Melting fiberglass

[McRat]

header wrap???  I noticed I started to melt the fiberglass header wrap on my up-pipes.

What else would you use?

[Dean Los Angeles]

Thermo Tec makes header wrap that is good to 2000ºF
http://www.thermotec.com/exhaust-insulating-wrap-graphite-black.html

[McRat]

Thanks!

[John Burk]

McMaster has 5000 deg carbon fiber tape - $3.50 or so a ft for 2' wide .

John

[manta22]

Most header wrapping tape is made from a woven ceramic fiber material; it should definitely NOT melt!

Regards, Neil  Tucson, AZ

[McRat]

Yeah, and neither should inconel.

The header wrap that melted was Moroso, IIRC, and it is white.  I assume it's fiberglass but maybe not.  When it melted, it left a black glassy residue on the pipe.

[manta22]

Here's a link to a manufacturer of ceramic fiber.

http://www.fiberfrax.com/files/Fiberfrax-Woven-Textiles.pdf

I don't know if anyone uses this particular brand of fiber in their header wrap but unless it's a crappy substitute it should be reasonably close. They recommend an operating temp of up to 2300F-- and its melting point is 3260F! Maybe Moroso is foisting off cheaper stuff?

Regards, Neil  Tucson, AZ

[McRat]

Hmmm...  Dunno.  I'll see if there is another package on the shelf.

[Dean Los Angeles]

Inconel melts at about 2500ºF. If you are getting over 2000 on the pipes you need more than pipe wrap!

[McRat]

It's actually common to see EGT's past 1800°F (where most gauges stop) with "tuned up" turbo diesels.  Normally, it only has to endure it for 10 seconds or so for drag racing or sled pulling.  But apparently LSR is not so forgiving.  That's what I have to work at over the winter. 

[Jonny Hotnuts]

THis might be crazy but what would happen if you used a water injection setup on the header to lower the EGTs.

[McRat]

I've thought about that, but never got around to playing with it.  I do run water injection on the front end, but what about running it on the backside? 

Problem is injecting into a 90PSI, 2000°F degree stream.  Standard water systems aren't going to work.

[1212FBGS]

yep you can spray water on your pipes...especially if ya like welding cracks all the time....there is thicker pipe wrap and wrap it twice.....ya also might want to open up your hot side a little to let some of the heat out....as dean alluded to if u are melting things ya better look in other places

[McRat]

Some of the problem is that the fuel continues to burn after the valve opens.  Diesel burns slow.  Running a bigger A/R on the turbine hsg is something I'm trying next.  But no matter what, it takes big backpressure to make big boost numbers unless you compound chargers.  As far as hotrod diesels go, I'm not pushing much boost, 45-60psi, but since it's a single charger, drive pressure is high.

[Blue]

Some of the problem is that the fuel continues to burn after the valve opens.  Diesel burns slow.  Running a bigger A/R on the turbine hsg is something I'm trying next.  But no matter what, it takes big backpressure to make big boost numbers unless you compound chargers.  As far as hotrod diesels go, I'm not pushing much boost, 45-60psi, but since it's a single charger, drive pressure is high.

This is actually an injection and burning issue.  If the fuel doesn't finish burning before about 20 degrees ATDC, the EGT is driven by post-burned fuel and not power.  Check your injectors for proper atomization and possibly upgrade to a high pressure system.  There are also diesel additives that help atomization and increase burn rate under extreme conditions.  Some of these also decrease delay time which is risky, but allows you to go to a higher RPM.