it just cooks everything within time!
And a turbo blanket also helps!
 
Sheldon

Sheldon

Malta Area Rep.
Skalabala said:
Have seen 300rpm gain with wrapped mani and dp.
And remember that you must put the wrap in water before applying it :)
Stainless must be wrapped, it just cooks everything within time!
And a turbo blanket also helps!
Click to expand...

what heatwrap have you used? apart from the high temps, stainless manifolds like mine will need attention they look ugly by time!
 
dark_knight

dark_knight

Member +
yeah.. look at that COST Skalabala.. no thanks.. can't have heat-wrap more expensive than my entire turbo setup.. :) lol
 
wildchild

wildchild

Member +
dark_knight said:
allow me to disagree with you wildchild, on account of the fact that if the manifold is not wrapped then the engine and turbo temps will rise. how..? if heat is escaping, then how will it again be that the engine+turbo temp will rise..?
Click to expand...

This is where most ppl get it wrong mate.
when the exhaust header heat dissipates to the surroundings, its heats up the radiator as well as the turbocharger as they are closeby. when turbocharger gets hot, it will be pumping in hot air instead of cold air. having a FMIC will reduce this heat but remember that ur still forcing in hot air rather than cold air. when its compressed, it gets hotter. Overheat also tends to kill bearings and seals sooner.
heat wrap wasnt discovered without a reason. it keeps the heat inside the wrap from escaping till it reaches the down pipe. although its not 100% effective, it still gets the job done. There are different types of wrap material on ebay. here's a link on one.

http://www.ebay.com/itm/DEI-1-x-15-...Parts_Accessories&hash=item2a21a767c3&vxp=mtr
 
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