S197steve

Hey guys, I think I can answer my own question but wanted to get some feedback from anyone with a bit more experience. Right now my car is in the 430rwhp range, with 3.31s, stock wheels and stock drive shaft. Those three components are all components I plan on changing out but as with most of us, my accountant (aka wife) won’t allow me to do all at once so I need to prioritize.

The wheels I want (TRMotorsport MT1 18x9.5) are significantly lighter than the stock 18” bullets I have on there now. By dropping about 7lbs on each wheel I know there will be some sort of performance increase but I’m not sure how much. I assume braking distance will improve the most, but how about acceleration? Will there be a seat of the pants improvement? Since I’ll be going to a wider/lighter tire I believe there should be a significant increase in mid-corner grip along with corner exit grip. Will a wider front tire hurt my turn-in feel and response?

The driveshaft and gears would be done at the same time, so I know I’d get fairly significant seat of the pants performance gain but I don’t think I’ll really get any real cornering benefits with these mods.

I’m striving to build a well balanced performance car, one that isn’t too biased towards track or strip but is a good combination of both. Right now my car is faster than most in a straight line but even with the Saleen suspension parts, it doesn’t handle nearly as well as many modern sports cars.

Assuming my ultimate goal would be to lower my lap times (don’t have any yet), will the addition of the TRMotorsport wheels help me gain a more poised and balanced car in the corners or would my money be better spent on the acceleration aiding mods such as the d/s and gears?

I currently drive the car daily (52 mile round trip) and hit the twisties a few times a month. I haven't done any trackdays in my yet (20+ on motorcycles though) but am planning on doing two with my dad over the next few months.

Thanks for any input you can provide!

Argonaut

I use to swap between 17" OEM and 17" 5Zigens (~19lbs) for the track. You can clearly feel a difference when you run them back to back. I can best describe it as the car feeling lighter on its feet - it just responds quicker. Does that mean lower lap times...maybe, but not much.

In general we like to say that other things held equal, wider tires have more grip and lower profile tires have better transitional response. But in reality tire behavior is vodoo science and these are gross generalizations. Grassroots Motorsports does lots of tire tests and it pretty routine to see wider tires offer more grip up to a point and then start dropping off. Its also common to see them with higher lateral G but lower course times due to feel. And - different tires react differently to changes in width or profile. So the bottom line is - its hard to say what a change to a wider tire will do for you. I ran 275 square on my Mustang and was happy with them. I also ran 255 square for a while and they were ok also (different, less sticky compound though). In Corvette's its pretty common to see monster rears - in the 315 to 335 range - and 275-305 fronts. So...its a crap shoot. More important than size is which tire you run. Track tires make a HUGH difference (I'm sure you know this from your motocycle days).

And of course I have to mention the obvious (at least to anyone who has done a few Track/AX days): $300 spent on training will lead to far lower lap times than $3000 spent on car modifications. Its always fun to watch an expert driver in a Miata catch and pass a less skilled driver in a Vette, Porsche, Viper, etc.

Have fun out there. To me high performance driving is the IT sport, I love it. For track days, if you haven't already done so, make sure your brakes are in order before spending money on other mods though.

Lil_Chef

^^ or a skilled mustang driver passing a Z06, boy i love the look on their faces when that happens.

+1 though, Driver mod = best investment ever

Menace

Steve, we're in a bit of the same boat. I want my car to just perform well in all aspects. I have never done any type of auto crossing or anything so I don't even know where to begin with that. Will I ever get into it? Maybe, maybe not. I know the wheel/tire combinaton that I went with probably isn't going to do well at the track, but on the strip I think it should do reasonable well... We don't have a bathroom scale so I wasn't able to check out the stock 17" cast aluminum compared to the new setup, but by feel they are considerably heavier all around. I expected that, and it was a balance between performance/overall looks that I decided on.

Philostang

So by now most of us are pretty familiar with the idea that "driver mods are the best." That gets said over and over, largely because it is TRUE.

I want to offer a twist on that though. Some mechanical mods offer a different character to the car that you in particular, as a driver, really find comfortable. If that happens, it's like getting a bump in the driver mod category, because suddenly your will and perception has changed (for the better). Thus, you end up faster (and may wrongly attribute it to an improved mechanical mod).

I suspect that different tire combos can be like this. Obviously when you go from street tires to a dedicated track tire, you're going to see improvements, but these are not the only sorts of changes or tweaks one can do with tire set up. In the end, there are many factors that are playing into the "crap shoot" Argo identified.

Also, since nobody mentioned it yet, if you're thinking of prioritizing straight-line/go-fast goodies and cornering goodies, go with the cornering stuff. You have plenty of power now, and your goal (a good one, I might add) of lowering lap times will be best served by whatever can get you the highest average speed, not highest top speed. For the math challenged (or those on a testosterone overdose), the mistake is to think horsepower = higher ave. speed. Wrong, wrong, wrong...and if you don't get that, come out to the track with Argo or I and we'll demonstrate it to you. I've dusted cars with far more power than I have (Cobras, GT500s drop like flies, Corvettes, Porsches -my favorite victim, and the shocker once was an Audi R8). All these guys can/do pull away from me like mad in the straights, and they were all forced to give me point bys eventually. Some of these car have great cornering ability, so really bad drivers are the culprit. Others had decent enough drivers, but they couldn't negotiate a corner, so all that fury was lost playing catch up. Cornering is king on the track.

Best,
-j

Sleeper_08

Back to your original post if you want to change the rear axle gears be careful on going too high on the ratio. It is dependent on the tracks you are running at but probably 3.73 is the highest you would want to go.

IMO for road course work replacing the driveshaft may not be worth the money.

Rubrignitz

Agreed on the gears. I had set aside the money to yank my 4.10's and go with 3.73's but now that fund has become a Fays2 watts link. Can't wait to get that puppy.

The 3.73's will have to wait for now but I definitely plan to get rid of the 4.10's in the next month or two. You have no first gear with 4.10's and traffic is challenging...at least with a manual. IMO 3.73's are perfect for daily driving and occasional track usage.

S197steve

Thanks guys, this is exactly the type of feedback I was looking for!

In regards to the driver mod, I know how important it is! I remember the first time I did a motorcycle trackday and thought I was the **** because I was a fast street rider. A few laps into my first session I was passed by one of my good friends... on the outside... with his left hand giving me the middle finger. :-) At that point, I learned how important it was to improve the nut behind the throttle. By the time I left the track scene (in 2009), I was riding in the advanced group on a street prepped 600cc Honda and was passing guys on full race prepped 1000cc bikes.

The downside is that while I'm sure some of those skills will transfer over to cars... I feel like I'm back down at the bottom of the totem pole, but want to make sure that I'll have a car set up that will help me the most. I don't want to use my HP as a crutch for respectable lap times.

Like a few of you have already said, I assume that since I already have plenty of HP, the gears & d/s wouldn't be as necessary because I'm not skilled enough to fully utilize the power I have now. That being said, it sounds like good lightweight wheels (plus wider rear tires) will help me get around the track faster (when I do finally get there later this year) more than small improvements in acceleration.

I'm currently using Hankook EVO Ventus 12 (255/45s) and they were a huge upgrade over the stock tires. I'd probably keep that same size for the front, but get 275s for the rear as I'd get the 18x9.5s on back.

Oh, and just as an FYI I do have new pads/rotors on tap as well... no use in going fast if you can't stop. :-)

Sleeper_08

Most of us our track our cars regularly use the same size tires and rims front and rear, even those with boost. As the Mustang is front end heavy in stock form and even worse when you add an SC and associated parts then you want to run a good size tire up front.

275s are popular and also 285s. If you run a tire this large you will experience tramlining on the street

http://en.wikipedia.org/wiki/Tramlining

Are your springs and shocks stock - if so you should talk to Sam Strano about the best options. He is very knowledgeable and a great vendor to deal with.

In my case I'm running Steeda Comp springs to handle weight of the SC and just switched from Tokico D Specs to Koni Yellow adjustable shocks/struts.

Also what is your front camber set to? For the track you want more than on the street.

As has been mentioned in other threads the more you mod your car to go fast on the track the less suited it is to use as a DD.

Argonaut

I'll second a couple of the above comments:

I had 4.10s in the car when I started tracking it. They are no good. The biggest problem is you'll lower your top speed. I forget what it works out to but with 4.10s your top speed in 4th is in the 130 range (5th is an overdrive and useless on a track). IMO 3.55 is the best gear for track use but 3.73 is ok. Kind of depends on what tracks you run.

The Stang is an understeering pig (in stock form) and putting bigger meats on the rear might very well make it worse. At one point in time I considered using smaller tires on the rear to try and loosen it up (don't laugh, there are more than a few cars that turn faster laps with the wider tires on the front).