Dyno room exhaust venting

[osubeaver]

For those of you who use an engine dyno, what setup do you use to vent the exhaust gases? This year, we were moved into a room that used to have a 6L turbo diesel on a dyno and there is vacuum that pulls the exhaust. We measured the flow from the vacuum to be about 150 SCFM and we think that it is not enough and that we are getting some serious back pressure. The reason we think this is because we have had the end of a muzzy muffler blow off at 10,000 RPM! It sheared 8 rivits right off.

[osubeaver]

For those of you who use an engine dyno, what setup do you use to vent the exhaust gases? This year, we were moved into a room that used to have a 6L turbo diesel on a dyno and there is vacuum that pulls the exhaust. We measured the flow from the vacuum to be about 150 SCFM and we think that it is not enough and that we are getting some serious back pressure. The reason we think this is because we have had the end of a muzzy muffler blow off at 10,000 RPM! It sheared 8 rivits right off.

[Andycostin]

Is the muffler sealed to the venting?? I find it hard to believe that low vacuum flow rate would cause this, but i may be wrong. How long is the vacuum tubing before it exhausts to atmosphere?

[osubeaver]

I actually don't really know where the tube exits to atmosphere. I'll have to check it out tomorrow. Right now we just have a piece of flexable metal tubing about 10' long that goes to the floor vent and I don't know where it goes from there. The flexable tubing was just slipped over the muffler and header wrap was wrapped around it, but it's not a perfect seal. I safety wired the muffler to the header and the tube to the muffer, so apparantly the easiest thing to break was the muffler end blowing off.

[Daves]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>The flexable tubing was just slipped over the muffler and header wrap was wrapped around it, but it's not a perfect seal. <HR></BLOCKQUOTE>

Would this change the effective length of your exhaust, hence changing your performance characteristics? Intrusive measurement.

[osubeaver]

Well, we hooked a manometer up to the inlet pipe on the floor vent (with the exhaust all hooked up) and it read about 5 inches of water. Surprisingly, the reading basically did not change when we did a full throttle dyno pull to 11k RPM. Now I am wondering why in the hell the muffler blew up.

[boy racer]

did the 6Liter turbo diesel have back pressure problems too??

it pumps significantly more air then your little 600 does.

and you can't develop enough pressure with your motor to shear off any rivets...try putting your hand over the exhaust sometime...preferrably with a welding glove on if it's hot.

[bigtoyota9]

We have around the same setup our venting system is from an old diesel engine test room. We just aim the muffler at the inlet to the stack which vents at the top of the building and dont have any problems with fumes. We are using a muzzy muffler and are having no problems. We have had the fire doors close on our stack before when we had been running all weekend. I dont know why a vented vacuum exhaust stack would cause your more back pressure. I would check and make sure there arent fire doors in your stack that have closed on you. Other than that im outta ideas.

[osubeaver]

Well, upon further examination it seems that the muffler had been re-rivited together with aluminum rivits. I just think they got really hot and were easier to break that way. http://fsae.com/groupee_common/emoticons/icon_confused.gif