Heat Management Of Turbos Manifolds Pipes Etc .

[discopotato03]

This is an area that should interest all performance car people especially the turbo brigade for obvious reasons . The topic should be split in two to cover longevity of underbonnet essentials and minimising charge air temperatures .

The primary drama is usually radiated heat from exhaust manifolds/exhaust turbine housings and the dump + engine pipe/s . You only have to look at the standard set up to realise that the manufacturer went to a fair bit of trouble with heat shields to make it long term reliable .

Often we change the mix of bits to suit our performance needs and the heat shields get the flick . This can cause major heat problems to everything under the lid and can cause fuel fires amongst other nasties . I'm interested to hear other peoples experiences with heat shields , thermal blankets particularly of the aluminised (sp?) type which some car makers ie Ford use . I have tried using the Thermotech wrap on cast manifolds and cast dump pipes without cracking them . I have also used their wrap on a steam pipe manifold which also stayed in one piece though I only had it for 6 months . I remember thinking that some form of shield around the turbine housing would have helped , the engine pipe was wrapped .

Its difficult to know how well the turbine housing copes with the "tea cosy" , would probably depend on the material spec of the housing . If its an early diesel housing ie TO4 its probably a lower spec material only designed to cope with diesel exhaust gas temperatures . I have seen a few of these particularly the split pulse type cracking up on the inside from overheating .

I reckon water cooling would be essential for the cartridge bearings survival and a bit of time should be spent to make sure it thermosyphons properly when the engines shut down .

High mount turbos have the potential for problems because the heat exposures have moved from down low in the bay to up high and closer to components not designed to cope with turbo heat . Real race cars are not going to have the sort of things around that make the mobile lounge room comfortable and there are more freedoms to relocate the essentials .

Anyhow I'm interested to hear what did and didn't work for others .

Cheers A .

Edited March 1, 2006 by discopotato03

[2BNVS]

i had a heat shield on my turbo and i didnt really like it, heat was still pretty high, surrounding plastics were extremely hot, and also my air con pipes were pretty damn hot

i got a xtr turbo bag and so far so good, under bonnet temps are reasonable, my air con pipes are fine and so are my plastics around that side of the engine bay.

ben...

[RANDY]

I'm of the kin that; if it was there from factory, there's a good reason for it!

When you start modifying turbos and dumps, you need aftermarket shielding or ceramic coating. Stuff catching on fire doesn't sound like fun. =-]

[Bl4cK32]

Cubes and myself saw a rotary with a large highmount turbo (read gt42?...it was frikkin huge) and the guy had it on the dyn o for a few hard runs, then he took off up the street a few times.

The guy came back, and shut the car off and opened the engine bay. Cubes and myself were looking at his turbo bag on the car. You could actually go and put your hand on the thing it was that cool.

When my setup is finalised, i'll be using a mixture of all the things. Ceramic coatings dump and manifold, wrapping the pipes, and using a turbo bag.

[StockyMcStock]

good thread!

turbo bags + manifold wrapping seem a good way to go. people debate the longevity of steam pipe manifolds with thermal wrap, but i personally have never had a problem with my wrapping. i had a set of extractors wrapped for near on 2 years, removing the wrap two days ago and they were perfectly fine underneath. however, extractors don't get as hot as turbocharger manifolds.

[rev210]

Thermal wrapping as I have said in many a thread is great as long as it is done right. Coating the pipe with a ceramic based coating is a great idea before wrapping and it's very cheap at the level of the ceramic coating thickness just providing for anti-corrosion. The stuff to use is VHT flameproof in 'flat white' it is the only colour that has the ceramic pigment and will live happily under the thermal tape.

thermal tape always gets its bad wrap (pun) from people who didn't take the time to do it right.

Cast iron must be very evenly coated and well sealed to ensure cracking does not occur hence why the thermal tape guys reccomend against wrapping cast iron manifolds since they are often not 'round' enough to have the tape even.

[CAT_SPEW]

Does anyone know where I can buy a roll of this thermal wrap over the net? I've been looking on Nengun and can't find anything????

[Tangles]

Following the previous query:

Does anyone know where I can buy a Turbo bag?

[lwells]

Thermal wrapping as I have said in many a thread is great as long as it is done right. Coating the pipe with a ceramic based coating is a great idea before wrapping and it's very cheap at the level of the ceramic coating thickness just providing for anti-corrosion. The stuff to use is VHT flameproof in 'flat white' it is the only colour that has the ceramic pigment and will live happily under the thermal tape.

thermal tape always gets its bad wrap (pun) from people who didn't take the time to do it right.

Cast iron must be very evenly coated and well sealed to ensure cracking does not occur hence why the thermal tape guys reccomend against wrapping cast iron manifolds since they are often not 'round' enough to have the tape even.

The Design Engineering Inc (DEI) thermal tape seems to be the most popular because it has a 1/4" guide on the tape to help get the overlap right.

When you talk about "ceramic based coating" under the wrapping, do you just mean the VHT paint with the pigment, or actually getting a ceramic coating applied professionally (or either)? According to the DEI site, one should also apply a layer of their heat paint over the top of the wrapping to protect it.

Finally, does any of this change if we are talking about stainless or mild steel vs. cast iron?

[rev210]

I usually spray the paint over the top of the wrap too as DEI suggest. DEI is my tape of choice for the markings.

Ceramic coating commersial style is better than the VHT for thermal sheilding, the VHT is if you don't have the extra dollars to do that as well.

[grim32]

Does anyone know where I can buy a roll of this thermal wrap over the net? I've been looking on Nengun and can't find anything????

Following the previous query:

Does anyone know where I can buy a Turbo bag?

Horsepowerinabox.com have both of them

[caminperth]

Questions on the coating - though they may have been answered before and I just can't read - does it reject heat from the surface, therefore stopping the metal from getting hot? Therefore a coated exhaust housing would not get as hot, therefore putting less heat loading on the bearings?

[rev210]

If you ceramic coat the turbine housing you usually do the 'inside' of it too, the coating acts as an insulation.

Bearing heat soak, is not an issue.

Edited March 2, 2006 by rev210

[Roy]

Bearing heat soak, is not an issue on a water cooled turbine.

Why not. You shut down the engine you still have a glowign red exhaust housing that is surroudned by still air and with the blanket on it the heat isnt goign anywhere quick...adn there isnt any coolant running with eh engine off?????????????

[rev210]

Why not. You shut down the engine you still have a glowign red exhaust housing that is surroudned by still air and with the blanket on it the heat isnt goign anywhere quick...adn there isnt any coolant running with eh engine off?????????????

Or if you think about it most of us know to 'cool down' our molten hot turbo engines after a good thrashing regardless of turbo beanie. When you do this because the turbo isn't being shlacked into glowing redness it cools down rather fast thanks to oil and water circulating through the bearings. Basically if you wanted to measure the minimum time you had to cool down the turbo the turbo beanie would add a few more seconds or perhaps none, but if you are allowing only for the minimum in the first place you are a bit silly. Of course we aren't silly so we cool things down to be sure to be sure and that is quite enough time for the oil not to turn into coal in the turbo bearing beanie or not.

A simple way to put it is that the exhaust turbine housing is not designed to be a heat transferer to be rid of nasty hotness away from precious turbo bearings.In fact being made of cast iron it's quite possibly the worst thing to ever use if it was supposed to do this, which it isn't. This we leave to the 'water-cooled' and oil cooled features of the turbo notice how the turbo makers are always crapping on about it in their brouchures?

I'm pretty sure I'm right about this but, my desciption may not be correct. I am really only having a go at trying to explain why I have absolutely no experience of what people are talking about with this turbo beanie = bearing failure. I've never seen or heard of it or experienced it myself, and I guess I can't see why either?

[discopotato03]

Roy turbo water cooling was explained to me as follows .

Water is a very useful coolant because it takes a lot of heat energy to boil it . What we want the coolant to do is absorb the heat from the thermal mass of the turbos bearing housing and some conducted heat from the turbine housing and take it elswhere . Generally there is not a lot of material in the bearing housing casting so it can only absorb and temporarily store so much heat energy . The danger period for the turbos bearings is hot shut down because oil and airflow ceases . If the turbos heat is enough to cook the oil in and around the bearings it will kill itself .

What I did with the old FJ20 was to add water cooling that was not standard , the BB turbo had it so with the cost of the things it made sense to use it . The fellow who used to run Road and Rally Centre set it up so that it would thermosyphon when shut down and do the heatsink thing for the two or three minutes it took to get the core down below waters boiling point .

FJ20's like I suppose most iron blocks have a coolant drain bung low down on the exhaust side so he figured this as being the most convienent place to find a water supply . The bung was drilled and had a short piece of steel fuel line brazed into it for the water line (EFI hose) to clamp to . That bottom hose actually scribed a "U" shape so it would prime and not form an air trap . I ratted up the required banjos and bolts to fit the turbo . The turbos water outlet must run up hill and mine re entered the cooling system on the head side of the thermostat (FJ20's have the thermostat on the heads water outlet not the blocks water inlet like an RB) . So the water path started low down where its cool and dense . When the engine was shut down the water in the turbos water jacket would start to boil and the steam bubbles would gurgle up the pipe to the head and out through the thermostat and via the radiator cap to the overflow tank . Because the hot water flowed up out of the turbo it was replaced by cooler water from low in the block . When I say water boiling in the turbo I don't mean hammering and banging violently like a cooling system in melt down mode . It was all very gentle but entertaining to listen if it was quiet (this was in the pre riot days) . So it was really set forget and automatic . The crucial bit is that the hot water MUST be able to flow uphill to the head so no highest point before this or it may form a gas trap and not self syphon (thermosyphon) . I also stay away from any other water lines ie heater hoses because they don't always flow in the desired direction . I wanted it to be an independent system to make sure it worked . The lines can be 5/16 or 8mm so don't need 1/2 " lines to cool a small thermal mass .

I've put this idea up on other sites though people have hysterics as soon as they hear "water boiling in turbo" for some odd reason . Its really not an issue if the hoses are routed properly and works very well .

Two more cents spent , cheers A .

Edited March 3, 2006 by discopotato03

[rev210]

discopotato03,

Clever very clever.

[Warpspeed]

I agree totally with disco, thermal management and low under bonnet temperatures are all part of having an efficient and trouble free package.

Thermal wrap is one way, probably best for guys with tube manifolds. If you are still running the cast iron factory manifold, the best way I have found is to construct a fairly close fitting mild steel sheet metal box right around the entire manifold. It must be as air tight as you can make it. There should be a jacket of completely still dead air in there, which will insulate surprisingly well. If the sheetmetal cannot curl right up behind the manifold, it should seal tight against the engine block surface. The surface temperature of the steel will probably be in the region of 90C to 120C, a lot cooler than a 1,000C+ manifold.

HPC coating is supposed to be excellent, but I have never tried it myself.

[Roy]

If you ceramic coat the turbine housing you usually do the 'inside' of it too, the coating acts as an insulation.

Bearing heat soak, is not an issue.

Rev/Disco...interesting

Im 100% behind the above. The best place for the heat is the exhaust gas, so shoudl do your best to keep it there.

As for th eblanket...i haer what you are saying, but i suppose im stubborn and still reluctant to go down this path As for bearign failure, your right, i dotn think you can really sight issues where ppl have used these kackets and had turbo failure...i doubt that woudl be the case.

Its just that with a carefully build shield, i think the pocket of air around the housing like Warpspeed suggests is a better option....beign anail i supose, but i just dont all that heat nto goign anywhere. Ppl say its cool to touch after a hammering...so that means the heat is goign somewhere and you woudl assume mos tof its going into the coolant/oil etc Im sure the cars coolign system and oil system could handle the additional heat load, but id rather not see it be burndened with it, especially if you ahave an oil only turb like me

So id suggest you could very well be right, but as always, i suppose it depends on the trade off and what you have and want:laugh:

[Guilt-Toy]

Very interesting topic for me too. i have a bit of a story to tell.

My car just had its GT3540 installed and running (high mount) and it just went somehwere for a exhaust repair and when the guy left it there and shut it off my mate turned around and looked at the car and there was smoke bellowing out of the engine bay.. being a champion that he is he ran to car popped the bonnet while my other mate got the fire ext and put the fire out.

Apparently the whole heat shield under the bonnet caught on fire and it all dripped over the engine and melted bits of my coils and all over the cam covers and my smicko manifolds and turbo

But it was caught in time and all that was lost was the heat shield under the bonnet so the car does not catch fire anymore. It also cleaned up really nicely so appart from the small black patch on the top of the bonnet you cannot tell.

I would like to cover the turbo with something to prevent my paint from bubbling as a few mates i know with high mount turbos on 1600's bubbled there paint (a month worth of driving has not bothered mine yet)

So yeah such a close call ! So now you know that stuff under the bonnet catches fire VERY easily.