[02'TrueBlue]

I recently modded the stock GT hood on my 2002 mustang so it would let air in to cool off the engine, and i think it looks better too. Only problem is, passing 60MPH it starts shaking and blows upwards as if someone's pulling on it, and closer to 90-95, I'm afraid to go any faster because it looks like it'll fly off any second. I cut the hole from just the V6 hood vent to just about the full size of the scoop from that point back and it helped a little but I want to try and reinforce the scoop to the hood (forgot to mention the thin cheap piece of plastic connecting the scoop to the bolts started tearing) and stiffen up the scoop after that so it doesn't lose its shape and start bowing as I reach higher speeds. Any methods of doing so and how to compete them? fiberglass, bondo, etc...

 

[Meehlimo]

Ill tell you this. when those clips went on my buddies gt during a ride home from the track. we hit 70 it flew off and 200 feet or so behind us came down hit the ground n shattered into so many peices. anyway dont use 3m tape to hold it. you if you could should make new clips to reinforce the old ones.glues n bondos on parts like that are a destined fail.

 

[Bullitt5339]

Put an uncut scoop back on it, problem solved. It doesn't let as much hot air out as you think.

 

[Nicks79]

+1 it creates backward pressure anyway, if you are looking for some air flow go with a crawl hood. All your doing by opening that up is pissing in an ocean of piss with underhood air anyway

 

[Dave]

+1 it creates backward pressure anyway, if you are looking for some air flow go with a crawl hood. All your doing by opening that up is pissing in an ocean of piss with underhood air anyway

Yep, cowl hood or as some manufacturers more accuratly call them, "heat extractor hoods". MM & FF did a test several years ago on a Fox body and from the faster times in the 1/4, estimated a 20hp gain just from the cooling effect.
Dave

 

[04sonicbluegt]

Holy cow! Please elaborate on that, 20hp sounds like a bunch. Probably a F/I car?

To the OP I would stick an uncut back on, like said before you're just going to make backpressure. The amount of air coming in from the opening in the scoop is going to be much greater than the amount of air you're going to be able to squeeze through that small opening. The backpressure and the flimsy plastic the scoop is held on with is what is causing the shaking that you see, and there is no way to fix that by just reinforcing the hood scoop. The only way to get around that would to be to cut a huge hole in your hood to try and match the amount of air coming in. The plastic that holds that scoop on is really flimsy to begin with, there's not much you can do to reinforce it. When I got my 04 it had the cutout in the scoop missing, so I was looking for ways around getting another scoop. You should have seen that sucker shaking at 140mph, lol.

 

[Bullitt5339]

Actually, to be technically correct, since that area of the hood is typically a low pressure area, it is trying to suck the hood scoop off, not blow it off.......... :winks

 

[Nicks79]

LOL bullitt once again FTW

 

[02'TrueBlue]

Yeah i figured those would be the responses I'd get. :mesad:I was just hoping for a way to justify what I did. I didn't want to do it originally but was talked into it by a few people and it's the worst decision I've made so far. Now more $$$ wasted on a new scoop....or maybe an excuse to get a new hood! What are everyone's favorites?

 

[Bullitt5339]

HO Fibertrends makes one of the best hoods I've ever seen. My 4" cowl didn't move as much as my stock hood does, and the great hood latch area is probably one of the best I've seen in an aftermarket hood. The latch area is what to pay the most attention to. If the latch is done properly, the rest of the hood will most likely follow.

 

[04sonicbluegt]

So bullitt, you're saying the oncoming air isn't trying to rip the scoop off? That doesn't make sense.

 

[racin366]

It has to do with aerodynamics, its like on a plane, it doesn't get pushed up it gets sucked up. The wing shape of a plane creates negative pressure on the top surface that pulls the plane up. Because of where the windshield is in relation to the scoop and the air trying to find the smoothest path over the vehicle as possible you get low pressure above and especially behind it and from the sound of what the OP did, he's on borrowed time before that thing becomes a UFO. A very dangerous UFO. Stay off the highway until you replace that thing, you don't want to be the reason somebody is dead.

 

[02'TrueBlue]

Bullitt - Those hoods look great, I've been interested in the 2000 Cobra R for a while but just haven't sold myself on it yet.. looking all over for a pic of a TB with a stock GT bumper with the hood for inspiration but can't find one anywhere; only cobra r conversions or with cobra bumpers

 

[04sonicbluegt]

Thanks for the explanation on that one racin. I never thought to relate airplanes to hood scoops :laugh:​

 

[racin366]

No problem. The plane analogy makes it easier to wrap your mind around that's all. When something is moving through air at speed the air acts more like a fluid than gas.