J's Racing spent over two years developing their kit for the DC5 using aerodynamic data gathered from endurance races and numerous motorsport events. Whilst developing the kit, they also took into account street applications.
Unlike many other 'aero kit' manufacturers, J's design their kits with performance in mind and not as a 'dress up' part, although their kits do look fantastic! As such, the benefits with the Type-S kit as you would expect are:
- Increase in downforce
- Decrease in aerodynamic drag
- Cooling efficiency
- Weight saving
Mine will be the 3rd J's DC5 kit in the country, however if we're being accurate it will actually be the First facelift kit on these shores and will also be the first to have the front wide fenders.
I'll give a brief run down of the parts that make up this kit.
Type S Front Bumper with Carbon Under Panel
When the temperature of cooling water reaches a certain point, in order to avoid possible risks, the ECU will make several changes including fuel increase and retarding the ignition point which will cause a reduction of power. Now a stock bumper with its narrow air opening to the radiator cannot utilise the full capacity of a cooling system even with an aftermarket radiator. The J’s Racing Type S front bumper is designed to significantly increase the airflow to the radiator first by a wider opening and second by closing the gap between the frame and the bumper. The kit reduces the water temperature by approx. 10oC compared to the stock bumper and additionally the carbon fibre underpanel provides increased downforce.
J's Racing front bumper - Notice the wider air opening and large front splitter |
My car in OEM form for comparison |
Type S Carbon Front Side Wings
By catching the air which goes around the side of the car and by aiding its downward flow, the carbon Front Side Wings produce significantly more downforce. Additionally when used with the J’s Racing front canards, the effectiveness is further increased. This is because the escaped air flow leads to the underside of the canards and creates an increased atmospheric pressure difference at the top and bottom of the canard i.e. Greater downforce in this case.
J's Racing Type S Carbon Fibre Front Side Wings |
Type S Carbon Front Canards
The canards creates a strong front downforce which will enable faster corning speeds. It will also produce beter balance between the front and rear when used with the GT wing.
J's Racing Carbon Fibre Front Canard |
Front Wide Fender
Recapping back to my CE28's post, I made a comment wishing I had ordered wider front wheels with a lower offset. This is one of the reasons why. To compensate the increased width I will be running Eibach hubcentric Pro spacers at the front to fill the space.
The fender is designed to provides an extra 15mm over the stock fender enabling the use of wider tires for more traction. The duct on the fender streamlines the air turbulence from the wheel spin, which effectively reduces the drag. Note, the J's fender used to be 20mm wider than stock. At the time of my order they reduced this to 15mm. I'm hoping I'll have one of the last manufactured 20mm fenders.
J's Racing 15mm Wider front fender |
Keeping low pressure underneath the car will enable higher pressure above the car to apply added downforce. By extending the width of the body and significantly reducing the air sucked from both sides, the Type S Side Skirt with Carbon Under Panel is designed to maintain an area of low pressure underneath the car.
J's Racing Side Skirts with Carbon Fibre Under Panel |
The rear bumper is designed to reduce the “parachute” effect (air mass trapped inside the rear bumper increasing drag) by adding several ducts (bumper left and right ducts, and license plate left and right ducts). The new side fin shape structure streamlines the air on the side of the car and works with the diffuser to produce more downforce. The diffuser moves air out from the underside of the car at a faster rate, thus decreasing the air pressure below the car and allowing the slower moving air above the car to push the vehicle into the ground i.e. Increased downforce.
J's Racing Rear Bumper |
License Plate Vents |
Side Air Vents and Rear Canards |
Rear Diffuser |
3D GT Wing Type 1 - Wet Carbon
Proven to be very effective in competition, the three dimension (3D) GT wing has become a standard item in the GT Championship Series. In order to maximize the wing area and to minimize the drag, it adopts a 3D banana shape. The 3D GT-Wing produces an overwhelming down-force and balances out the downforce produced at the front. The width of the wing is 1600mm and the wing angle is adjustable in 4 stages. Note, Umemoto San told me they could produce wings of varying widths to accommodate various competition regulations. However this part is a right A$$ to get hold of (they are typically made to order as with most of J's parts), it's one of the two parts I am waiting for that is holding up my project at the moment. Additional note is that First Moulding make the C/F wings and bonnets for J's Racing as well as other prestigious Tuning Companies such as M&M Honda
J's Racing 3D GT Wing |
Notice the 'Banana' Shape |
Buddy Club Carbon Fibre Bonnet
Yes, I know. Why mix and match the bonnet when you've effectively got the whole J's kit? That thought has repeatedly gone through my mind and still does today.
Firstly, let's take a look at the two:
Buddy Club Carbon Fibre Bonnet |
Concentrating on form factor, they both benefit the car by having large vents near the exhaust header to release heat from the engine bay. The J's vent appears to be wider than the Buddy Club, however the Buddy Club vent looks to be directly above where the header would sit. Whether one is better than the other at releasing heat I can't comment on, so for me it came down to aesthetics when I made the choice.
Both are very pleasing on the eye, but the Buddy Club in particular is a crowd favourite. This is not the reason for me liking it but explains why I like it. It is an unoffensive/ un-outrageous 'cool' design that goes with everything.
From the picture above, the J's doesn't look as nice, but it really is.
Initially what put me off is it is very aggressive looking. However in saying that the J's Aero kit is an aggressive kit! It definitely has grown on me since not choosing it... and additionally I can't think of anyone that has this bonnet in the UK, or even the States for that matter.
However there is also one other factor that comes into play - price. Quite simply, the J's bonnet would be over £1k and then there are extras to buy like the inner protector tray for when it's raining (not a necessity, but for peace of mind); the Buddy Club includes this as part of the package and is significantly cheaper.
In saying all this though, if I could go back in time I would choose the J's bonnet..