Thermasan

[gdbeckst]

I’m getting ready to install my new exhaust system and am deciding where to place the thermasan injector I am fabricating.

The thermasan installation instructions say to place the “Sanijector” before the mufflers. Right before the mufflers is going to be an O2 sensor
for my EFI install. My concern is that the thermasan operation may affect the O2 sensor reading which could cause issues during closed loop fueling.

Ideally I’d have two O2 sensors, one for each bank of cylinders, but may just start with one. On the other bank I could put the sanijector to try
and isolate it from the O2 sensor.

Anyone have thoughts on this?

I bought new ceramic coated headers (dougs) and want to use the preexisting O2 sensors in the collectors. Not much room between that and the muffler,
maybe 12 inches at most.

Is there any potential issue with placing the sanijector after the mufflers? Not hot enough? Wondering what the original motivation for installation
before the mufflers was.

 

[sgltrac]

I believe they installed in front of the mufflers because of higher exhaust
temps and better combustion.

Why in the world do you feel the need to install a complex, unnecessary and
possibly ineffective system to an already complex potentially unreliable
40+ year old coach?

Sully
Bellevue wa

> I’m getting ready to install my new exhaust system and am deciding where
> to place the thermasan injector I am fabricating.
>
> The thermasan installation instructions say to place the “Sanijector”
> before the mufflers. Right before the mufflers is going to be an O2 sensor
> for my EFI install. My concern is that the thermasan operation may affect
> the O2 sensor reading which could cause issues during closed loop fueling.
>
> Ideally I’d have two O2 sensors, one for each bank of cylinders, but may
> just start with one. On the other bank I could put the sanijector to try
> and isolate it from the O2 sensor.
>
> Anyone have thoughts on this?
>
> I bought new ceramic coated headers (dougs) and want to use the
> preexisting O2 sensors in the collectors. Not much room between that and
> the muffler,
> maybe 12 inches at most.
>
> Is there any potential issue with placing the sanijector after the
> mufflers? Not hot enough? Wondering what the original motivation for
> installation
> before the mufflers was.
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

 

[6cuda61]

Hmmmm....not sure if a mix of headers and sanijector thing is going to work as per OEM. Perhaps the exhaust gas velocity may be two high. I hope im
wrong or your going to have one heck of a mess in your mufflers.
--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[gdbeckst]

> I believe they installed in front of the mufflers because of higher exhaust
> temps and better combustion.
>
> Why in the world do you feel the need to install a complex, unnecessary and
> possibly ineffective system to an already complex potentially unreliable
> 40+ year old coach?
>
> Sully
> Bellevue wa

As an electrical/software engineer, complex, unnecessary, and possibly ineffective systems are my speciality . For the funsies, and originality.
My grandfather ordered the coach with a Thermasan and I want to put it back to how it was .

Quote:
> Hmmmm....not sure if a mix of headers and sanijector thing is going to work as per OEM. Perhaps the exhaust gas velocity may be two high. I hope
> im wrong or your going to have one heck of a mess in your mufflers.

I can’t imagine the small amount of extra moisture in the system will cause too much of a problem. If it does I’ll just need a new muffler or two
perhaps… everything aft of the headers is stainless steel so hopefully it can handle this. Not too worried about it though.

Quote:
> Hello Don,I am intrigued about your headers. I have just purchased my 76 Glenbrook with 76,000 miles on it and the exhaust manifolds need to be
> done. A friend suggested Stainless steel headers and not sure if they are available. Are yours custom made?

I just sold some used SS headers from circa 1996 to cuda6 above. They held up for about 5 years of driving and 20 years of sitting. That being said,
they weren’t pretty, but were still functional. I’m doing a frame-off restoration and couldn’t stand to see them next to all the shiny new parts
.

Based on the state of the SS headers and what I’ve read about headers “glowing red” during periods of heavy engine load, I’d say that headers
are somewhat of a “wear” item. If you don’t maintain them (ie: recoat/protect from heavy corrosion/rust out), you’ll probably have to replace
them every 8-10 years. This is just my opinion.

I’m trying out the ceramic coated headers from Dougs (part D755Y) and we’ll see how well they last. They are mild steel but have a polished silver
ceramic coating rated for 1400F. There are also matte black ones available from Dougs. I’ve also seen bare mild steel from some vendors, and
periodically stainless steel ones from Dougs as well. They all have different part number suffixes.

All this being said, it seems I bought the last set of D755Y from Dougs/Pertronix direct. They seem to be available from other vendors on the web.
With the pandemic situation, manufacturers are halting production of/discontinuing older products, especially ones like this that are for niche
applications. Hopefully they do another run of GMC MH headers soon…

Either way, I’ll be holding onto my headers for use as a template if I need to make custom ones in the future. Gotta start getting some practice
with my TIG

 

[boybach]

What is the advantage of headers? My coach is plenty fast, roars up hills etc. Are they for better gas mileage or bragging in sigfiles?

BTW, I would love to be able to burn my crap. Seems like a great way to "go"

Larry
--
Larry - Victoria BC -

1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses

 

[6cuda61]

In this application i can only really offer 2 reasons.....one, exhaust manifolds crack/warp and are really expensive to replace....two, better ezhaust
gasket life. There may be a little better exhaust flow as well but i dont think there is much performance gain.

> What is the advantage of headers? My coach is plenty fast, roars up hills etc. Are they for better gas mileage or bragging in sigfiles?
>
> BTW, I would love to be able to burn my crap. Seems like a great way to "go"
>
> Larry

--
Rich Mondor,

Brockville, ON

77 Hughes 2600

 

[jim kanomata1]

The Headers we use on our coaches are designed to gain torque at low RPM,
not to race.
Better known as Tri Y Header design.( 2000-3200 rpm )
The O2 sensor will not be influenced by the Thermastan,

> In this application i can only really offer 2 reasons.....one, exhaust
> manifolds crack/warp and are really expensive to replace....two, better
> ezhaust
> gasket life. There may be a little better exhaust flow as well but i dont
> think there is much performance gain.
>

> > What is the advantage of headers? My coach is plenty fast, roars up
> hills etc. Are they for better gas mileage or bragging in sigfiles?
> >
> > BTW, I would love to be able to burn my crap. Seems like a great way to
> "go"
> >
> > Larry
>
>
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>

--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502

 

[Matt Colie]

While at Thetford and as the last engineer on the Thermosan program, I can tell you that I did not have an olds 455 in the program. I can tell you
that some coaches mounted and extra "muffler" to create more turbulence to better burn the effluent. We (I) found it to be of no value in several
tests. The injector probe had (has?) a fine scree that will hold any particulate in the exhaust flame as needed. There really was nothing to hold.
The system started in the black tank with a relatively fine screen so there was very little particulate to deal with in the exhaust.

We did find that there was a small issue with the GMC application. They didn't shake and bounce as much as the others so the waste did not get broken
up as well as we might have liked. There was still stories of people doing full cross country runs without having to dump.

These systems performed very well for the most part. When I parted company with Thetford (a long story by itself), I was trying to introduce a
commercial system for the transit buss market. Greyhound was interested, but I never got to complete a prototype.

In four moves since I worked there, the box of T-san stuff has been lost.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

 

[boybach]

idle rumination over my scrambled eggs this morning ...with all the bright young engineers out there these days surely someone could re-imagine the
thermasan concept by combining a mascerator with a (black) water injection system? :?

Larry
--
Larry - Victoria BC -

1977 Palm Beach 40,000 miles, PO said everything working but forgot the word NOT. New Atwood fridge, water heater & furnace. New SS exhaust system,
6000w Onan, Iota Converter, R134A A/C, New fuel lines & heat exchange hoses