rear sway bar/what now

[irishpwr46]

^^^^so what is a good tire to start with?

 

[don_w]

Page 2 should be visible now...

 

[SoundGuyDave]

Thanks, Dpn!

Irish: You want something grippy, but not TOO soft, both for wear, and for audible feedback. Look for an "extreme performance summer" tire with a treadwear of 200-250 for a good tire. I've used the Nitto 555, and it's good, if a little on the hard side. I've also used the Dunlop Star Spec, and it's a great rain tire, and solid in the dry. Others like the Kumho Ecsta XS. Avoid the RE050A and it's competitors, they're a bit too quiet for good feedback, but they are grippy!

 

[Vapour Trails]

70mph is 6500 rpm with 3.55 gears and 275/35-18 tires, OR 6500 rpm with 3.73 and 275/40-18 tires, or.... you can use tire size to adjust the NET final gear ratio quite a bit.

Really???? Tell me more.

Actually with 3.73s, 6500 rpm is 67 mph with 26.66" wheels/tires. I used excel to make my own calculator for this.

The stock engine honestly makes it's power from around 3000 up to around 6200 rpm, and then it starts to fall flat. If you've modded the engine to let it breathe better at higher rpm, you'll need to adjust your final drive ratio to place that powerband where you need it. With 275/40-18 tires, the stock 3.35 gear effectively eliminates the utility of 5th gear on-track, since a 6275 shift from fourth puts 5th gear at about 4300 rpm and 151 mph, and unless you're making beaucoup power, you're aero-limited at that point. Gears aren't a drag-only deal, they're a tuning tool. Period.

Sure they're a tuning tool, but lets look at the options.
4.10s = each gear suffers from a very narrow band of useable speeds, you'll be up and downshifting quite often and you might need to use 5th on a straight. Not a good option.
3.73s = offers better acceleration, but a very modest increase over 3.55s, so why spend the money.

In reality I don't see changing the gear ratio of the rear end being of much utility to the Mustang corner carver. The 3.55 stock gear is the best compromise. If you got the 3.31 gear, then 3.73s would be a worthwhile investment.

My reference to 70 mph in 2nd was directed towards auto x. If 2nd gear can reach 70 mph, you will never have to do more than one shift during of an auto x run, and that's a good thing.

All sticky tires will do is make him fast and sloppy, and when he does lose it, he'll just be doing it at a higher speed, that's all. Not-so-sticky street tires are great to learn on for a variety of reasons. First, they talk to you, and you can really start to learn what your car's doing by listening to the feedback from the tires. R-comps are dead silent, except for a split second when there's a tiny bit of growl. Then you spin. Second, street tires are usually very predictable in breakaway. They warn you that it's coming, and you can feel them gradually let go once you push too hard. They also recover pretty predictably, as well. The skills (throttle-steer, snap-opposite-lock) that you learn controlling and recovering on street tires are lifetime skills, and they apply directly to sticky street tires, R-comps, and even full slicks. R-comps give almost no audible feedback, and grip like crazy until they don't grip at all. Without the skills to recover, you don't hang the tail out a little on exit, you just spin, since the tires let go apparently without warning. There actually was a warning, but without the experience base from street tires, a novice driver won't know what they're hearing and feeling to get them to be ahead of the car, rather than reacting to it.

I have my doubts that one would develop the input speed required to excel at auto x if you're driving slow because of your tires. Auto x is a completely different animal than track racing. There are probably more driver inputs in 60 seconds of auto x than a couple laps of an average road course and they are coming at you much faster.

I never made any improvements in my auto x driving until I had tires that were up to par with what the car & driver could accomplish. I went from the bottom 20% of my local club to the top 20% in short order.

As far as being sloppy, the fastest guys in my local club drive S2000s and set the FTD nearly every event while spending at least a few tenths of a second going sideways each trial. If car isn't getting away from you once and awhile, you're not driving hard enough to be competitive.

 

[irishpwr46]

Thanks, Dpn!

Irish: You want something grippy, but not TOO soft, both for wear, and for audible feedback. Look for an "extreme performance summer" tire with a treadwear of 200-250 for a good tire. I've used the Nitto 555, and it's good, if a little on the hard side. I've also used the Dunlop Star Spec, and it's a great rain tire, and solid in the dry. Others like the Kumho Ecsta XS. Avoid the RE050A and it's competitors, they're a bit too quiet for good feedback, but they are grippy!

seeing as my car is a daily driver, im gonna need a good set of rain tires. are the dunlops a good choice for all around driving and what size would be good for 18s??

 

[Random Asshole]

I got a set of 17in RE050A pole positions if you are interested. They are pretty nice tires. They feel alot nicer on the road than my kumhos do. I liked running 17s cause the car had a bit more pep. (Just like the tire/ratio subject above proved)

If you want a dedicated track set, I'll sell them to you dirt cheap. I paid 900 installed. I'll take 550obo most likely with shipping.

 

[SoundGuyDave]

Really???? Tell me more.

Actually with 3.73s, 6500 rpm is 67 mph with 26.66" wheels/tires. I used excel to make my own calculator for this.

Stock tire height is roughly 27", and the following are the most popular "aftermarket" heights:
275/40-17: 25.66"
275/35-18: 25.57"
275/40-18: 26.66"

Based on that, we can come up with a quick 6500RPM 2.00:1 trans ratio set of speeds for various gears:
tire...............................3.35........3.55........3.73........3.90......4.10.....
275/40-17: 25.66".........74.2.........70.0........66.6........63.7......60.6
275/35-18: 25.57".........73.9.........69.7........66.3........63.5......60.4
275/40-18: 26.66".........77.0.........72.7........69.2........66.1......62.9

Also a home-built Excel spreadsheet... I stand by my original numbers:

6500RPM with 3.55 gears and 25.57" tires is 69.7mph. 6500RPM with 3.73 gears and 26.66" tires is 69.2, which is certainly close enough for horseshoes, both being within 1mph of the target.

Sure they're a tuning tool, but lets look at the options.
4.10s = each gear suffers from a very narrow band of useable speeds, you'll be up and downshifting quite often and you might need to use 5th on a straight. Not a good option.
3.73s = offers better acceleration, but a very modest increase over 3.55s, so why spend the money.

It's a given that the taller the gear (higher numerically) the less road-speed range there is per gear. With a stock 3650 trans, based on 6250 redline shifts, and minimum 3000 rpm, here's how it plays out with 25.57" tires (275/35-18):
gear..............3.35..........3.55.......3.73.........3.90.........4.10
1st: 3.38:1 ... 0-42.........0-40.......0-38.........0-36........0-34
2nd: 2.00:1 .. 34-71......32-67......31-64.......28-25.......28-58
3rd: 1.32:1 ...52-107.....49-102.....47-97......42-88.......42-88
4th: 1.00:1 .. 68-142.....64-134.....61-128....59-122.....56-117

You are obviously correct that there is not a huge difference in the 1-2 gear performance between 3.55 and 3.73 gears, BUT, when you get into 3rd and 4th, that begins to change. On a road course, excepting brutally slow 2nd gear 30mph turns, most corners are taken in the 45-60mph ranges, with the straights being in the 90-120mph ranges. Both cars will stay in third for the short straights, and both cars will require upshifts for the longer straights. Here, the slightly taller gear will show an edge, since the 3.73 car WILL pull on the 3.55 car, all other things being equal. If your car came with the 3.35 (or was it 3.31?) the difference is even more dramatic. In fact, a case could be made that the 3.90 would be an excellent choice for the shorter tracks, where the main straights aren't all that long, since you would have such an edge coming off the corners, and could probably hang 3rd gear when others would have to drop to second.

In reality I don't see changing the gear ratio of the rear end being of much utility to the Mustang corner carver. The 3.55 stock gear is the best compromise. If you got the 3.31 gear, then 3.73s would be a worthwhile investment.

Disagreed, and agreed. In terms of "worthwhile investment," that is always the question, no? Is the extra .1 or .2 seconds per lap worth the $500 for gears and install? If you're swapping to a T2R or another aftermarket differential, then you should consider gear choice to be wide open, since there won't be an associated install charge.

My reference to 70 mph in 2nd was directed towards auto x. If 2nd gear can reach 70 mph, you will never have to do more than one shift during of an auto x run, and that's a good thing.

Seems like that takes a lot of the fun out of things to me... I agree that minimizing the number of times you need to shift is a positive, since upshifts are just wasted time. Top speed on an auto-x course is absolutely loafing along compared to even short club-level road courses, though, and we almost NEVER use first gear, except when pulling out of the pits, or MAYBE on a hairpin.

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I have my doubts that one would develop the input speed required to excel at auto x if you're driving slow because of your tires. Auto x is a completely different animal than track racing. There are probably more driver inputs in 60 seconds of auto x than a couple laps of an average road course and they are coming at you much faster.

Maybe Sam will chime in here with respect to techniques, but I have instructed my fair share of auto-x drivers making the transition to road courses, and almost universally, they are FAR too rough with their control inputs. I'm not referencing speed here, just severity of change. They yank the wheel, not turn it, and tromp on the gas and brakes. I may be wrong, but smoothness will pay off a lot at any speed, and plays directly into car control skills, of which the most important is maintaining a balanced chassis. I will concede that you make more turning events than I do at a track day, BUT here is were we start to differ in opinion.

Sticky tires cover a multitude of sins, since you can use them like a crutch to cover poor steering, braking, and accelerating techniques. If you have sticky rubber, you can yank the wheel over to turn, and the rubber will just grip, and you make the corner. That's great, you made the corner, but you still spiked the "traction circle" needlessly. If you were smooth, but quick, with your steering input at the same speed, you would use a lot less of your traction budget. That means that the car has grip to spare, so you can actually increase your speed through the corner, but not if you spike the tires with a wheel yank! Starting off on harder tires FORCES you to be smooth, just to try to keep up. Once you get into the habit of easy control inputs, though, you'll be able to maximize the traction from your crappy tires, and still be relatively fast. NOW put on the sticky stuff, and apply the techniques that you've learned, and you will KILL the other guys who just bought sticky rubber but can't drive them to the limit. Take a look at Sam's videos: in particular, pay attention to the rate of change, which is actually rather slow, despite how busy he is in the cockpit. Smooth means that you get a settled chassis to work with, where throttle steering works, and where trail-braking isn't an invitation to a spin. If you throw the car around, you won't be able to use the more advanced techniques to maximize what you've got.

I never made any improvements in my auto x driving until I had tires that were up to par with what the car & driver could accomplish. I went from the bottom 20% of my local club to the top 20% in short order.

Just playing devil's advocate... If you had learned to drive first, and not worried about final placement, is it possible that you might have stayed in the bottom 20% for a little longer, but then catapulted to the top 5% rather than top 20%? Remember, I'm NOT advocating getting a set of nice, 500 treadwear all-seasons here, just starting on something like Nitto 555s, or Star Specs.

As far as being sloppy, the fastest guys in my local club drive S2000s and set the FTD nearly every event while spending at least a few tenths of a second going sideways each trial. If car isn't getting away from you once and awhile, you're not driving hard enough to be competitive.

I disagree to a point... When you're first starting, yes, the car will get away from you until you get your techniques refined. When you start to "push it" and you have the skill set to back you up, it's vanishingly rare that the car will completely let go on you, like being sideways. When the car is sideways, ALL that you're doing is scrubbing off speed, and pissing away momentum and rhythm. If the tail end steps out of line a little bit, you can easily correct with throttle steering or opposite lock, and you lose almost nothing. If the car starts to push a touch, a slight lift or a dab of left-foot brake can snap it back on-line, and you lose almost nothing. When you go flat sideways, or worse, you've given up valuable tenths of a second trying to chase hundreths or thousandths. Not a good bargain, if you ask me.

As much as I hate it, NASCAR is a great place to study car control skills applied. They're in a 4-wheel controlled drift exiting almost every single corner, and they do run the ragged edge the whole time. How often do you see one of them get really sideways and still keep their track position? Almost never.