How much heat wrap for centre section
 

And maybe the backbox on a classic ?

shall i buy 10m or 30 m ?

10m is about £9 delivered, 30m is £20 delivered



cheers

Waste of money! In the engine bay yes! Under the car i wouldnt bother!

Its not worth and as above is waste of money.


Jura

Anyhoo,is there anyone who has done it and knwo how much they used ?


cheers

Can't help on the question but I think that if it gets wet, it's ****ed. That's what the other two are saying.

Ask yourself this ? How many people on here have you seen with a back box wrapped?

ive seen a few system done.

i was thinking more of fitting it to protect it as its mild steel from rusting/rotting more than anything

Wrap isn't weather proof lol :) and besides they fail at the flange more often than not :) For the cost of about 100' of wrap to do it properly :eek: you're better off spraying it up with VHT paint if you can really be bothered.:)

Had my entire stainless system heat wrapped and sealed for about a year and a half apart from the rear silencer. All is well (it helps with the emissions too) + the turbo spools up quicker, its not a cheap choice though. If your wondering what system i am running, the car has syms equal length headers 38mm pipework, a 3" 100cell sport catted downpipe, 3" double resonated (stainless internal baffling) centre section, and a 3" cobra sport rear silencer with 4&1/2" tail. It all depends what your intentions are really, i did it for spool up and to bring power in earlier.

On a similar vein (sorry for hijack) how much heatwrap for a 3" downpipe? Cheers.

^50' to completely wrap my classic decat pipe :)

Find it hard to believe wrapping a centre pipe will help spool :) but who knows :)

Wrapping the parts underneath the car are only going to make it rot faster, it absorbs moisture and therefore the exhaust is damp longer. The only benefit I can see would be to possibly reduce sound levels slightly as some grades of stainless can be rather tinny.

you need to understand what is a HEAT WRAP and what is it for once you understand that then you can ask yourself the same question.

I have wrapped a complete exhaust system including back box. I did this in an effort to reduce noise. It was a total waste of time, no noise reduction and certainly no performance gain. From memory, including down pipe, centre section and back box, it took three and a half rolls.

Wrapping the headers, uppipe, downpipe and turbo exhaust side are all worth doing as you reduce under bonnet temperatures and improve performance. Fact.

If you use cheap heat wrap then expect it to fall off fairly quickly. Also consider the thermal properties. If you stretch the wrap and can see light through it then obviously heat will escape easily. If you are going to wrap it then do it properly.
I use DEI heat wrap because of its quality, longveity and thermal properties. It is expensive @ £55 for a 2" X 50' roll. £105 for a 100' roll. Headers on one of my cars were wrapped over 3 years ago and the wrap is still good. At a recent mapping session a customer commented that it was 5 years since I wrapped his headers and downpipe and they were still in good order. The DEI wrap has stiching down the side which helps greatly to judge the overlap. This greatly reduces wasteage and overwrapping. There is no advantage to over wrapping and in extreme cases this will help with cracking of tubular headers.
I do not spray the wrap with paint aerosol. I have found this makes the wrap brittle in time and then the wrap flakes off.

A 3" open neck D/P will take over three quartes of a 50 foot X 2 inch roll. Tubular GT2 type header sets take just over a 50' roll. 100 foot roll will do tubular headers and 3" D/P with a little left over.

A 3" pipe has a circumference of 9.5" approx. The wrap is 2" wide. Allow 35% for overlap. I guess that works out around six and a half feet per foot of 3" diameter pipe. That is on straight pipe. Obviously bends take a good bit more. It is quite surprising just how much wrap is used on bends.

As a rule of thumb I run a length of wrap along the component to be wrapped and then measure off X 6. This works quite well on downpipes, tubular header runners, uppipes and so forth. On a straight length I multiply by 5.

Guide to heat wrapping.

I have used all the heat wraps I have come across over many years but so far I am settled on DEI wrap because the thermal properties are as good as anything else I have found and better than most. It is close weave so there are no holes when streached. It has a stitch down each side to act as a guide to overlap so it is easy to use and because there is less excessive wrapping, more economical in use.

Heat wrapping is not difficult if you follow these instructions but you cannot expect to achieve a professional standard on your first heat wrap operation unless you follow these instructions carefully.
Because of the cost of heat wrap ties I only use stainless steel tie wire and generally the more ties the better the job.
To use tie wire it is best to have a set of tie wire pliers/ lock wire pliers which makes twisting the tie wire that much easier.

The DEI heat wrap has a stitching down each side to show the amount of overlap required and you should follow the overlap guide stitching where possible. This is not possible on the inside of tight bends.
The wrap should be applied damp but not wet. There are chemicals in the wrap to help it bind and these should not be diluted out. You can use a house plant leaf sprayer or any other water aerosol/spray to dampen the wrap or set the tap to a very fine trickle and run the wrap through the trickle quite quickly. In a few minutes the water will have spread evenly throughout the fabric to dampen it. Do not let the impregnated chemicals run out. Keep away from foodstuff.
Wrap from the bottom to the top with the appropriate overlay.
Keep the wrap as tight as possible.
Remember that the wrap on the outside of a bend requires more material and therefore the corresponding inside of the bend will have big overlaps and on a tight bend this can be almost 100%.
Do not cut the wrap in to short lengths but try to apply in continuous lengths and certainly 15 feet at a time. Wrapping a section with a single length of wrap results in a neater job.
A 3" open neck downpipe wll generally take three quarters of a roll of wrap done properly.
Remember. Keep it tight.
Tubular headers will take a full 50'.
Tie at the end and then every 3 inches but on curves or corners you can increase the number of ties.
The tie must be applied while the wrap is still damp.
Cut off any strands and loose ends.
When put on the car first there will be a lot of moisture released from the wrap. Do not be alarmed.
On damp and humid days the wrap will absorb moisture so again there will be a lot of steam.
It is quite normal for the wrap to smell for three weeks after applying as it dries through thoroughly.
Wrapped properly it can last for years.

Happy wrapping.

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My HEI wrap is now over three years old and still looks the same as when I put it on (thanks Harvey). You can hold the down pipe with your hand when the engine has been running hot it really is good stuff.

:thumb: