"Dear Sir, please report to the Emission Test Station

[Ron Mummert]

Originally posted by SvXit


No. I was subjected to a 4-wheel dyno test near my home in MD. When I went two years ago, they were not set up to dyno AWD vehicles, so they just did the tailpipe test. This year they had they dyno and said I was way over the top on NOX emissions, so I'll have to retake it at the end of this month.

Olu, take the car to the Columbia, MD facility just off Broken Land Parkway. The dyno's kaput more often than not. I wonder though, if you flunked test number one on the dyno, if you could do the retest with the sniffer? Tell Kevin I sent you. There's a guy in New Windsor who has cats for sale on the cheap. You may know him.
Have fun & good luck.

Ron (perfect emissions every time).

[DavieGravy]

Why are the dynos bad? When I looked at my car, all wheels were turning in the same direction.

DavieGravy reported that all his tires were spinnning in the same direction. My question: does this specific dyno system have four drums (or two sets of wheel rollers)?

If there are two sets of drums (total of four), I'll partially buy off on the test procedure, otherwise, something is suspect.

This is just a personal question that begs an answer. The only four drum dyno I've ever seen was in Europe and was used to determine differential dynamic braking force (i.e. front vs rear or same axle side to side braking force.) The Dutch vehicle inspectors were hell when it came to clearing an American vehicle. The primary reason: insufficient braking force, front/rear or same axle side to side. These guys loved giving you a pink slip that indicated you have a problem. The Dutch didn't seem to understand the dual brake system that was created in Europe. Who else better situated to test right front/left rear braking force!

Still wondering about a stateside four drum roller system designed to test emissions.

Mike

[Ron Mummert]

[QUOTE]Originally posted by Rosevineboy
[B]DavieGravy reported that all his tires were spinnning in the same direction. My question: does this specific dyno system have four drums (or two sets of wheel rollers)?


I take it Davie's comments were a joke?

Yes, four drums. A double roller for each wheel.
Scary!

Ron.

[DavieGravy]

[QUOTE]Originally posted by Ron Mummert
[B]

Originally posted by Rosevineboy
DavieGravy reported that all his tires were spinnning in the same direction. My question: does this specific dyno system have four drums (or two sets of wheel rollers)?


I take it Davie's comments were a joke?

Yes, four drums. A double roller for each wheel.
Scary!

Ron.

When I said all wheels turned in the same direction, what I meant was that last time I got my emissions done, and when they rolled the vehicle onto the 4 rollers, I looked at my car and all wheels turned in the same direction.

When you say dynos, do you mean the roller drums they put the vehicle on to do the emissions test?

I'm thoroughly confused here. Why would that be a bad thing for our cars?

Dont' the drums spin freely with the wheels?

Like I said, if all wheels turn in the same direction, what's the problem?

Why can't we go in the 4wd lane along with all the other AWD/4WD vehicles?

Confused, very confuesed. ???????????

And what is a "double roller?"

Sorry if I'm missing here.

Thanks.

Okay, looks like I started something that is being blown out of proportion, not only by myslef by others also.

In response to DavieGravy's last reponse, I can tell the young man is confused. When you go back and read the previous posts, I can understand why. I think I too, would be confused.

My question, (I thought) asked if there were two sets of rollers. That would mean four drums, right? If I am wrong, someone please correct me.

The observation I made referenced the way vehicle emmissions were tested in the Lone Star state. I've never seen a double set (my words) of drums, wherein front/rear tires each sit within a drum assembly that contacts each side of the tire patch. They don't have these in Texas, at least for emmissions checks. The inspection tech informed me that if the vehicle was AWD, then they conducted an RPM test (one low, the other high with a sniffer tube). If there is another state using a double type roller system, i.e. four drums, then I would be curious as to how the test was conducted. That's all I was curious about.

Davy, yes, all the tires/wheels must turn in the same direction. If they didn't, I wouldn't want to be in the same facility. Kinda like having the front axle in a forward speed and the rear axle turning the opposite direction. That can't happen. At least on any AWD I am aware of.

The dyno question is a little harder to answer. My understanding: this machine is used to measure horsepower, torque and braking force. Could a dyno with a front and rear axle setup be used to check SVXs, yes. Dyno's can simulate load, drive angle (degree of slope), force created by the vehicle drivetrain, etc.

Didn't mean to confuse anyone, just curious about other states and how they test AWD vehicles.

Hope all of this info is a little more clear/precise. If not, send me a PM and we can go from..........

Mike