Inexpensive auto exhaust system?

[MongoTom]

My garage is well insulated, heated and even slightly air conditioned. I'm trying to vent auto exhaust in something more than the hose out the door manner. I'm looking at duct booster fans like these http://www.tjernlund.com/Tjernlund_M-Series_Specifications_8506014.pdf mounted to help exhaust the fumes from an exhaust hose through one of the garage walls. The 4" version will move about 200 CFM and an idling small car shouldn't generate more than that. The maximum operating temp is 140 degrees F, but again exhaust gases at the end of an 11' crushproof hose shouldn't be that hot, especially considering that cool air will be entering the hose along with the exhaust. The hose is about $100, the duct booster fan about the same, so for less than $300, I think I can push exhaust through a wall without seriously disturbing the thermal efficiency of the building.

Mostly I'm looking for a check of my logic. Do you think this will work or am I seriously off base here? Thanks for the help.

 

[kbs2244]

I would like to see a fan with the motor out of the air flow.
Exhaust is very corrosive.
A kitchen stove exhaust fan is a starting place for the type of fan.

 

[58Yeoman]

I've got just the fan that you need. I bought it a couple years ago for a project that never materialized. I paid $20 for it at an estate sale; it's for a Rohn wood stove, left side. It's new, never used.

The inlet measures 4 1/2", the outlet is about 3 5/8" by about 4". You can have it for $20 plus shipping. It would cost a lot more to buy from a dealer or online.

 

[AE2]

I am certainly no expert on this, but in my opinion, if there is not a specifically engineered and manufactured solution for removing exhaust gases in your price range than I would certainly install numerous carbon monoxide detectors in your building to work in conjunction with your system.

 

[stanleyrleonard]

Saw a setup years ago at a guys garage where he rebuilt engines and bench tested the results by direct hook-up to the exhaust before selling them. His approach was that since hot air rises vent through the roof--I've seen this in dealerships as well; and, of course, I would probably have at least a 5 HP exhaust fan vented through the roof just as added protection for those long days in this spot. Stan

 

[Richard Cranium]

mount that electric motor that Yeoman is offering you into the wall and then use one of the flexable hoses to get the exhaust to the blower

 

[MongoTom]

Sounds great. I'll buy Yeoman's wood stove fan and give this a shot.
And yes, I already have a CO detector in the room. I can barely drive off my lift without the thing screaming at me, so if this works without that noise, I'll know it's working very well. Thanks again for the input!

 

[jimindm]

You do not say how big your garage is. But if the carbon monoxide tester goes of in just moving a car in that tell us a few things. Garage is not very big, could be well insulated if it has any size at all, garage is very air tight no matter what, and the list goes on.

If you put an exhaust fan in remember you must make that air up some where. If 200cfm is going out, you somewhat have to plan for about the same to enter.

Not saying your idea is good or bad as far as exhausting a vehicles exhaust. Where will that incoming air come from, and it will come in. A window or door is one thing, a chimney for a furnace is another. especially if the furnace is running. Really important if you have a garage attached to the house. And that door is left open, while a furnace or water heater is running.

If you have 10 foot ceilings, you are exhausting a 10x20 space every ten minutes of run time. Something to think about.

I have an exhaust fan, with no inlet, It move considerable more air than the one you show. But I will tell you when it is on you know it. Just closing the shop walk door is a challenge. Once it is closed you can see the overhead kind of pull in taking the slack out of the rollers and guides.

Think about it very carefully.

 

[JonnyMac]

Monoxivent is a company that specializes in this. Probably way above what you need but they have plenty of ideas and options...

 

[wssix99]

Monoxivent is a company that specializes in this. Probably way above what you need but they have plenty of ideas and options...

+1 No need to re-invent the wheel. These exist for large garages already but I'm not sure what the purpose would be for a smaller space. http://www.firerescue1.com/fire-pro...he-choice-3-systems-to-remove-engine-exhaust/

Are you going to tell us that you have a huge, fire department-like garage? <insert envy here>

Personally, I like to breathe in the exhaust. It makes me feel silly...

 

[58Yeoman]

Tom, for some reason, I can't send PM's. Geez... Here's the costs.

Tom,

The total cost by USPS is $34.65; FedEx is $33.17. These are totals which include the $20 for the fan. Your decision, if you even still want the fan. No obligation.

[email protected]

Thanks,
Phil

 

[58Yeoman]

Hey Tom, I'll take your package to the post office today. Thanks.

 

[maxpower_hd]

Sounds great. I'll buy Yeoman's wood stove fan and give this a shot.
And yes, I already have a CO detector in the room. I can barely drive off my lift without the thing screaming at me, so if this works without that noise, I'll know it's working very well. Thanks again for the input!

You may want to install a second one down lower nearer to the breathing zone. Sort of like a High Level alarm as opposed to an initial alarm. If both are going off you need to skedaddle until the room clears out. If only the one at the ceiling goes off at least you will know your breathing zone is clear even if you evacuate. Just extra piece of mind.

 

[sberry]

Absolutely a car will set the thing off in a small garage, you need to clear the air before closing the doors and reset an alarm. Vapors in spray cans are bad too. With a small garage I open the door and back the azz end of the car out if I really need it running, unless I absolutely had to its just more junk in the way.
We contemplated something for tractors then took stock at how often it was a problem. Once in last couple years we use it and we wait till a nice day and back outside to do tuning.
A shop should have an intake and exhaust fan, I can actually turn mine on and park in front of it. Put fan near the tailpipe in the bay and open vent, turn fan on, vent whole garage. As for efficiency, how often do you need to work on running engines in inclimate weather?

 

[CoogarXR]

Not to thread-jack, and maybe I just don't understand... But, why not just put a hose on the tail pipe and plumb that through the wall? I had a mechanic buddy who had a setup similar to that.

 

[wssix99]

The 4" version will move about 200 CFM and an idling small car shouldn't generate more than that.

ASHRAE Handbook - HVAC Applications (SI); Chapter 15 - Enclosed Vehicular Facilities; Parking Garages gives some instruction and equations for estimating CO and CO2 production from exhaust.

I used this for sizing the HRV in my garage. (my City requires passive ventilation and I was able to use these equations to get an active ventilation system approved for my heated garage) Using my calculator and the ASHRAE equations, an average car should put out 150 cfm. So, you'd probably need to design something to pull excess air from your garage so you don't have a fan sucking on your tailpipe. (I'd think that could do weird things to your car's performance if you are trying to work on it.)

I missed the bit about a CO detector. I guess that would be a nice thing to have for a completely sealed garage, but they are such a PITA - and they only have finite lives.

So far, the HRV has worked out well for us and has kept the air quality great. (We run it whenever the lights are on, which are also hooked up to the garage door openers - so things run for a bit after cars leave the garage.) The only thing is the HRV works too well in the summer, so next year we may be adding a damper to circulate outside temperature air through the fan. (The engines of the coming-and-going cars add a ton of heat to the garage and the HRV holds on to it too well in the summer.)

 

[MongoTom]

Sorry, I've been making this work and haven't checked in for a while. To answer some of the questions raised, my garage floor is 25 X 25 with a 12 foot ceiling. The CO detector is at chest height and I'm planning to get another for the room.

So, I used Yeoman's motor, bought a 4" X 11' crushproof hose, rigged them together, built a short duct through the wall and hooked it all up for maybe $210. I turned it on for the first time today. I attached it to my 3.5L RAV4 and ran it with the system running for over 30 minutes in the completely closed garage. No alarm, no drama and the exhaust gases venting outside reached just over 80 degrees, so I'm not overly concerned about heat in the vent system. Apparently there's enough leakage around the doors to bring in sufficient replacement air. I did this so I could work on my Miata. With half the displacement pumping exhaust gases out, I suspect it will work fine even though it's much older and not nearly as clean running.

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[psjoyal]

That turned out pretty slick.

 

[MongoTom]

Yeah, kind of the "hose through the wall" concept, but with a boost. Just ran the Miata up to operating temp without a hiccup. Well, the vent didn't hiccup, but the Miata has an issue and I'd rather solve it in the garage than outside in the 90 degree heat.

 

[wssix99]

How do you let in excess fresh air to the hose so you don't **** on the tailpipe and mess with the cars' emissions system? Did you create a fitting for the tailpipe with additional venting or put a centralizer in the crush proof tube to hold on to the tail pipe?

 

[MongoTom]

It's a 4" hose over a 2.5" tailpipe. Nothing but friction holds it onto the pipe and so far, that hasn't been a problem at all.

 

[SALIV8]

that looks great to me. turned out better than I expected.

And cool of 58 yeoman hooking you up!

 

[MongoTom]

Yep, he's the best!

 

[bdbecker]

It's a 4" hose over a 2.5" tailpipe. Nothing but friction holds it onto the pipe and so far, that hasn't been a problem at all.

I doubt it will ever be - you don't need (or want) the hose to make a perfect seal around the exhaust pipe. Very nicely executed setup - that should serve you well.