Hood Vents?
03-12-2009, 09:19 PM
#61
Developer
John, as you know, normally the area at the base of the windshield is high pressure at speed, hence the opportunity to use cowl induction.
But I have wondered about the recess in our cars before the windshield wipers... it is far enough away from the windscreen that it might actually be low pressure in that location at speed.
If I am right, then all you would need to cause more air to move through the engine bay is to remove the rubber seal at the top of the engine firewall. That would provide a pretty good gap between the firewall and the hood all the way across the car, and the air would escape out the windshield wiper recess.
I am reminded of my old stock cars days - lowering engine temps was as easy as adjusting the hood hinges to hold the hood 1/2" up at the rear.... same thing.... only in this case it would be stealthy and better looking.
At least it would cost nothing and do no harm to try.
But I have wondered about the recess in our cars before the windshield wipers... it is far enough away from the windscreen that it might actually be low pressure in that location at speed.
If I am right, then all you would need to cause more air to move through the engine bay is to remove the rubber seal at the top of the engine firewall. That would provide a pretty good gap between the firewall and the hood all the way across the car, and the air would escape out the windshield wiper recess.
I am reminded of my old stock cars days - lowering engine temps was as easy as adjusting the hood hinges to hold the hood 1/2" up at the rear.... same thing.... only in this case it would be stealthy and better looking.
At least it would cost nothing and do no harm to try.
03-13-2009, 09:18 AM
#63
Rennlist Member
HTML Code:
If I am right, then all you would need to cause more air to move through the engine bay is to remove the rubber seal at the top of the engine firewall. That would provide a pretty good gap between the firewall and the hood all the way across the car, and the air would escape out the windshield wiper recess.
Carl,
You need to build us a hood vent, there would be a market for those!!
Regards,
Ken
03-13-2009, 01:11 PM
#66
Rennlist Member
Carl, no way! The high pressure zone is as wide as it is shown on the pressure graph plot. everthing around the windshield, the opening between windshield and hood as well as a few inches back is all HIGH pressure. verified with a sunx sensor, when i was trying to compare nose pressure to base-of-windshield pressure. the only thing a little lip before hand would do would be to reduced the pressure zone, but it still would be positive pressure, unlike the middle of the hood where there is low pressure. the entire a/c area is high pressure. if you open the rubber seal, as I have on my car, you would be forcing air into the engine bay. AND, in my case, forcing air into the air box, as I have it ducted to it via a rear air box vent. If you, or anyone saw lower engine bay temps by doing this on other cars, it was probably taking the above hood air flow, raming it down the engine opening and venting out the bottom. (creating some lift). not a problem for most all street cars, but if you are doing track events, open road racing, or want to increase downforce, that isnt the way to do it.
mk
mk
John, as you know, normally the area at the base of the windshield is high pressure at speed, hence the opportunity to use cowl induction.
But I have wondered about the recess in our cars before the windshield wipers... it is far enough away from the windscreen that it might actually be low pressure in that location at speed.
If I am right, then all you would need to cause more air to move through the engine bay is to remove the rubber seal at the top of the engine firewall. That would provide a pretty good gap between the firewall and the hood all the way across the car, and the air would escape out the windshield wiper recess.
I am reminded of my old stock cars days - lowering engine temps was as easy as adjusting the hood hinges to hold the hood 1/2" up at the rear.... same thing.... only in this case it would be stealthy and better looking.
At least it would cost nothing and do no harm to try.
But I have wondered about the recess in our cars before the windshield wipers... it is far enough away from the windscreen that it might actually be low pressure in that location at speed.
If I am right, then all you would need to cause more air to move through the engine bay is to remove the rubber seal at the top of the engine firewall. That would provide a pretty good gap between the firewall and the hood all the way across the car, and the air would escape out the windshield wiper recess.
I am reminded of my old stock cars days - lowering engine temps was as easy as adjusting the hood hinges to hold the hood 1/2" up at the rear.... same thing.... only in this case it would be stealthy and better looking.
At least it would cost nothing and do no harm to try.
03-13-2009, 01:21 PM
#67
Rennlist Member
Ive always wondered about doing this. (wrapping headers) . its supposed to keep more heat in the exhaust, to reduce restriction. also, keeps the engine bay cooler. dont see it too often at the track though, and I wonder why. hassle factor. can you imagine trying to do a 928 header wrap with the headers on the car????? ahhhhhhh!
mk
I trimmed the middle out of that seal leaving about 8 inches in place on each end. I believe it works. As I mentioned the other thing I did to reduce underhood temps was to wrap the exhaust manifolds. I actually have the exhaust wrapped as well all the way to the tips.
Carl,
You need to build us a hood vent, there would be a market for those!!
Regards,
Ken
mk
HTML Code:
If I am right, then all you would need to cause more air to move through the engine bay is to remove the rubber seal at the top of the engine firewall. That would provide a pretty good gap between the firewall and the hood all the way across the car, and the air would escape out the windshield wiper recess.
Carl,
You need to build us a hood vent, there would be a market for those!!
Regards,
Ken
03-13-2009, 03:41 PM
#69
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03-13-2009, 04:39 PM
#70
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03-13-2009, 04:55 PM
#71
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very cool shots! two of them running WCGT this year?? what was this event where the pic was taken. some kind of promo day? test day? I notice the touring car in the background from Bmmerworld.
edit: Race next weekend! This should be a good one. Sofro in the GT3 porsche with Curren and Davis in their V8 monsters vs the other rookies. Not many big names left and the field is kind of small. But, there are the 2 new volvos with pobst and pilgrim running. Tourng is a disaster, unless there is some late entries. 8 cars officially signed up with 5 more to put in names. If realtime racing pulled the plug there would be an 8 car field. hardely TV worthy. They should give our ITE SCCA racing some TV time. 60 car fields, more diversity and closer racing!
ha ha
mk
edit: Race next weekend! This should be a good one. Sofro in the GT3 porsche with Curren and Davis in their V8 monsters vs the other rookies. Not many big names left and the field is kind of small. But, there are the 2 new volvos with pobst and pilgrim running. Tourng is a disaster, unless there is some late entries. 8 cars officially signed up with 5 more to put in names. If realtime racing pulled the plug there would be an 8 car field. hardely TV worthy. They should give our ITE SCCA racing some TV time. 60 car fields, more diversity and closer racing!
ha hamk
Last edited by mark kibort; 03-13-2009 at 05:19 PM.
03-13-2009, 05:06 PM
#72
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Even the Street Version has the forward radiator vents AND the rear "engine/exhaust" Vents. Best version I have seen yet that would look great on a 928, even on a street 928.
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03-13-2009, 05:22 PM
#73
Rennlist Member
dont know what the aero of the aston Marton would look like but the front vents surely are radiator flow vents. the rears, i was looking for a few months calling dealers for replacement parts so I could use them on my mod. i couldnt find them. so, i ended up with some of the best looking raw alumininum mesh I could find. those vents are great looking on the Aston though and would look great on the 928
mk
mk
03-13-2009, 05:41 PM
#74
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hmmmm. I've got a spare hood....
I bet you wouldn't even have to worry about rain going in there. It would only go in when you're stopped, so it would drip right down behind the fan. Maybe even put a bit of a scoop on the underside of the hood to direct the air up and any rain water down and forward...
I bet you wouldn't even have to worry about rain going in there. It would only go in when you're stopped, so it would drip right down behind the fan. Maybe even put a bit of a scoop on the underside of the hood to direct the air up and any rain water down and forward...
03-13-2009, 05:45 PM
#75
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dont know what the aero of the aston Marton would look like but the front vents surely are radiator flow vents. the rears, i was looking for a few months calling dealers for replacement parts so I could use them on my mod. i couldnt find them. so, i ended up with some of the best looking raw alumininum mesh I could find. those vents are great looking on the Aston though and would look great on the 928
mk
mk