HopmanJones
HopmanJones Reader
8/15/22 9:45 a.m.

Anyone here have any experience with the skidplate from Pro Shop Noble? It seems to offer better coverage than the Paco skidplate  

https://proshopnoble.com/products/pro-shop-noble-na-nb-mazda-miata-skid-plate

 

engiekev
engiekev HalfDork
8/15/22 10:38 a.m.

No input from me but that looks like a really nice piece for the money, raw metal cost is way up.  What is the thickness? Ideally 3/16 minimum if it is aluminum.

Keith Tanner
Keith Tanner MegaDork
8/15/22 10:44 a.m.

Interesting. Here's what I see...

Pro Shop Noble.

1/8" steel. Four mounting points, fairly far apart so structurally it's not as strong as it could be. Goes far enough forward to shield the steering rack but is unsupported in that area so it would bend easily from a hit in that area. No ventilation so there's no cooling of the oil pan. Most of the increased coverage is covering areas that aren't vulnerable, like the subframe.
I'd call this the better choice for aero and for keeping mud out, but I don't think it'll withstand the same hits as the Paco and I would expect to see a decrease in cooling.

Paco Motorsports. Ignore the big V thing, we're just talking about the panel under the engine.
3/16" aluminum, which should be stronger than the thinner steel. More mounting points that are closer together means it's also going to be more robust on hits. It doesn't cover the steering rack. It may actually increase chassis rigidity given the rear mounting point locations and style. Cooling slots to get some airflow over the ribbed oil pan. If I'm remembering right, it'll be compatible with the factory undertray as they don't overlap.
Not as good for aero, better for impacts, better for chassis stiffness, will not keep mud out.

engiekev
engiekev HalfDork
8/15/22 11:37 a.m.
Keith Tanner said:

Interesting. Here's what I see...

Pro Shop Noble.

1/8" steel. Four mounting points, fairly far apart so structurally it's not as strong as it could be. Goes far enough forward to shield the steering rack but is unsupported in that area so it would bend easily from a hit in that area. No ventilation so there's no cooling of the oil pan. Most of the increased coverage is covering areas that aren't vulnerable, like the subframe.
I'd call this the better choice for aero and for keeping mud out, but I don't think it'll withstand the same hits as the Paco and I would expect to see a decrease in cooling.

 

Paco Motorsports. Ignore the big V thing, we're just talking about the panel under the engine.
3/16" aluminum, which should be stronger than the thinner steel. More mounting points that are closer together means it's also going to be more robust on hits. It doesn't cover the steering rack. It may actually increase chassis rigidity given the rear mounting point locations and style. Cooling slots to get some airflow over the ribbed oil pan. If I'm remembering right, it'll be compatible with the factory undertray as they don't overlap.
Not as good for aero, better for impacts, better for chassis stiffness, will not keep mud out.

I'm ignorning your ignore statement: please tell what the "big V thing" is and whatever it's supporting off the front end! 

Paco seems to be the way to go if you want to protect the pan.  What is the intended use case? If its SCCA RallyCross then you probably don't need anything at all, unless your region courses are insanely rocky, but the Paco would be nice for piece of mind.  If its Stage Rally that's a whole 'nother discussion.

HopmanJones
HopmanJones Reader
8/15/22 11:56 a.m.

Intended use is SCCA RallyCross. All my other cars have had skid plates and they always take a hit, so in my mind it's cheap insurance. I have observed on a lot of threads about rallycrossing miatas that people run without skidplates, which is very curious to me. I liked how the Pro Shop Noble version offered more coverage but also noted the weak mounting tabs. I figured if I got that one, I'd treat it as a starting point and weld on gussets/reinforcements to strengthen at least the mounting point areas. Since it's steel, that makes welding/modifying a little bit easier.

The Paco one seemed more robust but offered minimal coverage of the underside. I suppose if it's compatible with the factory undertray that would provide at least some level of protection from grime and dust.

I'm also curious about the big v thing. I could see that making a skid plate extension super easy by providing plenty of mounting points.

Keith Tanner
Keith Tanner MegaDork
8/15/22 11:59 a.m.

Mark Rivera aka Paco is a loon. The big V thing is a big push bar for his Miata. I don't think it ever made production, but I know it hit his FB page.
https://fb.watch/eW9ICuS8z7/ 

His designs are always interesting to me because he comes from a sheetmetal world, so he almost never uses tubing in his designs. He and I will often come up with very different solutions to the same problem because of that.

I'm not convinced the extra "coverage" of the Noble one is worthwhile. It's mostly just covering the thick steel plates that are the subframe, and it's weaker than they are :) It looks bigger but it's not actually doing anything with that size. That's why I'd choose it for aero (because air cares) but not for protection (because rocks don't).

Keith Tanner
Keith Tanner MegaDork
8/15/22 12:05 p.m.

Here's what the subframe looks like from underneath - the front is at the top of the picture, those are the rack mounts at the very top. The Paco brace covers what's inside that cutout (ie, the engine). This is a late NB subframe from the looks of it but the earlier ones are very similar.

RevRico
RevRico UltimaDork
8/15/22 12:07 p.m.

I'm trying to remember what brand mine was. I thought it was Paco, but sure didn't look like the pictured one. Mine had rounded corners and no vents.

I wish I could remember so I could warn you not to buy it because none of the screw holes lined up with anything on the car, and one of them wa cut so close to the edge that putting a bolt through it broke it. 

Pretty sure I gave it to Slowbird, but I haven't seen her post much lately. 

engiekev
engiekev HalfDork
8/15/22 12:31 p.m.

For rallycross, 1/8" is probably fine as you're mostly trying to keep dirt/chunks from blasting the critical components, more than protecting against boulders from imploding parts like stage rally.  Lots of the stage rally folks run HDPE sheet in the rear to help debris/gravel "skip" across critical parts, its cheap and easy to replace.  Havent seen a lot of rallycross folks use it for skid plates though.

I ran my NA Miata which was on lowering springs at a rallycross and it was shoveling dirt with the subframe in huge 1-2ft ruts, nothing broke.

Keith Tanner
Keith Tanner MegaDork
8/15/22 12:34 p.m.

There are a bunch of metal replacements for the stock undertray out there from a wide variety of sources. I don't think any of them are strong enough to be considered skid plates.

I built this one for rally use. 3/16" aluminum (can't remember the alloy). It won't fit a stock subframe and maybe not a four cylinder engine. It's covered in scars now and I've hit it hard enough to bend the rear mounts, but the main plate hasn't deflected at all. 

There were UHMW pucks on the frame rails and under the rear diff, but that's more of a tarmac rally thing. Came in handy when my wheel came off at Laguna Seca, though, I just rode the UHMW instead of destroying the diff and cats.

I also had deflectors in front of the shock adjusters that protruded through the lower control arm.

Here's what happens when the wheel comes off at 80+.

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
8/15/22 5:24 p.m.

In reply to engiekev :

I smashed the oil drainplug off of Evan's NA driving over the banking at I96 in third gear * despite the 1/8" skidplate.  Ask Matt Wolfe about that one smiley

 Also comprehensively reshaped the skidplate on the gravel at Frostburg one event.  (Right between the second "berkeley" and the first "dammit")  It looked like it was wrapped around the rack.  But the intercooler and radiator were okay, which is what mattered.

 

* on 185/60-13 tires

engiekev
engiekev HalfDork
8/15/22 7:31 p.m.

I96 banking is a pretty extreme condition, even though its after the course ends, hah!  I'll have to keep that in mind for September event.

RevRico
RevRico UltimaDork
8/15/22 7:34 p.m.
RevRico said:

I'm trying to remember what brand mine was. I thought it was Paco, but sure didn't look like the pictured one. Mine had rounded corners and no vents.

I wish I could remember so I could warn you not to buy it because none of the screw holes lined up with anything on the car, and one of them wa cut so close to the edge that putting a bolt through it broke it. 

Pretty sure I gave it to Slowbird, but I haven't seen her post much lately. 

Found it, it was a Garage Star skid plate. Don't buy that one. 

HopmanJones
HopmanJones Reader
8/16/22 9:03 p.m.
RevRico said:
RevRico said:

I'm trying to remember what brand mine was. I thought it was Paco, but sure didn't look like the pictured one. Mine had rounded corners and no vents.

I wish I could remember so I could warn you not to buy it because none of the screw holes lined up with anything on the car, and one of them wa cut so close to the edge that putting a bolt through it broke it. 

Pretty sure I gave it to Slowbird, but I haven't seen her post much lately. 

Found it, it was a Garage Star skid plate. Don't buy that one. 

Perfect, thanks!

HopmanJones
HopmanJones Reader
8/16/22 9:14 p.m.

Thanks all for the input. I'll go with the Paco. 

Now I have a lot of reading to do on suspension. The car came with bilstiens with sleeves and eibach springs. Not sure what the front are yet but the rears are 350lb. 

engiekev your threads on my reading list. 

Keith Tanner
Keith Tanner MegaDork
8/17/22 12:22 a.m.

The spring rates are printed on the spring on Eibachs. If memory serves, it's length-rate-ID. 

HopmanJones
HopmanJones Reader
8/17/22 7:18 a.m.
Keith Tanner said:

The spring rates are printed on the spring on Eibachs. If memory serves, it's length-rate-ID. 

Thanks!

engiekev
engiekev HalfDork
8/17/22 8:01 a.m.
HopmanJones said:

Thanks all for the input. I'll go with the Paco. 

Now I have a lot of reading to do on suspension. The car came with bilstiens with sleeves and eibach springs. Not sure what the front are yet but the rears are 350lb. 

engiekev your threads on my reading list. 

I have been slacking on that project and need to do some more suspension experimentation. 

What kind of Bilstein are they? The Spec Miata Bilstein's are valved pretty stiff, need to be re-valved for rallycross.  Off-the-shelf Bilstein I'm not sure, I don't think anyone has really put them on a shock dyno and compared to Koni Yellow or similar.  Who has a shock dyno that we know :) ?

 

 

 

 

 

 

Keith Tanner
Keith Tanner MegaDork
8/17/22 9:11 a.m.

Spec Miata Bilsteins are normal aftermarket Bilsteins. If they're revalved, they're cheaters :)

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