EA211 engine:- heat shielding & how to sort the design flaws in the coil pack wiring

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Part 1 of 6
Vehicle used in this guide
UK spec, 2014yr model, Mk7 Golf Estate (GSW), GT (Highline) trim, 1.4lt TSI (140PS) CHPA petrol engine, MQ250 6speed manual gearbox, multi-link rear suspension.

Vehicles that this guide is applicable to
All VAG (Audi/Seat/Skoda/VW) MQB platform cars with the same EA211 petrol engines

Introduction
This is not a fully detailed “How-to guide”, more a “heads up” on the badly routed wiring loom for the ignition coil packs. Also this thread deals with heat shielding various items which have to be removed “IF” you decided to sort the coil pack wiring out. As I have done the GTE air duct conversion, which blanks off the cold air in to the engine bay, & as I have a full length engine bay under tray as per the GTE, my engine bay now gets slightly hotter than before. Not dangerously hot, as the GTE engine bay gets far hotter due to more electrical items & less free air space, but hot enough to consider taking appropriate remedial action!

Part 2 of 6
Research
Basically this thread was kick started by a couple of posts (now moved here) on my “how to retro-fit a bigger capacity battery” concerning me telling someone about “Low-e” materials & why a polished metal surface will reflect more radiant heat away than a black fabric. These scientific facts have nothing to do with visible sunlight, & comes under thermal design for buildings.

Earlier post moved from my “How to retro-fit a bigger capacity battery” guide:-
QUOTE:-
“”I did Technical Architecture at University instead of opting for an Honours Degree in Electrical or Mechanical engineering...

So thermal design & heat transmission etc is part of the remit...

Heat will flow in an object/solid/liquid/gas until the temperature is the same (equilibrium). The transfer of heat will be by either conduction, convection or radiation.

So battery in engine bay, engine emits (radiates) heat to heat up the air around it to reach the same temp as the engine. The air in the engine bay will then heat up any object in the engine bay, by convection. Anything that is in direct touch/contact with the engine will heat up by conduction.

Radiation, most people just think of sunlight & thus an engine bay is not in direct sunlight so this does not apply. Wrong! Sunlight is short wave length, as the source (sun) is at a very high temperature. Lower source temperatures including red heat from metal are long wavelength radiation & are what is called "far infra-red" which is why we can only see this "invisible" heat from a hot engine in a thermal imaging camera! So the engine will radiate heat to heat up any item in the engine bay, even if in dark garage!

There is then the whole "thermal resistance" of the materials to consider. i.e. does the material present resistance to the flow of heat from one side of the material to the other side?

A good example of this is the bulkhead in your engine bay, black felt type material to provide sound insulation & some thermal properties when cold. However it has a silver coloured corrugated aluminium foil on top to stop this black felt from gaining/absorbing heat from the turbo etc...& this is in a dark engine bay..so no visible radiation...so why??

Basically shiny metallic surfaces have a low emissivity in both the visible heat radiation & the invisible far infrared heat spectrums...& they can work in both direction..ie wrap the battery, & it can stop the battery emitting heat...& also stop the battery gaining heat from the surrounding air.

Low emissivity materials are concerned with the heat absorbed & radiated by the material & this can have NOTHING to do with sunlight or visible radiation! Which is why you have aluminium foils inside building walls etc. as "low-e". The same applies to engine bays, wrap the items you want to protect from heat in polished silver or gold foils, not a black fabric!

I could write a whole thesis on this if you want but a good webpage on wiki here:-

https://en.wikipedia.org/wiki/Thermal_radiation

& the specifics on Low emissivity materials are here-

https://en.wikipedia.org/wiki/Low_emissivity

END QUOTE

Also the VAG 1.8T engine as used on the MK4 Golf, Audi TT (MKI), Skoda Octavia MKI) etc had a problem with the coil pack wiring. The loom was cable tied down tightly to the top of the engine & thus over time, heat aged the wiring which got brittle & caused misfiring, starting problems etc.. You ended up having to get a “repair section of wiring loom”, which included a whole new loom section for the coil packs but required you to wire back to the ECU & several sensors along the way! To do this job involved removing the battery, air box, scuttle panel, ECU, etc, & the book time was 2.5hrs. I helped a mate do his MK4 Golf GTI in the same time, & NOT a job I want to have to do again! Unfortunately these engine with the coil packs do not make it easy to use a “blanket” wrap like the one used on the 1.8T repair kits, so you have to wrap the wiring loom directly!

So taking a closer look at my car I notice that yet again VAG have made an utter mess of the wiring loom on these engines, with cables forced down into spaces which are surrounded by hot metal, & with cables bent 180deg over the edge of the coil pack plugs!


Parts required/Materials used
I decide to go for the most flexible & most reflective & lowest “e” material for the wiring, which was DEI “Reflect-A-Gold” tape in a 1.5inch x 15ft long roll.

For the heat shielding I went for a less “bling” silver colour & chose the best, for flexibility to mould to small shapes & self adhesive which was Zircotec “Zircoflex 1, SA” in a half sheet size.

Part 3 of 6
Wiring loom
Basically you will have to remove the air box, pipework & wiring loom. The pipework from the turbo to the throttle body has “O” ring seals which will need replacing with new, unless they are new (1yr old). Mine were 3.5yrs old so I fitted new. It is fairly obvious to remove all the items, you do need locking clamp pliers or similar tools to undo & lock open the spring clamp/bands. The air box is located on three ball studs, so just requires pulling up off them. The pipe from the turbo to the throttle body is held in place by the visible spring tabs, so just prise open with hand & pull pipe off the connection.

The electrical connectors are standard VW jobs, so easy to remove, the ones with the white tabs on them require you to slide the tab along the wire to unlock the connector from the plug. The angle covers require small slot head screwdrivers or similar to help undo the tabs to remove them.

You then have several options, either clean the existing loom up & just directly wrap the new heat shield fabric around this, or go the “whole hog” & carefully cut & remove all the fabric, cable ties etc & then re-wrap the whole loom like I did! I purchased the DEI “Reflect-A-Gold” 15ft long 1.5inch wide tape which was just enough to do the whole lot with some spare. I cut it into 3ft long lengths & then split these into either 3 x 1/2inch wide or 2 x ¾ inch wide strips. I used more of the ½ inch wide strips & to do the “branches” of the loom, & the ¾ inch wide strips to do the main thick “trunk” of the loom.

Basically carefully cut/remove the section nearest the existing loom down the right side of the engine first. This allows you to then get an “end” & unwind the loom fabric tape. Once you have removed & cleaned with meths/IPA/panel wipe, then you need to spread of the wings to each connector, & then organise it. Use a hair drier, or hot air gun (on low) to heat up any sharp kinks in the loom & then straighten them out. When wrapping a loom start at the connector in a branch & work towards the main trunk. This is because you then cover & trap this finishing end with the main trunk wrap, otherwise the ends will un-ravel over time! I used some fabric tape to act as “clamps” to hold sections of the loom in place, & wrapped over them. I also did two complete wraps over the section which sits on the engine cam cover, to provide additional heat/abrasion protection. When wrapping you wrap tightly & cover half the width to no less than 1/3 the width of the tape with the next turn. When starting a main trunk wrap at a branch I did a turn around a branch before wrapping it tight against the main trunk, with two turns then you have to put a crease in & move/wrap the tape down the trunk, to the next branch & stop that piece/cut, then start with a new piece of tape.

You will note that I created more “branches” as this gives the loom more flexibility & allows the connectors to be removed easier. Also I moved the wiring for coils packs for no.3 & 4 cylinders, so they now come from the front of the engine, instead of going between the coil packs & then approaching from the rear of the engine. Because of this I have been able to fit an angle cover on No.3 coil pack! I would have been able to fit one on No.4, but it was very tight, so decided to not do it.

Part 4 of 6
Heat shielding
Now you can go mad & 100% bling by wrapping everything in Reflect-A-Gold foil if you want. However if you want a more discreet look which is effective then read on. Basically you want to stop the surfaces of components directly facing the engine from getting too hot. This is more important on the air intake pipes as we do not want the air in the pipes which cross the top of the engine getting too hot. The air going to the engine needs to be cool, & yes we the intercooler built into the intake manifold after all these pipes, but it helps if we can cool the air going into this as then the air exiting the intercooler will be even cooler & thus more oxygen dense, so the engine retains max performance on a long drive & does not suffer too much “heat soak”.

Again I cleaned thoroughly all surfaces with meths & then IPA (isopropyl alcohol & NOT India Pale Ale) or panel wipe. I used newspaper to roughly shape & trial fit first before cutting out the pieces on the sheet of heatshield! I only did the surfaces which directly face the engine as the top surfaces are protected from this direct radiation, as they only get affected by the engine bay air getting hot, i.e. convection.

I also removed the rear resonator which connects from the airbox pipes with Helmholtz resonator (pan pipes), to the turbo. This requires a TX-star T30 bit on a thin 6inch long extension to get to the two bolts to remove it. The bolts are one top, one bottom, facing the battery & are 8Nm (6lbft). The “O” ring seal requires to be renewed, but mine was perfect condition so just put clean engine oil over the seal to lubricate re-fitment.

Part 5 of 6
Battery
Go for a drive to get the engine bay hot, stop get out, & go feel the battery fabric cover. It will be warmer on the side facing the engine & on the side facing the front will be warmest towards the side facing the engine. The sides furthest away & the top will be cooler! This is due to direct radiant heat. The black fabric insulation jacket for the battery will trap heat as a “high E” fabric, which is what you want in winter. However in summer you don’t want this! So you can either remove the fabric in the summer or heatshield the battery in some other way. The fabric is actually a fibreglass mat which VAG call a heat shield & state that AGM batteries require these if installed with them in hot temperature places..

Now you can either place the heat shielding on the outside of the insulation, or on the inside of the insulation, or on the battery itself. The best place is possibly the outside of the fabric cover, but this look too “bling” for my taste. However you cannot put the metallic foil near the “+” terminal cutout as the terminal crosses over the fabric, so electrical danger! So place the fabric on the inside? Unfortunately the insulation padding is on this side so the cover bulges outwards making the shape difficult to cover with the heat shielding! So that just leaves covering the case of the battery! This is what I ended up doing as it is the tidiest & most discrete way of offering heat protection for the battery. The only downside is that you will have to get a new piece of heat shield every time you renew the battery!

To remove the battery it is best to open the bonnet, & close the doors & wait for the electronics to go to sleep which is about 30mins. Undo the battery bracket clamp bolt & remove both items. Then connect a 12v supply “+” to the “+” cable & the “-“ to the bayonet bulkhead “-“. Then remove the “-“ clamp from the battery & then the “+”. If you don’t have a 12v supply you will have various fault codes appear when you re-connect!

Again use meths, IPA, panel wipe, etc. to clean the surfaces & cover as much as you want. I just covered the side facing the engine, the side facing the front & the first ½ of the side facing the bulkhead. I just used one piece & started on one side & carefully wrapped it, keeping pressure on the foil to stop wrinkles etc.

Part 6 of 6
Results
Having done a long 124mile drive over fast twisty driving roads & on a warm sunny day I note the following. Even towards the end of the journey with the engine “heat soaked”, the car felt more responsive, & quieter than before! The engine note has changed, so that it is deeper/sportier under load in 3rd gear. On certain sections on the way back home there are long steep (60mph speed limit) hills which usually have people turning off at the bottom junctions. This happened to me again, so gave me a chance to put my foot down in 2nd, floor it to 6,000rpm (start of red line), change up to 3rd, & keep it floored & then short shift to 6th at slightly over the posted limit speed. The engine did not make any harsh metallic wastegate rattle etc. sounds, just deeper, more purposeful, faster turbo response, & did not sound strained at 6,000rpm, & it just kept going with loads of “shove”.

On stopping the car at home I lifted the bonnet & yes the engine bay was hot as usual, BUT the top, unshielded parts of the air intake pipework was cooler than they usually are! This is due to the underside being shielded from the direct radiant heat from the engine, thus less heat soak! I also got a calibrated 45.1mpg (UK) over the 124mile trip & the car is driven in sport mode & using Shell V-power.

Conclusions
The combination of the ITG (VWRacingline) foam panel air filter, GTE air intake mod & this heat shielding, has transformed the engine way more than I could have hoped for!
I have virtually eliminated the metallic rattle/rasp which is usual for this engine when under load, & made it quieter in general. When cruising at 2,000 to 2,300rpm in 6th gear (60-65mph) this car is sooo quiet on smooth tarmac, you feel you have to whisper to each other!! The earlier spool up & quicker turbo response, resulting from more oxygen rich dense cold air, produces more power which the variable cam shafts (both in the 140/150PS engines) really do make more use of!

Forget warranty voiding re-maps, & just modify the car to how VW could & should have made the car at the factory!

In for group buy heat shields!

Man i thought you cut metal and surrounded the pipes. Just a wrap. Very professional looking. Not surprised. I'll have to try this out when i have time.

Adurm said:

In for group buy heat shields!

Man i thought you cut metal and surrounded the pipes. Just a wrap. Very professional looking. Not surprised. I'll have to try this out when i have time.

Click to expand...

Self adhesive heat shield materials have ben around for awhile & the DEI gold for the wire loom is very good & the Zircoflex stuff as I used on the air intakes is a great heat shield..they even do a 2x & 3x thickness version & a gold version & a structural/more ridged version...& of course they do the ceramic spray coatings which are used by the supercar manufactures....on exhausts, engine bays, intakes etc..

I have a smooth air intake hose wrapped in fiberglass header wrap then aluminum tape on that. Looks awful. I wonder if your method would provide better heat shielding. Or if mine does anything beneficial. Yours would certainly look better.

Would you share where you purchased it from?

Adurm said:

I have a smooth air intake hose wrapped in fiberglass header wrap then aluminum tape on that. Looks awful. I wonder if your method would provide better heat shielding. Or if mine does anything beneficial. Yours would certainly look better.

Would you share where you purchased it from?

Click to expand...

I got mine from a UK based motorsports store, so no use to you...

Just google Zircotec/zircoflex as that's the brand. I used the "! version which is single layer...if you want more heat reflection get the "2" double layer which is still as malleable as the single layer as they claim.

Thank you kindly.

Adurm said:

Thank you kindly.

Click to expand...

Zircoflex, only one distributor in USA as its a UK company..actually was part of our nuclear industry...

www.thermalcontrolproducts.com/index.php/our-products/thermal-barriers/zircoflex/

& they only do the single & triple thickness sheets & only in full sheet size..I used 1/2 sheet..both are in self adhesive that they do thought...& the reflect-a-gold I used is USA...DEI in Ohio...