Front splitter

#1
Hi

for track use i´m going to build a front splitter.

It will be designed to bolt on very low on the body, so that if unscrewed one can not or hardly see the boltholes. It will cover and close the open gap between the lower front of the clip and the radiator, thus ducting more air through the rad and avioding air entering under the car by bypassing in front of the rad.

it will be a modular design. Base version is for street use


Than there will be a medium length splitter extension ( about 3")


And one with about 5" witch also is planned to be wider and has some guide flaps on the side ( my be some small canards as well. Both the medium and max spliiter extension will be bolt on to the base version and additionaly supported by struts mounted to the front vertical bar of the front frame.


Construction will be vacuumformed CFK with some core material used for the extensions.

What you think ?

TOM
 

New Member
#2
I think it will look good Tom, thinking of doing one myself.
I made two for my Ultimas, these were in plywood bonded into the body.
Of course it may only fit RCR's.
If it fitted to my front SGT body, I'd share the costs with you.
 

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#4
Hi Tom,
I am not an aerodynamics specialist....so my comments are not made on a fundament of knowledge, rather then on assumptions.

The splitter itself will work but the efficiency based on the total aerodynamics package on the GT40 might be disappointing.
I would in addition to the splitter also build some side guards which lower the body shape to the same level as the splitter. Why ? Because I assume the air the gets around the splitter will cause a slight overpressure on the side which might results into a flow under the body ....

I also would think about the original little side wings on the front fender, will help to improve overall airflow, because the front of tiers on a GT40 stick outside the body and will prevent a laminar airflow..

What I did is to build wings on the nostril to prevent air from "falling" into the coolant flow outlet....so like rails on the left and right side...it improved airflow a lot there. Before my whipper arm was just working fine....now the arm starts lifting at around 90km because the airflow is very straight....
I think the Mark IV had it also originally right ? take a look here http://www.histomobile.com/histomob/internet/41/267701.jpg


Last but not least I think a splitter only work at 100% in conjunction with a diffusor that has a "long " air tunnel under the car....

The GT40 has a very straight and even floor pan so it should be fairly easy to control airflow here ....


I can recommend a book
Fahrdynamik in Perfektion: Der Weg zum optimalen Fahrwerk-Setup
from Wolfgang Weber. I learned a lot while reading it...it deals several chapters with your topic....

Just my 2'cnt...but again I am not an subject matter expert on this ...
 

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#5
Hi Tom,
I would in addition to the splitter also build some side guards which lower the body shape to the same level as the splitter. Why ? Because I assume the air the gets around the splitter will cause a slight overpressure on the side which might results into a flow under the body ....
..
Hi Carlos , thats exactly the plan, also the rear diffusor and gurney flap. Thos parts are fairly easy to build. So i would like to start with the more complex one.

TOM
 
#6
Just a suggestion Tom....maybe consider using a flexible material for the lowest part of the splitter? The first big bump you hit on compression could tear the thing off if it won't "give" and rub a little on the (uneven) ground. This could be important at high speed...if it caught on something and tore off then you'd be running it over, and getting a bunch of air under the front of the car at the same time....no big deal at 50mph but potentially a really big deal at 150 mph.....
 
#7
One big downside would be that the front clip would no longer be able to be opened at a gas station or for any other quick servicing with a splitter.

On a road car, being able to open both front and rear clips without having to have two people completely remove them from the car is a huge plus.
 

roaldin

Active Member
#8
I have a front splitter that looks very similar, I'll see if I can dig up a pic'.
I haven't had it on the car for a while because it is just too impractical for the street unfortunately.
You think driveways etc are a pain in the neck in a gt40, wait until you try it with a splitter...

Tim.
 
#9
One big downside would be that the front clip would no longer be able to be opened at a gas station or for any other quick servicing with a splitter.

On a road car, being able to open both front and rear clips without having to have two people completely remove them from the car is a huge plus.

RCR Front clips are true to the original part. Also on the inner panels. Thus they do not have a tilting mechanism anyways, Just slide on and off, like the real thing and giving full acces to everyting mounted in the front.

TOM
 

Jim

New Member
#10
Hi Tom, I too am not an aero expert, but I believe to make your project a success, a lot of time($) will have to be spent. Probably have to look at a rear diffuser or wing to balance the effects of a splitter. Keeping in mind that Ford did a lot of work to make the GT40 stay on the ground without taking up excess horsepower. If you have the effort and time to put together a package that works, I'm sure you'll have customers ready to buy your developed pieces. Best success! Ranger Jim
 

Mike D

Lifetime Premier Supporter
#12
Wait a second Tom... aren't you the guy that lambasted as blasphemous the rear diffuser I was working on with a friend for the GT40? Now you're considering a splitter? What gives lol??
 

Randy V

Administrator
#13
I have a relatively extensive engineering background, but I am not an aerodynamicist.

In my experience in working on numerous racing cars over the years, i have found that the ca is like a teeter totter. If you make one end heavy, the other end gets light. Crank in too much wing in the back without enough front downforce, the car will push into high speed turns (I've lived through a few of those episodes). Conversely, if you have more front downforce than rear, the tail of the car gets very light at speed. This is also not a good thing. Aero needs to be balanced front to rear in order to be the most effective.

That said (along with previously mentioned lack of education credentials), i like the designs.. Is the GT40 already too heavy in the rear (aerodynamically) and this splitter is being made to counteract that?
 
#14
I don't know anything on paper either but I have driven several hundred laps around tracks and more or less worked out a pretty good balance on my GT40.

Once you have the car in mechanical balance @< 100MPH, with tire pressures, springs, shocks, anti-roll bars then.....

1. A 1-2 inch gurney attached to the rear adding height to the existing duck bill will lower lap times a second or two if there are 2 or more 100 mph corners. Do this first and then work on the front, #2-#5, until you take enough front lift off to return to areo balance

2. The front can be balanced up to about 145MPH by sealing the openings at the front of the car and forcing ALL the air flow into the car through the radiator.

3.The front ride height MUST be a inch lower than the rear. I run my car at F3.75/ R4.75.

4. Small canards at the nose look the part but I think that any improvement is due to preventing airflow into the wheel wells and less so by adding direct down force.

5. Ducting in the radiator exhaust nostrils to prevent turbulence in the bodywork between the radiator and the exhaust exits will do more than you think. You can feel the difference.

6. The next step would be to completely seal the bottom of the car. Nothing can be achieved further with difusers without doing so.

The results are quite noticeable even for a amature (like Me). My guess is the car is still making lift but it doesn't effect balance under 145MPH now. Before the car was areo pushing at 100 and going to over steer when I was forced to lift. Now the car is pretty neutral with the ability to tune push/oversteer with the antiroll bars above 100 MPH.

Overall the chassis/areo downforce ballance would suport another 5-10mph in these high speed corners if I took off the street tires and ran slicks.

In the end the car will not be a GT40 if you fix the areo issues and try to make a real downforce car out of it. My solution was to build a SLC.

So there you go. do this stuff first and see if it is fast enough for you. I bet it is......
 
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