Aero with and without a square wheel setup ??

[HISSMAN]

So, I currently am running a 11.5" (305/19) rear, and 10" (285/19) front setup. I've been running courses like Mid Ohio (Summit and Shenandoah). I've fixed a lot of the oversteer with suspension geometry, and of course a slightly wider rear. Now, I have a APR GTC 200-Drag wing sitting under the tree for Christmas.
So, with that much wing on the rear, compared to no wing, with the wider rear tires will in in effect unbalance the car in the other direction? I just hate having to buy another set of wheels and tires at this point. I do have the APR front wind splitter that I can adjust to gain more front end, but not by much in the slower corners as it just isn't large enough?
I'm only a couple years into doing this, and still learning a lot, so please don't make too much fun of my questions if they are purely ignorant..:doh:

Thanks!

:cheers:

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[Elgyn]

You might be surprised at how much down force a wing doesn't do. Most aftermarket wings(or areo mods) are for looks and any of the actual race wings don't do much below 100mph. There's a few good youtube videos(with the maths) that are worth watching.

 

[HISSMAN]

That is what I am hoping.

 

[Austinj427]

I think with that wing it might be noticeable, but probably only in the faster sweepers. It's not as stupidly massive as an ACR wing, but it's at least adjustable.

Next time you hit the track with it on, play around with it. Start out with the least amount of down force and if you can tell it's forcing the car to push, add some more chin splitter.

 

[Grintch]

That is what I am hoping.

Your hoping the expensive wing you just bought doesn't do much?

 

[wildcatgoal]

Not going to notice anything from that in slower corners (or a front splitter).

You don't need to change your wheels. You need to balance your aero and adjust your sway bars (if you have the ability to). Play with adjustments on this "wing" too.

Two points for thought:
One friend has one of these and had it basically as straight up and down as it'd go and then adjusted relatively flat and did back to back 1/4 runs (3 each) and got faster times every time with that wing in a flatter position. Thus, when it is adjusted flat, it is probably reducing drag as it's primary efficacy. For Road Atlanta, I'd probably opt for flat or close to it. For Atlanta Motorsports Park (slower, technical) I'd be more vertical.

Another friend had one of these before the larger APR 300 wing and had it set somewhat more vertical than not and found that it dented inward on the trunk lid toward the back of the mount and was kind of unscathed up front of the mount. So, that tells you there was some downforces happening almost pushing the backside of the mount and pulling the front side of the mount. IMHO, the mounts aren't big enough for what is, evidently, a functional piece. That said, he regularly is >100 MPH. This never happened until repeated 100 MPH runs (road course, street racing, no drag racing).

 

[ddozier]

So, I currently am running a 11.5" (305/19) rear, and 10" (285/19) front setup. I've been running courses like Mid Ohio (Summit and Shenandoah). I've fixed a lot of the oversteer with suspension geometry, and of course a slightly wider rear. Now, I have a APR GTC 200-Drag wing sitting under the tree for Christmas.
So, with that much wing on the rear, compared to no wing, with the wider rear tires will in in effect unbalance the car in the other direction? I just hate having to buy another set of wheels and tires at this point. I do have the APR front wind splitter that I can adjust to gain more front end, but not by much in the slower corners as it just isn't large enough?
I'm only a couple years into doing this, and still learning a lot, so please don't make too much fun of my questions if they are purely ignorant..:doh:

Thanks!

:cheers:

You may not want to hear this but you are missing one of the biggest advantages the Mustang has when looking at tire wear. You really should consider a square setup when you purchase your next set of tires. A properly managed set of tires will last considerably longer when you have the ability to move them front to rear as well as side to side. If you do a lot of track days this will pay for your wheels in a season with the savings from tire life.

It is interesting to me that you are having an issue with oversteer, without knowing your entire setup its hard to say what might be the issue. My experience has been that the rear is very locked down on my setup and I have been working on front grip since day one and I only have the GT350R rear wing with a 3" front splitter. I have after two seasons and many many spring changes feel like the car is fairly neutral with a hint of driver induced understeer and the rear end is virtually locked down even at my 425whp level.

If you have time and want to list out all your changes from stock as well as your intended use for the car I may be able to point you to a few things to try first. It is a very good idea to get the mechanical grip sorted to your driving style prior to adding Aero mods to the mix. It is important to understand what the car is doing or not doing before you add another variable like aero.

Dave

 

[HISSMAN]

Your hoping the expensive wing you just bought doesn't do much?

No, just hoping that it doesn't upset the balance too much.

 

[Eritas]

Tell Santa to make you a 250 instead. APR's 200-300-500 series wings are complete crap. Very draggy and don't make that much downforce. The straight (2D) 250 wing is one of the best wings to come from them.

Keep in mind that when a wing is parallel with the ground, it probably has a true 5-7* angle of attack due to the angle of the airflow over the car. So a true "0*" AOA would be achieved with the leading edge raised 5-7*. Most wings at the track and especially the street are stalled, with over 15* AOA (relative to the ground) so they're probably well over 20* relative to airflow.

Wings do make a difference at lower speeds (60mph), just adjust your alignment and swaybars accordingly. You don't "need" a splitter, but a small 2-3" splitter wouldn't be a bad idea.

 

[Rumbloki]

I have after two seasons and many many spring changes feel like the car is fairly neutral with a hint of driver induced understeer and the rear end is virtually locked down even at my 425whp level.

Dave

Did you try simple spring kits before going to coilovers? If so which ones worked best for you?

 

[ddozier]

Did you try simple spring kits before going to coilovers? If so which ones worked best for you?

My build started with coil overs as I knew I would be changing a lot of things and wanted as many options as possible. After about 4 spring changes in the rear alone and another 3 changes in the front I finally feel like I have the setup that suits my driving style. Had many alignment changes and bar changes as well to get what feels good to me. The changes I made were fairly far from stock rates and are only really suited to a track only setup, they would be brutal on the street.

Dave

 

[JohnD]

It is interesting to me that you are having an issue with oversteer, without knowing your entire setup its hard to say what might be the issue. My experience has been that the rear is very locked down on my setup and I have been working on front grip since day one and I only have the GT350R rear wing with a 3" front splitter. I have after two seasons and many many spring changes feel like the car is fairly neutral with a hint of driver induced understeer and the rear end is virtually locked down even at my 425whp level.

This.

I have 285s front on 10s, 305 rear on 11s and so far in my time on track there is no way I can make this car oversteer without doing something intentionally off the wall. It's more likely to get loose on braking than under power. It's final steady state corner balance is push (understeer). I believe Ford set the PP suspension up to understeer at maximum grip since understeer is easier for the average driver to deal with than oversteer, and for that reason I kept the same stagger front/rear as Ford had. Makes for a very forgiving, easy and enjoyable to drive quickly car. I also have found the tire wear to be very even on all 4 tires and at the moment I'm not too concerned about rotating tires.

 

[Norm Peterson]

So, I currently am running a 11.5" (305/19) rear, and 10" (285/19) front setup. I've been running courses like Mid Ohio (Summit and Shenandoah). I've fixed a lot of the oversteer with suspension geometry, and of course a slightly wider rear.

I think we need more information.

Where on those tracks are you getting into "oversteer" and what are you doing with the controls (especially the pedals) at that instant? Of your tracks, I'm only slightly familiar with Mid-Ohio. But somebody here ought to know a bit about the others.

What suspension geometry changes have you made? Any big power mods?


Norm

 

[Competition Orange]

what kind of times are you running at mid ohio?

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