NB Stage21 Hood

Lokiel · Postby **Lokiel** » Sat Jul 30, 2011 2:51 pm

I purchased a Stage21 vented hood from Rupewrecht and have not yet gotten around to fitting it yet but have been asked how it fits so decided to give it a trial fit this weekend and summarise the results.

Here are the NA and NB Stage 21 vented hoods:

These hoods come in unfinished FRP (Fibreglass Reinforced Plastic), very light but not as light as the aluminium OEM hood.
Unfortunately the two molded rear vents don't have cut-outs so I'll need cut them out myself, leaving a small lower lip to try and prevent water dripping into the engine bay.
I was originally going to increase the depth of the front vents a bit but have decided not to since I now think they're big enough.
The windscreen nozzle holes need to be drilled out but you can clearly see in the hood where they need to be drilled (there's two small indentations).

I also have a set of Aero-catch hood pins I plan to install since I don't fully trust the metal latch molded into the front of the hood.

The hood has metal bolts molded into it to attach to the OEM hood brackets.

Unfortunately these bolts are narrower than the OEM bolts - more on this later.

Some initial fitting photos:

Here's the good news: The left and right fit is pretty damn good.

Here's the bad news: The lengthwise fit is 15mm too far forward.

Front Fit:

Rear/Windscreen Fit:

Since I can't do much about the hood's molded bolts, I'm going to have to re-make the OEM hood hinge brackets, drilling the holes 15mm further back. These brackets need to be unbolted and require the fenders to be removed to get at their mounting bolts. Since I need to re-make the OEM hood hinge brackets, I'll use the same bit size as the Stage21 hood uses.

Like all aftermarket hoods, this one needs some work to fit - if the mounting points were 15mm further forward, this hood would fit perfectly.

Steampunk · Postby **Steampunk** » Sat Jul 30, 2011 4:20 pm

are the vents/extractors going to be blanked off? or are you going to design some fancy rain/water drainage system?

Lokiel · Postby **Lokiel** » Sat Jul 30, 2011 4:57 pm

1red5 wrote:are the vents/extractors going to be blanked off? or are you going to design some fancy rain/water drainage system?

Easiest thing to do is make some rubber blanking plates I can put in when I park and it's raining. I thought about doing some sort of draining system using silicon hoses but that looks ugly. My car is mostly a garage queen since I work in the city so I don't need to worry about this as much as DDers do.

bruce · Postby **bruce** » Sat Jul 30, 2011 5:14 pm

That would be a 'bonnet'. Hood is an american term.
Would it be easier to relocate the bolts in the fibreglass? It might be more work!
I wouldn't be impressed with that.

Steampunk · Postby **Steampunk** » Sat Jul 30, 2011 5:48 pm

bruce wrote:Would it be easier to relocate the bolts in the fibreglass? It might be more work!

Wha....?
Have you not taken your seniors pill today brucey?

Lokiel · Postby **Lokiel** » Sat Jul 30, 2011 6:02 pm

bruce wrote:That would be a 'bonnet'. Hood is an american term.
Would it be easier to relocate the bolts in the fibreglass? It might be more work!
I wouldn't be impressed with that.

FYI: Stage21 calls them "Hoods". Google searching "+Stage21 +bonnet" isn't as productive as "+Stage21 +hood". I think "Hood" is appropriate for the subject title.

The fibreglass bolt relocation would be preferable but I have no experience with working in fibreglass. I think I will make the effort to look into this since there's plenty of boat supply stores here in Brisbane.

Based on other aftermarket hoods/bonnets I've heard experiences about (Garage Vary and Chaser's Scoote 2), I expected it to need some re-shaping and shaving which doesn't seem to be the case but the fact that the mounting bolts are out by 15mm is something I didn't expect.

geofiz · Postby **geofiz** » Sat Jul 30, 2011 6:08 pm

I have recently fitted the same bonnet to my NB, and had none of the problems you encounterd with fit left to right or front to rear. The only modification required was to slot the holes on the bonnet catch as the bonnet was sitting around 5 mm lower than required at the front.

Seems like it is luck of the draw with the placement of catch and bonnet hinge points.

Russell

bruce · Postby **bruce** » Sat Jul 30, 2011 6:59 pm

I imagine you'd have to drill/cut the mounts out and make new holes for them to be bonded into. All this without making a mess and destroying the outer finish.
Here's another idea - can you shorten the original hinges at their hinge?
Otherwise I would say 'slot' the original bolt holes, but there's not enough meat to do that.

Lokiel · Postby **Lokiel** » Sat Jul 30, 2011 8:57 pm

geofiz wrote:I have recently fitted the same bonnet to my NB, and had none of the problems you encounterd with fit left to right or front to rear. The only modification required was to slot the holes on the bonnet catch as the bonnet was sitting around 5 mm lower than required at the front.

Seems like it is luck of the draw with the placement of catch and bonnet hinge points.

Russell

What year and NB model is yours Russell?

Mine is a 2004 NB SE with an aluminium bonnet. I'm wondering if there were any differences between bonnets and their hinges across the NB models. It may me a matter of me simply installing a set of NB8A hinges?

Have you got any pictures of yours installed and did you cut the ventilation holes in the two side vent moldings?

Lokiel · Postby **Lokiel** » Sat Jul 30, 2011 10:31 pm

I'm starting to think that there are differences in NB bonnets/hoods because Stage21 in Japan have 2 versions of this bonnet for the NB: http://aero.auto-style.jp/index_aero.php?pkey=parts_free_word&limit_maker%5B%5D=STG&limit_car%5B%5D=4022&set=0&page=1&max=10

Looks like I have the wrong version for an NB8C

geofiz · Postby **geofiz** » Sun Jul 31, 2011 12:26 am

Lokiel,

No close up pictures on hand, but have a look at

http://mx5cartalk.com/forum/viewtopic.php?f=70&t=47948

Third photo down.

Lokiel · Postby **Lokiel** » Sun Jul 31, 2011 10:27 am

geofiz, based on the photo you referenced above, is your car an NB8A?

geofiz · Postby **geofiz** » Sun Jul 31, 2011 11:06 am

Yes is it, but I have an NB8B front clip (headlights and bumper) which is going on shortly. Before i fitted the FRP bonnet, I tried the NB8B front on, and the fit with the original bonnet was unchanged.
I can confirm the fit in a few eeks, when I put the new new front end on.

On a separate note, my bonnet has the two main vents opened, and I have noticed that the vent holes are located over the top of my radiator (42mm ASI). This makes suspect that they will not be terribly functional for under bonnet cooling / air extraction, but this was a secondary consideration when I obtained the bonnet.

If you are moving your bonnet back 15mm, this may be improved on your car.

Russell

Mr Morlock · Postby **Mr Morlock** » Sun Jul 31, 2011 11:29 am

seems like a poorly made product.

bootz · Postby **bootz** » Sun Jul 31, 2011 2:47 pm

geofiz wrote:Yes is it, but I have an NB8B front clip (headlights and bumper) which is going on shortly. Before i fitted the FRP bonnet, I tried the NB8B front on, and the fit with the original bonnet was unchanged.
I can confirm the fit in a few eeks, when I put the new new front end on.

On a separate note, my bonnet has the two main vents opened, and I have noticed that the vent holes are located over the top of my radiator (42mm ASI). This makes suspect that they will not be terribly functional for under bonnet cooling / air extraction, but this was a secondary consideration when I obtained the bonnet.

If you are moving your bonnet back 15mm, this may be improved on your car.

Russell

It would be best to ensure that the area in front of the radiator is isolated from the vent otherwise you will be taking air away from your cooling system. This would be counterproductive for you. It might pay you to block off the front vent totally and open out the rear vents.

It's pretty bizarre that they decided a functioning front vent was okay but moulded in fakes were sufficient for the rear. :roll: