Just for posterity that wish to understand I’ll type it out.
A water brake engine dyno has things it cannot measure because of its very nature. One of those things is transient response. And that is HUGE. And it’s not just a drag race problem. In other words it’s limit in transit response doesn’t just affect drag race engine builds.
Unless you are running at Daytona or Talladega where you almost flat foot it around the track, you will require the engine to rpm (accelerate) from the lowest rpm to the highest rpm and do that over and over and over.
A circle track is nothing more than a drag race between corners. It’s that simple. Just like a drag race.
A water brake dyno (assuming you are doing acceleration testing and not steady state or step testing) controls the rate acceleration while doing the test, usually at a rate set by the operator.
A test by most guys is 300-325 rpm/sec. Larry Meaux has published multiple times several different cars with measured rpm acceleration rates. Off the top of my head I think the highest rate was around 2000 rpm/sec and I think the lowest was about 400 rpm/sec. And that’s during the same run.
So using 300 rpm/sec doesn’t replicate what happens in the car. You can use higher rates than that and 600 rpm/sec is kind of a standard too. If you start accelerating the engine quicker than that, even at a 50 times a second sampling rate you miss too much data. So guys use slower rates for data. It also makes the observed power higher than it would be if you used a higher rate.
So saying all that I want to be clear it doesn’t make the testing useless. Because it’s not. But certain testing covers up things like the engines ability to rpm.
So let’s take the above dyno testing as an example. We have a TRACK TESTED manifold, and a throughly Chrysler tested manifold that both say and I’m paraphrasing here “short branch runner length manifolds” do not perform as good as other manifolds and in the Chrysler book that was referencing either the Strip Dominator or the Offy Port-O-Sonic. It was tested and the Torker was a loser at the track where it counts.
So we either need to stop dyno testing (that would be ignorant) so we need to understand the WHY that makes this so. Again, it the nature of the machine and the testing methods being used.
When the dyno controls the acceleration rates (transient response) you can’t just say manifold A is better than B because it made more power at 300 or 600 or even 1000 rpm/sec.
Luckily I’m old enough to have used this stuff long before I ever used a dyno. I can’t tell you how many times I’ve pulled a Torker or some dual plane intake off a car and dropped a Strip Dominator on it and went quicker and faster. Never once did I have one go slower that was at least built for it. Meaning it’s not built to tow a barge, haul 80,000 pounds or it’s geared to run 200 mph when the engine is making 300 hp.
The short answer is you can NOT make air turn a corner and not pay a price for it. It doesn’t always show up as a power loss because of the nature of the dyno and the testing method. Corners and air are bad. Corners and air with fuel (gasoline) is worse. Corners and methanol is downright horrible.
This shows up in cylinder to cylinder distribution but it doesn’t always show up as a power loss because the dyno is controlling how fast the engine accelerates and not the engine itself.
Were we able to test at higher acceleration rates and still collect all the data then you would see less power from the Torquer or DP intake.
I have dyno tests for IIRC 6 different intakes. Same engine. They were tested on a water brake and an inertia dyno. Both engine dyno’s, not a chassis dyno.
What they learned was the best manifold on the WB dyno was the worst on the inertia dyno. And the best manifold on the inertia dyno was the worst on the WB. And the second best was the second worst etc. from top to bottom they were almost perfectly inverted.
Then they went to the track and tested the intakes. And guess what?? The best WB intake was the slowest and the best inertia dyno was the fastest.
That’s because the inertia dyno did not control the rate the acceleration like the WB dyno does and that is why the seeming anomaly.
This is why if we don’t understand the testing methods and the nature of the tool we use we can be fooled by just the numbers.
The answer is if performance matters then you dyno the engine and then go test and VERIFY the test results. Not just believe the numbers.
Luckily for us, this type of thing has been field tested for decades now.
The guys who struggle with the numbers are the guys who refuse to learn.
The Torker is a bad manifold. They are doorstops for any decent build. Unless you are reliving your salad days.
