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Nice video, but don't believe always believe all that you see !

First of all, they don't mention the wheel rates (spring rates) or anti roll bars in the comparaison, so it's quite hard to make a judgment. They are the only influence on body roll and camber change.

When he says that the car rolls and the outside tire is nicely optimised, but that the inside is wearing badly...Usually, race cars have such high load transfer that the grip generated on the inside tire on a non-aero car (like the mustang in the video) becomes negligible in the overall handling of the car, so camber change on the inside isn't as bad as portrayed, wear isn't as bad either because the load is so low. In fact, some race car even run a reverse-ackerman steering geometry, meaning the outside wheel ''turns-in'' more than the inside because you get more grip by steering the outside wheel more than controlling the load on the inside tire.

For example, this is low-downforce race car with mcpherson strut in front, the inside wheel lifts quite a bit under cornering. Is it a bad race car ? It could be improved yes, but it corners pretty well !

sherwood-gt3-1205.jpg


McPherson strut suspension isn't as bad as it is protrayed in the video, yes it loads the shock in bending and suffers from excessive play & wear in racing. But it has less excessive camber change like double-wishbone with really short arms, think miata, RX8, MX5, s2000. Those cars have to run high spring rates because if they were soft the camber change would absolutely kill the handling.

Also, a performance product comparaison without lap times, cornering G, speed, track, car setup & different drivers is pretty ridiculous.

Wouldn't buy it ;)
 
Wow thanks for all of the details. Really informative and I'm glad you've taken the time to provide us furthermore details. You pointed some good things, thanks for sharing your experience
 
oldschoolZ said:
Nice video, but don't believe always believe all that you see !

First of all, they don't mention the wheel rates (spring rates) or anti roll bars in the comparaison, so it's quite hard to make a judgment. They are the only influence on body roll and camber change.

When he says that the car rolls and the outside tire is nicely optimised, but that the inside is wearing badly...Usually, race cars have such high load transfer that the grip generated on the inside tire on a non-aero car (like the mustang in the video) becomes negligible in the overall handling of the car, so camber change on the inside isn't as bad as portrayed, wear isn't as bad either because the load is so low. In fact, some race car even run a reverse-ackerman steering geometry, meaning the outside wheel ''turns-in'' more than the inside because you get more grip by steering the outside wheel more than controlling the load on the inside tire.

For example, this is low-downforce race car with mcpherson strut in front, the inside wheel lifts quite a bit under cornering. Is it a bad race car ? It could be improved yes, but it corners pretty well !

sherwood-gt3-1205.jpg


McPherson strut suspension isn't as bad as it is protrayed in the video, yes it loads the shock in bending and suffers from excessive play & wear in racing. But it has less excessive camber change like double-wishbone with really short arms, think miata, RX8, MX5, s2000. Those cars have to run high spring rates because if they were soft the camber change would absolutely kill the handling.

Also, a performance product comparaison without lap times, cornering G, speed, track, car setup & different drivers is pretty ridiculous.

Wouldn't buy it ;)
Click to expand...

You are conentrated on the wrong aspects, in my opinion. The only real advantage to a double-wishbone setup vs McFail strut is the straight line stability because of the dynamic camber change which is virtually nonexistant on McFail cars.

Yes, inside tires are not that big of an issue in a race car, but that doesn't change the fact that suspension geometry is invariably better on a double wish bone car.

Pinpointing cars like the Miata, S2000, etc, and saying that they have to run high spring rates because of excessive dynamic camber without mentioning static arm angles, ie, ride height, is the same as comparing McFail struts to double wishbone setups without mention ride/roll resistance.

On that note, this kit seems to be engineered for a car that's lowered already, so it *shouldn't* suffer from excessive camber gain/loss through the camber arc. (This is entirely speculation, but given how the parts are marketed, i.e. not for OEM, I can't imagine the upper arms being at an extreme static angle.)

McFail can be made to work, yes, but a proper double wishbone setup will always work better...
 
Synoptic Tuning said:
You are conentrated on the wrong aspects, in my opinion. The only real advantage to a double-wishbone setup vs McFail strut is the straight line stability because of the dynamic camber change which is virtually nonexistant on McFail cars.

Yes, inside tires are not that big of an issue in a race car, but that doesn't change the fact that suspension geometry is invariably better on a double wish bone car.

Pinpointing cars like the Miata, S2000, etc, and saying that they have to run high spring rates because of excessive dynamic camber without mentioning static arm angles, ie, ride height, is the same as comparing McFail struts to double wishbone setups without mention ride/roll resistance.

On that note, this kit seems to be engineered for a car that's lowered already, so it *shouldn't* suffer from excessive camber gain/loss through the camber arc. (This is entirely speculation, but given how the parts are marketed, i.e. not for OEM, I can't imagine the upper arms being at an extreme static angle.)

McFail can be made to work, yes, but a proper double wishbone setup will always work better...
Click to expand...

Yes, straight line stability :) , you know how much the camber thrust generates in terms of force vs. toe in or toe out ? Toe has a lot more influence on stability than camber. Modern race tires are quite camber sensitive, but usually only at peak slip angles which you don't reach in straight line running.

Why would double wishbone be invariably better ? Double wishbone with short arms (such as all production cars) have quite large camber gains because of the short arc. If you look at all GT cars that run a double wishbone in the front, they usually run VERY high spring rates to reduce the camber gain, there are also aero reasons as well.

S2000, RX8, Miata, It's a fact that these cars have to run quite high spring rates when lowered: 1 because of the reduced travel 2 because of the high camber gains. MX5 Cup cars run very high spring rates in the front because the front suspension (same as RX8) goes into camber loss past a certain point, leading to mid-corner understeer. Double wishbone is obviously better here...I don't see how ride rate would change if you have the same wheel rate on a McPherson strut and double wishbone car ? Roll resistance would change because of the change in roll center height, but not ride.

McFail (as you call it) isn't all that bad, it's definitely not the best. But converting to double wishbone with short arms isn't that much better, plus this comparaison is laughable. No lap time, no car data, no cornering G. Just vague quotes like ''the contact patch is very flat on the ground'' while filmed by a phone at 100+ meters from the car. lol
 
Sorry for the vagueness, I should have said: a double a arm setup let's you run less static camber, which let's you brake and accelerate in a straight line better.

You mentioned the lack of ride and roll rates from the video in your previous post. I was just pointing out the irony.

GT cars run ridiculously high rates because, among a plethora of other possibilities, they are (usually) too low and restricted to OEM suspension pick up points. This leads to cornering forces being translated into jacking forces (A far more important phenomenon in my opinion than excessive camber gain). They need the added rates just to keep the outside shocks off the packers. Not to mention that a lot of people like to control most, if not all, the body roll with the end of the car that isn't propelling it forward. On a RWD car that would be the front, (which is why ever so often we see the inside front wheels off the ground) and on a FWD it would be the rear. You can't just say that they do this because of the camber. A bland statement like that is just as bad as the video, if anything!

We can go back and forth for days on this, each car is different, but that doesn't change the fact that a proper double wishbone setup will always, yes always, be better than a McPherson strut.
 
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1h de ma session en ChumpCar a Watkins Glen


Je me suis fait bumper au premier tour le dimanche, au moins on a pu finir la course, contrairement a Sajan!

 
La première vidéo, c'était quel stint le samedi?
Le dimanche, c'était dès le (re)départ de la course? Si oui j'ai profité de l'accrochage pour me faufiler, c'est moi dans la Neon de Mopar 4 Life qu'on voit vers la fin... fallait pas lifter dans les Esses! ;)
 
Seb. c'était la dernière stint de la journée samedi.

effectivement je n'aurais pas du lifté mais c'Est exactement comme ça que j'avais rouler le samedi sous la pluie, réflexe! surtout que j'avais juste un tour a faire et on devait mettre du gaz et changer de driver, mon focus était de revenir au puit en 1 morceaux! :( au moins on a pu finir!
 
Je rigolais. Le gars derrière a la responsabilité de contrôler. C'est pas comme si tu lui avais fait un brake check non plus là. C'est poche. Tant mieux si vous avez pu terminer. Le gars a eu des conséquences? C'était pas le même gars/team que celui qui a punté Sajan toujours?
 
Non c'est le gars du Néon Rouge et noir, il est venu s'excusé en fin de journée...

Pas de mal... mais l'auto est croche et doit aller au carrossier. a suivre...
 
Inboard video from PBOC race at Sebring, fl

Voici un video de notre course a sebring avec PBOC. Environ 80 voitures qui prenaient le départ, toute marque confondu.
Les temps jouaient de 2,05 en radical et les autos moins rapides 3,00. Beaucoup de circulation.

il s'agissait de notre 1re fois à la piste.

Mon père en cayman S PDK, classe gtb1: meilleur temps 2:28:9
Moi en boxster S, classe stock F: meilleur temps 2:29:3

le vidéo est dans la cayman

Le départ est à 4:00min, je suis la boxster argent à (5:00min)

beau dépassement à 9:45min entre 2 open cars

mon père qui commence à me rattraper à 20:00min et me dépassera a l'avant dernier tour: 22:00 min

PS: I'd like to say a great thanks to Greg(Gregster) who works on our cars and keep them at a top shape level for us to race.

enjoy


 
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Seb, c'est vraiment cool!

Look at the data with your dad!! Whenever you see that you are braking; but not going to -1.0 -1.2G, and its only -0.5, -0.6... He should stay on the gas longer (not coast), and brake harder.

I know you and your dad race for fun, but if you take the time to look at the data between practice and the race, you could get maybe 1 second or more!

Are you at Daytona?? I will be there in 2 days!
 
Fuzz said:
Seb, c'est vraiment cool!

Look at the data with your dad!! Whenever you see that you are braking; but not going to -1.0 -1.2G, and its only -0.5, -0.6... He should stay on the gas longer (not coast), and brake harder.

I know you and your dad race for fun, but if you take the time to look at the data between practice and the race, you could get maybe 1 second or more!

Are you at Daytona?? I will be there in 2 days!
Click to expand...



True Kevin, when i look his videos, i always give him some tips to go faster.
My dad is often too early in corners and i keep telling him when i look his videos.
He doesnt trail brake much, doesnt look far enough, etc... But hey, i'm twice is age younger and im really competitive. He just wants to have fun with his old budies and race his son as you said hehe

just for reference, in his class, midpack runs 2.25 & 2.26 at sebring and top 2.23. So he has lot on table.

In my car, lap record from an old semi pro racer Ari Straus is (2:29.370; 2013-02-02 )

Next weekend is PCA race. 250 cars registered in RACE + 100-150 cars in DE

Biggest event of the year.

So no Daytona for me, i wish you good luck, i drove 2 sessions at daytona in October 2014 and my balls were biggggg

are you racing or DE at daytona?


can you develop on that? but not going to -1.0 -1.2G, and its only -0.5, -0.6... I have no clue really....
 
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