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Hooray, coilovers for Xmas.. questions about shocks..


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So just how much will using, say, the ground control camber plates that do NOT require cutting lower your car? I was planning on using those just because I hate to cut up the body and want to avoid it if possible.... And how much camber adjustment will those things give? At least 2 deg each direction I would hope?

 

PS blkmgk, you car is awful purty, can I have it? smile.gif

 

 

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Morgan

http://z31.com/~morgan/s30

http://carfiche.com

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Ya know...

 

If you isolated a racing camber plate from the strut tower by sandwiching a piece of high-density rubber sheet about 1/8" thick betwwen it and the tower sheet metal, I bet you can kill a lot of the road noise.

 

The bolt holes for the camber plate would have to be oversize and you would have to put isolator sleeves on the bolts themselves. Similar to how the heater fan mounts in its housing.

 

And you would have to test it on a skid pad or on a race track in case my idea is dangerous...

 

 

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John Coffey

johnc@betamotorsports.com

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Okay, still SOME confusion here smile.gif Removing material from the spring perch up top will lower the body but I'd think it would remove some travel. I'm not real clear here but I guess removing above where the spring mounts makes the difference? I'd still think that would change where the body sits and move things on the strut rod....

 

As fo rmeasurements: Wheels and tires on my RX7 are 225/45ZR17s (Nittos) - height is 24.5

Wheels and tires on my Z are 225/50/15's of various brands (ahem). Height is 23inches. I thought these were a much stranger size!

 

Looking at them it looks like a MUCH bigger difference! 1.5inches moves the hub and body of the car only 3/4 of an inch upwards, yes?

 

I guess this comes down to what you're trying to do - better handling or better looks. I'm happy with my ride height now but not if it means trashing struts! Going upwards but filling the wheelwell wouldn't be too bad would it? I had no bumpstops before - I will this time (sigh). I don't want to section my struts and play bingo with cartridges and spacers dang it!

 

Seems to me that sectioning the struts but not going shorter on the carts makes the problem worse. Lowering the car via coilovers but not sectioning the strutscarts is bad too. This is a street car. I've got no idea now what to do except maybe put it together and let it eat - hopefully not struts!

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mr coffey is right about using comparimg a sledge hammer to camber plates & coil overs.the gc camber plates have torrington bearings and are very good but have slight rattle.i put some carrera plates in rear because i found them local .those rattle real bad and its even worse cause its right behind your head.camber plates require major surgery to top of strut tower-like a sawzall to start with.they do lower car about 1 to 1.5 inches cause you ditch the rubber isolater.i built a 72 z its car for a friend and we used mr2 cartridges.gc shortened strut tubes and every thing fit but they supplied all parts.i run the gc 12 inch long spring kit with stock length struts on my 77.it is plenty low-rear axles go upwards to wheels and i still have about 2.5 inches travel.i dont lower it for the track-it handles better with a little lean.if i was going to build a street car again i would not use coil overs.i would also like to let mr coffey test drive my car some time at a race track for some input on set up.seting up a car thats fast on track takes lots of time.

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> Okay, still SOME confusion here Removing

> material from the spring perch up top will

> lower the body but I'd think it would

> remove some travel. I'm not real clear

> here but I guess removing above where the

> spring mounts makes the difference? I'd

> still think that would change where the

> body sits and move things on the strut

> rod....

 

You're not lowering the body per-se (its a unibody car) you are actually raising the strut into the tower, wich brings the lower control arm and strut rob up a bit in their range of travel.

 

It doesn't reduce available bump travel because the strut (shock) insert is still the limiting factor. The shock will bottom before the lower control arm or the strut rob will bind/bottom.

 

> Looking at them it looks like a MUCH

> bigger difference! 1.5inches moves the hub

> and body of the car only 3/4 of an inch

> upwards, yes?

 

From a ride height perspective, 3/4" is a lot. From a suspension travel perspective, it works out to about 5/8" because of the distance the center of tire is from the lower spring perch. If we are looking at 2" of available bump travel at rest, having to lower the spring perch 5/8" takes away 31% of that!

 

> I had no bumpstops before - I will this

> time (sigh).

 

Great idea! On a lowered car you'll destroy the shock or break something without them.

 

> Seems to me that sectioning the struts but

> not going shorter on the carts makes the

> problem worse.

 

You have to go with shorted shock cartridges if you section the struts. The stock height ones will not fit (except for putting the fronts in the sectioned rear struts).

 

> Lowering the car via coilovers but not

> sectioning the strutscarts is bad too.

 

Not true. Its not a bad idea. You just need to be aware of the reduced bump travel and make the appropriate allowances in vehicle setup and how you drive. Putting in a good set of bump stops (the progressive urethane ones are the best) to protect the suspension is important. Not hitting railroad tracks at 80 mph is important too.

 

> This is a street car. I've got no idea now

> what to do except maybe put it together

> and let it eat - hopefully not struts!

 

Sorry to get your head all screwed up. Sometimes benchracing makes people (like me) point out minor things as if they are important. Again, set it up with stock length struts, the coil-overs, and the shocks you have (make sure you replace the bad ones). Put in good bump stops and slowly work down on the ride height (over a few weeks time) until you hit a good compromise between looks and driveability.

 

 

 

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John Coffey

johnc@betamotorsports.com

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...And this brings up another thought, and another question..

 

Thought first:

I you drill out the isolator center hole where the strut rod nut bolts on, weld on a 1/4 inch flat piece of steel stocl, drill the hole for the strut rod and nut to bolt to, you still have the rubber isolator bolte in place for the spring, which is where a lot of the spring rattle, and noise comes from. I might try this for giggles, as I have a few of the isolators laying around, and welding on a flat piece would take about 10 minutes to prep and complete.. This would allow the strut rod the addtional reach, because you are gaining at least 2 inches in the range for it to move, but would only be worth while if you are lowering the car enough to accomocate that amount... would it be needed? Not likely on a street car. Would it transmitt to much noise? I don't think so, due to the fact that the isolator is in place for the spring assembly...

 

Moving on to the question: Would it make better sense then to go with 16 inch wheels instead of 17s? My ONLY reason for going to 17s is tire availability.. However, Currently the HiPo selection of 16s is still there.. For a while at least... What I don't want to happen is that I am forced to replace another set of wheels 5 years down the road because I can't get ZR or Y rated tires for it...

 

Mike

 

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http://hometown.aol.com/dat74z/myhomepage/auto.html

"I will not be a spectator in the sport of life!"

mjk

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Mike, I think the isolator is there for NVH reason because of the spring AND the damper (strut cartridge) loads. Impact loads (hitting a sharp bump, expansion strip, etc.) are transmitted through the strut very well, since the time constant of the strut is very large compared to the time characteristics of the impact load. The strut damps more as the speed of the suspension movement goes up (Force=damping*Speed), so a sharp bump is transmitted well by the strut and the noise will come through well, especially on a stiffer (more damping) strut.

 

Of course, this is bench racing again, you might prove me wrong with your experiment. wink.gif

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Mike/Pete,

 

I have read through all 27 replies twice now and I'm still confused on what or what not to do on a 95% of the time street Z car concerning coilovers and camber plates. I know putting the coilovers on the car will stiffen the ride and putting camber plates on will transmit road noise - this is a given. Whether the harshness of the ride or interior road noise is unbearable seems too subjective to give a definitive reply. But can you gentleman give a synopses based on your experiences with the use of camber plates and coilovers. And also, cut, not to cut and where to cut the strut tubes. Perhaps since the both of you live relatively close to each other you can talk, agree or disagree on each item, and report back to the group. I think this would help TREMENDOUSLY on clearing up some key issues. I love this thread and all the replies but to form an opinion on what works based on a lot of subjectivity is hard for me and perhaps others. Again, this is for a street Z with 16" wheels with a performance suspension in mind.

 

Thanks Guys,

Danno74Z

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Hrm, perhaps I should consider the GC plates for my car then? 2inches or so would be nice to get back! These puppies real expensive? Might just see if I hit the bumpstops first before investing! BTW - I DO have to cross railroad tracks on the way to the local cruise spot so that test will be in full effect smile.gif Noise isn't a real big issue, I figure the car's going to be noisy no matter what I do....

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You guys might also want to look into the camber plates sold by Erik at EMI Racing. Although it sometimes takes a while to get them (he's a professional racer and is at the Daytona 24 hour test his week) his plates are about the best.

 

They bolt up under the strut tower, don't require any sheet metal work, and also allow caster adjustment. You can reach him at: emiracing@mindspring.com.

 

I don't remember the price, but I guuess its about $250 per pair, with the fronts being a bit more expensive. FYI... these camber plates are the same ones sold by MSA.

 

 

 

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John Coffey

johnc@betamotorsports.com

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