front underbody diffuser

[ctrlaltdelboy]

one of the guys on Prime is developing this - I have already expressed my interest, maybe some others are interested too

http://www.nsxprime.com/forums/showthread.php?t=40142

[Kevin]

I think there is another thread where he says the high speed stability of the car is worse, as without a ducted bonnet the air from the radiator has nowhere to go.

It's also missing the front spoiler as well. For sort of thing to work properly, it would be lower at the front than at the back.

The ideal setup for your car Darren, would be a plate from the lowest front edge of your Wings West spoiler, gradually rising up back to the floor of the car.

The guy on prime doesn't fill me confidence that he has measured anything. His quote the 'brakes seem cooler, by seat of the pants feel', makes me laugh.

[Pande]

I agree, this design just looks alittle far fetched. The brake ducts are set too far back. the hosing used for the ducts is cheap flexi. The positioning of the brake ducts would seem air would not pass through the duct at the same rate it was entering. This would cause an air bubble effect.

But I aint no expert on aerodynamics so maiby im just talking sh** after a heavy drinking session last night. :roll:

[ctrlaltdelboy]

Hi Guys

I pointed Al at this thread and he came back to me with some relevant feedback to the comments made here - I thought it would be valuable to post them here

Darren



Thanks Darren and I find that some of what they are talking about is based on pure speculation. First for Kevin I did do some measurements and spent over 4 days playing with the initial design, researching source of materials, measurements and so on. It fits on both the Wings West setup and also the stock black front lip. In fact when I installed my Wings West air dam, I was told by the manufacturer that it can be installed over the stock black front lip which I did.

The diffuser fits just above the lower lip of the front air dam or wings west air dam. It can be mounted below these if you want, but I chose not to have fastening screws showing below the air dam. So it does have a smooth air flow from the front of the air dam at it's lowest point to the rear of the main chasis structure or as we used to call it the front firewall.

As far as the brakes ducts being made of cheap plexi, they are not. They are made of an high impact plastic from a well known manufacturer of NACA ducts, and other brake ducts which have been used by NASCAR teams and the like. If these break, then you've hit something really big and probably damaged more than just them. As far as whether they will pull in much air because they are too far back, have Kevin do some reading on why the NACA duct were designed and how much air it will pull in even at low speeds. In fact have them take a look at a picture of the original Spice Car built by Comptech. You will notice that on the lower sides below the driver and passenger area, there are two NACA ducts used for cooling purposes. Shad at Comptech said they pullled in a lot of air. You can see that they are very far back from the front of the car and on the side which you would think would have little air flow capability. Obviously these worked great on the Spice car and this is why I choose to go this route for my brake cooling. It's also one of the few ways you can do the NSX (without body changes) for a brake duct which also wouldn't bottom out and get damaged or cause additional drag.

Please have Kevin and Pandle access this site http://worldhonda.com/NSX/technology/t3.html from Honda as to where I got my initial inspiration. The main difference in my design is that it goes all the way to the front of the air dam and not just to the radiator bracket. Also I added the NACA brake ducts which they don't have.

Finally it's up to the buying public to make up their own minds as to the effectiveness and cost benefit of buying any aftermarket part.

Thanks for your interest.

[Kevin]

Thanks Darren and I find that some of what they are talking about is based on pure speculation. First for Kevin I did do some measurements and spent over 4 days playing with the initial design, researching source of materials, measurements and so on.


As far as whether they will pull in much air because they are too far back, have Kevin do some reading on why the NACA duct were designed and how much air it will pull in even at low speeds.


Al needs to read more carefully. My comment on measurements do not refer to measuring for fitment. I am refering to measuring actual brake temps, measuring downforce and measuring an improvement in lap times.

I also did not mention anything about NACA ducts. For info, I have plenty of books on racecar aerodynamics as well as suspension, braking and composite material text books. My comments are not based on speculation. Any other comments I made, were to suggest improvements on this design and make it more effective.

Attached pic is the NSX-R. You will see in the attached picture the black front tray has a 'bump'. This will create a high speed airflow area, which will create downforce. Also the parts of the tray to the front of the wheels raises up, these smooth the airflow leaving the underbody into the wheel well. The edges on the sides of the aluminium parts of the undertray are there to prevent air from the wheel well entering to the centre of the car, not the other way round as Al suggests.

It's a bit more involved than just a pure flat floor.

[modarr]

I would consider the most salient point raised in this discussion was the the 'ducted bonnet' mentioned by Kevin.
Undertrays are all well and good but without an alternative route for radiator air (wheel wells or bonnet) the benefits will be reduced and engine cooling may be affected.

By the way, did I mention I'm in the process of bodging one for my car...just as soon as I find my can opener.

Mo...and I am serious.

[ctrlaltdelboy]

thanks for the input Kev and Mo - some very valid points made there, I can certainly see where the downsides of the flat floor design are.

apart from any other shortcomings I reckon the biggest factor to bear in mind is that to do anything like this without first installing a scooped bonnet has got to be a no no as Mo pointed out.

still like the NACA ducts though as a cool factor to have incorporated into the design.

Following Kevin's points and the attached pic, I am definately feeling that a design mimicking the oem one has got to be better, with the open area under the wheels and the front tray incorporating the bump and rise.

So if Al is sticking with his current design I guess I'll bow out

anyone up for making one up incorporating the best of both designs?

Kev?
Detlef?

[Kevin]

Detlef is working on making direct copies of the NSX-R undertray.

Without a vented bonnet I wouldn't do anything yet, and I still have wings to make!

SoS have a GT500 bonnet which is working out at £650 at the moment. I wonder how much a group buy on those would be?