I come to all you handling gurus for some advice!!

After spending most of Saturday blitzing the back roads around Austin and Marble Falls I’ve found a few shortcomings with the Mustang that I’d like to address if possible. I realize the car will never really be considered ‘nimble’ but I’d like to improve some aspects of the handling.

I’ve raced sportbikes on the track for several years so I’ll try to translate the lingo into car talk... :-)

1. So when I’m going into a corner a briskly (I’m on stock tires and suspension) I can feel the front end push a little bit. The turn in seems a bit vague, not as direct as I’d like it to be.

2. Once I get the car into the corner it seems to settle in and track quite well. However very minor steering corrections seem to unsettle the chassis rather easily. Also, bumps in the middle of the corner are never good, but the GT seems to ‘wallow’ or ‘jostle’ around the rear end when hitting a small dip or raise mid-corner.

3. On corner exits the car was great actually. I was able to do a little rear-wheel steering in some of the corner exits, but it certainly isn’t the fastest way around the corner. :-) I would like to be able to put the power down a little better as I tended to get some unexpected wheel spin a few times.

All in all, I was surprised with how well our “muscle car” performed in the twisties. I did definitely go a bit faster than is prudent on public roads, but I was always well within my comfort range. The nice thing is that I know the car has more potential when on the track.

I also found that this car seems to likes a more swooping arc around corners. I tried the slow in, fast out approach and that was fun… also the fast in, (brake hard) and fast out approach but that really seemed to unsettle the rear end and to be honest, I don’t like going fast into the corners on the public roads… lastly I just tried to set my speed at the start of the corner and then carry it all the way through and then accelerate out.

So, now that I’ve written a book on my impressions (sorry, no cliff notes) I’m looking for advice on what would be the best route for me to take suspension wise. This is my daily driver, but I’m going to start doing some trackdays around here and would really like to improve the handling some. Since it will be my DD, I don’t want anything hard core suspension wise or anything too pricey. Also, I can’t do it all at once… I’ll have to pace myself with these mods.

I know better tires will help, but I’m looking more for actual suspension bits… on my old racebike I dropped 6 seconds off my time at Texas World Speedway (and 4 at MSR Cresson) when I swapped to a high performance shock and fork internals. I’m hoping to be able to feel similar improvements with the car!

Any advice you all can provide would be much appreciated!!

 

At this point, all I know is that you have a GT (and I didn't see that on the first read). Stick? 17" or 18"? Tire make/model? Inflation pressures?

But for starters, struts & shocks. Consensus on choice is Koni adjustables, D-specs, anything else (in that order). Tire choice/inflation pressures and wheel width relative to tire size will affect turn-in.

Don't forget - it's a 3500 lb car on a 107" wheelbase with 235-width street tires. IOW, it's naturally going to be better at sweepers than slaloms and other extreme transient maneuvers.


Norm

 

Hey Steve,

Actually, I like your account simply for the fact that it nicely details the kind of thing people should be paying attention to when they try out the OEM set up. The gurus will chime in soon, but I did want to suggest spending some time with the search function. Your experiences are very common, and a good deal has been written here on appropriate fixes (and explanations for the causes to the shortcomings you witnessed).

I would recommend looking for F1Fan's write up of the S197 chassis. He posted it in eight parts, it is very thorough, and it will give you a nice foundation on which to start planning your mods. I tried just now finding it quickly, but I'm not sure where it went. I do have a copy (dated 9.15.07) I saved to a Word file, but you might want to PM him for a direct link. Personally, I think it should be a sticky.

Norm has already made contact, so you're in very good hands.

Best,
-j

 

Thanks for the replies guys, I did try the search function but it always seems to come back with random stuff... It seems easy to me, but for some reason I can never find what I'm searching for!

Norm, I didn't put any specifics about the wheels/tires as I assumed my signature pic and noting that I was on stock tires was sufficient. Also, my tire pressue was 32psi cold. I didn't check it at the end of the run to see what it was hot, but I assume an increase of about 4-5psi. I have a manual, is there any other option :-)

 

RIght now, I'm on my work computer, and many if not most pictures don't make it past the corporate nanny. Point being that while I know what my 235/50-18's on 8.5" wide wheels with my choice of inflation pressures (NOT 32/32, BTW) feels like during an extreme road debris avoidance maneuver, that probably differs a bit from your setup if you're on 17's at different pressures.

About the tranny? I'd rather ask than guess wrong, and the type itself probably says something about the way an individual is likely to drive (or at least indicate what the car itself might be doing to you).

I'm assuming that Brenspeed is reference to a tune. If so, is it oriented toward the dragstrip or to a more responsive "feel" on the street?


Norm

 

Oh ok, I'm at work too and apparently we don't have as strict a 'net nanny' as you all have. :-)

I am on 18s as well and my tire pressure was set at 32 because I had a 190 mile drive out to Austin and didn't think to drop the psi down a bit before we took off to the twisties. In hindsight, I probably would have lowered them down 30 front and 29 rear.

As far as the tune, I assume that it's drag biased as that seems to be the desire for the bulk of Brenspeed's customers from what I gather. I am currently running the 93 tune and it has a significant kick in the pants around 3,500rpms... so I tried to keep my rpms up over that point all the way through the corners and out the corner exits. I didn't want to get hit with that 'punch' while exiting out of a turn... sort of like avoiding the point where boost kicks in for those turbo guys.

Lastly, I did do a good bit of the left foot brake and right foot throttle technique (two footed driving) and made sure to match revs on my downshifts... the nice thing about going fast around the corners and going slow in the straights is that it allowed me to do most of the necessary braking through shifting. Only a few times did I need to brake going into the corners... that sort of entry speed just isn't needed on public roads IMO.

I tell you though, coming from so many years riding on the track... it was difficult to resist the urge to take the 'racing' line through the corners (even though it wasn't race pace).

 

Sounds like you've been bitten by the bug.

Some of us, see my sig, have a real bad case and my car is a year round daily driver!

Probably the single most important upgrade you could make is tires. Not sure about your weather down there but if it gets too cold then you would need another set of tires for the winter.

The S197 chassis is pretty good out of the box but with the right mods can be downright awesome - even with a solid rear axle.

If you are going to run the car on road course track events one of the first things you should probably consider, depending on the tracks you run, is upgrading the brakes with better pads, DOT 4 fluid and SS lines and a brake cooling kit.

 

I definitely share your assessment of our stock handling. Push, wallow, and twitchy in the rear

Here's some advice I gave out to a guy on our local board:

If money is a concern, here is the basic order I'd go in:

1. Wheels/tires (unless already done)
2. UCA and LCAs (if need to fix wheel hop)
3. Single adjustable dampers (Tokico D-Specs or Koni 'Yellows')
4. Performance springs, camber bolts or plates, adjustable pan hard
5. Rear sway bar.

When you get to the end of this list (plus a good alignment) you should have 'on rails' handling you are looking for.

 

I did 13 track days and inumerable AX runs last year and to tell you the truth I never could dial that understeer out. So I just learned to adapt to it. It actually means you can completely toss the car into a corner and be confident you will come out heading the right way. I have Eibach pro springs, D-specs, camber plates and chrome moly LCAs, UCA and PHB. If I were to attempt to get the car a little more neutral my next step would be an adjustable rear sway. On a near stock power level GT, doing a handling upgrade in stages, my list goes like this: 1) better tires, the widest you can fit on your rims something like Nitto 555, NT05 or KDWs or even Falken 615 (all sticky street tires). 2) Aggressive alignment with a 0 toe and -2 camber (your turn in will improve quite a bit). This amount of camber will mean you'd need bolts or plates. 3) Dampers and springs - do them together to save time/labor (springs are cheap). 4) adjustable PHB. 5) Control arms. 6) adjustable rear sway.

Oh yea - as I'm sure you already know (coming from the bike world), the true #1 handling upgrade - hands down, by far is seat time.

Like Sleeper points out - if you are heading to the track, upgrade your pads and fluid. This is a heavy car and you can quickly toast stock brakes on a track.

HTH, Brad

 

If you're looking to take the Stang out to TWS, the first thing you need are new pads and fluid. My first time out, I boiled my fluid during the second session and used up about 1/4th of my stock pads by the end of the day. It's a high speed track (as I'm sure you know) and stopping a 3500lb car from 130mph isn't very friendly to the stock brakes. I've got Steeda's rear sway bar and I feel like it helped push the bias more towards oversteer than understeer, I didn't feel it push much at all at TWS except for The Carousel (Turn 10), but Turn 9 (off-camber) brought my back end around on me once. My next step is Konis, they supposedly eliminate a lot of the wallowing feeling and twitchiness in the rear.