OK since Watkins Glen was mentioned recently in another thread. I need to sort some things with my 914/6

I just got back from the glen and was a track slut, instructing for a BMW club... I instructed and got free track time!!! way cool!!! and a free dinner in the glen club!

I have the handling issues pretty well sorted. The car responds to my right foot beautifuly I can make it push, throttle steer, etc depending on the turn

Entering the braking zone for the bus stop, and turn one Im pretty much going as fast as the gears I have allow!! 135+

I had issues with the rear brake lock under high speed braking, and have dialed it out with the proportioning valvle. I now believe its a lack of downforce, that caused my braking prob, not chassis set up. If I get some good downforce I can dial in some more rear brake, and that would be a good thing.

Id like to get downforce without a big ass wing stuck up in the clean air!!.

The car has the 916 type fiberglass spoiler on it now, but im not sure if that thing works at all..

Are those nascar type spoilers made for retail, or are the custom fabbed for each car? MJ Hanna sent me some pics of his car when I was in the market that had what looked like a functional spoiler on it.

Is that the way to go?

heheh the six speed, my friend hasa g50 6 speed. I think that would go great in my car with some close gears.

Are you getting lift ?? or do you need downforce ??

Marks car had a 6 inch Sheridan style rear "spoiler" on it.

The main function is not downforce.. but to stop air from circulating too close to the rear of the car. The spoiler makes this happen further behind the car so it cant "lift" the rear end at high speed.


B

Brad the rear of the car get squirrely under hard braking at speeds over about 125. Im thinking if I had some downforce the rear would stay planted. Actually it feels like lift

At the glen. climbing the esses the rear feels light when I change direction.. then braking for the bus stop the rear starts to step out a bit ( major pucker factor). I throw the car around the bus stop, but thats not the fastest way.

I think need someway to get some downforce..maybe the sheridan wing is what I nedd

Do 914s generate lift like my early 911 does?

thanks for the insight

The 914's will lift big time in the rear without some sort of spoiler on the rear (over 120 mph)

I do think a Sheridan "spoiler" would help you out. Its really the last step before you end up with a mondo wing.


B

Here's a pic of the rear spoiler on my car. It's larger than the normal duck tail. I haven't enough track time with it to say how well it works but a friend that has the same spoiler says that in turn 8 at Willow Springs which is a high speed sweeper at the end of the back straight, his car is much more planted and stable.

So if I want to be a lazy ass I can call sheridan and would know what Im asking for and be able to crank one out for me?

Here's a side profile.

He would. Tell him Brad Roberts sent you from the 914club.

Drews "spoiler is cool. You can buy them moulded to Carbon Fiber decklids for our cars.

B

Here is the current aero state of my car LOL

hard to see the rear spoiler

Here is a shot of my rear spoiler. I've mounted the oil cooler in the middle of it. I want to make it as wide as the car but I haven't come up with a final design yet.

Paul

Oh.. I never noticed the "end plates" VERY NICE.

B

Hand laid-up fiberglass and a whole lot of sanding with more bondo than I wanted to use.

Paul

Nice work Paul, not to sure about having the cooler where is might catch some debris..... Then auto-x is different than club racing.. both are equally as intense
Im just trying to find a way that the rear of my car doesnt get unsettled when I hit the brakes at 130~

Tim,
...catch some debris?

It is safer there than up front where it will catch everything.

Paul

yea I come off the track and I chips all over the front of my car, and rubber snots all over the rear.. I guess anywhere you place an oil cooler its vulnerable

4 words: Glovebox



M

I'm gonna do f/g lids and the Sheridan 6" "SCCA" spoiler as soon as my bank account gets an IV drip of cold cash.

I don't think our 914's can really achieve "downforce" with anything resembling a stock body; but if we can get closer to "zero lift" that makes a humongous difference.

My car so far has felt very stable at the speeds I've seen (we'll see what I have to say on Wednesday). My old blue 911 was a different story, with NO front or rear spoiler at all. That car felt like a plane at liftoff when it hit 110-120mph. Scary.

Hey Tim,

I noticed you have the IMSA front spoiler, not the 916 type, and your rear's are way to small to my opinion.

You know, the early Carrera 911 & Turbo has these rubber lips on the front and rear spoilers to compensate the drag/lift factors....if one of them is eliminated, the whole thing gets a bit screwy on the road. So what I'm seeing here, you got a big front spoiler now (compare to 916) and almost nothing in the rear, that's pretty screwy.

How about try this before you go bannanas in putting different spoilers on,.....add a strip of thick gauge aluminum with slot holes and secure it vertically to your current rear spoiler at the lowest setting of the slot holes. Work from there till you achive in what you want, then maybe find something to replace with the proper height/shape of your makeshift spoiler.

Kinda of a fun project, huh?

jerry

He currently has a 3 inch spoiler on the rear.. it actually works very well for 4cyl cars with his "Old School" IMSA air dam but not very well for cars that can generate 120+ straight-a-way speeds.

I like your idea about trying the "extensions".. but its hard to experiment with a race car. You dont have much track time to test new idea's and you cant exactly test it on the street (at least with Aero stuff its hard to test)


B

very good idea!

now who was it that told me the 916 style front spoiler had actually really good aerodynamics?
most people don't like the looks of them. (i would if mine was straight, argghhh) ...

i'm thinking about adding another lip underneath, as the 916 front spoiler does not go very low.

Andy

Now here is a rear spoiler. The thing stands up about 10" off the edge of the lid.

Too much IMO.

Paul

Nice car.. but there is a certain point at which you create more drag than anything.


B

I've got the IMSA style spoiler on the front and added a 2" piece under it to keep air from getting under car. Have about 3" clearance. Also have the Sheridan 6" rear spoiler.
I think the purpose of the end plates on a wing is to keep the air from sliding off to the sides so the pressure will push down. I like the way Paul added the end plates, nice job, been thinking of something similar. Car is very stable at 135+ under threshold braking with no step out. BTDT
Tim, I'd suggest that you get someone to watch your car under high speed braking to see how much the nose drops. You may have to go to heavier springs in the front.

what about an 'indy car inspired rear air diffuser', you know one of those things that sucks thea air from under the car into downforce?

I started with #650 springs in the front WAY to much spring. Right now Im running 450# front 350# rear and it seems to work well.

I have had people watch the car turning and braking, they say it corners flat, and they see the rear get loose under braking, not the front diving.

Looks like im going for a wing rather than a spoiler.Spoke to someone today and he recommend the wing. Hank at GT racing owes me a serious discount given the amount of stuff Ive bought from him throught he years.... lets see how I make out

Anybody know other source of "real" wings??

and not Crawford I cant afford there stuff.!!

It just hit me that the trunk floor should gilled, and then a small duckie, with about 3/4" trimmed out from the bottom edge of the deck lid. I know guys cut holes in the rear panels, but it seems like you could control it better.

Ducktails create more low pressure behind the car than downforce anyhow, right?

There is enough room under there to build an under-trunk wing.

so many physics, and so little money.


Chaparral

Fabcar creates real wings.

Fabcar's Products page

LOL yea Fabcar/smart racing/crawford make real wings.... And more dinero than Hanks.....

Im looking for a cheap wing that works

Actually not cheap... less than the rest works

Tin,
I was going to make my own wing but it was too much work. I was going to do a wooden buck and wrap it in f-glass. What about a wing from a SCCA formula car?

Paul

Paul thats exactly what I think will work!!

any sources for a formula continental wing or
the like?

A friend of mine has an AIR 935 tail on his car.. the wing cross section isnt the same from one end to the other, what a POS.

The thought crossed my mind to have a bud that used to shape surfboards make a foam core for me, then Id wrap it with carbon... Id like a real airfoil though, low drag and high downforce.

ill have to get some grassroots and check adds for suppliers for the formula series

I was worried if I was to make my own it would fail and come apart in the middle of some high speed corner. If I bought it from someone and it failed, my wife and kid could get a PI lawyer and go after him.

Paul

Here is another big ass "spoiler"

The above pic was taken at the Daytona 24 hours in 1981. Althought I didn't take this shot I could have because I was there. And I slept in my 914. (oh, my ackin' back)

Paul

now that just looks stupid.....

Or...

"I have wings!"

"Prince Charles is not only Heir to the Throne of England, he's a racecar!"

"CLUNK!"*

*continued from 'i have wings'


That second car would look great with early chrome bumpers.



m

that last pic that ury posted, is that a tail shifter? or a 915?

Its a cheap conversion to sideshift (he kept the original tailshift end cover instead of replacing it)

B