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Discussion Starter #1
In preperation for some tracking the car, I'm trying to gain a bit more downforce on my 91. I am currently fully stock with regards to the body. Going to start with the front end first. I'm thinking maybe a better splitter and mild vented hood?

What are the current options (it's 2013 now) are for vented hoods that actually provide a downforce benefit. The assumption here is that I'd be using a radiator relocation kit. I also don't want something that has crappy fitment.

One combination I've heard of is the newest generation of madpsi vented hood with the Border relocation kit. I belive this setup does not involve cutting the frunk wall. Is madpsi still selling hoods? Most of the references and posts I've seen are from 2010 and older. The website still lists a hood.

Yes, I have read many of the threads on this forum regarding aerodynamics and peoples custom modifications of the frunk/hood. My head is spinning from 2 days of straight reading...
 

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Discussion Starter #3 (Edited)
That was the gist I was getting from my reading, hence my interest in the newest madpsi offering. I suppose I can message him directly.

I do have an old spare hood with a couple of dents in it too, so maybe I can make use of that for track days somehow by cutting it up.
 

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Discussion Starter #5 (Edited)
Bill are you saying that more flow over the roof and less under the car is simply going to create more lift over the roof and worse separation at the rear, and that greater benefit would be achieved by venting the high pressure air in the front wheel wells? I thought less air directed underneath the car helps with downforce?
Not trying to start another long thread, but I thought that was the jist (or at least the findings) of people with vented hoods?

Doesn't the forward sloping wall right behind the radiator act as some sort of lifting surface also?

If I were looking for just a bit more downforce at the front, perhaps a splitter and speedflaps would be more than adequate?
 

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The problem is that hood vents have to be modeled carefully to determine the net effect on air flow and pressure. A properly implemented hood may increase down force, but equally an improper implementation will increase drag and reduce the effectiveness of the rear wing (I'm assuming you've already pushed the rear wing back at least 9 inches?)

On the other hand a decent splitter will most likely knock a couple of seconds of your lap times.

Alleviating the high pressure zone under the wheel arch would probably be a more effective stratagem than venting the hood.
 

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border hood is one of the better ones. Terminal velocity through the radiator is roughly 60mph, the smaller border vents help speed the air back up as it crams out. For best results you need to seal the underbody of the front as stock it vents under the car, and you should do what bill says, add a splitter. Look at the splitter on the border car, its gigantic. They also used vented and louvered fenders, huge high pressure zone in the fender wells.
 

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Your race car looks absolutely awesome Bill. Any more pics of the rear of the car? Is that plexiglass that you have mounted on the rear?
 

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Discussion Starter #11
Looks like vented fenders would provide a good amount of lift reduction, and front splitter would be the next best thing. I'm trying to keep this vehicle dual purpose. It's not my daily driver, but I do use it on the street so trying to keep modifications mild and tasteful also. Starting this next season (spring) I'm going to begin doing some tracking with it, but will undoubtedly be in the "novice" category. Trying to get the light front end sorted beforehand. I'm going to be out there to have fun mainly, not worrying about a quarter or a half a second.

I'm thinking the hood mods are out of the realm of what I'd need at this point in time.
 

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jagibbs said:
Looks like vented fenders would provide a good amount of lift reduction, and front splitter would be the next best thing. I'm trying to keep this vehicle dual purpose. It's not my daily driver, but I do use it on the street so trying to keep modifications mild and tasteful also. Starting this next season (spring) I'm going to begin doing some tracking with it, but will undoubtedly be in the "novice" category. Trying to get the light front end sorted beforehand. I'm going to be out there to have fun mainly, not worrying about a quarter or a half a second.

I'm thinking the hood mods are out of the realm of what I'd need at this point in time.
border works out of the box, relocating your radiator helps, but it doesn't require any body mods, should be able to find one in the realm of 300 for fiberglass.
 

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Apokryphos said:
would you need vented fenders if the wheel well liners are intact? also, what do these relocation kits look like? I've never seen the parts for one.
with fender liners removed you will vent some air up out of the rain guard too. I have been tossing the idea around of making something custom fender liner wise in order to take advantage of that.

How much is vented I am not sure, high pressure zone in fender wells, and a lower pressure zone from air passing over the rain guard should (in theory) help pull some of that air up and out that way.
 

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jagibbs said:
In preperation for some tracking the car, I'm trying to gain a bit more downforce on my 91. I am currently fully stock with regards to the body. Going to start with the front end first. I'm thinking maybe a better splitter and mild vented hood?

What are the current options (it's 2013 now) are for vented hoods that actually provide a downforce benefit. The assumption here is that I'd be using a radiator relocation kit. I also don't want something that has crappy fitment.

One combination I've heard of is the newest generation of madpsi vented hood with the Border relocation kit. I belive this setup does not involve cutting the frunk wall. Is madpsi still selling hoods? Most of the references and posts I've seen are from 2010 and older. The website still lists a hood.

Yes, I have read many of the threads on this forum regarding aerodynamics and peoples custom modifications of the frunk/hood. My head is spinning from 2 days of straight reading...
jagibbs,

I too am located in Herndon, VA. I have an ASK vented hood, as well as their engine lid, and Border fenders too. Those these parts are not on the car yet, you are welcome to take a look if you think it will aid your research. If you wish to discuss please drop me a line [email protected]

Cheers,
Steven
 

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mr2azzkicker said:
jagibbs,

I too am located in Herndon, VA. I have an ASK vented hood, as well as their engine lid, and Border fenders too. Those these parts are not on the car yet, you are welcome to take a look if you think it will aid your research. If you wish to discuss please drop me a line [email protected]

Cheers,
Steven
Hi mr2azzkicker,
Could I possibly come take a look as well? I am also planning to go with a front splitter and vented front hood. I also live locally in Herndon.

Plus, I do have the new MadPsi CF Duck Bill Trunk Lid if you would like to see it in person =)

Regards,

Chase
 

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vertigo93t said:
Hi mr2azzkicker,
Could I possibly come take a look as well? I am also planning to go with a front splitter and vented front hood. I also live locally in Herndon.

Plus, I do have the new MadPsi CF Duck Bill Trunk Lid if you would like to see it in person =)

Regards,

Chase
Sure, no problem. I would like to see the duck bill trunk lid.

Cheers,
Steven
 
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