JRZ Infos

[projet_rs]

yes!, still questions for my shocks

I need your help to chose them !

I wanted some bilstein RSR, but i discovered the JRZ,

and since, these are these shocks that I want!


First question, are the JRZ shocks better than the bilstein RSR ? ( I will use mes shocks without torsion bar, just with springs)


I contacted JRZ manufacture ( with 400 miles of at home ), and they proposed to me 3 different modeles :

- The single adjustable damper is adjustable in rebound.
- The double adjustable damper is adjustable in both bump and rebound.
- The triple adjustable damper is adjustable in both bump and rebound and also in the low speed range of the bump.


which model advise me?
and which are the advantages and the disadvantages?

Thank.

Alex.

[Wil Ferch]

I think other people here can help better than I.....first of all..nice pics on your project car. You seem well on your way to a fairly radical car...so you should have some idea of the kind of shock performance you're after.

I can only talk about my own very limited experience. The rest is what I've gathered through the years from people like on this board.

Single adjustable shocks ( in rebound) are very nice in that you can start to match the damping characterisitics with whatever spring rates you end up with. Note that "shock absorbers" are more correctly called "dampers" as the English say, since they will serve to damp the oscillations that would occur from the energy release of a twisted spring. The energy stored in the spring ( coil spring or torsion bar) when twisted must be controlled when released, therefore it is more important to have ( at least) rebound ( extension) damping. In fact, most shocks have a 3:1 or 4:1 ratio on rebound damping vs jounce( compression) damping because of this energy release characteristic. Meaning...the spring offers a degree of resistance (control) during jounce that isn't there during the release process....which requires more control during release ( rebound).

Therefore...the additonal damping....for jounce...as well as for low speed vs high speed characterisitics..is simply "added tunability" for these other factors. Some would say these are "lesser" factors compared to the basic function of a shock... but like all things in racing...you start chasing down extra features as your speed and experience build up. You end up going after smaller and smaller increments at ( proportionally) more and more cost and complexity....
such is life !!

Hope this helps somewhat and also hoping others can add a bit more detail.

Wil

[Craig 930 RS]

The single actually function as a poor-man's 'double' - the compression also changes to a lesser degree --- but is not adjustable *independent* of rebound. I've got em -

[Wil Ferch]

Craig is correct....I ( for example) have single-rebound adjustable low gas pressure Koni's (front) and similar adjustable hydraulic Koni's rear.

Although catalogued as "single-adjustable" ( in rebound)....they actually do change ( a small amount) in jounce too, but not independently, and not as strongly as when you change rebound. Nice "poor-man's" double adjustable feature !!!

Confused yet?

Maybe Grady Clay can jump in too and add a few words.....

Wil

[projet_rs]

thank you for your help,

and it is an important advantage to use a double or triple adjustable damper ?

Alex.

[Jack Olsen]

I would only get double- or triple-adjustable shocks if I had a suspension man on retainer to come with me to re-adjust my suspension for every track I go to.

As it is, I can't afford that. So I have single-adjustable JRZ's.

[ted]

What is your purpose for coil overs, racing with slicks?
Do you want 900lb springs in the rear?
If you plan to track it with coil overs you might want to consider a full cage connected to the top of the stock shock mounts.
You appear to not be intimidated by the slope.

A racer I know has a track 911 with double adjustable JRZ front and rears.
With his help and at the same time to keep costs down he recommended single adjustable fronts and double adjustable rears for my 911.
Agree if I did not have a JRZ contact my first choice would have been custom valved Bilstien coil overs or just stay with stiff torsion bars and revalved shocks. Less stuff that needs adjusting.

[projet_rs]

good, the reason would like that I buy the simple one, but passion. . . .

I'm waiting the price quotation, and I wil decide . . . .




Alex.

[Wil Ferch]

A recent article in Excellence magazine , I believe, directly addresses the issue of shocks for a track 911, and how it resulted in vastly different lap times. I believe the remote reservoir Fox/ JRZ /Moton (?) set up was the best, and info found in this article can be related to the original question.

Perhaps someone here can post/scan the article or the original poster can get a back-copy once we identify the specific issue date.

Wil

[projet_rs]

Originally posted by Wil Ferch
A recent article in Excellence magazine , I believe, directly addresses the issue of shocks for a track 911, and how it resulted in vastly different lap times. I believe the remote reservoir Fox/ JRZ /Moton (?) set up was the best, and info found in this article can be related to the original question.

Perhaps someone here can post/scan the article or the original poster can get a back-copy once we identify the specific issue date.

Wil

that would be really cool to have this article


if someone . . . . .


Alex.

[projet_rs]

Originally posted by Wil Ferch
A recent article in Excellence magazine , I believe, directly addresses the issue of shocks for a track 911, and how it resulted in vastly different lap times. I believe the remote reservoir Fox/ JRZ /Moton (?) set up was the best, and info found in this article can be related to the original question.

Perhaps someone here can post/scan the article or the original poster can get a back-copy once we identify the specific issue date.

Wil

is the article present in the SmartRacing's catalog ?





page 41


Alex.

[Craig 930 RS]

Was the article a bit biased? Open question for you to ponder.

[MuffinMan]

While the article showed a clear advantage with the adjustable shocks, keep in mind that an expert shock tuner was also on-hand to tweak the set-up. Would your average weekend racer at the track, without a professional, yield similar gains? I think it depends on how diligent he/she is in changing a setting, recording results, changing a setting, recording results, rinse & repeat until an optimum setting is found. This task is fun for some and tedious for others. The task becomes more daunting as you move from single, to double, to triple adjustable shocks.

[Craig 930 RS]

Rob makes a critical point - I wouldn't recommend adjustables for most people. Never good for a fun thing like a Porsche car to be a confusing PITA.

[Lukesportsman]

Just remember that the more adjustable the suspension is, the farther off you can be. I found this out the hard way on my first tube chassis race car as I ended up with a bunch of preload and rear steer the first time off the trailer. I chose to go single adjustable with the Mustang, and probably still haven't dialed in the perfect setup. Sometimes another factor to adjust is just that. As Jack said, without a suspension guru I'm not sure its $$ well spent. It always sounds COOL though.

[projet_rs]

Originally posted by Lukesportsman
As Jack said, without a suspension guru I'm not sure its $$ well spent. It always sounds COOL though.

but I like to become complicated the life !


Alex.

[Wil Ferch]

Alex:

Maybe you've just answered you own question....

The added complication of multi-adjustable shocks is only worth it to real racers who also have the time / money / and technical support to dial it in correctly. Multi-adjustability can just as easily get you into a big mess !

For bragging rights....I would think having a premiuim quality ( or remote-reservoir) set up would still do the "trick"...eh?

Wil

[skinnerd]

I would definitely go with the Fox remote reservoir shocks (if budget allowed this).
I have the article at home....I can get it tonight and scan it in tomrrow if that helps.
Perhaps someone else can get it to you quicker???

ps.... these are expensive; a little over $3K US to do all 4 corners.

[projet_rs]

Originally posted by Wil Ferch
Alex:

Maybe you've just answered you own question....

The added complication of multi-adjustable shocks is only worth it to real racers who also have the time / money / and technical support to dial it in correctly. Multi-adjustability can just as easily get you into a big mess !

For bragging rights....I would think having a premiuim quality ( or remote-reservoir) set up would still do the "trick"...eh?

Wil

this is why I wished to know if there is a large advantage in term of performances between the simple ones and doubles.


Alex.

[projet_rs]

Originally posted by skinnerd

I have the article at home....I can get it tonight and scan it in tomrrow if that helps.

Oh YES ! ! !

I'm waiting tomorrow



Alex.

PS: my email: projet_rs@yahoo.fr