NOT Another...Yes...another auotx build thread

[csamsh]

That would be the proper tire for that size rim.(My opinion) With the correct offsets - front & rear it will fit. Size of rear sway bar (Stock design) being the determining factor, rear shock design & 2.5 degrees of negative camber in front. Might be able to get by with 2 degrees depending upon actual / physical tire size and configuration of rim.
I made templates and have taken many measurements. Don't know hwat offsets Volshag gave you but measurements from one rim manufacture to another seem to vary quite a bit. I'm sure they got it figured out though. 10 percent more rubber is quite a bit of an improvement & need for these heavy boats / high CD beasts.

Yup I'm thinking 295/35/18 Rivals would go great on these wheels.

Planning on ~3 degrees

I have Whiteline bars so it's not a problem.

I don't the exact offsets that I have but they are different front and rear. Shouldn't need any spacers though.

 

[2008 V6]

Yup I'm thinking 295/35/18 Rivals would go great on these wheels.

Planning on ~3 degrees

I have Whiteline bars so it's not a problem.

I don't the exact offsets that I have but they are different front and rear. Shouldn't need any spacers though.

-3 degrees + for racing -2 for street

We were finally able to solve an ABS issue with our car so the driver can now enjoy proper camber. Before, anything past -2.4 degrees camber the ABS would kick in & hamper hard braking - Now running -3.3 on track & keeping the front tires happy. Soft springs & thick sway bars – the exact opposite from what it should be - but it’s used as a street car also.
Street tires 265 on a 9.5” rim.
The BFG Rival 295 - 35 would be a VERY NICE compromise for your rims
Yokohama AD08R 295 - 30 would be a GREAT choice too

 

[csamsh]

295/30 seems awfully short though...if I were considering that it would be the 315/30 Rivals.

Ideally...I just stick with 315/35 V710's!

 

[Vorshlag-Fair]

295/30 seems awfully short though...if I were considering that it would be the 315/30 Rivals.

Ideally...I just stick with 315/35 V710's!

Yea, the 295/30/18 is a short tire... 25.0" tall. That's 2" shorter than the stock diameter and the tires alone would lower the car a full inch. It would have lots of fender gap and effect the gearing, too.

http://www.tirerack.com/tires/tires.jsp?tireMake=Yokohama&tireModel=ADVAN+Neova+AD08

Early on when we were testing available 18x10 and 18x10.5" wheels (none of which fit the front and back without massive spacers or caliper clearance issues) we mounted up several 285/30/18 tires, as shown above. This is a 24.8" tall tire, so only two tenths of an inch shorter than the 295/30/18.

As you can see, they are so small they are comical. Absurdly short with a massive wheel gap on the blue GT with stock ride height. Even on the red car, which is lowered considerably in these pics, it looks silly.

Stick with tires in the 26-27" tall range for an S197 and you will be better off. The Hoosiers we run (315/30/18 in R6 or A6, shown above) are only 25.6" tall, which is still on the short side.

The Kumho V710 Mark mentioned above comes in a unique 315/35/18 size, which is 26.4" tall.... just right. We still use these from time to time (see above), but since Kumho has no NASA tire contingency... we end up on the HoHos more times than not.

Other common, better matched tire sizes for an S197 include: 265/40/18. 275/40/18, and 285/35/18.

Cheers,

 

[neema]

I don't know what tire or rules you guys are trying to stick to, but toyo/nitto make a 305/35/18 in the r888/nt01. That should work great with an 11" wheel.

or if you want a track tire, there's the rebadged hoosier/continentals in a 305/660/18 for $130 a piece (deal of the century!)

 

[csamsh]

I don't know what tire or rules you guys are trying to stick to, but toyo/nitto make a 305/35/18 in the r888/nt01. That should work great with an 11" wheel.

or if you want a track tire, there's the rebadged hoosier/continentals in a 305/660/18 for $130 a piece (deal of the century!)

Yeah 305/35/18 is perfect I think, but neither of those tires have a home in autocross. The NT01 and R888 aren't good enough for R-comp categories, and they are too good to be a street tire, by virtue of its treadwear. No-man's land, at least in the SCCA.

The slicks are pretty useless, I need DOT certification for autox. Come to think of it, you take a hit for those big Conti's in nasa tt also, as Terry now knows.

 

[2008 V6]

Yea, the 295/30/18 is a short tire... 25.0" tall. That's 2" shorter than the stock diameter and the tires alone would lower the car a full inch. It would have lots of fender gap and effect the gearing, too.



Never really cared about looks! Function over looks for us every time - Not trying to sell sticker space either - Tire OD affects gear ratio at different track configurations. We are low budget - Running a 4.10 rear ratio & a modified T-5 with a .80 final drive ratio. We would be pushing the RPMs by having to hold in 3rd & 4th with a 30 series tire if we wanted the quickest times at the drivers favorite local– not needed at this stage. Tire weight is also a factor – I do admit not much but everything helps. We are only doing HPDEs and don’t think that will change anytime in the near future.
Currently using a 265 – 40 AD08 on a 9.5” rim not for looks but because for us, at this stage of the drivers development, it is easier to read. Breakaway is much more gradual. Turn in is definitely not as quick as a lower aspect ratio but the 40 series in this tire gives excellent feedback & decent in the rain. Not the quickest but very, very user friendly. Excellent training tool. If we needed to pull every last second out of our car we would be on a much lower aspect ratio with no worried about the visual aesthetics.

If we ever upgrade the car we will run a 295 or 315 on a square 11” or 12”setup. Don’t think that will happen anytime in the near future though. Development stopped a while ago - no need to sink more $$ in a car that is not ever going to be class specific.

 

[a50cobra]

Interested in hearing how the V710's are for autocross. I am sure they are great for the track.
I know nothing compares to the purple stuff, but I mean, do they heat up and grip rather quickly? Do they last longer (thru extended heat cycles)? Etc.
I will stay tuned. Best if luck!!

 

[csamsh]

Never really cared about looks! Function over looks for us every time - Not trying to sell sticker space either - Tire OD affects gear ratio at different track configurations. We are low budget - Running a 4.10 rear ratio & a modified T-5 with a .80 final drive ratio. We would be pushing the RPMs by having to hold in 3rd & 4th with a 30 series tire if we wanted the quickest times at the drivers favorite local– not needed at this stage. Tire weight is also a factor – I do admit not much but everything helps. We are only doing HPDEs and don’t think that will change anytime in the near future.
Currently using a 265 – 40 AD08 on a 9.5” rim not for looks but because for us, at this stage of the drivers development, it is easier to read. Breakaway is much more gradual. Turn in is definitely not as quick as a lower aspect ratio but the 40 series in this tire gives excellent feedback & decent in the rain. Not the quickest but very, very user friendly. Excellent training tool. If we needed to pull every last second out of our car we would be on a much lower aspect ratio with no worried about the visual aesthetics.

If we ever upgrade the car we will run a 295 or 315 on a square 11” or 12”setup. Don’t think that will happen anytime in the near future though. Development stopped a while ago - no need to sink more $$ in a car that is not ever going to be class specific.

Gearing is much more of a concern for me- I don't really want a short tire. I run out of 2nd gear around 65 already with a 285/35/18, so going shorter is no bueno for autocross

Interested in hearing how the V710's are for autocross. I am sure they are great for the track.
I know nothing compares to the purple stuff, but I mean, do they heat up and grip rather quickly? Do they last longer (thru extended heat cycles)? Etc.
I will stay tuned. Best if luck!!

Terry seemed to have good luck with them, and there's a pretty decent ESP racer up towards me that likes them too. He said he sprayed them pretty consistently, so I guess they heat up ok. I will know the first weekend in October! Back to back events. On break until then though...stupid work training. Who needs to make money anyway?

 

[csamsh]

Whiteline MT82 mount bushing insert

This is copied and pasted from a couple other places- if you already know about my car, skip to the "install" portion.

Ok- so I installed this thing at long last and took the car out for some evaluation of different shifting scenarios that have been problematic.

My Setup

I was somewhat apprehensive about feeling any sort of noticeable impact from this product given how my car sits. I run AST 4150 monotube coilovers with 550# front, 250# rear springs, Whiteline sways on 3/4 hard, MGW shifter, and some other stuff. The tires/wheels I have on my car right now are 285/35/18 Hankook RS3's with 18x10 wheels. What does all of this mean- my car doesn't move around a whole bunch. It's pretty planted, in a way that I could only imagine back when I ran Konis, Eibachs, stock sways, and narrow little 9" wheels. So- when I give my review, bear in mind that my car is Track Prepped.

Install

HA! So much for "10 minutes, no tools." I originally tried just jamming the thing in there. Well- didn't work. The cross member has a little lip that covers up the bottom "hole" in the bushing that the flat part of the whiteline piece sticks into.

Next- I tried taking off the nuts off the studs that go through the bushing and jacking up the tranny. This may have worked if the car was on four jackstands. As I had it, just the front raised, there wasn't enough give in the driveline to get the tranny up high enough.

I ended up just taking off the crossmember. This would be REALLY EASY with a lift- just zip six fasteners loose in about 2 minutes. On your back with jackstands, there's a lot of going back and forth between sides of the car, especially if you're like me in that the parts of suit jackets that don't fit without tailoring are the shoulders and chest. The mount is almost in the exact middle of the car, far from both sides and the front of the car.

After greasing the bushing insert, I ended up having to beat on it pretty well with a deadblow hammer to get it in there. To say nothing else- it's not going anywhere.

Review

There is a stretch of interstate that runs near where I live that has four exits in a couple miles without much traffic. Hitting all the on and off ramps up and down that stretch is a decent test loop- the on ramps are varying radii, and fall in the 60-90mph range at "corner exit." They have nice "entry points" that are good for heel-toeing and apexing. The frontage road is EMPTY and a nice concrete surface, so it's a good place to test straight line braking, 0-60, and 5-60. How nice is the surface? I've cut a 1.8X 60' on my RS3's.

NVH

I didn't notice any NVH increase. Take this with about a tablespoon of salt- my car is not exactly geared towards "low NVH." I refer you to the earlier comments about my setup.

Shifting

1-2, WOT, straight line. This shift used to give me the most trouble when I'd drag race. It was usually pretty "crunchy" and hard to really nail. 2-3 was always the easier one for me. I always thought it was something with synchros, shift fork, or whatever. The bushing insert greatly improved the FEEL of this shift, but I don't know that I'm any faster.

2-3, WOT, straight line. No noticeable change is speed, feels better though.

3-2, straight line, coming down from redline in third. Not really a shift that will happen much on track, but one you'll encounter when driving around town like an ass. Lots of help from the insert- feels a lot better, easier to hit second, probably because it's easier to yank out of third. 5-4 and 5-3 have a similar "better" feeling, but it's less pronounced.

3-4, 4-3, 4-5, 5-6, 6-5, 6-4 are mostly unchanged. They feel a bit better, but feel no faster. None of these were problem areas anyway.

Now- the moment you've all been waiting for-

2-3 and 3-4, WOT, sweeping turn. DAMN. Wow is this ever better. I used to really have to "guide" the shifter around hitting the onramps in my test loop. Lots of them need a 2-3 shift between 6k and 7k rpm. With the insert, I can just bang gears like it's a straight line. The combo of the MGW rear mount and the whiteline insert is tits. The improvement here is worth three times the price of admission.

So concludes the review.

Closing thoughts
To all you whiners out there concerning $10 for shipping. Y'all can go off with boots and asses and figure out what goes where. Even $100 for this part would be well worth it. At $40 shipped, it's the Deal of the Century. Whiteline really hit this one out of the park. Now they just need to make some motor mounts.

 

[Conekiller]

Any update on those 18x11s forgestar wheels clearing a stock style rear swaybar for sure? That's about the only thing holding me back from ordering a set at this point and I need to order soon since the current tires are almost done in.

 

[csamsh]

Any update on those 18x11s forgestar wheels clearing a stock style rear swaybar for sure? That's about the only thing holding me back from ordering a set at this point and I need to order soon since the current tires are almost done in.

I won't be able to comment on this, I don't have the stock rear any more. However, the Vorshlag guys could definitely try it on their black car before they turn them over, I would be ok with that.

 

[csamsh]

So a small, no-pictures update here-

New Parts!

I had some whining wheel hubs, so I put the new hubs with ARP studs in. I can now run spacers with impunity. And there was much rejoicing. yay. yay. Seriously though, I like a little spacer with the D-Forces until I get a chance to grind down or cut my swaybar studs.

My 18x11's are made, and the tires are mounted. Terry has tested them on his 2013 GT, and from the pictures, it looks like they fit great! More here.... Shane you're in luck. Terry's black car still has the stock style rear bar, and it looks like they fit. Time for you to order set #2! If you want gunmetal...I have gunmetal. Order some in Tennis Ball Yellow and I'll trade you!
http://www.vorshlag.com/product_info.php?cPath=0_141_142_268&products_id=624
And those are mine in the picture! Cool. I will finally get them October 5th in Dallas at a Camaro-Mustang challenge event thing. Fingers crossed for being the fastest non-Terry's red car Ford.

I'm also getting a Cobra Suzuka GT w/Schroth harness installed before that event. After my last autocross, one in which my being all over the place contributed to a spin and general bad performance, I am pretty mad at these stock seats, and more than ready for some real ones.

And now for something completely different-
After I put my new hubs on, I went for a drive and had a pretty loud humming sound. At first I was worried that the hubs weren't on right, but I decided to yank the RS3's and put the stock wheels with Pilot Super Sports back on. It was the tires. Those RS3's are LOUD. I haven't driven on the PSS's in a few months. I had forgotten how much better the RS3's on 18x10's are than the 19x9's w/ PSS's. The decreased weight, more grip, and all that. I swear officer, I didn't mean to squeal the tires leaving that stoplight...

 

[Vorshlag-Fair]

I won't be able to comment on this, I don't have the stock rear any more. However, the Vorshlag guys could definitely try it on their black car before they turn them over, I would be ok with that.

We did test fit Mark's 18x11s to our black 2013 GT (still for sale!) and they fit very well. This set was mounted with huge Kumho V710s in 315/35/18, which are very fat:









So yes, we have the secrets to fitting an 18x11" front and rear, under stock fender contours. Here's the page to order from.

Enkei 18x10.5" wheel that so many Mustang autocrossers use - but now there is a better solution

And yes, our 18x11" set-up has a different offset for the front pair of wheels than the rear pair. Because you HAVE to do that on anything wider than a 10" wheel. These custom 18x11" wheels fit better than those off the shelf Enkei 18x10.5" wheels (see above) that so many SCCA Solo racers use - which stick out past the fenders, allow tire-to-fender rub under cornering, and make the rear track wider than it needs to be - grabbing cones left and right, and making the differential work harder (a narrower rear track lessens the speed differences from the inside/outside wheels). Sure, this Enkei was the only option for wider Off The Shelf wheels for Mustangs for years.... but now we have the 11" solution, that fits.



And we have the 18x12" rear solution, that also fits under the rear fenders, with a bit more effort. The 11" is as wide as you can go in front without cutting fenders/adding flares, but we have an 18x12" front solution if you are willing to go that route as well.

Thanks,

 

[2013MustangGT]

@Terry

What do you think of staggered fit, like the Boss, for the Mustang on road courses? I was thinking of doing 10" in the front and 11" in the rear.

Thanks

 

[Vorshlag-Fair]

@Terry

What do you think of staggered fit, like the Boss, for the Mustang on road courses? I was thinking of doing 10" in the front and 11" in the rear.

Thanks

Personally I'm not a fan of staggered fitments on almost any race or street car (with exceptions for rear engined and/or extremely high powered cars). A lot of OEM cars come with a staggered wheel/tire width front to rear, and in 100% of those cases it is narrower fronts to ensure UNDERSTEER. There are liability reasons why car makers have almost universally tuned their cars to PLOW / PUSH / UNDERSTEER from the showroom floor.

When cars start to do ^^this ^^ most drivers tend to crash. A lot. Why? Because the natural tendency is to lift the throttle or jam on the brakes when a car begins to yaw into Oversteer, which only makes matters worse. Doing that causes more weight to tranfer to the front axle, increasing front grip and lessening rear grip. The cure for oversteer is actually the opposite: to apply more throttle (temporarily), to counter-steer, to increase the turning radius, or some combination of the 3. (the car above doesn't normally oversteer, but I was doing the driftoro thing on purpose)

Conversely when a car is plowing like ^^ this ^^ (which Mustangs tend to do when pushed hard) those same natural driver tendencies (lift throttle or apply brake) actually helps cure the condition temporarily, so auto makers tune their cars for understeer. At all costs. When it comes to sportier cars, they help this by putting narrower front tires on the car relative to the rear. Corvettes started doing this in the late 1990s, 911s have been doing it for decades, Vipers have always had staggered fitments, the Boss Mustang, and on and on.

This tendency for massive understeer is my least favorite thing on any OEM set-up. Unless the car has massive horsepower relative to braking and cornering grip, this staggered wheel trick isn't needed or in any way desirable. For almost all Mustangs I would start with an 18x10" front and rear first, unless class rules didn't allow that (and if so, I'd switch classes, heh!). That's a great dual purpose street/autox or street/track wheel size, as it allows for up to a 295mm tire and you can rotate front to rear. Beyond a certain level you will want more tire, so I'd go with the 18x11 front and rear. Then you need to start thinking about cutting fenders for a 18x12" front and rear set-up, where we are now with our TT3 car. And even then, it isn't enough tire. At the 3770 pound race weight we have to run for the power we make in this class, it is easy to overheat even the 315mm tires we use.



In the video above (which was from the first session at TWS last weekend, on a semi-damp track) you can see classic cases of oversteer and a good recovery at 2:18, and snap oversteer and a loss of control at 2:41, even with an experienced driver trying to catch it. Oversteer isn't fun, and I'm not saying that going to a square set-up will make that happen. In the wet it happens on almost everything. But in the dry you don't want a skinny front tire relative to the rear, almost ever. And not on any S197.

 

[kcbrown]

Personally I'm not a fan of staggered fitments on almost any race or street car (with exceptions for rear engined and/or extremely high powered cars). A lot of OEM cars come with a staggered wheel/tire width front to rear, and in 100% of those cases it is narrower fronts to ensure UNDERSTEER. There are liability reasons why car makers have almost universally tuned their cars to PLOW / PUSH / UNDERSTEER from the showroom floor.

Yep, this.

But in the case of the Boss 302, it's got a higher rate rear sway bar (and the same rate front as the GT). Wouldn't that compensate for the offset?

There's also the matter of the front sway bar and the shocks. I expect that even the springs will have an effect on understeer/oversteer.

Why put a higher rate rear sway bar on the car and stagger the tires if the goal is to maintain understeer? Note that the non-Boss Mustangs come with a square tire setup, so it's not like there isn't already understeer in the basic setup. Then again, comments by expert reviewers (Randy Pobst) have said that the Mustangs have neutral characteristics in the corners. I'm not sure if that's in relative terms or absolute terms.

I can't wait to take my car onto the track to experience what this car does for myself. Gotta break the engine in first...

 

[Norm Peterson]

But in the case of the Boss 302, it's got a higher rate rear sway bar (and the same rate front as the GT). Wouldn't that compensate for the offset?

Adding rear roll stiffness works to oppose the understeer brought on by fitting larger rear tires, but I would not use the term 'compensate' to describe this sort of balancing act generally. Within some narrow range of cornering, maybe.

There's also the matter of the front sway bar and the shocks. I expect that even the springs will have an effect on understeer/oversteer.

IIRC, the Boss also runs relatively firmer rear springs as well as a bigger rear bar. Presumably, that means there's also a bit more rear rebound damping, but that's strictly a guess based on what firmer springs "want" for damping.

Why put a higher rate rear sway bar on the car and stagger the tires if the goal is to maintain understeer? Note that the non-Boss Mustangs come with a square tire setup, so it's not like there isn't already understeer in the basic setup.

I suspect that it's a way to maintain a little understeer under the lower lateral-g cornering that should cover any reasonably sane street driving without resulting in much heavier understeer out toward the limit. That the car then gets progressively "less tight" the harder you drive it as the LLTD effects become a relatively bigger part of the picture. The larger rear tire also dials in a little extra cushion against random right feet that don't understand the concept of throttle modulation as well as they should.

Then again, comments by expert reviewers (Randy Pobst) have said that the Mustangs have neutral characteristics in the corners. I'm not sure if that's in relative terms or absolute terms.

At the very limit it may well be pretty close to neutral (though we don't know anything about such matters as whether any leading throttle was being used or only maintenance throttle).

Other reviewers have suggested that with the Boss/LS there is a greater handling balance sensitivity to how hard any trail-braking is being done. That at least sounds consistent with trying to balance an understeer effect with an oversteer effect, given that the two effects do not necessarily increase at the same rate with respect to lateral-g.


Norm

 

[csamsh]

.....and we're not Randy Pobst, so his opinions have questionable use to us.

 

[kcbrown]

.....and we're not Randy Pobst, so his opinions have questionable use to us.

No, but I thought we were all trying to become him (at least as regards driving capability)!

I figured his observations would be of more relevance to the likes of us (who are pushing our cars to the limit) than to the average person driving on the street, because his observations come from driving the car at the limits.

Anyway, we're all different in terms of what kind of handling balance we like, I guess, hence this forum...