zeeboost Posted September 22, 2003 Share Posted September 22, 2003 Hi all, I recently became the owner of a 280zx w/a 350 , and as part of my campaign to achieve more performance and effeciency, I was wondering how much it would benefit me to cut a hole in the hood, put a hood scoop on and allow cold air to hit the filter. I know that I would get a performance gain out of it, but I also know that it will probably hurt my cd, so I'm thinking all in all I'd probably come out even, right? I searched the archives for this but couldn't find the results I am looking for. Also, if I add a hood scoop, I'd be worried about driving it in heavy rain conditions. If anybody has any advice I'm open to everything. Thanks all in advance. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted September 22, 2003 Share Posted September 22, 2003 You would probably be better off fabbing a ram-air induction of some sort and running through or near the grill. You won't destroy the hood with a scoop and it will not require body work. Just my $.02. Davy Quote Link to comment Share on other sites More sharing options...
zeeboost Posted September 22, 2003 Author Share Posted September 22, 2003 I've thought about that, and when I searched through the archives, I found a lot of people doing that. I don't really care for the way it makes the engine bay look more cluttered up with the exception of greimann's former car [hats off to you]. Plus, it seems like the hood scoop would be able to allow more air into the filter. Thanks though for the suggestion -- it is the most probable. Any one else? Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted September 22, 2003 Share Posted September 22, 2003 I agree. If the hood is straight please don't cut it unless you have your heart set on it. Straight metal hoods are hard to find. There is a huge amount of air being forced through the grille opening waiting for your engine to breathe in. There are several members that have top notch examples on their rides as we speak and even have pics for your veiwing. Can't recall names right now but do a search........ Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted September 22, 2003 Share Posted September 22, 2003 you posted above while i was typing. You could go viper scoop. (I have one I am going to fab in) Cowl scoop looks good, turbo bulge, 280zx hood vent type scoops, scoop from a 70's comet/fairmont/zephyr, shaker scoop would be different and I could go on..... Quote Link to comment Share on other sites More sharing options...
Guest Drewz Posted September 22, 2003 Share Posted September 22, 2003 you can view some here although I don't know if I would deal with them again!!! http://showcars-bodyparts.com/scoops.html Quote Link to comment Share on other sites More sharing options...
Phantom Posted September 22, 2003 Share Posted September 22, 2003 I actually did a study on "ram air" as a senior project for my mechanical engineering degree - in 1971. To make a long story short - the "ram" effect doesn't begin to show any contribution to horsepowwer until the car attains a velocity of 90 mph. Once above that it starts to really contribute. The big improvement is the lower air temperature. It is worth about 5% on your net HP. Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted September 22, 2003 Share Posted September 22, 2003 I took the trouble to attempt to calculate HP gain (loss) from hot or cold air intake using the engine dyno HP correction factor published by the SAE. In a ZX the underhood temperature can get around 140f. Assuming cold air is 80 degrees, or lower, you can gain about 20 hp according to the formula. See a more indepth discussion here: http://home.earthlink.net/~dvgreimann/airbox.html Quote Link to comment Share on other sites More sharing options...
blueovalz Posted September 22, 2003 Share Posted September 22, 2003 When I did my ram-air for my 240sx, the gain I got from it when I needed to pass on the highway was ALMOST as good downshifting from 5th gear to 4th gear for the pass, prior to the install. Now this was including the new K&N filter (which replace the OEM filter) with the install, so I'm sure this helped too. In this photo the filter is inside the canister with the AFM attached to the other side of the canister. As was previously stated, the ram effect is not noticable unless you are at highway speeds, but when I was doing a lot of traveling on 2 lane highways, this set-up made passing the long trucks much easier. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 22, 2003 Share Posted September 22, 2003 You could go viper scoop. The hood scoop on the previous generation Vipers (GTS Coupes) didn't work. Most of the fast Viper racers (Mumford, Schley, McCann, etc.) blocked the scoop off. Quote Link to comment Share on other sites More sharing options...
Guest Z-rific Posted September 22, 2003 Share Posted September 22, 2003 That was a good article, and I plan on doing something very similar myself. It is intersting, though, that we are trying to keep everything as cool as possible, and this guy goes and paints the box black. It looks nice, but we all know black holds more heat than lighter colors. I have a friend who used to do racing engine work. If he were to paint engine parts (heads, manifolds, etc.) he would always paint white. He swears by it. Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted September 22, 2003 Share Posted September 22, 2003 That was a good article' date=' and I plan on doing something very similar myself. It is intersting, though, that we are trying to keep everything as cool as possible, and this guy goes and paints the box black. It looks nice, but we all know black holds more heat than lighter colors. I have a friend who used to do racing engine work. If he were to paint engine parts (heads, manifolds, etc.) he would always paint white. He swears by it.[/quote'] What you don't see is the interior of the box is painted silver, but the color really doesn't matter in this case because the moving air (convection and conduction) inside the box by far counteracts any heat gained by black body absorbtion (radiation) . When it comes to determining the proper color for managing radiant heat, think of it in terms transmittance. Do you want the hotter body to transfer heat to the colder body or do you want the heat to be reflected. As for an engine block, heads and valve covers, they should be black so the radiant heat transfer is maximized from the block to the engine compartment. The heat that doesn't go out the block has to be lost through the cooling system, causing it to work harder. Exhaust manifolds should be bright. Chrome, VHT silver or white. You want the heat to stay inside the walls of exhaust system so it can be expelled out the back of the car. What color should a radiator be? Unpainted is the best because a radiator does not loose heat due to radiation, it is lost through conduction, where a layer of paint effectively insualtes the tubes, reducing efficiency. Copper/brass are usually painted with a thin coat of black for cosmetic reasons and to prevent corrosion. Quote Link to comment Share on other sites More sharing options...
Guest Aaron Posted September 22, 2003 Share Posted September 22, 2003 Yeah, what Dave said. My dad used to get a magazine put out by nissan for nissan mechanics and would bring them home to me to read. I remember an article in the mid 80's that said nissan had done all kinds of testing to determine what color was best to help keep engines cooler. Black was the winner. As they explained it, dark colors are hotter when exposed to sunnlight, but once they are put in a shade, they are cooler. Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 23, 2003 Share Posted September 23, 2003 Color isn't everything for radiation heat transfer: Read this: http://www.electro-optical.com/bb_rad/emissivity/emisivty.htm It's really the emissivity of the surface. A glossy black surface is not that much different in emissivity than glossy white paint of the same surface texture/material: http://www.electro-optical.com/bb_rad/emissivity/matlemisivty.htm#Black%20Coatings Funny, I don't see the band/wavelength those emissivities are for, but I'd assume it's long wave infrared (8 to 12 micron) since that's the primary form of radiant heat rejection from surfaces. The numbers shown are probably averaged over the 8-12 micron band. Yeah, that science stuff can lead to better hot rodding . Quote Link to comment Share on other sites More sharing options...
zeeboost Posted September 24, 2003 Author Share Posted September 24, 2003 Thank you all for the replies. I suppose since my hood is generally rust free I won't butcher it up. I found a setup on an 85 GT that should be compatible with my carb. I'll put pictures up when it's done, but for now I'm upgrading the cam. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted September 24, 2003 Share Posted September 24, 2003 And who the hell wants to try to find an oil leak on a black engine? No thanks. Like playing where's waldo. Also... If painting the engine really made such a dramatic difference in temperature drop, every single race enging would be black... I don't know about you guys, but i've never seen a racepreped engine painted black. Plus it looks ugly Quote Link to comment Share on other sites More sharing options...
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