The next project for the Rebel is a hood designed to extract heat and air out of the engine bay area. It should help reduce engine bay temps and front end lift.



I'll post more images after it has been painted and installed.
Next then will be indepth testing to see if it works as the vendor claims.

[ 06-05-2001: Message edited by: teamzr1 ]

The hood has been painted and installed.
Here is a slideshow of how it looks on the Rebel.

http://teamzr1.com/c5hood/hood.htm

Next is testing of thermal and air flow/movement.

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 testing

Again ongoing test result finding will be posted in the extractor hood webpage.

John

2nd round of testing results.

My main goal is reducing front end lift at high speeds since I have no cooling issues at this point.

I ran the next testcase by having the temps from the last testcase to compare to.
I sealed off the hood's openings (all 8) and re-ran the same tests as last time on the same day so the outside temps were just about the same.

At this point it looks like this high dollar extractor hood is all show and little go for the temps reported in 2nd round of tests were the same as when the hood holes were open.

I was able to determine if front openings were extracting air by using longer lengths of yarn.
Clearly at speeds about 50 MPH the yarn was being forced towards back of the car but all it seems to be doing is extracting the same air as the inlet openings and very little of the engine bay air is being carried with it.

More tests to follow.