[flash]

why not go over 6k? how can you not tell you are at 6200? that screech will certainly let you know. i think your instructor would have been better off watching an accelerometer to see how much you were pushing in the corner, and not the tach

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[Cloud9...68]

Flash,



I hear you, and am not in a big hurry to spend a lot of money on a bunch of fancy gadgets dreaming of instant 20% reduction in lap times (I'm a luddite, remember). This all started with a thought of, "hey, wouldn't a Go-Pro camera be a cool thing to ask for for Christmas", to help me understand how well I'm following the correct line, which led to a perusal of the web sites of the various ads in Grassroots Motorsports for "simple" data acquisition systems, which led to this thread, etc. Once I get back to the level of smoothness and precision I had before the rebuild (been sidetracked by a dead starter and a back injury), my lap times should be pretty decent, so I look at this data acquisition stuff as a possible means to help take my driving to the next level once I begin to plateau. There do seem to be a lot of drivers who at least claim get a lot out of them, but I agree that they tend to be on the higher end of the experience and competence spectrum.

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[flash]

with things like this, everybody who has one says they "get a lot out of it", whether they do or not. nobody wants to admit they bought a gadget that does nothing for them.



most of the people i know who have gotten these things, actually slowed down. they were paying attention to the wrong things. it's the instinct you need to develop, not a recognition of data.



of course, once you are in the top 3 of the fast group, then perhaps that last little bit attainable more readily with data. before that though, it's pointless and more often than not counterproductive.



i feel the same way about simulators. sure, you can "learn" a course to some degree, but they are useless for learning to drive. they can't teach you weight shift, which is the single most important skill. being able to "feel" the car move is essential to driving smoothly. without that, you will always be making mistakes. entry points, exit points, and all that are far less important than being able to feel the g-force in a turn, and know that you are rolling over on the edge of a tire, or pushing too hard and headed for an end swap. you can't get that from data in any useful fashion.



i'm not sure how to explain it better than that. it's really very esoteric. but that is what separates great drivers from good ones.

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[JWahlsten]

I'm with you guys. While technically inclined, I know you only have so many brain bites on to use on the track, and a lot of those are used making sure where everyone is at least in a race.



For DE I can't see the data acquisition system being effective until you're very comfortable at speed and aren't making progress without it. However, if you hire a coach (good money spent) and they use data, I could see it being another tool in the toolbox to get better faster. Like Flash said though, one needs to be able to feel what the car is doing. Without that, you're never going to be more than mechanical in your approach to what the car is doing and needs you to do.

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[Cloud9...68]

As I think about it, I think Flash is right. When I started doing DE's, I read several books and articles on the subject of track driving. Interesting stuff, but when I got behind the wheel, I was always so focused on the task at hand, that I could never remember anything I had read. The only thing that improved the quality of my driving, which ultimately manifested in much better lap times, was seat time.

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[flash]

yup - when you start focusing on minutia, you mess up the rhythm. most instructors don't know how to teach rhythm, so they try to point out small stuff, so you think you are getting your money's worth. you come away thinking "wow - he really found a lot of stuff". in reality, all he did was put a bunch of crap in your head that will confuse you the next time out.



the best thing i can suggest to anybody wanting to learn to drive, is to go ride a motorcycle. you will quickly learn to understand about gravity, momentum, and weight shifting. surfing or skateboard riding do much of that too. applying those concepts, and learning how you can feel it in the seat and pedals will go a long way toward being smooth



data won't help you with any of that.

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[Cloud9...68]

Agreed - I understand and have experienced what you're describing, but have been away from it for so long that I've forgotten my own experiences. To take it a step further, I think it would be better to not even pay much attention to lap times early in the learning (or in my case, re-learning) process, and just focus on the dynamics of the car.

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[flash]

agreed. you should not be paying attention to lap times until nobody is passing you and instead you are passing everybody else. one majorly screwed up turn, and you can quickly go from your fastest lap to your slowest.

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[hot968]

sorry this is off subject Cloud9, but what kind of rims do you have on your 968? I tried to enlarge the photo but it wouldn't do it. They look great.

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[Cloud9...68]

Thanks - my wife really like them, too, and she seldom comments much on the 968. I don't know of a way to enlarge an avatar, either. They're Enkei NT-03's. They're very lightweight, and are marketed as a racing wheel, but there's no reason they couldn't be used on a street car. Here's a link to some better photos:



http://www.sakarimotorsports.com/enkei-n...95-6540sp/

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[flash]

you cannot enlarge an avatar.



the rims are somewhat light. there are a number of rims a LOT lighter in that size. but, bang for the buck, they are hard to beat. not great for a naturally aspirated track car though, as the tires you have to put on them cost you an effective 15hp, and don't provide any real advantages. but, a lot of people who are not math-inclined think they are a good choice.

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[Cloud9...68]

We're getting way off topic, but what do you mean by "the tires you have to put on them cost you an effective 15 hp"? These wheels come in a wide range of sizes (the one I linked is just the first one that popped up, and isn't the size I have on my car), so I'm sure a large selection of tires would fit on them, some of course heavier than others. And yes, there are lighter wheels out there, but as you said, in terms of bang for the buck, they're not bad.

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[Dubai944]

My take on data logging is that the benefits for DE and occasional track drivers is that they are mainly useful for making fun videos of your track activities so you can integrate data onto the video and admire yourself and brag to your friends about your own lap times, g forces and top speeds!



Data logging really only becomes seriously useful for race drivers and engineers once the driver reaches a point where the driving part is no longer a mystery and you can turn lap times within tenths consistently lap after lap. Then it becomes useful to analyse setup changes and compare different drivers in the same car.



If you are logging track position, throttle, brake,steering and gear change inputs you might get some benefit in DE from comparing your own lap data to that of a pro driver or instructor driving the same track in your car, but you will still need them to explain it to you and until you become consistent yourself you may not be able to duplicate the inputs that make them quicker even if your know what they are.



I am currently using a Race Technology DL1 data logger which integrates with my Dash and the Motec ECU and logs most things. DL1s were mandated in the last series I ran in as a way for the race organisers to monitor GPS derived power estimates to try and control power to weight categories so I have it set up but it's complicated and not something I would recommend for recreational driving.



Personally I find logging useful mainly for suspension setup to see the real changes in cornering force and mid corner and exit speeds when I change spring rates, shock settings and alignment values. Lap times and corner speeds don't lie. As far as improving my driving, I occasionally like to compare my lines and inputs for my fastest laps to see where they were different, but beyond that I have come to the conclusion that unless you have the support of a dedicated team of race engineers you will get limited benefit from endless examination of log data.

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[Eric_Oz_S2]

I have found data logging quite useful for comparing laps and seeing where I have had a quick sector time or not. It won't teach you to drive, but it is useful in comparing different lines, etc. I also find it helpful to compare g readings on high speed turns where you can see how much you are leaving on the table. I use the racelogic box myself, an find it quite good. You can also set a reference lap and it will give you the sector time difference against your base lap.

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[flash]

if you spend the time to crunch the numbers, a couple of pounds of tire weight has the effective loss of about 15hp. rotating mass at the outside has the largest effect on acceleration and braking. the worst possible thing you can do is to add weight there. that is why a car on 17s will be quicker around the track than one on 18s, all other things being equal.



were i to set up a DE car today, i would run a 17x9 all around, with a 245/35 on it. it is lighter, smaller in diameter, giving a large advantage in final gearing, and all without giving up any width. i would also have the ability to rotate tires.



it's really simple math. but nobody out there today is doing the math. they see somebody do something, and think it's right, just because they did well. in reality it had little or nothing to do with the component or setup. nobody wants to think outside the box, or actually consider the physics involved.



re: data - and back on topic - i'm not saying that data isn't useful. i'm saying that there are very few drivers who can actually benefit from it. they just don't have the skills or understanding of what's going on to apply the data. ok - you're going faster or slower through a section. but why? and what do you do about it?



if you wait until you are smooth, before filling your head with all that gobbledegook, you'll then have enough of an understanding of what does what to be able to apply that data.



in summary, i think dubai hit the nail on the head.

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[Cloud9...68]

Thanks, especially to Flash, for the collective slap upside the head. First it was simulators (which I spent weeks researching after a guy who started doing DE's the same time I did and was immediately much faster than me told me he thought his low-budget simulator was helping him, when it was actually probably the sensitivity he had gained for g-forces from his occupation as a pilot), then it was books, and most recently a video camera which quickly morphed into interest in data acquisition, when all along I had learned first hand that the only thing that really creates improvement is seat time. Just impatient, I guess.



As far as wheel and tire size, that's another topic for another day...

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[flash]

lol - yeah - i'd be happy to go through the wheel thing with you. the people you are listening to are wrong. i don't care how long they've been doing it. it just means that they either have not learned from the mistake, or haven't taken the time to consider all of the parameters. these are the same kinds of guys who wouldn't think about changing gearing on a track by track basis. i do. i'm pretty sure that in one day i could make your car a second a lap faster.

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[Cloud9...68]

Thanks; let me spend a little time with the rotational mass calculator, then I'll give you a call.

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[flash]

figuring out the weight distribution will be the tough part with that. i ended up having to actually test it by using different tires and wheels, and then doing controlled acceleration tests, and then using that to calculate backwards to hp. it wasn't fun. but, it did result in better lap times. i had to learn this one the hard way. i always thought bigger was better when it came to tires. not the case in a momentum car like the mgb or the 968, where you don't have nearly enough power relative to teh mass of the car to accelerate like you need to.



lol - your data acquisition system would show it though.

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[flash]

some quick plugging showed going to 18s gaining over 100lb effective weight from the stock sizes, and dropping to a lower profile 17 losing well over 100lb effective weight from stock



that makes well over a 200lb effective difference between a car on 18s and a car on lower profile 17s. that will show up VERY fast in lap times.

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