Careless Posted February 9, 2008 Share Posted February 9, 2008 as team nissan mentioned, radiator fans mounted in a specific way would aid in retaining downforce simply because the air is sped up and thrown out quickly if the hood has areas for hot air to exit instead of stay trapped and build up. Think about it, instead of air congesting itself under the hood and expanding due to heat and being trapped in there, causing an area of high pressure, it is being thrown out of a relatively large sized opening after being sped up, meaning it's going faster out than it was going in, and it's not being trapped and slowing the car down. (this is in the case of the F50) Quote Link to comment Share on other sites More sharing options...
Wedge Posted February 9, 2008 Share Posted February 9, 2008 Wouldnt completly blocking the under side of the engine compartment and then ducking the hood ,make it better for coefficient of friction and hot air not going in the engine compartment then you use the airdam ducks and route a pipe to the brakes to cool them . like this : Quote Link to comment Share on other sites More sharing options...
mikedoubleg Posted February 10, 2008 Share Posted February 10, 2008 as team nissan mentioned, radiator fans mounted in a specific way would aid in retaining downforce simply because the air is sped up and thrown out quickly if the hood has areas for hot air to exit instead of stay trapped and build up. Think about it, instead of air congesting itself under the hood and expanding due to heat and being trapped in there, causing an area of high pressure, it is being thrown out of a relatively large sized opening after being sped up, meaning it's going faster out than it was going in, and it's not being trapped and slowing the car down. (this is in the case of the F50) I understand your point as it would work just like a spoiler. BUT i was arguing about the fan that are no way powerful enough to do any sucking. Back in the old days of big turbos on 4 wheels and fire coming out of the exhausts, downforce generator were not prohibited on racing. If I recall correctly i know of only two cars with fans that were actually powerful enough to create downforce. the lotus F1 car and the Charparral (excuse spelling). the charparral 2j had a snow mobile engine of 70-80hp in addition to its normal operation engine. The snow mobile engine drove to fans that were taken of a military tank cooling system. The car looked so squared and ugly it is a sin to look at it but as everybody knows you can't judge a book by its cover. Underneath the car there was some ducting that and a plastic skirt around the car connected to the car suspension so it would always be close to the ground whether the suspension is compressed or not so the vaccum created by those fans would always be efficient. The Lotus F1 car was the Lotus 80 which also had a downforce generator. The problem with the lotus was that the fan was driven by the drivetrain. It sounds like a good idea as the faster you go, the faster the fan would spin, the more downforce would be created. Under braking, the fan would spin slower inducing lost of downforce. In the picture of the corvette I posted on my previous post, you can observe how the radiator is angled up front. It is that because it provides much mor efficient cooling than upright radiator. A radiator exchange the heat from the engine so blowing ambient air directly to the radiator give the air an easier path than having the radiator mounted at 45 degrees in your engine compartment hence removing more heat from the radiator for the same amount of air blew through it. Also with race cars, the nose of the car is so low that it is obvious to angled the radiator as you can fit a taller radiator when you fit it angled. The ducting on the The ducting on the F50 and other race/exotic cars are there for 2 reasons, to create downforce as you mentioned before although it is more efficient and easier to fit a lip/spoiler with those small wings(think DTM) on the front bumper. the second reason for the air ducts on the F50 and race cars is to stop the hot hair from he radiator from entering the engine bay and to focus the incoming air to the radiator core. Now for the rims, the rims are used to suck the hot air from the brakes as many have mentioned before and do not except great result without proper air flow (air duct from bumper to an adapter on center of rotor as the ventilated brake rotor are indeed fans). If you ask me, i'd rather have a super light weight rim without the fan's blade but only a proper air duct system. Back on the topic, the Koenigsegg magnesium wheels act as fans. Quote Link to comment Share on other sites More sharing options...
mikedoubleg Posted February 10, 2008 Share Posted February 10, 2008 Also please do not flame me as i'm trying to help. All i wrote is from my personal knowledge that I gained from the library and books so if anyone knows better, please correct me in a adult manner as i'm eager to learn from this forums. Quote Link to comment Share on other sites More sharing options...
Careless Posted February 10, 2008 Share Posted February 10, 2008 Also please do not flame me as i'm trying to help. All i wrote is from my personal knowledge that I gained from the library and books so if anyone knows better, please correct me in a adult manner as i'm eager to learn from this forums. lol of course not man. you posted some great info with pictures. what's more to do? I know of the chapparal, it's mentioned in a book I've glanced over regarding aero. I didn't know they were snowmobile engines though. As I said though, and I italicized the word... The rad fans I commented on do not provide down force, they help to retain, or aid in relieving some of the resistance to down force caused by say... hot air expanding in a hood with no ventilation. I see it as the same method to the madness of all those people drilling holes in their rear bumper covers to aid in free flow of trapped air. it makes sense... the bumper acts as a cup that will redirect air flowing under the car and trap it... creating a sort of parachute. Putting holes there allows that air to flow through faster. I'm curious to know if running some plastic tubes through the passenger compartment from areas of high pressure in the engine bay would relieve some of the lift-inducing air that is trapped under there. Not even fan assisted tubes... just regular 3 or 4 inches tubes. Is there something you've come across as such? I guess it falls under "ducting" but this is a little more 'out there'... Quote Link to comment Share on other sites More sharing options...
HeatRaveR Posted February 10, 2008 Share Posted February 10, 2008 If I recall correctly i know of only two cars with fans that were actually powerful enough to create downforce. the lotus F1 car and the Charparral (excuse spelling). The Lotus F1 car was the Lotus 80 which also had a downforce generator. The problem with the lotus was that the fan was driven by the drivetrain. It sounds like a good idea as the faster you go, the faster the fan would spin, the more downforce would be created. Under braking, the fan would spin slower inducing lost of downforce. The Lotus 80 used ground effects for aerodynamic downforce, not a drivetrain-powered fan. It was the Brabham BT46B that had a drivetrain-powered fan, as you can see here: To get around the rules banning "moveable aerodynamic devices", Brabham routed the fan intake through the radiator, so that the fan was technically there for "cooling". Pretty sneaky, huh? ;P Naturally, just like with the Chaparral, all the other teams had a hissy-fit and the design was banned right after it kicked everyone's asses by 30 secs at the '78 Swedish Grand Prix! Lotus had considered a fancar design for their Lotus 79 car, but it never came to fruition due to the ban. Quote Link to comment Share on other sites More sharing options...
mikedoubleg Posted February 11, 2008 Share Posted February 11, 2008 lol of course not man. you posted some great info with pictures. what's more to do? I know of the chapparal, it's mentioned in a book I've glanced over regarding aero. I didn't know they were snowmobile engines though. As I said though, and I italicized the word... The rad fans I commented on do not provide down force, they help to retain, or aid in relieving some of the resistance to down force caused by say... hot air expanding in a hood with no ventilation. I see it as the same method to the madness of all those people drilling holes in their rear bumper covers to aid in free flow of trapped air. it makes sense... the bumper acts as a cup that will redirect air flowing under the car and trap it... creating a sort of parachute. Putting holes there allows that air to flow through faster. I'm curious to know if running some plastic tubes through the passenger compartment from areas of high pressure in the engine bay would relieve some of the lift-inducing air that is trapped under there. Not even fan assisted tubes... just regular 3 or 4 inches tubes. Is there something you've come across as such? I guess it falls under "ducting" but this is a little more 'out there'... Oh boy, I like this forum, people are civilized unlike most v-tech, big wing fools or the german's car fanboy pricks. Top class Gt cars such as DTM and super GT (JGTC) have a fully ducted engine compartment so the air is blown up through the hood's vent or behind the front wheels. Look at the picture on the bottom left. Look at the fender vents Quote Link to comment Share on other sites More sharing options...
mikedoubleg Posted February 11, 2008 Share Posted February 11, 2008 The Lotus 80 used ground effects for aerodynamic downforce, not a drivetrain-powered fan. Thanks for the correction. You are one smart bloke. Quote Link to comment Share on other sites More sharing options...
nemo1080 Posted February 11, 2008 Share Posted February 11, 2008 very cool stuff. learn something every day! Quote Link to comment Share on other sites More sharing options...
Careless Posted February 12, 2008 Share Posted February 12, 2008 the Motul R34 is amazing in that the 4.5 litre engine sits so far back, and it just looks plain badass. a lot was taken from this car and remodeled for the z-tune edition. I think the reason why the hood is multi-slotted is due to the fact that the added surface area of the slots will create more friction, so in a hard turn, there is more area for the exiting air to grip onto and create some sort of resistance/friction. I'm sure it helps at least enough to keep the nose down or from getting squirrelly due to the position of the engine. Quote Link to comment Share on other sites More sharing options...
nemo1080 Posted February 13, 2008 Share Posted February 13, 2008 4.5 ltr??? what engine did they use? Quote Link to comment Share on other sites More sharing options...
mtcookson Posted February 13, 2008 Share Posted February 13, 2008 Yeah... I didn't know the GT-R ever had the 4.5 in it. I know they definitely put the VQ in, which did make for a faster car than the RB26. (I dislike the RB26) Quote Link to comment Share on other sites More sharing options...
Careless Posted February 14, 2008 Share Posted February 14, 2008 it had a VH45 in it. take a look at the cutaway, there are 2 inter-coolers, and two different sides to the intake plenum. you can also see 3 of the 4 coil packs on one side of the engine, below the plenum. even the new GTR has a 4.5 litre in it for the touring cars. not the 3.8 Quote Link to comment Share on other sites More sharing options...
mtcookson Posted February 14, 2008 Share Posted February 14, 2008 Finally found it... the '03 JGTC definitely had the VQ: http://www.sportcompactcarweb.com/features/0504_scc_nissan_skyline_gtr/index.html Quote Link to comment Share on other sites More sharing options...
Careless Posted February 14, 2008 Share Posted February 14, 2008 ahh... good call. at least we know it's not a GTR engine. that cutaway is pretty close to the photo, so i guess it's showing all the coil packs. i wonder why the new GTR has a 4.5 litre though =/ either way, look how far back into the cabin they put it. CHEATERS! Quote Link to comment Share on other sites More sharing options...
g00kb0i Posted February 16, 2008 Share Posted February 16, 2008 08 gtr's are 4.8 ahh... good call. at least we know it's not a GTR engine. that cutaway is pretty close to the photo, so i guess it's showing all the coil packs. i wonder why the new GTR has a 4.5 litre though =/ either way, look how far back into the cabin they put it. CHEATERS! Quote Link to comment Share on other sites More sharing options...
mtcookson Posted February 19, 2008 Share Posted February 19, 2008 08 gtr's are 4.8 3.8 V6 in the GT-R 4.5 V8 in the SuperGT GT-R (GT500) Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.