MJM

ALMS? The race series with low car counts that just got taken over by Grand-Am?

Meanwhile over in Formula 1, the teams at the front of the grid all own wind tunnels. The teams at the back of the grid don't.

TLGunman

You need both tunnel, and CFD, since many times you're only going to be getting trends, not actual on track type numbers. You can get different results in different tunnels, for the same parts, ditto with CFD.

Shaka

Why would you want to buy a peice of junk that can't possibly work and only adds weight?

RedLS1GTO

That does NOT pass the eyeball test of this engineer...


For the record, I'm not claiming to be an aero expert and I could be wrong, but I do have a bit of experience (mostly with aircraft design).

Cobra4B

Because it looks cool and will let everyone at the car show know I have a racekor!!!

kmagvette

Looks like a Tranny/Diff/Other Stuff cooker

AU N EGL

You guys happen to notice the Diffuses on the C6ZR1 team cars? more of an inverted wing at 45* up angel vs a diffuser.

0Louis @ LG Motorsports

They do that due to rules, must be flat with minimal deviation.

TLGunman

No strakes allowed, can't start fwd of the rear axle centerline, must be in a single plane

VGLNTE1

I see a lot of people pretending to be experts, but no facts.

Cobra4B

Yeah.. the guys who built the ALMS Viper and first GT2 C6 don't know jack.

VGLNTE1

Don't really care if they own a Dinosaur or can fly. post facts and help people out, And who here "built" those cars? You mean The car GM designed? Or the car SRT designed? Cuz neither are in here

Cobra4B

So you don't understand that Riley Technologies built the new SRT ALMS car with SRT's permission?

Or that LGM worked directly with Riley to build the first C6 GT2 cars before GM came in and screwed the privateers and decided to take it "in-house" to Pratt & Miller.

They're not street cars, not even close. Yes they use the factory chassis as a starting point, but that's it.

VGLNTE1

So a crew member that's in here designed the viper? Lol
Get back on topic. Either post some facts on how to improve the difusser or at least post something useful. Not into a internet pp measuring contest

VGLNTE1

Found a side shot off Google

TLGunman

Ok, for the diffuser to function, it needs to let the air expand, as smooth as possible. Lets assume the curvature of that diffuser is such that the air stays attached all the way along the curve. Then there is the sudden transition to the flat area, that appears to be parallel to the ground. If the air is expanding and attached, it's going to be forced to change direction there. That change is going to cause turbulence, and choke the diffuser.

It's possible that the air won't stay attached, if the curve is too drastic, and it separates and misses the flat section. If that's the case, why have the flat section at the diffuser exit? mounting? could be, but I think it could be done better.

C5Natie

I wish the owners of that car could chime in to say what testing they did or what results they got. I understand what people are saying about the flat section following the curve. I wonder if that transition area may even cause some lift? Anyway it does look cool. My guess would be that it should be somewhat functional if what appears to be a serious race team is using it...I hope.

jcsperson

I'm pretty sure this is the car running that diffuser:


Kenny Blankenship


Neal Connell

One of them posts on CF as CRE_Vette.

RedLS1GTO

That is EXACTLY what I saw...

Long story short, you want as much expansion as possible (aka lower pressure created with same volume air) AND you need the flow to stay laminar while doing so. By the eyeball test, this design very clearly fails at 1 of those... not sure which without seeing data.

el es tu

Ive been designing a diffuser for the c6 over the last few weeks and have redesigned it more times than I care to remember. One thing Ive found in my researching online through the various tech sites and reading as many documents on diffusers as possible, is that that general design should work.

However as TL stated there is a problem though with that flat section as it shouldnt be there - it may actually increase drag and decrease downforce since youre going from expansion and that nice curve where the vortices of air are shooting out in a controlled manner, to the flat area where vortices get mucked up. This could cause that air to "block" the rest of the air that's trying to come out.

To the nayssayers who think anything that isnt designed in a wind tunnel is a waste of time: flattening as much of the underside of the car as possible may increase downforce but it will almost always reduce drag and give you more top end acceleration.

Try driving at a relatively lower "high" speed (110 to 125 is all that youll need to see this) maxing out your rpm with the window open and then close the window without upshifting. Youll gain more speed. Doing this in 4th (this was done a few years ago in what is now relegated to my daily driver), I went from 125mph to 130. Drag plays a huge role in slowing your car down. IMO eliminating drag is better than adding more power - especially if you spend more time in the triple digit speed range. It is because of this that Im interested in seeing how much top end speed a stock drivetrain c6 will gain by cleaning up its underside - my guess is going from the stock 186mph to somewhere in the mid 190s. Only problem is finding a safe place to perform the test.

Engineering experience: I stayed at a holiday inn