TOPIC: A New kind of mod...on the Exhaust

I just got off the phone with Ron, and he gave me a tip on a new idea. This involves the Exhaust system, and how the downstream O2 sensor functions. This will be centered on the idea that the downstream O2 sensor's output to the ECU is based on the Temp's it reaches.

Ron said that increasing the downstream O2's temps, has been shown to increase MPG's by as much as 8 MPG's--all by itself.

There was not enough time to speak with Ron on more in-depth exploration of this idea. I was already aware of the concept of the downstream O2 acting as a temp. sensor as feedback to the ECU. And so this should be a simple enough mod to try. I already have some of the needed materials on hand...

Tracy G

Heat wrap/insulate exhaust? Or at least on either side of cat converter?

I visualize this mod to be using header wrap over the exhaust pipe, at least between the downstream cat and downstream O2 sensor. Possibly over the pipe between up/downstream cats as well. Summit Racing website lists a whole variety of header wrap products. Harbor Freight here has stainless zip-ties, probably cheaper than the ones the wrap Mfg's offer. I'd avoid using radiator hose screw clamps- too likely to work loose from vibration/heat cycles, IMHO.

Another note on header wrap's-- avoid the idea of going all-in with this idea, as in "I'll just wrap ALL the exhaust pipe all the way up to the manifolds!" I've seen header wrap kill headers, the aftermarket hot-rodder type. That close to the engine the exhaust pipes get VERY hot, and wrapping those pipes can cause the steel to crystallize and crack.

Meanwhile, I need to jack up the Outback, and look for the downstream O2 sensor-can't see the bugger just lookin' underneath it!

Tracy G

Many years ago Louis Lapoine had this tip on his lubedev.com site.

quoted below:
19. To seal maximum warmth inside the exhaust pipe, insulation in the form of Reynolds Aluminum Foil is employed by us to insulate the oxygen sensor. We wrap three inches in front and three inches after the sensor to keep it much warmer. We double a one-foot section of foil to wrap that around the pipe and around the sensor itself. Do not remove the sensor. Then we repeat the process four more times per each sensor. Finally we use .030" copper wire to wind around the aluminum foil about one-inch apart to keep it from blowing away. Then we wrap several layers of duct tape to keep it sealed against water or snow. The wire comes from any welding supply. The goal is to fool the car's computer into sensing too rich a mixture so it adjusts with a slightly leaner mixture and possibly a slight advance in timing. The end result is smoother engine operation and better MPG. This trick is especially important in severe winter climates.

We used this as one of the xtra mods when I worked with Dennis Lee / BWT with the HAFC kit.
At one time I had found insulated spark plug sleeves. Made out of material like a header wrap. Slipped it over the O2 sensor and then wrapped the pipes from manifolds down to the cats. IF you go this route you'll have to make sure the sleeve is big enuf for the O2, Not all are. Foil worked but was fragile compared to the high tech exhaust wraps. Those on budget might want to tray the foil to see if they gain anything.

Tracy, what you say is true for NON-Groovy engines.

Almost every issue an engine has-including overheating of the exhaust manifold-is corrected when The Groove is applied, as it takes the energy from combustion and turns it into power.

This means the other by-products of combustion (heat, noxious gases and sound) take another form. POWER to drive the piston.

Now, if your engine does NOT have The Groove, then by all means, do NOT insulate the manifold. For Groove equipped engines though, keep EVERY BTU inside the exhaust that you CAN, because the ECU MUST make those BTU's up by adding waste fuel to the system.

Ain't it crazy? Forcing waste through a system when the waste itself causes so many problems?

Ron

Guys, you've GOT to start thinking like real Gadgetmen!

If you look for something to insulate your exhaust, remember it's just a pipe. So, instead of looking for "Exhaust Insulation" or some such, look for "High temp pipe insulation" and you'll quickly find the best stuff to use.

It's beautifully designed, can be cut with a razor knife, and is found in thicknesses as little as 0.5"-which will fit virtually any exhaust configuration. You just open it a little and wrap 3' at a time! Zip ties can then be used to hold it if you like, or even scotch tape, it works so well!



And did I mention that it's only about a $2.00 per FOOT?

The heat wrap is EXPENSIVE and it's a PAIN to install!

Here's where you can get it...
Fiberglass Pipe Insulation Covering for Hot & Cold Service Pipes

Enjoy!

Ron

That's a great idea, Ron! thanks for the link to the Mfg. I simply hadn't thought of this stuff- and I've seen it before at work...

I guess I had not thought of this mainly since I had/have some reservations about the outer white layer's durability in weather and road conditions. BUT since is is so cheap, it could be re-done or fixed easily. It would be WAY cheaper than any "header wrap" that's for sure.

Something else I've tried to find without success is-- a really heavy duty aluminum foil. See, I have done extreme temp pipe insulation before. On my Rocket Ovens! The kiln and boiler industry has this thick white ceramic wool insulation that can be made with a REALLY heavy duty aluminum foil backing. It's expensive and comes in big heavy rolls. I wrapped this over a kind of corrugated stainless chimney liner made for the woodstove/chimney industry. The combination really works, for my application.

But I've been unable to find an extra thick aluminum foil, at least nothing in any reasonable amount or price.

Anyhow, I'm glad you brought up the pipe insulation you did, Ron!

Tracy G

Grant,
Remember reading on a forum about a guy that was getting over 80mpg on his vehicle just
by wrapping his 02 with layers of foil. He had an OBD I system, had only one sensor I think and the 02 had only two wires I believe.
Of course others on the forum did not believe his results but he didn't care. He was not there to
convince anyone, just was thrilled at his results and wanted to share. By the way he posted his improving results and his brushing off the naysayers, I truly believe he was really getting the results he claimed.
I guess that is why we have OBD2 now. The previous system was able to be fooled by those with enough determination toward better mileage.

Tracy - after reading this thread, I called a friend of mine who does HVAC at the commercial/industrial level to ask where I could get some of the 3M stuff Ron suggested. My guy swears by the ceramic blanket you mention here, for a number of reasons that may be of interest to anyone considering this addition to their vehicle(s):
1 - a 1" thickness provides the same insulating capacity as a 16" concrete firewall
2 - if saturated with water and then wrung out before application, it can be conformed to the pipe. this means there wont be gaps for heat to escape at joints
3 - the blanket can be peeled apart in layers, so you can customize your installation (or economize for weight/cost).
he also suggested protecting the conformed pipes with some sort of vapour barrier after application for longevity.

Take note: while not exactly a hazardous material like asbestos, you can still get fibres in your eyes/lungs when handling it, just like fibreglass. face mask and goggles until youve soaked it down.

I'm going to pull the stuff he gave me apart into 2-3 layers (16" length of a 24" wide roll - likely enough for my exhaust system from flexpipe to beyond downstream o2, including the cat).
I figure if 1" is rated to 2400 degrees, 1/2 to 1/3rd of that is probably higher than what's passing through the pipe to begin with...especially with lower exhaust temperatures from less fuel being burned more completely. If manufacturers did this at the factory, they'd put muffler shops out of business

Greg, your continued input is highly valued, my friend.

Under this level of application, you need only get the ceramic fiber rated for 850 degrees, as fuel, even highly oxygen saturated fuel, burns no higher than 800. It takes a major reaction to get it higher (like in the Cat). So, just the lowest level of hear tolerance is needed.

And don't any of you DARE start thinking "I'll just use three layers of household insulation as it's rated at 250." (someone DID do that!) Because the rating is like a melting point.

Now, with the stuff I recommended, it will handle this application beautifully, and is a DREAM to apply, and all you need to hold it in place and water-tight is some cable ties. Here's a quote from that page:
To install pipe covering, simply open the hinged part of the pipe insulation and place the opening over the pipe. The pipe insulation will self close around the pipe. Once the fiberglass is fitted snug around the pipe, peel the release paper from the self-sealing lap and press the ASJ jacket closed from the middle towards the edges of the pipe insulation. Make sure to rub the jacket closed to ensure a secure seal. Seal two sections together with a piece of butt strip tape making sure to rub the tape to create a secure seal. Additional ASJ MAX Tape is recommended for large projects and projects that require multiple cuts of the insulation. Use of PVC Fitting Covers for elbows, tees, unions and other pipe fittings should be installed after installing fiberglass pipe insulation.

Hell, and if THAT's not clear enough, there's even a VIDEO to show you how to use it!

Hi Greg! Yes the ceramic wool stuff is made in different types and temp.ratings. Far as resistance to heat, and heat transfer, it's about the best available short of space Shuttle tile material. (good Luck getting any of THAT!)

And yes you want to be careful handling it, use goggles/respirator mask, long sleeves, etc. It gave me some irritation when I was using it on my oven projects.

One thing about it is it's not very durable, the stuff I used is rather fragile, IF you can score some for free, that's Ok, as it's costly, and I only found it in 25 ft. long by I think 48" wide rolls. Then there's the issue of wrapping it w/ something to protect it. I doubt that it can hold up very well in an under-car environment for very long. IF you find a way to use it and install it, you could be the guinea pig- or rather Wendy can!

As far as practicality, cost, availability, ease of installation, I think Ron's idea is better. I do wonder still about it's durability under a vehicle. The durability issue is probably why I instinctively thought of header wrap tape.

Purely speaking on insulation value, I think the Owens-Corning tubular stuff might be better. It's available in those various diameters and thicknesses, so one could look at their exhaust then judge which size is best.

Wetting the ceramic stuff then compressing it, might give better ability to mould to different configurations. But that reduces thickness, and drives out the air trapped in the ceramic. Ya want the air inside the insulatiing material just like you fluff up a sleeping bag before climbing in. It's the air that does much/most of the insulating work. Then it's a question of how high a temp the material can withstand before failure (melting).

Regarding the material science factors, the ceramic wool and the woven basalt fiber header wrap will stand up to anything normal cars/exhaust systems can dish out. The header wrap should be most durable and needs no top over-layer to protect it. But- it lacks any "loft" or trapped air. As Ron says- if the Owens-Corning tubular stuff can handle 850 F, it's probably good enough temp wise, it's far cheaper, and looks easy to work with. They didn't design it to go under cars on exhaust pipes--that's where We Crazies come in--Right?

Oh and I Repeat what Ron said about trying to use regular pink house insulation---DO NOT DO THIS! IF you do, you are a
Moron!!!

BTW, Greg, if you ever want to make a Rocket Oven- that ceramic insulation is the Bomb for that, it's what I use to keep the heat in the Oven body...LOL!

Tracy G

On the durability issue...

Since this stuff us so CHEAP (as in inexpensive!) if it only lasts five years instead of 50, WHO CARES?!?!? After just a year ins ervice it will have paid for itself many times over.

Great discussion, guys!

Now, how about getting some discussions going on the rides you've done. Reports of long-term effects of these modifications are equally important with the ORIGINAL posts! Then, invite others to participate in the discussions by PM'ing them using the mail function in the forums!

Let's KICK IT!!!

Ron