Traveling Dyno Runs

[Fredensborg]

I'm planning on taking my car to the Street Machine Summer Nations in St. Paul in a couple weeks, I've watched cars do dyno runs on the traveling dyno machine in years past and have always wanted to do it. What do I need to know before I do one? I've always wanted to have a baseline of HP/torque numbers for my car because it has performance upgrades that were on it when I got it , so I really have no idea what kind of numbers I actually have.

Plus, it just looks like a lot of fun to do a couple runs!

My car is a 351C 4V with a C6 trans, intake, carb, headers are all aftermarket. I don't know for sure, but I think the motor may have been bored .030 and have a different cam.

Is there any danger in trying a dyno run? Obviously its a 50 year old car and, sh*t happens as they say...so there is always some risk I suppose. My tach quit working last summer, is that an issue I should be concerned with?

When you do a dyno run, do you just wait until they say "go" and then just floor it? or is there more to it than that?

The dyno machine will be there, I will be tempted...just doing my due diligence now.

 

[tony-muscle]

I don't see any danger in dynoing your car. Just make sure you rev it to the where you feel comfortable. If you need to let go early that's okay. They typically include 2-3 runs so better ask first. You can look at the graph and see if you are past max HP or not before the next run They will guide you through the whole process. Different dynos work differently and there are not necessarily apples-to-apples comparisons. Also figure out which gear you will want to be at. You typically want to be at 1-to-1 which is third gear in the C6. However, keep in mind that you will be speeding at 120-150 mph depending what tire diameter and rear end ratio you run. This means that you need to make sure that your tires and drivetrain can handle it. If not, then run the dyno in 2nd gear, which I did many years back when I had my C6.
They will typically tell you to hold steady, say at 1,500 rpm, and then give you a signal for you to floor it. Depending on how well your carb runs, instead of flooring it all at once, go a little slower, maybe a second from no gas to full.

PS: consider running it with the hood open to keep the underhood temps under control.

 

[71ProjectJunk]

At one time I owned and ran a Dynojet, there should be no issues with doing a couple of pulls on a chassis dyno. The guys running it should tell you all you need to know.

 

[Hotstang]

As a guy who had #8 rod fail on a dyno for oil starvation just be aware of the rpm. Most of the time on the street we reach 6000 before a shift but almost never in high gear. As the rpm build in high gear it is much slower than lower gears so your time above 4000 to say 6000 or whatever you are comfortable winding it to is a longer. With a stock Cleveland and no oiling mods sustained high rpms are a killer, not necessarily from the stress on the parts but our engines use priority oiling that starts at #1 rod and ends at #8.
After tear down of my engine you could see how the #1 &2 rod bearings looked good but as you head back the bearings got worse with a failure of the bearing followed by the rod on #8.
This engine would have lived on the street for a long time but multiple high rpm tuning runs on the dyno killed it.
But all is not lost, the rebuild with new crankshaft stretch it to 408ci and I don't have to turn as many rpms to get the power.