travisnd

Would blocking them off the front bumper openings create any meaningful increase in IATs thereby affecting horsepower? I know the stock coupe/verts came with the bumper openings fully blocked off. Should you leave a partial opening on one or both sides to allow a little fresh air into the intake? (An aftermarket intake drawing air from the radiator cavity isn't an option)

Thoughts?

sperkins

So you're running the stock airbox?

travisnd

Yep.... had to put it back on when I installed the Wilwoods up front.

I'm wondering if blocking off bumper openings and putting a little more rake into the car will make the front end stick a little more.

sperkins

I'm guessing you're only talking about doing this for the Rd Atl race since that costs points in PT/TT. Why don't you just throw the aftermarket airbox back on for the ST2 race?

I covered my front openings in June and it didn't make a lick of difference, but mine are solid anyway. I just tried it for the aero advantage. DIdn't work.

PushinTheLimit

But it can't hurt right Scott? I would think any air that you can push over the hood rather than through the fenders and tires would be a better option. I blocked mine off too for the Roebling Road event and I couldn't tell any big differences there...

travisnd

Why would it cost points? Those openings come blocked on C5s from the factory. Just like I can run the OEM '02-'04 airbox and '04 Z06 shocks w/o taking points... why couldn't I run OEM bumper cove fillers?

Jason

Because we asked Greg and he said no.

travisnd

Ahhh... well then I guess my post on NASAforums is worthless. Glad I didn't start taking the fascia off last night

RX-Ben

Blocking off the brake ducts on the fascia is also likely a no (asked at nationals). There is expansive language in the rules so it seemed like a possibility.

varkwso

I blocked them at Roebling and did not notice a bit of diffference. I think it is more theoritical then practical.

travisnd

10-4... was curious if it's reduce front end lift at all.

varkwso

I had the same curiousity

geerookie

According to a wind tunnel study done on the C5 back in '02 comissioned by the SCCA for T1, blocking those stock already "covered" holes changed the forces on the front end from 13.25lbs of lift to 17.5lbs of down force and reduced overall drag by 9.2 lbs.

travisnd

Awesome... I'll probably tape them over for the ST2 race in a couple of weeks.

trackboss

A while back I made these to replace the plastic buckets on my car. I can make more if anyone is interested.

AU N EGL

I thought there was less lift when I crested VIRs back straight hill at 150

davidfarmer

geerookie, is that the World Challenge data you mention or T1? It would be a huge difference in a car with a splitter vs an OEM fascia.

Either way, I think theoretically you'd be deverting air over the car instead of through it, and likely dumping under it, so it could help. But I doubt you'd feel it.

I hear there are some tire changes in the rules coming up...regarding the 275/255 sizing breaks. Anybody know what's going on there?

L98Terror

No, but I would guess the cheater tire is going away. It is clearly a loophole

travisnd

I disagree... its sidewall is 0.3" shorter which gives it its own unique challenges.

drivinhard

my beef with that is where does that stop? the 275 isn't 20mm narrower than the 295 (about half that), but which one should be adjusted and which one is the "reference"?