Well it was really your comments in the carbon fibre poll thread regarding an aero kit that set me thinking. I had assumed that the marketing hype about the rear diffuser and spoiler etc. was just that - hype. But looking around under the car as I have been for the last few days while it has been up on stands it is obvious that DC has paid quite a bit of attention to airflow underneath. Sure, the diffuser may well be mostly there for aesthetics, but they have taken the trouble to put fairings on the lower suspension arms to smooth the airflow in this area, kept the floor flat and free from protuberances, added a smooth engine under tray and small 'splitters' in front of the front wheels on the front arch liners to isolate the turbulent air around the wheels. Car manufactures don't spend money on fitting bits you can't see if they don't do anything. Admittedly these bits are probably only there in improve high speed stability and counter the lift generated by the cars shape, rather than any generating extra grip but that's not to say they can't be used as the basis of a 'kit' that does! As I see it a proper full width splitter and lower side skirts to completely separate the airflow above and below the car may give some genuine ground effect - its just an educated guess as I am not a professional aerodynamicist!
I have just put my Spider back on the road for summer so I now have the opportunity to have the Crossfire off the road for a week or so and remove the skirts and bumper to take moulds - until now the xfire was my daily driver so I have never really had the time to pursue any of the more ambitious projects I have been dreaming up. Watch this space.

Simon

 

Simon... if anyone in this forum will produce Q U A L I T Y body enhancements FUNCTIONAL and or aesthetics... it is you...

as far as being a professional aerodynamicist, it shouldn't be that difficult to test out your design with a computer model. there are several programs in conjunction with a 3D modeling program that will help you (roughly ) sort out any kinks before physical testing.

if you are interested in any of the programs, let me know... i can duplicate
and send it off... if so PM me with your computer's OS.

i've seen your PT cruiser work and whatever you have posted here about the XF and your involvement and dedication is beyond reproach...

josh.

 

You're too kind Josh.

I would definitely be interesting to see what modelling software you have and if it can help with some flow simulation. I have meddled with 3D cad/modelling stuff at work in the past (we used it to produce SLA models before tooling up) Someone has already fully modelled the xfire for an open source racer simulator (not sure how accurately but it looks good). I'll PM you later.

Simon.

 

SIMON...
yeah... if you are talking about the XF simulator in a GAME called "MIDTOWN MADNESS", I HAVE THAT MODEL... THE KID WHO CREATED THIS ONE... LIVES AND WORKS IN INDIA... IT SEEMS PRETTY ACCURATE... I MAY HAVE TOLD YOU BEFORE, THRU HIM I HAVE ACCESS TO THE MAJORITY OF THE CARS ON THE ROAD NEW/OLD AND VINTAGE...


DO YOU RECALL WHERE YOU HAVE SEEN THE INFO ON THE 3D XF YOU CITED?

JOSH

 

It wasn't Midtown Madness but a 'proper' race simulator, Racer. It is an open source, multi OS project by a Dutch guy. Have a look here:
http://www.racer.nl

The crossfire model can be downloaded from the racerXtreme link on the left hand sidebar. The picture on the download page looks crude but the actual 3D model is quite good. The dynamics model need a bit of tweaking though as it drives nothing like the real thing - it slides a lot more easily than it should. I think the roll centers and tyre model are wrong but it can all be configured even down to specific tyre manufacturer. The actual dynamics model is very complex and all sorts of parameters can be changed to alter aerodynamic affects etc. have a play!

Simon.

 

... thanks Simon...


You really know the XF in and out!


josh

 

After bit of a lull in proceedings I have managed to make a bit progress with this project following the arrival of some ducting.

The stock cooling setup uses a plastic deflector, that also doubles as the hose/wire mount, to direct air to the centre of the disc via a hole in the backplate. The air is then expelled at the perimeter of the disc as it spins.
I have managed to find just enough room for the ducting to snake around the suspension component and exit directly into the stock disk cooling inlet on the backplate. Initially I made up an ali insert that fits in the end of the ducting that allows it to be screwed to the plastic deflector/hose mount. However this causes clearance problems on full steering lock. So I am now going to fab up an ali duct mounts that replace the stock deflector that are angled more rearwards to solve the problem. It looks like I am going to struggle to get this completed in time for Saturday's track session but I may get something together in time.
There is still some detail work to do on the moldings too, like adding a flange around the exit for the ducting, adding mounts for the flexible splitter's as on the original and generally improving the fit and finish.











Due to popular demand I am now looking at putting a proper kit together. I will publish costs etc. once I am happy I have something that works and is properly engineered.

So far the kit will comprise:

2 lengths wire reinforced silicone rubber ducting
2 GRP inlet moldings to replace fog lamps
2 GRP inner wheel arch moldings
2 Aluminum hub duct/outlet fitting
4 heat shrink couplings
sundry clips, cable ties etc.

I am also looking at adapting the wheel arch moldings to function as air boxes...details in next post.

 

As mentioned above I am going to make some mods to the arch moldings to allow them to be used as cold air intake boxes. This will require some internal baffles and some 70mm duct outlets to be grafted on exiting into the engine bay, just inboard and below the headlamps. Short sections of duct can then be run up to the intakes on the engine cover. I think it should be possible to make them dual function for brakes and intake.

 

Bravo as usual... I was over at the WERKS2 shop this morning finishing-up what I could before this weekend event. My little Crossfire was surrounded by 6 pro GT3 Porsches that are turning out 500+ hp and weigh a meager 2,200 lbs.

I was sad Then I realized there's dozens of those things on the track and only one little under powered, lonely, pathetic Crossfire... LOL

 

Simon...YOU are a true craftsman/engineer!

are you still offering the PTcruiser mods you made in the past?


josh

 

Thanks Derek, its a pity you don't get points for exclusivity! I did a set of tyres trying (and failing dismally!) to follow one of those GT3's
Perhaps this will make you feel better.

 

No joy in seeing a nice car trashed... The next time I'm over at the shop I'll take some photos. I was fascinated with the new 5 car hauler and mobile workshop. Just delivered, brand spanking new and about 1/4 of a million $... UGH !

Makes my pick-up truck and flatbed trailer look amateur.

PS: still having problems with the electric radiator fan going into hyper-mode all the time. Have not had the chance to figure it out. Also, having the BAS/ESP light illuminate after the interior gutting. No wires were cut, just removed the plugs and bound them. There must have been a sensor somewhere in that sea of AC/Heater wires.

I'll figure that stuff out after this weekend.

 

What's worse is the guy had been battling another car all race, finally got ahead then they both collided on the last lap!

...I don't even have the trailer.

I'm still working my way through the xfire wiring diagrams. Its a pain having to look at all those individual A4 schematic sections in the manual. I'm gradually printing them out and piecing them together.
The problem with this car is it is all run on CAN bus so everything is all interconnected. Thinking about it, I have a feeling that there is no separate fan for the AC condenser, so the cooling fan doubles for this function as well. That's probably why its constantly running now the AC has been disturbed. The ESP light issue seems more strange - I wonder if the system is actually on or off now? Have you disturbed anything in the centre console near the ESP switch when you took out the heater?

Like you say, you've just need to get something running for the weekend, then try and sort it out when time permits.

I'll try and have a closer look at all this when I get chance. I'm still battling with the low-tech grubby stuff underneath!

 

Yes sir, the wiring is a bloody nightmare on this thing. After gutting the interior and removing the various bits. I decided to just bind all the wiring looms into an acceptable position for the tech inspectors on Saturday morning so I can run the car. (no exposed wires rule).

I'll deal with it next week after I destroy a new set of tires and spank a few RICERS...