underbody splash shield

[Primal]

Hello all-- my first thread here, so feel free to redirect me if this topic has already been raised.
Looking at the pristine condition of my engine bay (my 2000 NSX just arrived last weekend), and the very open undercarriage, I would like to know if any of you have added additional under-body splash shields to reduce
dust/sand etc. from entering the engine bay (as well as the hood compartment)? If so, where can they be found; pros, cons, etc.
Montana roads can be pretty dirty~
Thank you-

 

[ky650]

You could get the NSX-R under tray to cover up the front. I'm not sure if you need the R hood with battery under tray though so there's a place for the air to escape? I haven't seen how well it closes up all of the gaps. If you go that route then you'd also have to remove the spare tire.

http://scienceofspeed.com/products/...oducts/NSX/Downforce/NSX-R_Battery_Undertray/
http://scienceofspeed.com/products/...s/NSX/Downforce/NSX-R_Front_Bumper_Undertray/

and maybe this for the rear?
http://www.difflow.com/nsx_5elementoriginal.html

In this photo there appears to be a tray that covers the engine bay area up but I don't believe that part normally comes with that diffuser. Perhaps they made it upon special request?
http://www.difflow.com/nsx/5original/yellow6.jpg

Pros would be better aerodynamics

Cons would be the obvious expense, weight, and regarding the engine bay I'm not sure if cooling is an issue or not for any of the components.

Congrats on the new purchase!

 

[Primal]

Thanks Ky650-- very helpful information (sorry for the delay in reply, I've been traveling a lot this summer). Reading a bit on the Difflow website, it appears they are willing to do some custom work.
I think your links should do the trick. Usually pretty cool up here in Montana, so I'm hoping the possible heat retention won't be much of an issue-- unless I succumb to adding a CTSC....

Thanks again!

 

[ProOnThaSnow]

^Where are you at in Montana? I've got a friend who has a waterjet - I'm sure we could come up with something that would be a relatively bolt on for covering up the underside of the engine bay. Your car could very well be the Silverstone car every friend I know keeps sending me pictures of, lol.

 

[shawn110975]

I would NOT do what your thinking..... the top of the engine glass has a vent near the trunk aero flows thru this.......... then the air flow from under the car pulls the air from the top thus making a whirlwind action around your engine and keeping and is pulled out the rear under. closing this off will raise engine temp and that extra heat could make those hundreds of plastics brittle under the heat.

and your mint engine bay is like all of our engine bays we clean them... thats how we keep them pristine. elbow greese.

now I have seen most of the undertrays you can buy are everything except the engine bay. you can cover everything up to.... the gas tank the rest is open for this reason.

but hell what do I know I am normally wrong so disregard everything I just posted

 

[chussey]

Hello all-- my first thread here, so feel free to redirect me if this topic has already been raised.
Looking at the pristine condition of my engine bay (my 2000 NSX just arrived last weekend), and the very open undercarriage, I would like to know if any of you have added additional under-body splash shields to reduce
dust/sand etc. from entering the engine bay (as well as the hood compartment)? If so, where can they be found; pros, cons, etc.
Montana roads can be pretty dirty~
Thank you-

I have had the same thoughts... seems we should be able to develop an underbody cover that increases aerodynamics, engine cleanliness, as well as still allow for proper engine bay cooling. Most new cars come with so many plastic front bumper and underbody covers it's a wonder they can cool at all... but they do!

 

[Primal]

I have had the same thoughts... seems we should be able to develop an underbody cover that increases aerodynamics, engine cleanliness, as well as still allow for proper engine bay cooling. Most new cars come with so many plastic front bumper and underbody covers it's a wonder they can cool at all... but they do!

Acknowledging Shawn's wise comments, I like Chussey's thoughts. It would seems one could design a levelor style shield angled like half open blinds... preventing dirt and gravel from coming in, while (hopefully) improving laminar airflow which should be more efficient than turbulent flow for both cooling and aerodynamic purposes. Perhaps worth discussing with the Difflow people?
ProOnThaSnow- I'm up in the far North Eastern corner of Montana- I've never seen another NSX on this side of the state in the past 15 years, but plenty of F350's!

 

[CL65 Captain]

Acknowledging Shawn's wise comments

Shawn is wrong. All of Honda's LeMans NSXs had sealed undertrays with the exception of a small air deflector for the tranny.

There are oddles and oddles of mid engine cars that have sealed undertrays with only small NACA ducts were needed for cooling. Off the top of my head - Audi R8, McClaren MC12, Ferraris from the 360 to the 458, etc, etc.

A sealed undertray is fine, all you need is some small NACA ducts to the tranny area and maybe one for the oil pan if you track the car or drive hard.

<img src="http://www.acuransxbroker.com/cars/51/fotos/04.jpg" />

 

[Primal]

Had to look it up... Thank you!
http://en.wikipedia.org/wiki/NACA_duct

 

[shawn110975]

I stand corrected again :redface:. I still want it on my NSX for sure

 

[Mac Attack]

Hang on a minute.

Shawn is correct. The examples CL65 posted were applications where the vehicles were engineered for closed underbodies. Even the race NSX.

Vrooom, or Jeff@carbon6 enclosed his engine with an extensive underbody, and had electrical problems. He traced it down to a melted/shorted wire due to the increased engine bay heat. You may want to search on that example.

I would not enclose the engine compartment of mine without doing a lot of testing.

My $0.02.

Dave

 

[docjohn]

debatable but I would not seal the rear underbody of a street driven nsx.

 

[RYU]

unless i engineered my underbody in a windtunnel environment and know exactly the flow of those NACA ducts through my engine there is no way I'd cover up the underside of my engine bay. I'm even hesitant to put on one of those rear "diffusers" that's so commonly sold here.

This is what happened at my last track event a few weeks ago. This is the VViS vacuum tank reservoir in the engine bay.

I enclosed the new one in gold heat shielding and some fire proof insulation. I feel sorry for my wiring under there. Winter project... ceramic coat my headers.

 

[ProOnThaSnow]

I was thinking if you made one, you could vent it, such as most newer cars' factory under trays... It wouldn'e be terribly hard to get a louver die and put them in the sheetmetal, but at the same time I don't know how much it would help keep the engine bay clean then.

Something like this with the louvers out facing the ground;

It would definitely require some testing, but may be possible to achieve - however the aero may have a negative effect from it. Thinking of it, with the exhaust running down there I don't think it would be an easy task to achieve, however with the right design and amount of testing, it wouldn't be completely impossible.

 

[Primal]

unless i engineered my underbody in a windtunnel environment and know exactly the flow of those NACA ducts through my engine there is no way I'd cover up the underside of my engine bay. I'm even hesitant to put on one of those rear "diffusers" that's so commonly sold here.

This is what happened at my last track event a few weeks ago. This is the VViS vacuum tank reservoir in the engine bay.

I enclosed the new one in gold heat shielding and some fire proof insulation. I feel sorry for my wiring under there. Winter project... ceramic coat my headers.

Are you running a SC or Turbocharged engine?

 

[CL65 Captain]

Hang on a minute.

Shawn is correct. The examples CL65 posted were applications where the vehicles were engineered for closed underbodies. Even the race NSX.

Vrooom, or Jeff@carbon6 enclosed his engine with an extensive underbody, and had electrical problems. He traced it down to a melted/shorted wire due to the increased engine bay heat. You may want to search on that example.

I would not enclose the engine compartment of mine without doing a lot of testing.

My $0.02.

Dave

Dave you are forgetting about Greenberet's full undertray and his extensive testing and top speed runs on the Autobahn. Minimal increase in temps. No problems with excessive heat when tooling around town.

http://www.nsxprime.com/forum/showthread.php/116208-Homemade-complete-rear-undertray-diffuser

 

[Mac Attack]

Thanks for pointing that out. I re-read your first post and you must be right - the key for the NSX is to have some venting around the transmission, oil pan and headers.

Jeff probably had the solid undertray shown below when this occurred:
http://www.nsxprime.com/forum/showthread.php/152048-Car-Looses-power-and-shuts-off-under-acceleration?highlight=melt

John@microsoft, CK_SB, Danny and others have made theirs work:

Although CK_SB noted a 20F rise in engine temps with his tray in place. On a race track though.



Just enjoying spirited drives around Montana probably won't be an issue. Do it and report back!

Dave

 

[Primal]

Thanks for the link on Greenberet's full undersheild-- great post, and quite humbling to read. Much of Greenberet's post focused on down force, and optimizing speed (apparently minimal effects on both), whereas my goals are primarily oriented around simple protection from sand and gravel, which lamentably are far easier to access here than the autobahn. It would appear that an under shield for gravel-free "spirited drives around Montana" is feasible and reasonable. Being vastly less talented than Greenberet at custom fabrication, I'll check with KY650's links and see what I can do when I get a bit of time in October. I'll post some photographs when finished. Thanks to all for the excellent discussion and knowledgeable information. Just one more reason to own an NSX.

 

[Nukem]

*Subscribed*

 

[Stephen@NCAutoUSA]

Downforce makes trays, you could probably just get them. As long as you don't go off roading I think they will do what you're looking to do which is protect the bottom area...

 

[ProOnThaSnow]

If you're interested, we could get dimensions off of either your car or mine and I am sure I could get it cut on the waterjet for a VERY reasonable price. Would save time, money and a lot of hassle. I also have access to a lift whenever I want to use it. My SFWD car is on it right now and I'm away at work.

LMK if interested - hell, maybe I'll do something similar eventually.

 

[Primal]

If you're interested, we could get dimensions off of either your car or mine and I am sure I could get it cut on the waterjet for a VERY reasonable price. Would save time, money and a lot of hassle. I also have access to a lift whenever I want to use it. My SFWD car is on it right now and I'm away at work.

LMK if interested - hell, maybe I'll do something similar eventually.

Will consider that option- thank you for the kind offer--

 

[ProOnThaSnow]

And you've been spotted in the heights tonight. Someone posted a picture on the MAEC (Montana Auto Enthusiasts Club) group page on Facebook about 20 minutes ago, lol. At least I think you're the only Silverstone NSX in Billings.

 

[Primal]

I haven't taken it to Billings yet-- a doppelganger no doubt. They say good things come in 2's.