Sujet technique sur les améliorations chassis

[Bacon]

Entre un GC 98-01 et un GD, c'est 100-150 lbs de différence. Mais je sais que les GC plus vieux (93-95) sont plus légers, mais de combien je sais pas.

[oli]

1300kg.. mais sur la pesé "d'truck" c'est moin que ca, jme souvien pu exactement ca fait un bail !

j'serais du pour le refaire !

1300 kg = 2860 lbs

Lol, merci pour la conversion, je me sentais lache! et la GD est a combien sur l'immatriculation?

[Swatch]

la GD est a combien sur l'immatriculation?

La SAAQ dit 1436 kg pour un WRX wagon 2002.

[homer09]

Entre un GC 98-01 et un GD, c'est 100-150 lbs de différence. Mais je sais que les GC plus vieux (93-95) sont plus légers, mais de combien je sais pas.

exactement. souvent le monde compare un GC RS ou meme L '95 versus un sti ou wrx GD. c'est claire qu'il y'a 400lbs de difference minimum!

mais chasis strippé vs chassis strippé, la difference ce limite à 100-150lbs.

[oli]

la GD est a combien sur l'immatriculation?

La SAAQ dit 1436 kg pour un WRX wagon 2002.

Bon on regarde une difference de 136 kg pour une '00-'01 VS un GD Wagon... C'est pas rien, ca dois ce rapprocher plus du 150lbs sedan a coupé. Je trouve ca interessant quand meme, de voir les chiffres, avant ca je me basais juste sur ma reference que j'etais pas certain, ca me donne des idées pour un projet future. Je regardais aussi une Leg BD, mais je prefere aller dans le 2 portes ci possible.

[homer09]

la difference entre une 4 et 2 portes GC c'est 15lbs.

[UGCspawn]

la GD est a combien sur l'immatriculation?

La SAAQ dit 1436 kg pour un WRX wagon 2002.

intéressant, pour mon SF' c'est 1381...

[Swatch]

Sauf que, le poid de la SAAQ, c'est le poid que le constructeur donne. En réalité, est-ce que c'est bien ça ?

Et, est-ce que c'est comme une moto et c'est un poid à sec sans aucun fluide ni même batterie ?

[Sylvain B]

Mon L 93 swappé version 6 pese 2650lbs avec une moitié d'essence. Banc de course en fibre, valise vidée mais aucune autre modif de réduction de poid.

Celui a yanos (GD 2002 swap version 7) pese 3200lbs aucune idée du niveau d'essence.

Ya plusieurs éléments mécaniques différents (5vitesse Vs 6 vitesse, brembo Vs 4 pot...).

Mais en général les GD sont au moins 300lbs de plus pour une mécanique similaire.

[oli]

Sauf que, le poid de la SAAQ, c'est le poid que le constructeur donne. En réalité, est-ce que c'est bien ça ?

Et, est-ce que c'est comme une moto et c'est un poid à sec sans aucun fluide ni même batterie ?

Ca derange pas ci c'est pour comparaison, specialement ci c'est par le meme fabriquant.

Mais en général les GD sont au moins 300lbs de plus pour une mécanique similaire.

...mesemble, j'ai juste trop de la misere a croire qu'un GD pourrais juste peser 100-150 lbs de plus. Apres avoir conduit les 2, c'est claire que le GD est plus rigide, mais j'ai aussi trouver qu'il semblais "sluggish" comparer a mon GC, p-e la clutch, who knows, mais c'etais mon experience.

[Kolia]

Allez donc vous pointer sur une balance du MTQ avec vos voitures! Réservoirs pleins. On va l'avoir la réponse!

[steph z-24]

ont a fait l'exercise deja avec les meme balance

gc stripper cager v8 et 6 vitesse contre GD stripper cager v8 avec vitesse

la différence etait de 100 lbs !

les 2 voiture etait stripper pas mal de la meme maniere et aurait encore pu perdre un 150 lbs

[Xchange]

Bon les gars... j'ai trouvé un excellent site!

http://www.buildafastercar.com/

Avec des calculateurs

http://www.buildafastercar.com/tech/Swa ... Calculator

Vraiment excellent!!

Je lis pis je vous dis ce que j en retiendrais

Car manufacturers- and even race cars- use large sway bars to keep body roll minimized while keeping the main springs soft enough to absorb bumps. For example, a Subaru Impreza gets roughly twice as much roll resistance from its sway bars than it does its main springs. Many owners upgrade their sway bars to units that are two or four times stiffer than stock! In such a case, nearly all body roll is handled by the sway bars instead of the springs. The driver will also begin to notice the lack of independence in the suspension as now the left and right are linked pretty rigidly.

[Xchange]

et encore un petit post interressant sur les sway :

Well, I think what matters is that your total spring frequency come out to the 2.0 to 2.5hz range. You can get that via springs or sway bars so long as you stop there. The trade-off is this that since sway bars change your spring rate depending on whether one or two wheels hit a bump simultaneously, it's impossible to valve a strut accordingly.

And now we get into that gray area I know little about. Is it possible to properly dampen a car with big sway bars? You're either underdamped in turns or overdamped on the straights.

I'm certain this is why race cars tend to use smaller sway bars: because sways make damper valving a compromise. However, on a street car, we make that sacrifice to reduce body roll while still being able to run soft, comfortable springs for a good highway ride.

If you look at a completely stock car with total wheel rates of 477lb/in and 347lb/in (as calculated above), it already has a spring frequency of about 2.25. (Actually your bump stops increase this while your soft strut tops and sway bushings decrease this, so the actual spring frequency is quite dynamic.) So, you're already pretty high on a stock suspension. Again, that's already in the optimal range for use on racing compound tires.

I know a stock STI feels mushy and has a lot of body roll, but I think that is due to the car's low roll center (also debatably a good thing). Body roll isn't necessarily bad so long as you have enough negative camber, but for sure the STI has more body roll than most similar cars with a multilink rear suspension. Another thing to consider is that a stock car rides on its bump stops, creating horrible corner entry understeer and a jacking effect on turn-in. There are a host of problems on a stock car that get fixed by adding a large sway bar even if it's not technically ideal. Adding a large sway bar can be three steps forward even if it's one step back. In other words, your choice of sway bar will depend on what other problems you haven't yet fixed.

I think Prodrive might have the right idea with their RB320 suspension. They keep the stock front sway bar and bump up the spring rates what I assume is a mild to moderate amount. Once you've increased your stock spring rates, I'm not sure a larger sway is desirable anymore so long as you have enough camber. Prodrive uses a slightly larger rear sway bar to aid rotation, which is understandable given the car's weight distribution.

Personally, I have the 27mm front and 24mm rear bars. This was somewhat against my better judgement, but it was the popular recommendation here so I went with it. I like them but because I don't own camber plates, the reduction in body roll is paramount for me. With camber plates, I think that Whiteline 22mm or Cobb sways (23mm equiv, IIRC, since they're hollow) are probably ideal. I run 315lb/in springs front, 250lb/in springs rear. This would still bump me over the "ideal" spring frequencies, but not by much. For those with even firmer springs, I'd probably keep the stock sway bars or, if anything, install a mildly larger rear for rotation as needed.

I don't mean to say that such-and-such is best, only that it's worth trying. I haven't actually tested all this in the real world. I know opinions are like assholes- everybody has one. However, at least Javid of 6gun racing has written some anecdotal evidence- from actual data- suggesting the theory is correct. A post of his on Nasioc is actually the reason I started looking into this.

AnorexicSTI- don't forget that with your car being so much lighter than everyone else's, your car will have a much higher spring frequency even given the same spring rate. This is important. Also, depending on where you're removed most of your weight, you may actually have a higher center of gravity than your competition, which will cause more body roll given the same spring frequency. (Don't worry, lightweight cars still kick ass from having a low polar moment of inertia.)

[jefars]

http://www.buildafastercar.com/node/9

Nice !

belle trouvaille !