zrtman1

Have been following this thread:

https://www.corvetteforum.com/forums...aero-lift.html

Pretty awesome thread with tons of good info, but all C6. I know a lot of guys have done the C5 to a C6... maybe care to share some info?

Was wondering about the C5 lift. How bad is it? I was thinking about hood vents but not sure if it will be better or worse. I have a coupe not a Z. Hitting 160ish on VIR back straight and letting off. Not sure what it will do cresting the hill so slowly increasing it. Car feels very planted nothing scary at all. Have G2 coilovers. All stock aero.

I know ACP nose and tray is probably the best, but also $$$. I like the plywood tray idea. Was hoping for something somewhat streetable even though I do not drive it much on street. I am not fast enough to really need aero but I like building things - the vette is my hobby/outlet.

Thanks!

TrackAire

I would really like for LG or some other racing specialists to chime in on this. I have a C5Z but do not want to change it to a total race car by gutting the front end to the point where it is no longer reversible back to stock if I want it that way. Sort of trying to have my cake and eat it too. I know there will always be compromises doing this, but I'm not racing for a trophy, just HPDE's and very interested in maximizing my performance through aero while trying to keep the car cool.

The C5's nose shape and especially the rear aero of the FRC make for a lot of challenges. Hopefully this thread will have a lot of good and proven input.

Mark@AMT Motorsport

The C5 and C6 have similar amounts of lift in my experience. 130+ and the front feels floaty, but nothing dangerous. Your car is not gonna flip over at VIR at 160. First front end aero thing I did was install Trackspec hood louvers, and it did make a difference in feel.

FASTFATBOY

With the correct amount of rake in the car more air goes over the car than under it. All these guys who slam their car on stock bolts really screw the whole dynamic of what GM intended for the car to make it turn and handle.

Mine is rock solid at 150 mph.

I saw or read a GM engineering paper on the C5 aero and lbs of downforce with the correct amount of rake in the car.

zrtman1

Well said!

I personally do not have a problem moving things around - my chassis was just a high mile base and not worth much. To run aero on the front I would think you would have to change it to a front breather and do some duct work for cooling.

I do not think it will flip - never crossed my mind - car feels planted. Guys take them 200 on the flat mile runs. I mentioned it because you crest the hill into a brake zone with an aero light front which would be even lighter cresting the hill as it unloads the front suspension. Any aero tweaks would help front stay planted

Trackspec vents are actually one thing I was looking at.

You always have good info that would be interesting to read if anyone had a copy.

MySR71

He's likely talking about this paper:

http://papers.sae.org/2002-01-3333/

TrackAire

Has anyone purchased this SAE paper and do they feel it is worth it?

Hi Volts Z06

Since I only have owned a C5, I'll comment on that only. Front end lift is real but it really just equates to an aero push. First time I noticed it I was at Pocono and we were running single infield (meaning NASCAR turns 1 & 2) which equated to speeds of over 160 + MPH. The car didn't want to turn in at that speed and you really had to lift and even brake a hair to get the car to turn to the point where you didn't feel like you were going to hit the wall. This was with a completely stock body. Although I added a wing and splitter the following year, the biggest difference came when I flipped the radiator and built an extractor hood.

apex26

Wondering if ASE tested the Z06 body or the coupe? Seems like worth knowing this especially if it's for the Z06 body (for those of us who have that).

TrackAire

I just saw this on another forum. Although the video is a little long, he compares multiple cars in a miniature wind tunnel with the most interesting one being the Toyota MR2 since it very much mimics the less than desirable FRC roof us Z06 owners have to deal with. Not the best design for aero (the C5 coupe is superior IMO) but we have to deal with what we have. Be careful as it appears he uses real science to show results, lol.

TrackAire

Has anybody ever used these RK Sports canard/spoiler to create a front aero system while keeping the car a bottom feeder?

http://www.rksport.com/product-p/rk-193.htm

I've never seen these in person but was wondering if they could be used as a foundation for building a front air dam type splitter yet keeping the center section open and boxing it in so the car remains a bottom feeder.

I've already extended the stock air dam lower (it rubs the track a lot but is made of rubber and is designed to wear and be sacrificial) and boxed in the sides trying to increase more air into the radiator and limit the air flowing under the car. I'm hoping the heat extraction hood helps limit lift from the increased radiator air flow. I have to deal with high temps most of the year, so engine cooling is priority one, then aero for handling performance.

Any thoughts on these RK Sports Canards?

Olitho

I really like my http://trackspecmotorsports.com/shop...tte-97-04.html hood louvers. They do extract a lot of air pressure if placed correctly on the hood. My car has a much better turn-in and planted feel, especially at speed. The car does not push as much either at corner exit when powering out. They are very effective and a much more budget friendly option to whole new vented hoods. They also work much better (and look way cooler) than the prior household HVAC looking louver panels I had.

fatbillybob

There is this really cool video of the hood ripping apart at 150mph+ from a racer I know. The slow motion is quite incredible. At 160mph at Daytona the fastest I have been the C5 in T2 trim no aero is rock solid but you can watch the front 1/3rd of the hood lift and buckle. All I could think about was the video of the hood delaminating. Another T2 C5 racer drilled the hood right at the front rubber hood rest points that are threaded. He then threaded hood pins right into the stock threads and said that this dramatically reduced the hood lift we see at Daytona.

I'm not sure the advantage of hood vents. Does that increase or reduce drag? Most of the cars I have seen with vents also are in higher classes with more horsepower. I remember seeing data that showed 911's with windows down and solid rear glass were faster than 911's with rear lexan rear windows with holes drilled in them. The reason was something about how the air moved inside the car.

Olitho

Yes, Fatbillybob, here is that video -


You can go straight to minute 2:00 for the incident.

zrtman1

I bought the book and it is interesting to read.

TrackAire

Thanks for posting that video....That looks a little terrifying. If I understand the situation, this was an aftermarket hood that let go. I wonder if any stock hood has ever failed like this?

So, from an aero point of view, was it built up under hood pressure or exterior suction (lift) that caused the hood to de-laminate or a combination of both?

It sure would be interesting to stick some pressure sensors under the hood and along various spots on top of the hood to see what is actually going on.

Olitho

That was not an aftermarket hood. That was a stock carbon fiber hood from the 2004 Z06 LeMans edition family.

96CollectorSport

Here's a link to a thread with the pressure testing you are asking about:

https://www.corvetteforum.com/forums...pec-vents.html

Converted_Germ

The pressure differential testing I conducted on the front end of the car showed that there was indeed a measurable amount of lift being generated @ 50mph. All of this lift was generated from underneath the hood. Both front and rear wheel wells are not high pressure zones and do not require ventilation to the boundary layer.

There was a noticeable difference in vehicle stability at 100mph+.

TrackAire

Thanks for the clarification....I saw carbon fiber and just assumed it was aftermarket.