has anyone found good aero pieces?

[_M_]

specifically looking for a front splitter and rear diffuser?

I think the rear diffuser on GT500s is functional, any ideas where i can get one on the cheap?

[danbev07]

I'm pretty sure the GT500 one isn't a functional diffuser, but looks like one.

APR Performance has an aero kit for our Mustangs. If you've got $4k to spend it might be a good way to go... heh.

http://www.aprperformance.com/images/zoom/DEEMFU/viewsize/IMG_2523_copy_cr.jpg

http://www.aprperformance.com/images/zoom/DEEMFU/viewsize/IMG_2540_copy_cr.jpg

http://www.aprperformance.com/images/zoom/DEEMFU/viewsize/IMG_2547_copy.jpg

APR can also make a customized diffuser for you if you give them a cardboard template of the projection showing the bottom of your front bumper. I believe they have a splitter ready to go for the CDC chin spoilers as well (similar to the ones on the FR500 cars)

[_M_]

i saw that earlier today. i may just order the rear diffuser...not wanting a widebody kit like that.

im going to call them about the splitter as well. im surprised they dont have one ready to go for the GT

[danbev07]

They make an air dam for stock GT fascias, to which you can have a splitter mounted.

I believe there's too much of an opening on the bottom-center of the front fascia to fully utilize the splitter.

[_M_]

thats a good point

[Bizzyb0nes]

they have a splitter which looks exactly like the steeda/3d carbon splitter. The diffuser isnt bad and looks nice in a race application...but looks to be far to much for a street car imo

[marksti]

I have the APR diffuser on my car..The part looks nice/fits well and was easy to install

On the front i have a Steeda front lip..which is nice...But I'm sure the APR unit ( I think they sell it in two sections...splitter/lip) would offer more down force.

I would also look into APRs or prehaps Roushs rear wings..

[_M_]

the diffuser looks to be a nice piece and really the only functional one out there. i kinda surprised steeda doesnt offer anything

[SoundGuyDave]

I would think really hard about the "functional" part of it... The purpose of a diffuser is to blend the low-pressure/high-speed airflow from under the car back into the high-pressure/low-speed airflow from over and around the car. There are a few problems relating to this that are present on the S197 chassis. First off, without properly designed and implemented underbody aero (smooth/channeled belly pan, effective side-skirts), there is no coherent flow under the chassis for the diffuser to work with. Second, the diffuser's length would have to be longer than the space available between the axle and the rear bumper cover to be effective. Therefore, the diffuser cannot be functional in any real, meaningful way.

[_M_]

I would think really hard about the "functional" part of it... The purpose of a diffuser is to blend the low-pressure/high-speed airflow from under the car back into the high-pressure/low-speed airflow from over and around the car. There are a few problems relating to this that are present on the S197 chassis. First off, without properly designed and implemented underbody aero (smooth/channeled belly pan, effective side-skirts), there is no coherent flow under the chassis for the diffuser to work with. Second, the diffuser's length would have to be longer than the space available between the axle and the rear bumper cover to be effective. Therefore, the diffuser cannot be functional in any real, meaningful way.

interesting. i can see that and understand/agree with what youre saying.

what is your knowledge around an effective front splitter such as the steeda piece? good or little to no help?

[marksti]

.........

[marksti]

Therefore, the diffuser cannot be functional in any real, meaningful way.
MMMM...If nothing else it will prevent the rear of the bumper as acting like a parachute slowing the car down a high speeds.....i don't know about your car..but there are straight aways around here that a decent car will hit 140+ mph

The apr diffuser is fairly large you could say...it does take up the gap and does cover the evap system/rear bumper cover.


With that said..I don't think AERO upgrades are a good idea (not cost effective) for most people that are running "stockish" cars...Money is better spent on suspension/brakes/chasis/power mods at that level of speed.

[SoundGuyDave]

Marksti: On your final comment about "stockish" cars, I agree 100%, the aero package should be the final icing on the cake, when you're trying to wring the final 10th or two out of a lap... Up at Road America, there are three spots on the track where I break 140, and the math says that I'm hitting around 150 going into the breaking zone at turn 1. At that point, I can feel the car trying to push through the air and failing... More horses needed... I still maintain that the diffuser discussed, AS A DIFFUSER, is a straight ahead fail. If you want to call it a belly pan behind the rear axle, then yeah, I will certainly buy your argument, as my GT/CS fascia has had the center support tab ripped apart from aero drag. As a functional diffuser, however, not so much.

__M__: Echoing what Marksti was saying, until you have your suspension and chassis tuning sorted, I would put aero bits on the back burner. Answering your question specifically, I would ask exactly what you're trying to accomplish with the splitter.

There are two main purposes that a splitter fulfills, 1) start the underbody aero chain by creating the low-pressure/high-speed flow path, and 2) to add additional downforce to the front of the car. Since we can kind of rule out 1) as damn near impossible with a production chassis S197, that leaves 2) as your desired target. If your car is handling well in low-speed turns (below 50MPH at turn-in, for sake of argument), meaning neutral to a touch of over-or-under, as determined by driver desire, but it's pushing on the higher-speed corners, then you have a viable candidate for a splitter to add downforce to the front, giving you more grip and eliminating the understeer issue. Then all you have to do is design and mount your splitter... Shoot for 2-3mm clearance off the track at threshold braking (use rub-tabs to measure your clearance), strong enough when mounted so that you can stand on the leading edge of the splitter and not have it deflect, and have it extend under the chassis at least as far as the front axle centerline. Now, experiment with splitter height, and splitter length (projection forward of the air dam/fascia) to tune the handling characteristics at speed. Oh, and when you design your mount, you're going to want to intentionally integrate some form of breakaway, so that if you do any form of agricultural driving, the splitter itself will be the failure point, and not get shoved back into the tires or suspension bits. Yes, you need to plan on your "machinery meeting the greenery" at some point, which will wipe out the splitter for sure, so you want to figure out how to do a quick swap to your spare... That means having mounts that aren't tweeked, and making sure that the splitter hasn't rendered your car undrivable when it failed. You want it really strong, but just BARELY strong enough...

[_M_]

thanks guys for the info. im looking for that little final touch on the car now. realistically my car is primarily street driven but im looking to finally start hitting the track on a more regular basis. Just moved to Nashville so i have to find out whats going on around here.

My car is a realtively heavy build. Mix of steeda and saleen suspension, JDM stroker, KB s/c, brakes, exhaust, T-56, trutrac, and all the accoutrements. I think the car feels amazingly stable at speed now, but just looking for that final touch to help in areas I may not be aware of (still learning), and the front end stability at high speeds seems to be an area of focus.

[SoundGuyDave]

Hold off on the aero stuff until you get all the rest sorted... Seriously. Learn how to "turn AND burn," extracting every last 10th from each corner before you start working on the car any more. With that much power, it's really easy to cover bad driving with sheer acceleration once you get the car straight. Once you really know how to handle a corner (trail-braking, throttle steering, all right at the edge of traction), start analyzing the car's behaviour under different types of corners. increasing/decreasing radius, hairpins, double-apex, chicanes, kinks, carousels, and all variations on- and off-camber, and can blow through them with solid consistency, you really won't know where the shortcomings of the car are. Your comment about front-end stability at high speeds may well be related to spring rate, alignment angles, damper valving, or even the way the REAR suspension is set up... How much anti-squat do you have dialled in out back? Are you lifting the nose under accel, and THAT is making the car feel "greasy?" What tires (brand, model, size, condition and pressure) are you running? What are you static alignment angles?

I think you get my point... I'm sure that I sound like a broken record, but driver first, car last... The better YOU are, the better your car will be, and when there is a weak spot found, you will know with confidence what the issue is, and how to fix it.

Understand that I'm NOT trying to demean your skills, since I have no idea of your track history, but it's solid advice for relatively inexperienced drivers. If you're up to the level where you intentionally use trailing-throttle-oversteer to get the car rotated in the corner, then that's a different matter, and it really comes down to getting the chassis dialled in first, then touching up with aero. Think coilovers with a selection of spring rates, DOT-R tires or slicks, you've done the chassis analysis and optimized all your angles (camber/caster/toe, roll centers front and rear, A/S%, etc.), dialed out bumpsteer, plotted your camber-gain curve, and know how your slip-angle relates to the tractive capability of the tires... My brain hurts just typing this...

For solid info in the area, try HERE (http://www.nasa-southeast.com/) first...

[marksti]

Soundguy sounds like a true racer....start with the driver :)

[SoundGuyDave]

"...Oh he can drive. He can drive beyond the limits of the tires, the engine, the car or anything else!"

Yup, start with the driver... Now, the driver that understands what the suspension, the tires, and the aero are doing to the car, now THAT'S a deadly combination! Put you or me into a Nextel Cup car, and we'll get flat run over, but put Boris Said in ANYTHING, and he'll have a shot at the podium. That's the difference!

[_M_]

cool thanks guys.

are either of you aware of anything going on in the nashville area, or groups i should contact?

[EagleStroker]

Get in with the SVTOA-Nashville chapter, they have a site just google it, local car guys will help you find local car events!

[marksti]

I just got my Moss Mustang flyer

Cobalt which is Moss' house brand came out with under car aero shield/splitter

It bridges the gap between the front bumper and factory frame and makes it nice and smooth..which should streamline under car aero alittle

Its stainless steel and costs about $270

[ZmanM3]

I just got my Moss Mustang flyer

Cobalt which is Moss' house brand came out with under car aero shield/splitter

It bridges the gap between the front bumper and factory frame and makes it nice and smooth..which should streamline under car aero alittle

Its stainless steel and costs about $270

Got some pictures?