S197 Aero?

[BOSS302r013]

Looking for aero for a 2013 S197 BOSS 302R.

Belly pans(more then stock)
Rear diffuser
Wing upgrade

Thx in advance.

JT

 

[VoodooBoss]

I’d start by following what’s on the 302S.

https://performanceparts.ford.com/boss-302/

 

[BOSS302r013]

Thx Rick.

Currently have 302S wing with large end plates & a splitter that goes back under engine.

Looking to upgrade. AJ Hartman has awesome aero but I was wondering if any of you guys knew other options.

Thx,

JT

 

[Fair]

If you have the 302R/S aero, that's a good start, but everything can be improved upon.



Belly pans or flat bottom panels are illegal in some racing series. NASA has a big penalty for ST/TT cars that use flat bottom panels between the front and rear axle center lines. Banned in American Iron also. A big expense for minor gains in drag, and they only add rear df when paired with a diffuser.



Rear diffusers are worthwhile, especially if you cannot get enough rear downforce with a wing (some classes ban wings or limit them greatly - Optima series has some classes where this is true). Again, a fairly large expense to do something that is properly built and actually generates some downforce. They can also limit your ground clearance and trailer loading ability, when made correctly. The stuff AJ Hartman is making is pretty damned slick.



Wing upgrade might be the best idea the OP listed, as the 302S/R wing is fairly low mounted. It is a decent wing. Maybe if you mount a longer chord element higher relative to the roof, and further behind the car, which improves efficiency. Again, AJ Hartman has a great wing to use.



Front Splitter upgrade: You should be able to make more than enough rear downforce with the 302S wing to over power the plastic LS faux-splitter's ability to match with front df. I am not a fan of the plastic LS front splitter used on the 302S, and would look at this area FIRST. It is made for looks and little else.



A longer splitter (not made of ABS plastic) that extends at least 6" from the lower bumper section is a good start. You can also add some dive planes (AJ Hartman units shown) as well. It is really hard to match the front df to a wing's rear df component on a sedan/coupe type car. To do so the splitter needs to be HUGE. Again, 302S were made for a series where they had to use a homologated OEM street car piece, and it is not a very effective. The splitter should go back to at least the front axle centerline, and as I've always said: if you cannot stand on it, then the splitter either isn't making enough downforce to matter -or- its going to rip off at speed. A vented hood will help improve the efficiency of the front splitter, too.



So that's my two cents - you probably have a decent wing but mounting it higher will help. Belly pans are expensive and not legal or worthwhile for most racers. Rear diffusers are expensive and add some complications, but can work if you get pretty wild with the design. But improving front downforce by replacing the plastic LS splitter with a real motorsports splitter is probably the area where you can find the most track time gains, and where I'd spend my time and testing.

Cheers,

 

[Grant 302]

Front Splitter upgrade: You should be able to make more than enough rear downforce with the 302S wing to over power the plastic LS faux-splitter's ability to match with front df. I am not a fan of the plastic LS front splitter used on the 302S, and would look at this area FIRST. It is made for looks and little else.

To do so the splitter needs to be HUGE. Again, 302S were made for a series where they had to use a homologated OEM street car piece, and it is not a very effective. The splitter should go back to at least the front axle centerline, and as I've always said: if you cannot stand on it, then the splitter either isn't making enough downforce to matter -or- its going to rip off at speed.

Nice post, but I disagree with a few of the parts in bold above.

There's nothing wrong with ABS for splitter construction. JMO. I like that it doesn't permanently deform with light ground contact.

And while there's nothing wrong with making aero components that take a human sized point load, it is absolutely not required for aerodynamic structures. Single digit psi loads are all that matter and none of us are that light.

It is really hard to match the front df to a wing's rear df component on a sedan/coupe type car.

This is absolutely true. But the single most effective thing you can do for a splitter is to mount it lower with spacers or lower the front end. As low as you are allowed for class or organization.

 

[Fair]

Nice post, but I disagree with a few of the parts in bold above.

There's nothing wrong with ABS for splitter construction. JMO. I like that it doesn't permanently deform with light ground contact....

But the single most effective thing you can do for a splitter is to mount it lower with spacers or lower the front end. As low as you are allowed for class or organization.

I will agree about mounting the splitter low to the ground, to a point. This was an extreme 10.25" extended lip version we tried for a short while. With the ducted hood, blocked off upper grill, and weak APR rear wing we had an aero imbalance - too much front df. Hard to do, but it can happen. And loading this thing onto a trailer was WORK that involved 12' long race ramps and a 6' rear ramp on the trailer.



But I will disagree about ABS plastic material used for splitters. I'd love to see one this big made from ABS. Even with the splitter struts I suspect it would come apart above about 120 mph. I've seen the actual LS splitter rip off at speed - one came off a customer's actual Boss302 LS at TWS at 140 mph, and I spent the afternoon repairing his front nose enough to allow him to drive home. They deform so much at speed that they can rip through the mounts, but they are so short (ie: they make so little df) that its not usually an issue.



For a budget splitter you can make at home, plywood is a better choice. You will still see plywood splitters in pro race paddocks, too. We've made a number of them from wood, including this Pikes Peak race car (for abrasion resistence - it was scraping the ground on the weirdly shaped roads up that mountain) and our E30 V8, which we "built for $2000" for the GRM Challenge.



We made the Subaru splitter with an aluminum under stricture and a serious air dam.



That splitter survived two years of abuse going up that mountain. The E30 splitter had #ExposedStruts holding the leading edge up, and an aluminum air dam to fit between the E36 nose and the splitter plane. It was very modest and could have been several inches longer, looking at this in restrospect...



Again, we just don't see ABS splitters used in any real race series, other than the rare homologated cars like the 302S. Too flexible. Splitters are usually made from carbon, plywood, or aluminum plate.

Cheers,

 

[Grant 302]

I agree that two 1/4-20 countersunk screws are a bit skimpy in ABS for pullout. That alone doesn't make ABS inappropriate for race or track use. It does deform under load...so does everything. Mine is slightly larger than an LS splitter and certainly bigger than the WC one. I've had it over 120 regularly and up to 150 at Auto Club. On it's first use at MRLS, I did check pictures for deflection and it does look like about ~3/4" at the unsupported corners. About what I was expecting when I checked it statically using just my thumb.

I would say that ABS isn't cost effective nor is it the best material for a splitter. But I don't think anyone here should hurry to ditch theirs if they have one. I do recommend putting in some Longacre washer/grommets between the screw heads and the ABS to prevent pullout. Like these:


...even if for peace of mind.

-----------

One more thing I would consider to improve DF on a splitter (if allowed)...are endplates or fences.

 

[Grant 302]

Deflection on my ABS splitter From the first use in May '15:

That picture also reminds me...

On that drive up to Salinas on the 101, the splitter and part of the lower facia hit a chunk of concrete (maybe a rock) on the road. I swerved right but didn't miss it. I think it actually might have literally 'split' whatever it was that it hit...causing the broken part to hit the facia. Either way it took it pretty well and just left the light spot to the right of the pair of red lines for the estimated deflection. I doubt many other materials would have fared as well that day.

 

[modernbeat]

Splitter deformed enough that it touched the ground, pulling it off the bumper.