bonnet vents
10-19-2006, 11:47 PM
#46
Drifting
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I think two or three small vents, on each side of the hood, for a total of 4 or 6 vents, will look better than two small ones, or one big one.
Similar to the look that "Fat Bully" has...
Similar to the look that "Fat Bully" has...
10-20-2006, 03:30 AM
#47
Drifting
Thread Starter
wally, yes there was recirculation but i stuffed insulating foam into all the gaps between the radiator and body. the other factor causing the poor airflow is the placement of my fans and lack of any shroud, only aprox half of the rad gets air drawn through when they are working. the water temp has definitely dropped since adding the vents.
bc, 'fat bully' has the type of vents i most like but im not skilled enough to make anything like that. i dont know if he bent the alluminium or if he molded pieces in glass fibre for that look but the alloy is very stiff and difficult to bend.
bc, 'fat bully' has the type of vents i most like but im not skilled enough to make anything like that. i dont know if he bent the alluminium or if he molded pieces in glass fibre for that look but the alloy is very stiff and difficult to bend.
11-04-2006, 03:19 AM
#48
Rennlist Member
I think i may try making one long opening toward the front of the hood, probably right above the oil filer cap. the lowest pressure is found in this area on the hood. it would serve no purpose to open vents at the rear of the hood, as this becomes one of the highest pressure areas, where the air from the nose and radiator would find a lower pressure under the car to vent to. Those air pressure plots for the 928 are pretty useful in determining where this kind of vent would be most effective.
mk
mk
11-04-2006, 05:16 AM
#49
Drifting
Thread Starter
mark, that alluminium is really stiff and difficult to bend cleanly.. will you simply cut a hole and put mesh over it? i think that could look good. i havent been able to take any more pics as the car is still in germany after our last trip to the ring, started running on 4 cylinders with the fuel injection shutting down to the other four - but thats a whole other story.
11-06-2006, 01:31 AM
#50
Rennlist Member
how about something like this? so, yes, some cut with a screen mesh over it.
(sorry, not the greatest picture art operator)
MK
(sorry, not the greatest picture art operator)
MK
Originally Posted by drnick
mark, that alluminium is really stiff and difficult to bend cleanly.. will you simply cut a hole and put mesh over it? i think that could look good. i havent been able to take any more pics as the car is still in germany after our last trip to the ring, started running on 4 cylinders with the fuel injection shutting down to the other four - but thats a whole other story.
11-06-2006, 01:10 PM
#51
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I think you would be better-served by putting the vents in the fenders, or at least on the outside edges of the hood. the vent in the middle works, but all the hot air goes straight back into the hvac opening at the base of the windshield. Mark, don't you have a cold air intake for the engine there, as well as interior air intake? I've been in cars vented this way, and the interior temp increase is very uncomfortable for racing, or even just driving around... don't mean to rain on anyone's parade, but you really want that hot air to roll off the hood and down the side of car...
Steve
Steve
11-06-2006, 01:31 PM
#53
Rennlist Member
dont know if that vent, which is about 1/3 the size of the inlet for the radator, is enough to raise temps at the base of the windshield much. However, its better than fender slats, which are used to vent pressure from the wheel area.
I dont have any venting to the interior at all. the base of the windshield area is sealed off from both the pass compartment and the engine, except for the big vent hole feeding the air box. what you really want is the air to come from the lower half of the nose, going through the radiator and out the top of the hood. it adds to the pressure (which is one of the lowest areas right at the front middle of the hood) and keeps the air from going underneath the car, which raises its pressure down there. venting it to the sides, reduces the amount of air traveling under the car, and directs it to the side, but does nothing for adding the faster moving air on top of the car , which is the lower pressure area that needs to be addressed for downforce.
im now wondering how we can vent the hood and not make it look bad and not add to increased temps at the base of the windshield. there could be an increaase pressure in the base of the windshield too, which might offset the temp rise. also keep in mind, im still using the front air ducts too, so the air from the base of the windshield is only 1/3 the source. I still pick up a ton of sand at the race track caught in my air filter, due to the front tubes doing a lot of the intake work! (like a vacuum cleaner!)
mk
I dont have any venting to the interior at all. the base of the windshield area is sealed off from both the pass compartment and the engine, except for the big vent hole feeding the air box. what you really want is the air to come from the lower half of the nose, going through the radiator and out the top of the hood. it adds to the pressure (which is one of the lowest areas right at the front middle of the hood) and keeps the air from going underneath the car, which raises its pressure down there. venting it to the sides, reduces the amount of air traveling under the car, and directs it to the side, but does nothing for adding the faster moving air on top of the car , which is the lower pressure area that needs to be addressed for downforce.
im now wondering how we can vent the hood and not make it look bad and not add to increased temps at the base of the windshield. there could be an increaase pressure in the base of the windshield too, which might offset the temp rise. also keep in mind, im still using the front air ducts too, so the air from the base of the windshield is only 1/3 the source. I still pick up a ton of sand at the race track caught in my air filter, due to the front tubes doing a lot of the intake work! (like a vacuum cleaner!)
mk
Originally Posted by svp928
I think you would be better-served by putting the vents in the fenders, or at least on the outside edges of the hood. the vent in the middle works, but all the hot air goes straight back into the hvac opening at the base of the windshield. Mark, don't you have a cold air intake for the engine there, as well as interior air intake? I've been in cars vented this way, and the interior temp increase is very uncomfortable for racing, or even just driving around... don't mean to rain on anyone's parade, but you really want that hot air to roll off the hood and down the side of car...
Steve
Steve
11-06-2006, 09:33 PM
#59
Rennlist Member
Its getting close to the area where there is no low pressure zone and you cross over to presssure. if you go further back than the rear part of the front rim, you get in this area based on the air pressure 928 flow curves.
if you want to use the air entering the air inlet for intake and radiator cooling for downforce, you have to put the vents around the oil filter cap area or just to the rear of the centerline of the wheel. two vents like austin martin would work too. 80 square inches for them vs my drawing of about 85square inches.
two narrow ones on each side or a long vent like i had drawn in that picture are a couple of ways to do it. I think im leaning toward the austin martin way
MK
if you want to use the air entering the air inlet for intake and radiator cooling for downforce, you have to put the vents around the oil filter cap area or just to the rear of the centerline of the wheel. two vents like austin martin would work too. 80 square inches for them vs my drawing of about 85square inches.
two narrow ones on each side or a long vent like i had drawn in that picture are a couple of ways to do it. I think im leaning toward the austin martin way
MK
Originally Posted by tv
this is aston like, but better if narrowed on each side and flared as they go back, nicks job with its paint scheme looks mclaren f1 like;