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The Strut thread - Koni / Illumina / Tokico / Carrera / Bilstein / Ground Control


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My understanding is that the larger the piston the more fine tuned the valving can be. Is that wrong?

 

Looking at the flyer, 6" stroke is more than I would want and linear valving is also not the best.

 

John, you said the other option was 36mm, I believe in that size they have adjustables and they have digressive pistons, remote reservoirs, etc. You going to have all that figured out for us too?

Edited by JMortensen
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The larger the piston the more surface area the valving can have.  It also gives more room for valving options.  This can make the shock more repsonsive and tunable but it also gives the oil a larger surface area to work against.  There's also a point where you're just adding weight/mass which can slow down the response.  The pistons on my Penske triple adjustables were 38mm and they had everything a S30 would want in a shock.

 

I'm not smart enough to know where the sweet spot is regarding piston size, vehicle weight, response, etc.  I rely on the shock manufacturer for that advice.

 

The 36mm is exactly the same kind of setup as in the brochure above.  One the low end (and the first ones released), the shock will be non-adjsutable with 5 different valving setups to choose from for the S30.  Bret has done a lot of development with S30s over the years (Steve Carlson runs a custom set of 34mms) and has a good idea of what the car needs.  I'll have to do some machining for the top mount (unless they release it in 14 or 15mm) and make a welded on adapter for the strut casting.  No eta yet.

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From what I've found the R36-5022-H0 (3000GT) damper fits in the 280z strut housings. This features a 36mm piston and 4" stroke stock. You can cut the bumpstops in half and have a stroke of 5.25". These feature a lower mounting stud, so no gland nuts are required to mount into the strut housing. If a 36mm damper is sufficient for the S30s in tarmac applications, what would the benefit be of going to the new motorsports 36mm unit over an off the shelf 36mm strut from bilstein in a 280z housing? I wonder if the same pistons and shim stacks are available? 

 

Here is the R36 strut:

http://www.allshocks.com/productimages/R36-5022-H0.jpg

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I remember you messing with those a year or two ago Justin. How could you install them without a gland nut though? Seems like you'd need something to hold the top of the strut tight within the housing, otherwise all of the stress would be handled by the stud at the end, not good. 

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I won't be running a gland nut to clamp the top of the strut but plan on running a shim to center the strut in the housing. These inserts are designed to slide into stock 3000gt housings and be bolted in at the bottom. I may just bore out my factory gland nut to be the shim that centers the strut in the housing. Ill be working on this in the coming month so i'll keep you posted.

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This revived thread reminds me .... Im running the single adjustable Koni 'race' struts with 425/375 springs. They are several years old now and seem to be seeping a little. Ive felt no problems with them but Im thinking maybe it time to replace or rebuild. Question is should I send them for rebuild or just replace? If rebuilt would they be better revalved? Im getting to the point of trying to eek out every tenth but have yet to play with struts.

 

Thanks

Cameron

 

PS - those larger diameter shaft struts seeem like a really good idea.

Edited by heavy85
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fwiw

I have been running the VW Sirocco/rabbit/jetta F4-P30-0032-M0 shock with shortened strut tubes for about a year now with out changing the stock valving. I'm using 250 Front and 275 Rear In/lbs springs. Many spirited runs through the local mountains and a couple of track days to willow springs and these have felt great. I was using a 235/45/17 continental tire and they seemed well matched...but I went to a 275/40/17 NT01 and the car feels under sprung. (no rear sway bar and stock front) 

Just figured I'd contribute my 2 cents :)

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  • 5 months later...

Bringing this thread back up.  After last weekend at the track I was thinking maybe I won't section my struts as I am getting decent suspension travel on very stiff springs with 8610s and zero rubbing or interference,.  I started an email thread with Mark Icard, John Tedder and Tom Harris, but figured I'd throw it out here.

 

Matt Isbell and Mark I. both are int he boat I'm in with regards to tracking their Zcars.  Matt has spoken with a few people about shocks, and Mark has spoken directly with Koni about building a more suitable shock for the Zcar. 

 

When I was playing with Porsches, Moton and JRZ made external reservoir shock setups for those 911s for $5K.  This was all the hardware and springs as well as the shocks valved appropriately.  The question is, what would you pay for world class performance for an external reservoir shock?  One of the most direct bits of feedback Matt got from Mike Skeen driving his car was "You need better shocks".  I think, for those of us who are truly trying to build Datsuns that can compete with these newer performance platforms, we may need to seriously investigate the options... So again, what would you be willing to pay for the truly ultimate shock kit for your Zcar?

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There should be more custom options from Penske, Moton, etc. since 2001 when I had the custom Penskes built for the Rusty Old Datsun.  And yes, these cars really do need shocks better then what's currently available.  The big costs were (and probably still are) the shock shafts.  Mine for the Penskes were custom made but there should be some off-the-shelf shafts available now that can be adapted to the S30.

 

I've had some discussions with Angelo at ANZE but my business changes ended those for now.  Might want to contact them and see if things are further along.

http://www.anzesuspension.com/home_CSStallerversion.cfm

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  • 4 months later...

Thinking about shocks now too.

 

QUOTE:

If there is no rule limitation, why not get rid of the struts altogether? Would open up the shock choices a lot.

As in just weld on the diameter / length tube needed to the spindle area? 

And design it around the most favorable shock housing?

 

If I have Illuminas now in the standard sectioned MR2 type configuration what is my best next step?

Running 425/450 springs and I have no complaints about the shocks at this time.

But maybe i am missing something.

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As in just weld on the diameter / length tube needed to the spindle area? 

And design it around the most favorable shock housing?

 

If I have Illuminas now in the standard sectioned MR2 type configuration what is my best next step?

Running 425/450 springs and I have no complaints about the shocks at this time.

But maybe i am missing something.

 

No, I was talking about going to SLA instead of strut. If you're going to pour thousands of dollars into custom struts, why not go the extra mile and get better geometry and a huge selection of high quality shocks while you're at it? As to your best next step, I can't do any better than the thread you're already in. Maybe someone else has an opinion.

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  • 1 year later...

Back from the dead. Found a vid today that might be of interest to some people who are interested in undertaking the task. I have no idea how he came up with the combination of shims or if the port volumes would be better/worse if he didn't have a dyno onhand. I guess if you are into ALOT of trial and error this could pay dividends.

 

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Interesting,  I never would have thought to use pistons for an ATV/MC on a car.  You can download the Penske manuals and see diagrams of each and the curves they generate, which is maybe what he did.  Unless the missing bit is missing was how he figured out how many shims to stack on these to get them to work.  I also thought the comment about nitrogen pressure changing the dynamic roll center was interesting.  Props to being willing to do this yourself.  That's a lot of work with some odd components to figure out.  Not a path I would have ever taken.

 

Cary

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  • 1 month later...

I saw this website awhile back. Shows how to modify a Bilstein shock to make adjustable.  Looks MUCH easier than modifying the Tein struts in that video. Plus all the valves are available with no modification. I know of 2 sets like this in existence and the guy who runs them is very fast indeed.

 

http://farnorthracing.com/shocks_2.html

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I accidentally posted my question on the faq clone of this thread so I'll repost here. With the updated 8610's is it possible to run them effectively with a 225F/250R spring rate or is it too light? I'd like to go 200/225 but that seems less of an option on the koni shock. Illuminas are presold till the end of July so I'm looking at alternative shock options and don't want to kill my kidneys in a car that will see primarily street use.

Edited by Geno750
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