TOPIC: Testing Pressure on Oscilloscope

I just received the raw data from one of the tests Mike Holler has run on The Groovy Sonata he's running.

These tests were done using an oscilloscope attached to the MAP and are exactly the way I received them about fifteen minutes ago.

STOCK IDLE



GROOVY IDLE



GROOVED IDLE PCV CAP





STOCK 3000 RPMs



GROOVY 3000 RPMs



GROOVED 3000 RPMs PCV CAP




STOCK LOADED



GROOVY LOADED




GROOVED LOADED PCV CAP




As you can see, there are a number of changes noticeable.
1) The range is wider on the Groovy Throttle assembly.
2) It apparently operates at a lower pressure range.
3) There is a visible "burp"halfway down the intake stroke. (Release Point)

All in all, a very disclosing set of graphs!

Comments?

HI Ron!

The results on the oscilloscope validates the results that you get on the gas analyzer, that there are dramatic changes, which brings me to this question which perplexes the heck out of me: on some of your u-tube videos, at an IDLE the gas analyzer is showing a change already, as does the oscilloscope readings. Now, if the idle passage is changed, i.e. moved to redirect the air in at the throttle axle where you say the groove is the least effective, and at an idle, the plate is closed with theoretically no air being drawn past the plate itself as it would be when it is cracked open even a wee bit, how and why can/is there a positive change when apparently the groove's effect is nill? Doesn't it start to work once the air is drawn past the open plate? I am obviously missing something important here in my understanding. Please help me learn!

Thanks, Ron.

Luke Wickenhauser
Gadgetman Saskatchewan

Hi Luke,

I'm hoping Ron will post more detail on the actual throttlebody involved but to your query, and I'll use the GM TB's as an example...

It may be the difference between engines that have idle air pathways and other engines
like the GM's that do not and the ecu is managing the idle by controlling the position of the throttle plate thus allowing an air flow over the groove.

My perception anyway.


Karl Fortner
Tacoma, Washington

Hey all... Thanks for your postings. This is exactly what I had hoped would occur.

Luke, you said "...how and why can/is there a positive change when apparently the groove's effect is nill? Doesn't it start to work once the air is drawn past the open plate?"

Air is moving past the throttle plate at all times. Even with the throttle body at the natural idle, some air passes The Groove. The engine, being at a higher state of vacuum, will pull from whatever source is available. In this case, it is the fine opening around the plate.

The IAC only allows for more air to be drawn in. In this particular instance, the throttle body has a design like this:


As you would probably guess, this would not have been my FIRST choice for a testing TB. It was the only one available, so we do the best we can with what we have available...

This IAC pathway was left un-modified.

To get testing done at what I would consider an "Acceptable" level would require one without an IAC, and to have roughly a dozen TB's available, each carrying 'revisions' of their own.

While this may not answer all questions (it shouldn't!) hopefully it gives your thought processes more to cogitate on!

Thanks Ron. I guess I always knew that there would still be some air drawn through the apparently closed throttle plate, but I did not know or comprehend that that small amount would have such a dramatic change. I am now more impressed than I was before, and I was quite impressed before, Ron, with your Groove!

Keep on testing!

Luke Wickenhauser
Gadgetman Saskatchewan