Drop Zone Coil-overs

[EBUCKS]

Anybody ever hear of them? They don't even come with the tool for adjustment.<BR>I've got KYB gr2 going in as struts. I've got a 95 MX-3 RS. <BR>Help <P>one

[HRO]

yep, my buddy has them on his civic. they are alright, his came with the tools tho. they were $450 installed. Do they make them for the MX now or something??<BR>if so, how much??

[EBUCKS]

Hey man. I just finished the test drive around Toronto. They feel pretty good. I have 450's up front and 350's in the back. I thought it would be way too stiff but I like the ride. The girl friend won't though. [img]shrug.gif"%20border="0[/img] <BR>I got them for $450. I used my friend's shop and know how, as this was my first time. I gave him $100 and a few beers. <BR>So sorry . . . they did come with the tools. I was mistaken. I guess they do make them for the mx now. I honestly never heard of them before and paniced when I found out they weren't GC. It's all good though.<P>one

[EBUCKS]

Question: I've got KYB GR2 struts and these Drop Zone coilovers. The spring rate is 450 in the front and 350 in the back. The MX-3 RS is a pretty light car and I think that spring rate is too high, and unecessary. Are my struts strong enough to support such stiff springs? Will they blow out in a short space of time?<P>one

[fatfmx3]

question for mx3vs<BR>did you make that hood or does some one make it

[tk1138]

EBUCKS: do you know the stock spring rates? Also if you have the damping coefficients it would be usefull to have those.<P>I can't say from experience, but if your ride is under damped you'll probably blow them.<P>Damping test: <BR>1.Push down on a corner of the car.<BR>2. Release the weight suddenly<BR>3. does it <BR>a.)go up then down? If so how many times?<BR>b.) just go up ?<P>If it's a. it's under damped, otherwise it's critically damped or overdamped.<P>Basically ALL automotive struts should be within their limits if b. is the case.<P>If it's a. then you'll probably have a shorter strut life, but some struts might be okay there.<P>Good luck

[EBUCKS]

Hey thanks man. It's definitely a. I don't know exactly the spring rate of the springs. They just said 450 and 350 on them. I would guess that is a generic description of the spring rate, but not the actual spring rate itself. However, when I push down on the corner of the car, there is not much movement anyhow. That's why I think that the springs are too stiff.<BR>But I'll just have to wait and see.<BR>Thanks again. <P>one

[ProtegeSTS]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by EBUCKS:<BR><STRONG>Question: I've got KYB GR2 struts and these Drop Zone coilovers. The spring rate is 450 in the front and 350 in the back. The MX-3 RS is a pretty light car and I think that spring rate is too high, and unecessary. Are my struts strong enough to support such stiff springs? Will they blow out in a short space of time?<P>one</STRONG><HR></BLOCKQUOTE><P>yeah, no way that GR2s are going to handle 450/350s. By the way, vehicle weight has nothing to do with it.

[EBUCKS]

Ok then, when my struts finally go, what struts should I get? I understand that the GR2's are just sport struts and I would need racing struts, in order to handle 450/350s. Maybe I'm wrong. Can you suggest a brand or type please? <BR>BTW thanks for posting Protege. Maybe you should change your name to MR2ESTOCK. <P>one

[tk1138]

The model of spring/strut suspensions is a 2nd order differential equation given by:<BR>m*a+b*v+k*x=F. Where m=mass, a= acceleration=d^2x/(dt)^2, b=damping coefficient, v=velocity=dx/dt, k=spring rate, y=vertical displacement from equilibrium, F=external force. For the coresponding homogenious equation, if b^2<4mk (this is the condition for being under damped), the solution is:<BR>x=C1*(e^(-bt/2m))*sin(((4*m*k-b^2)^.5/2m)*t)+C2*(e^(-bt/2m))*cos(((4*m*k-b^2)^.5/2m)*t)<BR>which is basically decreasing periodic oscilations. <BR> <BR>As m increases the amplitude of the oscilations decrease more slowly, and the angular frequency decreases asymptotically (never really goes away). <P>Adding mass to your car will effectivly reduce your stiffness, and increase the force (as seen by the spring & strut) for a given bump, not to mention lowering it=generally bad.<p>[ October 23, 2002: Message edited by: tk1138 ]

[ProtegeSTS]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by tk1138:<BR><STRONG>The model of spring/strut suspensions is a 2nd order differential equation given by:<BR>m*a+b*v+k*x=F. Where m=mass, a= acceleration=d^2x/(dt)^2, b=damping coefficient, v=velocity=dx/dt, k=spring rate, y=vertical displacement from equilibrium, F=external force. For the coresponding homogenious equation, if b^2<4mk (this is the condition for being under damped), the solution is:<BR>x=C1*(e^(-bt/2m))*sin(((4*m*k-b^2)^.5/2m)*t)+C2*(e^(-bt/2m))*cos(((4*m*k-b^2)^.5/2m)*t)<BR>which is basically decreasing periodic oscilations. <BR> <BR>As m increases the amplitude of the oscilations decrease more slowly, and the angular frequency decreases asymptotically (never really goes away). <P>Adding mass to your car will effectivly reduce your stiffness, and increase the force (as seen by the spring & strut) for a given bump, not to mention lowering it=generally bad.<P>[ October 23, 2002: Message edited by: tk1138 ]</STRONG><HR></BLOCKQUOTE><P>Im guessing this was meant for me.<P>Weight of the car has no bearing of if KYB GR2 can control 450 lb springs adequately. MY BAD. The mass of the car itself does enter into the rest of the system.

[EBUCKS]

Ok. TK the calculations all look good and familiar. I just don't think that any strut companies are going to offer up all of that info that I need to know, in order to get the correct dampening struts that would suit the current springs that I have. However, your info is greatly appreciated. Are you studying Mech. Eng.?<P>one

[tk1138]

Electrical engineering, but I do have a little interest in ME. Diff EQ uses this system to give students an idea of how '2nd order linear constant coefficient equations' behave. <P>If you have your stock springs still you can find their stiffness by measuring their length uncompressed, then adding a known weight and measuring the compressed length. k=m*g/x or k=F/x where x is the difference in the measurements & F is the weight. From that damping coefficients can be estimated: if critically damped b=(4*m*k)^.5 if under damped, b=(m*k-(2*pi*m*f)^2)^.5<BR>where f is the frequency of the oscilations and m is the mass suported by that system.<BR>This probably won't do anyone any good since strut companies don't sell their products by damping coefficients. If they do you'll probably need as high a b as you can get for those springs. <P>Do the mazdaspeed struts have calibrated adjustments, and what 5 ways can you adjust them?