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Turbo Heat Shield

RB20_ZED

By RB20_ZED,
in Engines & Forced Induction

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RB20_ZED Collaborator

RB20_ZED

Posted
Posted

(Did a search but couldnt find anything specific)

I took of the turbo heat shield today and in the process screwed up one of the bolts... so i left it off.

i just wanna know if it will make much difference if the heat shield is there or not? i mean it seems like it would be a benefit for the turbo...

anyone left it off and had any problems with melting nearby wires etc?

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https://www.sau.com.au/forums/topic/143030-turbo-heat-shield/
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steveo_r33 Proficient

steveo_r33

Posted
Posted

I took mine off when replacing my stock dump pipe with s steel piping...

Haven't had any issues.. the old heat shield looked gross and doesnt do jack...

now i can see s steel piping and it has cooling advantages 4 the turbo :-P

This was on a 33 btw....

Just make sure no air con tubing runs near your turbo area...or well anything ...

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

If there are wires nearby, you can potentially cook them.

Realistically, you should run a heatshield if possible.

It will keep under bonnet temps down, and in a turbo car this is very important. The hotter things get the less power you are going to make, also if you are not using proper CAI/Airbox your going to be having major heat intake problems

RB20_ZED Collaborator

RB20_ZED

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Just make sure no air con tubing runs near your turbo area...or well anything ...

hmmm what do u mean by "near" coz the closest thing to my turbo area is two air con pipes (with mangy insulation)

they are about 20cm away from the exhaust side..

white_saiyan Newbie

white_saiyan

Posted
Posted

There was a report in one of the later hot 4's issues about this. It seems that heat shields will have a minimal effect at close range to important things i.e- oil lines it seemed heat wrapping and heat shields both did a little bit to help but if you are really worried grab yourself a turbo beanie they rated the best. ;)

khunjeng Veteran

khunjeng

Posted
Posted

the only good theroy I have heard thus far is the beenie to keep the hot side hot...i.e. greatest heat/pressure difference - afterall thats how turbos work..

I had my shield removed and was thinking about what to replace it with...I was thiking a shield..maybe a bennie? where can u gte these from?

2BNVS Veteran

2BNVS

Posted
Posted

turbo bags are by far the best, they keep the heat sealed in the exhaust housing, even after a hard flogging i could work around my engine bay... going more for show with chrome i changed to a heat shield, although it doesnt quite heat "as" good, if made properly it still works great... the difference is and magazines have agreed, is that the turbo bag can directly touch components and can sit directly on the turbo itself, where as the heat shield must sit around 2-3cm off the exhaust housing itself so heat doesnt trvel through the metal...

in my situation it is a high mount, not low mount, but in either appication id recommend heat wrap and some form of heat shielding wether it be bag or metal plate

but the bag is the better item.

ben...

RB20_ZED Collaborator

RB20_ZED

Posted
  • Author
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thanks everyone for ur input - i dont really get why a max temp difference across the turbo makes it perform better... unless it has something to do with the design tolerances.

I have a bonnet scoop pretty much directly above the turbo so it has cool air forced down on it whilst driving.... guess ill put the heat shield back on or get a beanie.

is this a good turbo beanie?

http://www.agpturbo.com/product.php?produc...=257&page=1

lol

but seriously - wheres a good place to get one from?

Lachlan33 Community Regular

Lachlan33

Posted
Posted

I still have my heatshield in my boot. A couple of wires ran close to the turbo but I just relocated them. I tried to put the shield back on but some of the bolts just wouldnt budge so I didnt bother. That was a couple months ago now and thus far no issues.

khunjeng Veteran

khunjeng

Posted
Posted

the turbo blanket insulates the exhaust side to retain the heat.. this has two benifits...reduce engine bay heat (although its probably quite hot anyway) and reduces radiation loss from the turbo...why?

turbos work on heat and pressure and the conversion of kinitec energy to make the turbine spin. Once well known example is wacking on a 3" zorst.. it gives greater pressure delta and allows quicker spool and more boost total...as heat is also another important energy source...keeping the temp high in relation to the zorst temp helps produce a greater pressure difference and hence more flow..more flow..more spool..morse boost...anyway thats my basic physics understanding from the top of my head...so correct me if i'm wrong some1.

But i do notice Garret for example warn against use of the blankets in garage enviroments for BB turbos...not so much for water cooled ones...not sure what they are on about exactly.

te one of these....

http://www.horsepowerinabox.com/HPIAB2/category60_1.htm

RB20_ZED Collaborator

RB20_ZED

Posted
  • Author
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the turbo blanket insulates the exhaust side to retain the heat.. this has two benifits...reduce engine bay heat (although its probably quite hot anyway) and reduces radiation loss from the turbo...why?

turbos work on heat and pressure and the conversion of kinitec energy to make the turbine spin. Once well known example is wacking on a 3" zorst.. it gives greater pressure delta and allows quicker spool and more boost total...as heat is also another important energy source...keeping the temp high in relation to the zorst temp helps produce a greater pressure difference and hence more flow..more flow..more spool..morse boost...anyway thats my basic physics understanding from the top of my head...so correct me if i'm wrong some1.

But i do notice Garret for example warn against use of the blankets in garage enviroments for BB turbos...not so much for water cooled ones...not sure what they are on about exactly.

okay dont take this personally but that doesnt make sense - the turbo essentially uses the energy of a hot, fast moving gas to spin a turbine. The key principle is that the exhaust gas is moving with a high velocity out of the engine, through the turbine and out the exhaust. Sure, the temperature of the actual exhaust gas affects the turbo's performance by the fact that a hotter gas has more internal kinetic energy and therefore more energy to spin the turbine... but the actual temperature of the turbo doesnt increase its performance - well not as u explained it.

unless as i mentioned/asked before - the turbo's design tolerances are optimal for a certain "hot" temp range - meaning that it just functions better when its hot.

2BNVS Veteran

2BNVS

Posted
Posted

in summary, keep as much hot air inside the exhaust housing and dump pipe!

theres many theories with turbo bags how they are no good, i cant see whats wrong with a quality made one, with a quality turbo, ive seen a fair few and over years and years of abuse on tracks never a fail.

i got mine locally in wollongong, but check out www.gcg.com.au although they might be slightly $$$

ben...

sewid Grand Master

sewid

Posted
Posted
okay dont take this personally but that doesnt make sense - the turbo essentially uses the energy of a hot, fast moving gas to spin a turbine. The key principle is that the exhaust gas is moving with a high velocity out of the engine, through the turbine and out the exhaust. Sure, the temperature of the actual exhaust gas affects the turbo's performance by the fact that a hotter gas has more internal kinetic energy and therefore more energy to spin the turbine... but the actual temperature of the turbo doesnt increase its performance - well not as u explained it.

unless as i mentioned/asked before - the turbo's design tolerances are optimal for a certain "hot" temp range - meaning that it just functions better when its hot.

Yeah. Keeping the exhaust gasses hotter improves their flow out the exhaust.

The reasons behind this are fairly complicated and have something to do with gas flow and fluid dynamics. Something not many people here would be qualified to post about in detail...

khunjeng Veteran

khunjeng

Posted
Posted
okay dont take this personally but that doesnt make sense - the turbo essentially uses the energy of a hot, fast moving gas to spin a turbine. The key principle is that the exhaust gas is moving with a high velocity out of the engine, through the turbine and out the exhaust. Sure, the temperature of the actual exhaust gas affects the turbo's performance by the fact that a hotter gas has more internal kinetic energy and therefore more energy to spin the turbine... but the actual temperature of the turbo doesnt increase its performance - well not as u explained it.

unless as i mentioned/asked before - the turbo's design tolerances are optimal for a certain "hot" temp range - meaning that it just functions better when its hot.

It is a common misconception that the exhaust turbine half of a turbo is driven purely by the kinetic energy of the exhaust. While the kinetic energy of the exhaust flow does contribute to the work performed by the turbo, the vast majority of the energy transferred comes from a different source.

Exhaust exits the cylinder at high temperature and high pressure. It gets merged with other exhaust pulses, and enters the turbine inlet - a very small space. At this point, we have very high pressure and very high heat, so our gas has a very high energy level.

As it passes through the diffuser and into the turbine housing, it moves from a small space into a large one. Accordingly, it expands, cools, slows down, and dumps all that energy - into the turbine that we've so cleverly positioned in tho housing so that as the gas expands, it pushes against the turbine blades, causing it to rotate.

The amount of work that can be done across an exhaust turbine is determined by the pressure differential at the inlet and outlet. Higher outlet pressure, lower pressure differential, less work, less boost...hence why we like to wack on better free-flowing exhausts.

So why a blanket...my assumption is to get a better temp. differentail accross the inlet and outlet...for the reasons stated above and keep the gas in a high energy state..why?? for any1 who has done basic physics you can answer that one!

RB20_ZED Collaborator

RB20_ZED

Posted
  • Author
Posted
maybe you should read it again...its not the temperate mate, its the temperate and pressure difference that helps the turbine spin. However the point is, if you retain the heat with a blanket...the air inside should be hotter and buy your own admission this will help....

if the turbo is hotter how will the actual exhaust gases be hotter? its coming from the engine and spends 1 millisecond in the volume of the turbo - after which it may be 0.1 deg hotter but thats not going to matter since the gas has already done its work.

The larger exhaust works to increase the speed of the gas because there is a larger volume for the gas to expand into as it passes through the turbine - nothing to do with the temperature (except for the fact that the gas will be cooler due to the expansion).

there would be no reasonable way to make the exhaust gas hotter since it gets its heat from the compression and combustion within the engine cycle.

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