a while ago I fitted john banks gruppe-s headers to try them on my car.I had wrapped them but did not paint them.I ran them for about a month and then removed them as my own set where in transit.

I wrapped my own set with the same brand of wrap as I used on jb's(cool-it) but this time I also sprayed my set with DEI HT coating. I used a full tin on the headers and 1/2 a tin on the up-pipe applied in light coats.

I fitted my set yesterday and as with any headers, I keep checking for leaks. with jb's unpainted set I could tell the wrap was working. moving my hand around the flanges,they would be roasting but the wrapped pipe-work would be much cooler. my painted set however feel much hotter, even the surrounding area or just sticking my hand under the car , I can feel my set are far hotter than the unpainted set:confused:.

I did expect my set to be slightly hotter as my headers and up-pipe are the smaller bore gruppe-s version while jb's are the larger bore ones, so the engine will be slightly more restricted but it feels like my wrap is not working with them being painted. the highest egt's I have seen have been 850c.

has anyone found this after coating their wrap?

Hi John

It could be that the paint transfers heat better than the air which previously occupied that space ? Air is a very good insulator.

Andy

I painted my headers last week with halfords VHT paint.

Fitted them yesterday and just left on tickover for a 5 minutes to check for leaks etc (changed turbo & fuel reg also). The paint gave off tons of smoke as it heated up.

Done a runs this morning and again this evening, the has smoking now stopped but still a bit of a nasty smell :( .

Now its been 'heat treated' the paint may have dried out and be more thermally insulative,

I didn't paint the wrap on the up-pipe, so I could do a side by side comparison but to be honest apart from trying to tell which pipe gives the bigger blister when touched I'm not sure how to compare.

At least the paint should offer some moisture protection to the wrap and stop the car having a steam bath every time it rains ;)

Rich

Don't happen to know anyone with an infrared thermometer, do you?

If you are able to measure those temps, I'd be interested in hearing the results. My headers and up-pipe are wrapped and ready to paint!

I imagine that the VHT paint and also the wrapping itself will both stink quite severly until everything volatile has boiled off. Shouldn't take more than a few hundred miles, I imagine.

Good thinking Fatman, I can borrow one from work and check on Tuesday.

(I can't today - off to powerstation to get the car re-mapped :) )

Rich

Sounds good. Let us know...

Just to add to this debate, i have fitted mine and left them un-wrapped and had no problems. (this does include some "spirited" driving too)

sly

I wouldn't risk it, Sly Fox. Replacing melted wiring sounds expensive and messy. Your call, though.

Simon, i think you should have wrapped them. Stevebt could have lost his car due to not wrapping them. The heat melted the wiring loom:eek:, could so easily have shorted and started a fire.

Steven

So is this wrapping malarchy a fire precaution or does it actually achieve owt?

Mikey :cool:

hi guys,

i have just got a ra with cusco e/l headers and a full 3 inch decat system, the headers are wrapped but its a bit tatty, so if you tell me the stuff you are using i will use it on the headers and downpipe,also any advice on spray coatings.

thanks, robinh20

Not long wrapped my HKS manifold with DEI 2" tape.

Still to spray.

These were wrapped Dry.

Fitting soon LYK.

cheers for your concern steve,

I have been constantly checking the temp of wires and pipes, but no issues so far. I think i will wrap them as everyone else is, just seems a shame to cover them (mmmm, nice and shiney)

Any recomendations on exhaust wrap suppliers (demon tweeks, tas ??)

sly

If you want some heat protection but don't want to wrap them, get them ceramic coated instead.

My exhaust wrap came from Rally Design.

It does improve things Gridlock. Apart from saving the wiring etc., it keeps the heat in the exhaust gases and since that is part of the exhaust energy it will put more work into the turbo, this is for wrapping before the turbo of course. If you wrap the downpipe it will of course provide heat protection and will also make the car a bit quieter inside. It also deepens the exhaust note which sounds good. The Halfords VHT aerosol paint works very well at keeping the oil and paint from soaking into the wrap, once it has burned all the smoke off. :)

Les

Hey, Rich... did you manage to borrow that IR thermometer yesterday?

Sorry m8 - I completely forgot, had problems in work and went out for a drive during my lunchtime to clear my head.

I'll send an e-mail to myself in work to remind me tomorrow.

btw - still a little smoke and stink coming off the paint :(

Rich

Results:

After a 10 min drive with some hard driving at the end and left on tickover:

Wrapped and painted header : around 210 degC
turbo cast body (unpainted unwrapped) : 270 degC
wrapped downpipe : around 200 degC

Using the rally design wrapping.

Rich

Thanks for doing the testing Rich :) .

I was thinking about the pros and cons of painting and I reckon it's worth going ahead and applying paint to the wrapping. The argument could be made that the wrapping retains more heat if there's no paint due to an insulating effect from the air in the weave of the wrapping. Replacing that air with paint causes more conduction of heat.

This is fine provided you're able to keep the wrapping clean and dry whilst it's in use. That's not realistic, so we have to expect the wrapping to get oily, wet and generally mucky. So the condution effect is going to happen anyway! We may as well keep the wrapping cleaner in the first place - with paint.

I'd be interested to know what the temps would be without the wrap, would it be possible to find out and post the results. That would then complete the comparison.

thanks

mine are still un-wrapped, so we could probubly sort out some readings, somehow!

BUT (thanks to p20std's suggestions)i have now taken steps to protecting the wires from the heat.

I have insulated the surrounding pipework / wires with aerospace kevlar wrap which they use to protect the wires from heat /flames etc. I decided if this is what the military use, then it is certainly good enough for me.

It was also earier than taking of the manifold again to wrap it properly.

sly

sly