Vented hoods and turbos

[mid_life_crisis]

Originally Posted by Element Tuning

I often race with the Whelen Marsh Corvettes that run in Grand AM GT and USGT and they run a cowl type hood that vents at the windshield vs. most of the competition that vent more towards the front of the hood.

I would bet most street cars don't have vented hoods for better fuel efficiency and less drag. I was hoping I wasn't going to have to vent the hood since I don't have much front lift but the engine is just running too hot turbocharged while racing.

The '14 has a vent towards the front the way you do, so that the air movement over the hood at speed provides downforce on the front of the car.
Pretty cool technology that went into the car. They spent months on the scoops over the rear fenders that direct air to transmission (rear transaxle) cooler and another cooler I can't remember right now.

[Minhtyfresh]

Originally Posted by campy

If I remember correctly they just removed that entire plastic piece by the windshield. I'm not sure if that is what's holding the windshield wipers in place though, so removing it probably wouldn't be a good idea for a DD.

Oddly enough.. I engineer those big black plastic pieces by the windshield for a living (sadly), so maybe I could provide some insight.

Those are typically called cowl screens, or leaf screens.

These days, they have 4 main functions:
-Protect the wiper module system from the elements
-Project the HVAC system from debris injestion
-Visual appearance (a lot of customers prefer not to see raw metal and linkages from outside the car)
-Seal to the hood inner surface to reduce NVH and engine fumes.

Basically, if you don't care about your cabin air, your wiper system, or noisyness... Removing that piece will help quite a bit with engine cooling. Horrible idea for DD. Great idea at the track .

[Carwhisperer]

If my PD supercharger fits with this hood, i'll be going with it.

Always enjoyed the front end of STI's. This appeals to me.

[jamesm]

i definitely need one for my turbo. it gets pretty hot under there in the florida heat.

[Ryuu0u]

Originally Posted by Carwhisperer

If my PD supercharger fits with this hood, i'll be going with it.

Always enjoyed the front end of STI's. This appeals to me.

Isn't there another hood out there like that made out of carbon? If i decide to super charge I think I may get something like that.

[mid_life_crisis]

Except that you'll probably be better off with a vent than a scoop.

[zigzagz94]

Originally Posted by Ryuu0u

Isn't there another hood out there like that made out of carbon? If i decide to super charge I think I may get something like that.

http://seiboncarbon.com/store/produc...l#!prettyPhoto


You might be thinking of the Seibon FA-style carbon fiber hood...

[Element Tuning]

Originally Posted by Carwhisperer

If my PD supercharger fits with this hood, i'll be going with it.

Always enjoyed the front end of STI's. This appeals to me.

That's exactly what you do not want because now you have two sources trying to pressurize the engine. It actually doesn't even work at high speed to cool the intercooler on the STi. I actually cut a huge hole in my scoopat a race and had more downforce and much improved coolant temps.

Just remember air that goes in has to get out.

[Ryuu0u]

Originally Posted by zigzagz94

http://seiboncarbon.com/store/produc...l#!prettyPhoto


You might be thinking of the Seibon FA-style carbon fiber hood...

Oh thanks! I like that but with out the vents.

[Gen]

Would really like a hood along these lines:



Vents could be a bit larger and perhaps placed differently, but something a bit classier than the Seibon.

[Supermassive]

Originally Posted by King Tut

The only real concern I have with a vented hood at this point is sitting in traffic in the rain and getting my turbo blanket and wrapped downpipe wet. I would be willing to cut my OEM hood to add some vents if there was a vendor who made a kit with good directions and templates.

I recently sold my CF hood and went back to the stock hood. As far as things getting wet when it rains...well i never had any issues, of course i have no exhaust wrap since i went with ceramic coating instead. The turbo blanke is also far enough forward that the vents don't allow any water to reach it on setups like the P&L and FB.

[Supermassive]

Originally Posted by Element Tuning

Street guys really don't need this much but real race cars do because of the high speeds and how much pressure builds up.





Air can also be dumped out the sides of the bumper or underneath the car (least ideal).

I can actually attest to this...the FR-S generates a ton of underhood pressure. When I was running my CF hood it was extremely noticeable because it would flex the sides of the hood up (near the wheel arches). At 160 there was about a 1-1/2 inch gap between the hood and the wheel arches...I decided to slow down since i didn't want the hood to break. That hood was also vented so it's definitely a science as to where venting should be to alleviate that pressure. I personally think that function fender vents would help substantially...but that would require some serious fabrication to make work well.

[charged86]

Originally Posted by Supermassive

I can actually attest to this...the FR-S generates a ton of underhood pressure. When I was running my CF hood it was extremely noticeable because it would flex the sides of the hood up (near the wheel arches). At 160 there was about a 1-1/2 inch gap between the hood and the wheel arches...I decided to slow down since i didn't want the hood to break. That hood was also vented so it's definitely a science as to where venting should be to alleviate that pressure. I personally think that function fender vents would help substantially...but that would require some serious fabrication to make work well.

A few other people including myself noticed stock hood lift I was accelerating into a head wind on the highway and tha exact spot you mentioned near the high point of the fender started to lift. I only hit 103 or so. And I would have the same issue I would love a vented hood but would hate the rain and snow in my engine bay

[King Tut]

At 100 mph I have more improtant things to look at then how much hood lift there is.