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

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Well as I've mentioned in a couple other threads recently I am in the process of sectioning my struts. I was planning to upgrade to single adjustable Konis at the same time but they are no longer available. I currently have Illuminas and I think they are on their last leg plus I've also thought the Konis to be a superior strut, well and I will need shorter ones anyway (at least on the front) . The suspension is completely dissassembled (well except that damn spindle pin - erg) and I'm ready to start cutting I just dont know which strut to go with. This is a dual purpose street / autox and I'm going with FP next year but only local stuff. Just trying for fast raw times realizing I will be uncompetitive PAX wise. It'll probably only see one or two thousand street miles a year. So I'm looking for recommendations on which struts to go with. It seems that struts seperate the men from the boys so to speak so I would like to get decent ones without going stupid crazy expensive.

 

Choices I've seen are (non-stupid crazy expensive):

- the new SA konis but they have to be re-valved

- DA konis but the second adjustment can't be adjusted once installed

- new shorter Illuminas

- Carerra (dont know anything about them)

- Advance Design (dont know anything about them either)

- ???

 

So is it worth it to pony up to the more expensive options or should I just stick with the Illuminas?

 

Thanks

Cameron

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I'll jump in on this one also. I too have an entire suspension disassembled I plan to upgrade in the next couple of months for my race car. I've read all the posts on this sight and I'm in limbo for the struts I will choose. What I know:

 

I've run Carerra's for a number years. Non-adjustable. Great shock. Very durable. Can be custom valved by factory. About $130 shock.

 

The fast EP racers are running the Ground Control double adjustable. I think they are the cheapest double adjustable on the market at $300/shock. Can be rebuilt by factory.

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I realze that There would not be much interest in KYB GR2's but the photo will show something very interesting. The shorter strut cartridges are VW Jetta GR2's but have a longer cylinder stroke than the 280 Z GR2 front strut catridges which tubes are longer but with shorter shaft length...go figure... The Jetta strut is the one you use on 2 inch sectioned 280 Z front strut tube and the 280 Z front strut cartridge is used on the rear sectioned strut tube.. I have seen Illumina's for sectiond 240 strut tubes.. and these cartridges have a longer stroke length for the rear... I have re-thought my 2 inch strut tube sectioning on my project 250 Ferrari kit and opted for camber plates which will at least drop the car at least 2 inches + or - with the stock length strut cartridges http://pg.photos.yahoo.com/ph/larryjohnson97438/detail?.dir=8223&.dnm=fadd.jpg&.src=ph

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The fast EP racers are running the Ground Control double adjustable. I think they are the cheapest double adjustable on the market at $300/shock. Can be rebuilt by factory.

 

Known as Advance Design. They go for $400 each, and I've heard good things about them.

 

I have Illuminas with spring rates in the 250-275 range, which from what I hear is the limit for Illuminas. When it's time to replace them, I'll either bite the bullet and buy the AD's, or go with Koni's, which seem to be the best bang for the buck.

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Just a word on the spindle pins.:beatdeadh

 

I took my control arms to a 4X4 shop and had them removed along with the bushings and collars for $30 bucks, a bargain IMO. (Although they screwed up the threads on one pin no big deal I ordered 2 new ones)

 

 

If you have a 4X4 shop in your area I would strongly recommend doing this, is your time and aggravation worth $30? Mine is. In fact when the new bushings get here I'll probably have them installed too. I’m not lazy just not crazy about the “spindle pin†project, and yes I have done the burning of the bushings, disassembly and rebuilding of the LCA on my 240 before. (these LCAs belong to the Scarab).

d

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Carrerra's- junk. Koni's- junk after a few races, upper bushings don't seem to last. GC Advanced Design- really junk, not enough volume on the rebound side of the Z strut, couldn't ever make them work. Ditto the BMW application we tried for ITS racing. Total crap. The people I find that love them are also lose when they race me.

 

Bilstein P30-0032 revalved 300/100 in a shortened strut housing with some P/N 450424 gland nuts to adapt them to a Z strut thread. That's the non adjustable we went to in ITS after the SCCA outlawed our remote reservior double adjustables for that class, and also the shock that was used on the ERatadz Motorsports EP 240Z that finished second in the RunOffs 2 times before converting to the ShockTek remote reservior shock banned from ITS. Now I happen to have a set of the ShockTek struts for sale (only 4 sets ever built and the other 3 sets are in EP cars) if anybody has $2k burning a hole in their pocket for a great road racing shock. They're baseed on Penske and Bilstein parts, easily rebuildable and revalveable but ShockTek got bought and is defunct. Your best "still supported" alternative would be JohnC's remote reservior setup based on the Penske.

 

 

Ain't much, but that's what I think about shocks.

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Bilstein Ca. You can actually get Shox.com and some of the other distributors to work it out with Bilstein when you buy them instead of after the fact. Bill Hindorf is the racing support guy out there and Jack French is the parts guy.

 

We are talking road racing here, aren't we? I don't know nuthin' 'bout birthin' no drag racin'.

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Bilstein P30-0032 revalved 300/100 in a shortened strut housing with some P/N 450424 gland nuts to adapt them to a Z strut thread.

 

So do you recommend this strut with this valving as the best relatively low cost option? It's again for an autocross / street driver (probably around 2400 lb) and I'm just looking to go as fast as I can with quality components realizing I wont really be competitive. I'm running 225F / 250R springs but that's just because the general consensus on the board seemed to recommend. Last questions are any idea how much these run as I couldn't find them on the Shox.com site and how much do you section the struts (240) with these?

 

Thanks

Cameron

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Katman you are tough on shocks and I respect that. However, I know of EP racers that placed well at the runoffs and national level FP autocrossers that run the GC's and speak highly of them. Although they did recommend a rebuild each season and admit price was factor in buying them. I suspect "junk" to you would still satisfy a strong regional competitor?

 

As far as Carerra's, their rebound left something to be desired. I've only known a couple of others who ran them on vintage and ITS Z's. For a non-adjustable, I thought they were adaquate, but of course I've never ran a 10+ race schedule either.

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Carrerra's- junk. Koni's- junk after a few races, upper bushings don't seem to last. GC Advanced Design- really junk, not enough volume on the rebound side of the Z strut, couldn't ever make them work. Ditto the BMW application we tried for ITS racing. Total crap. The people I find that love them are also lose when they race me.

 

I can't speak for road racing but for autox/hillclimb I'm pleased with the GC shocks. It did take a couple of revalves to get them in the range that I needed. And for the money I couldn't build a similar set of anything else but there are far better shocks out there. If I were truly serious I would use Penske or Ohlins, leaning towards the latter in 4-way configuration (T44).

 

To answer your question about what real racers do (this will probably annoy many that race) is they look at their linear pots on the DA system and adjust so they the damper histogram is symmetrical. This will amost always make for a faster car. And in a non-aero car shocks will have one of the largest tuning effects outside of kinematic changes (suspension geometry).

 

If you have linear pots on your car you'll find that each track will require changes to valving, etc. to get a symmetrical balance. Then you adjust your shocks so that you roll gradient is minimized, which puts less torsional stress on the chassis.

 

Remeber that stresses on the shock shaft from the spring and how the strut works will cause the shaft to bend. It's best to run the piston either low in the strut housing or towards the top to reduce seal friction from this effect.

 

Cary

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Bilstein P30-0032 revalved 300/100 in a shortened strut housing with some P/N 450424 gland nuts to adapt them to a Z strut thread. That's the non adjustable we went to in ITS after the SCCA outlawed our remote reservior double adjustables for that class, and also the shock that was used on the ERatadz Motorsports EP 240Z that finished second in the RunOffs 2 times before converting to the ShockTek remote reservior shock banned from ITS.

 

So you used the same 300/100 valving in both the ITS and the Eprod cars? What spring rates were you running on both?

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Yes, simply because we never collected enough data after being forced into them to see need for a change. EProd cars we run about 500F/425R and the ITS car about 400F/350R on a 240Z. Bilsteins are to some degree "self adjusting" for different tracks. Bottom line is for the weekend racer its easy for the race engineer to be way more precise than the driver can achieve. My experience with shocks in non-winged cars for amateurs (albeit, extremely talented amateurs) is that the right shock tuning did wonders for tire life and overall race time, but not really much for individual lap time. In other words, the fastest laps we could run with el cheapo shocks were within hundredths of the fastest laps we ran with perfect shocks, but we could run them more consistently, and the driver wasn't scared doing them. And tire wear went to ZERO. You have to have a lot of track time and data acquisition to really maximize the benefits of an adjustable shock and for most racers that's just polishing turds.

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So do you recommend this strut with this valving as the best relatively low cost option? It's again for an autocross / street driver (probably around 2400 lb) and I'm just looking to go as fast as I can with quality components realizing I wont really be competitive. I'm running 225F / 250R springs but that's just because the general consensus on the board seemed to recommend. Last questions are any idea how much these run as I couldn't find them on the Shox.com site and how much do you section the struts (240) with these?

 

Thanks

Cameron

 

 

You may have to call. Revalving is about $65 per. The shock used to be inexpensive, like less than $100. I have a reciept for a car I did last year I'll dig up. Up to 240lb springs we actually got away with a Tokico BZ3039 which I don't think they make anymore, so the Bilstein is proly the cheapest all around way to go for spring rates beyond the normal Tokico Illumina range. However, for street/autox I wouldn't go this route- I'd try Illumina's so I had some adjustment to soften it up for street. We've blown out Illumina's at 250lb/in spring rates but that was years ago, anybody have any experience with them at Cameron's rates?

 

The Bilstein I mentioned requires struts shortened about an inch, I can look up specifics when I get back to work on Monday if anyone wants them. Bilstein could also revalve a stock Z shock if your strut length was stock.

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I've been running 200/250 for 8 years on Illuminas, daily driver, about 5 years autox and some track days. I blew one front, but that was on the big track after repeatedly driving over one of the curbs. Oops. Other than that one the rest have held up fine.

 

I'm really looking to go much heavier on the springs since I'll finally be trailering to events, so thanks for all that Bilstein info Katman.

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Katman you are tough on shocks and I respect that. However, I know of EP racers that placed well at the runoffs and national level FP autocrossers that run the GC's and speak highly of them. Although they did recommend a rebuild each season and admit price was factor in buying them. I suspect "junk" to you would still satisfy a strong regional competitor?

 

Hey, we won an ARRC in ITS with shocks that didn't cost us $200, for all four! Talk about junk! So yeah, you can be competitive with all sorts of shocks. I call everything that isn't on my race car junk. :)

 

My biggest problem with GC's was in a BMW app. I wanted them to work, everybody else in the class (ITS) was using them, and I love Jay's hardware. I was willing to write off our bad experience with them on the 240 as "we were just spoiled with the ShockTek's and didn't spend enough time with the GC's to get them to work". However, after 2 seasons of changing every possible thing ('cept GC's Advanced Design shock) on the BMW's and having both driver's always claim that the only way you could tell you were losing the back end was if you were looking out the side window, and the only way you could tell you were understeering was if you ran out of steering lock, I made a wholesale swap to Bilstein and proceeded to win the last 2 ARRC's. Went from scary cars with no feel to what a Bimmer should feel like- a blast to drive. I actually have two cars set up with radically different spring rates and two different Bilstein shocks and they both rock.

 

All my former Koni friends always complained about the upper bushing wearing out prematurely, and Truechoice hammers you on the rebuilds. Otherwise I like them.

 

We used to race Tokico but they don't really support racing so eventually our spring rates on the Z's outgrew their off-the-shelf parts, but I'd use them again on a street car. Bilsteins just seem to last, they're rebuildable and revalveable, and don't cost as much as Koni's.

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Good stuff here. Thanks guys. This explains a lot. I tend to view shock tuning as one of the last things to optimize when setting up. Trouble is too many other things get in the way of focusing on that aspect. I am getting better though. I am trying to focus more on what the car is doing and how it feels rather than just getting through the turn. You never stop learning.

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No doubt Bilsteins are very durable, a mate of mine does targa events in his 240, which involve several days high speed driving over temporarily closed often rough sealed public roads. In that sort of use Bilsteins will outlast and probably outperform Konis.

 

But the problem with Bilsteins for road and circuit work is that they can't be adjusted to take account of different conditions or changes to the car.

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Ditto what others have already said - this is great info. I think I'm going to stay with the Illuminas based on the conversation here. I already have the BZ3038s on every corner and from what I can guess they were probably installed around 1991 by a previous owner. When I got the car it had 500 lb/in springs (scary on the street 'cause it tended to skip around) and NO bumpstops. I put on the 225/250 springs and bumpstops at which time I noticed the rods on all the struts were blued in a small range of travel. jmortensen has said this discoloring is normal so how do I tell if the struts are good or not? The spherical bearings in the camber plated were also all siezed to the top of the struts. I ended up having to cut the bearings off after trying several other methods (gear puller, hammer, larger hammer, etc) - so my point is the threaded top end of the struts are no longer the straightest anymore but I can still tighten down the nut. Dont know if this matters but it bugs me. The rears have a fairly long spacer under them, maybe a couple inches long, and the fronts only have a single washer as a spacer. Anyone know the part numbers of the struts to use when I section the housings? Finally, I assume you use shorter ones on the front or due you use shorter ones all around and keep the longer spacers in the rear?

 

Thanks again

Cameron

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