I'll be writing a full report and appending to it as tests will be ongoing and indepth and will be posted on team website in the
Team Porject section.
Note: throughout this testing keep in mind the Rebel ('99 Mallett 435) sits 2.5 inches lower, has a large Donaldson airfilter inclosed within my own designed cold air box, has a LS6 intake manifold and fuel table tuned via a MAF translator.
These mods also help reduce air temps of the IAT and long term fuel table set to a almost perfect zero when not under WOT, thus the lean condition whch cause higher heat has been removed.If you review the slideshow on website you will notice Yellow yarn hanging from the scoop opening facing the windshield.
The yarn is heavy enough to be strong under higher speeds and also light in weight to move in same direction as airflow.
Using a VTOM with a thermal probe using a K type probe lead, I mounted the probe in airspace under hood, near the engine top but away from touching anything and close to back of engine to be as far from airstream as if could.
Weather's outside temp being reported by the gauge of the car said it was 83 degrees outside.
What was observed in first looksee of this :
- At Idle underhood temps = 189 Degrees
- Water and Oil temps go up to 207 degrees
- IAT = 130 degrees.
- Speed above 30 MPH underhood temps = 83-89 degrees
- Speeds above 30 MPH - water and oil temps stayed 190 degrees
- IAT maintained same temps as outside temps
The hanging yarn above 20 MPH began to suck inward into scoop opening and by 60 MPH length of yarn was fully sucked into scoop opening.
After traveling for about 10 miles on the highway at speeds of 65 - 85 MPH, assuring that probe temp was about 85 degrees, I pulled over, leaving engine running at idle and let oil, water and IAT get to the above max temps and then proceeded back up to highway speeds and watched all temps.
Within a few miles all temps went to the lower temps as listed above.
Speeds below 35 MPH would allow air movement as it being reported as about 83 degrees but not enough airlflow to maintain 190 degree oil/water temps.
This test only showed there is clear air movement, it does not prove that the air is being extracted out of the forward scoop vents and next testcases must answer that question.
Also the tests did not show if the hood reduced or caused front end lift at speed and testcases are needed to answer the most important question.
Negative of design:
Scoop edge facing windshield is hitting right windshield wiper arm at the top.
Left one is OK.
Water drain tubes are located in such that if you have any type of cold air box, the tubes then are right onto top of the box, preventing hoses to be used to route water down and under the car.
Center front edge of hood when uncrated was found to be cracked and had to be repaired before painting.
Cost of this hood, now knowing it is a stock hood with a scoop cut/glassed in, is not worth the value at this point of testingAgain ongoing test result finding will be posted in the extractor hood webpage.
John
