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

[clarkspeed]

As an update to this post, I'll call it...............

 

ECONOMICAL RACE STRUT INSERT OPTIONS

Bilstein (VW sport insert) non-adjustable - P30-0032 - $99 ea. Plus $70 for revalve at Shox.com

Advance Design - double adjutable - $399 ea. - Ground Control

Koni 8610-1437RACE - single adjustable - may need revalve - $160 - Summit

Koni 8611-1257RACE - double adjustable - $256 Summit

Carrera 32748 - non-adjustable - Still supported by QA-1? I'm still waiting on quote/answer.

Tokiko - Not suitable for higher spring rates.

 

For the price, I'm thinking seriously about the Koni 8611's. Any other users of this shock out there?

[mom'sZ]

Thanks John for some excellent information concerning the Konis.

The upper bushing/seal is crimped in place with three tabs off the housing itself.

I can confirm the Koni 8610-1437RACE do indeed seem to have this set up. It's actually the housing cap that's crimped. Will make sure the gland nut stays tight.

Clarkspeed: I am running the Koni 8610-1437RACE on my car (78 280z). Did not have them revalved before installation. I have not driven the car on the race track yet, so can't comment on there perfornance on the track. Also, I got mine at shox.com and they were only $130 each.

[johnc]

I would like to hear how the 1437RACE works on the track. The dyno charts us west coast guys have seen show a doubling of compression (to over 200) but others have said that Koni executives refute this.

 

I've sold a few sets of 8611s to customers. The compression adjuster is at the bottom of the shock so you need to machine a couple spacers to keep from crushing it. Drilling a hole in the bottom of the rear strut tubes makes it easy to get at the comp adjuster. Doing the same on the front tube just makes it easier to get at once the strut is unbolted from the steering arm.

[katman]

Hey John-

 

Checked my notes and we ultimately ran lower spring rates on the EP car with the slicks than we had on the ITS car that won the ARRC twice, so I stand corrected. We had tried higher and didn't like it. 400F/350R on the ITS car, 'bout 100lb/in lower on the EP car. Before we got the ShockTek's we only went 325/285 on the ITS car.

[johnc]

OK, I feel better. I was wondering how I missed something that significant. Thanks.

[mom'sZ]

I would like to hear how the 1437RACE works on the track. The dyno charts us west coast guys have seen show a doubling of compression (to over 200) but others have said that Koni executives refute this.

As soon as I get the car on the track I will let you know. I am considering running the car at a couple of autoXs just to shake it down.

 

I've sold a few sets of 8611s to customers. The compression adjuster is at the bottom of the shock so you need to machine a couple spacers to keep from crushing it. Drilling a hole in the bottom of the rear strut tubes makes it easy to get at the comp adjuster. Doing the same on the front tube just makes it easier to get at once the strut is unbolted from the steering arm.

I am considering the 8611s for the next upgrade. I don't think having to unbolt the steering arm would be that big a deal. Thanks again for all the information you have provided on these inserts.

[clarkspeed]

I'm curious about the 8610's also. Oh and the GC Advance Design's are 6-8 weeks lead time.

[clarkspeed]

Update:

 

Carrera 32748's no longer supported by Carrera (QA-1). QA-1 has no plans to move into strut insert applications.

 

Another cheap race shock bites the dust.

[johnc]

Also, the Koni 8611 shock to use is the 8611-1259RACE. The dimensions are:

 

Stroke: 6.02"

Max Length: 21.26"

Min Length: 15.24"

Body Length: 13.07"

Body OD: 1.71"

 

Dimensionally its exactly the same as the 8610-1437RACE and the old 8610-1149. They will also work with the OEM gland nut.

[heavy85]

Last night I e-mailed Koni about the difference in damping characteristics between the old and new struts. Following is that e-mail along with their response. It appears that the new struts should work just fine without revalving if I read this correctly.

 

Response from Koni:

 

"Cameron,

 

The compression damping did not change from the 8610 1149s. The rebound

damping, however, was changed to be more digressive so we could give the inserts a greater range of spring rates to work with than the out going 8610 1149s. I'm sorry that you have been mis-informed. Thanks for writing.

 

Gordon"

 

Original Message from me:

 

"Sent: Tue 12/20/2005 7:05 PM

To: racing@koni-na.com

Subject: Koni Web Site Contact

 

Comments : I autocross a 240Z and am in the process of shortening the strut

housings to run shorter struts and gain back some suspension travel. 8610-1149 used to be the strut of choice for this application but they are no longer available from Koni. I've been told the replacement is 8610-1437RACE but that the compression damping has been doubled. If this is the case the

'replacements' really are not direct replacements and require revalving to work properly in this application. Can you please confirm the damping

characteristics of the 8610-1437RACE in comparison to the old 8610-1149 and recommend a strut to use in place of the 8610-1149s."

 

Woo-hoo sounds like we may still have a decent low cost strut available from Koni unless I'm missing something.

 

Cameron

[Guest JAMIE T]

I spoke with Gordan last week about struts for our cars. I was particularly interested in the 2817's which are a custom build struts. You basically get a strut that can be valved basically anyway you want it and it comes with a steel housing that you weld you own bracketry to. After finding out that they are about $1500 EACH. Gordan talked to me about the ones you mentioned and seems to feel they are improved and would be suitable for our needs.

[johnc]

"Cameron,

 

The compression damping did not change from the 8610 1149s. The rebound

damping, however, was changed to be more digressive so we could give the inserts a greater range of spring rates to work with than the out going 8610 1149s. I'm sorry that you have been mis-informed. Thanks for writing.

 

Gordon"

 

And Gordon told Bryan Lampe early this year that compression damping had been increased. Doug from Koni told Erik Messley that Koni changed both rebound and comrpession damping on the 8610-1149 to better meet the needs of the biggest market for those inserts (European VW racers).

 

I have a shock dyno graph for the 1149. I'm going to try and get one for the 1437RACE.

[gramercyjam]

It would be helpful to know if any of the 8610 or 8611 would be suitable for springs in the 400-500 lb range.

[johnc]

If anyone has the skills to pull an image out of a PDF file, I'll send the dyno graph for the 1149. Send me back the image and I'll host/post it here.

[johnc]

Just got an e-mail back from Gordon Benson with a mixed dyno chart of the 8610-1149 and the 8611-1257. He says:

 

I don't have a full chart for the 8610 RACE but the 8611 RACE has the exact same valving for the rebound side.

 

So, that means the rebound valving on the 8610 was changed to match the rebound valving on the 8611 double. That is a big change from 8610-1149:

 

1. The 8610-1149 rebound full hard is about 1600nm at velocity .330mps while the 1257 rebound full ahrd is about 2400nm at velocity .330mps. That's 33% stiffer rebound at full hard.

 

2. The 8601-1149 rebound at full soft is about 600nm at velocity .330mps while the 1257 at full soft is about 1250nm at velocity .330mps.

 

So, that means the rebound valving range on the 8610-1437RACE has been moved up about 33% compared to the 1149. That's probably fine and would allow contorl of higher rate springs but it also means that it probably won't work for springs rates any less then about 300 lb. in.

 

For the compression (bottom of graph), the 8610 1149 and 8610 1347 RACE uses the _same_ footvalve and will build the same amount of compression force.

 

From this we can assume that the compression did not change on the 8610-1437RACE from what was on the 8610-1149. Checking the dyno charts confirms that there really isn't any change in compression damping for the 8610-1437RACE compared with the 1149. Its still a bit low (around 250 to 500nm in the .132 to .198mps range where cars usually work) so revalving to around 750nm is still a good idea.

 

The only other difference between the 8610 1149 and 8610 1437 RACE is that the top mount is different. Whereas the 1149 was 5/8" in diameter, the 1437 RACE is 14mm but includes a hat bushing to work with 5/8" bearing camber plates.

 

A minor change but one to keep in mind when sourcing camber plates.

[johnc]

Shocks dyno graphs (thanks to Cary for extracting them from a .pdf and making them large enough for us guys with old eyes to see). The first is for the 8610-1149. The upper half is rebound force and the lower half is compression force. Both forces are measures based on the speed of the shock shaft. Force is measured in Newton Meters and velicity is measured in meters per second.

 

 

The second graph is an overlay of two. The 8610-1149 curves along with the rebound curve of the 8611-1257RACE which is supposed to match exactly the curve of the 8610-1437RACE that replaced the 8610-1149.

 

[clarkspeed]

For someone like me getting ready to source some race struts, this thread is AWESOME!

 

And by the way, here is the quote I got from Shox.com

 

8610-1437RACE $159.00 eac strut insert

8611-1259RACE $249.00 each

 

Koni & Tokico have free shipping, for retail customers, to the continental USA and Canada. Further discounts are usually available when purchasing more than one item at the same time.

[heavy85]

So' date=' that means the rebound valving range on the 8610-1437RACE has been moved up about 33% compared to the 1149 ... means that it probably won't work for springs rates any less then about 300 lb. in.

[/quote']

 

Uh Oh - I already ordered a set thinking they would work based on Gordons reply ..... but I'm running 225F / 250R 'cause it also runs on the street some and you're saying they are too much for anything less than 300 lb/in

 

Looking at the graphs the old ones at about two turns is where the new ones are at full soft which would imply (based on your comment) that the old struts had to be run near the softest settings at my springrates - is that where people were running them? Does this mean I'm screwed or just have to run them on the softer(est) settings?

 

Thanks

Cameron

 

PS - my first sticky 8)

[mom'sZ]

Cameron:

 

I already have a set of the Koni 8610-1437RACE inserts installed on my car. I ordered them before they were even available in this country. The car is being prepared for SCCA ITS but at the moment I'm driving it around on the street with the exact same spring rates you have. The ride is firm but not harsh. It never bottoms out. Typical Zcar rear end squat upon hard acceleration is completely eliminated. Nose dive under hard braking gone as well. And handling is awesome. With 40 series Toyos the car is on rails. You have to pitch it wildly into corners at stupid fast speed to even get it to slid. I personally am still coming to terms with the limits of the car. And this is with NO sway bars, I have a set of fatory sways but they are not even installed. I wanted to see how it handled without them. What John is talking about is road race handling on the track. Under those conditions handling is a very individual thing and his path of development and yours may not be the same. I don't think you are going to be disappointed with your Koni's.

[driftz240]

HEY JOHNC

Heres the secret sports setup,

have fun unless your a translator

www.sissk.co.jp/secretsports.htm

they offer a adjustable drop in, i belive 1.8 inch short stroke and valved very agressive..but im told there to be the hot setup these days in japan for s30

TRY WWW.TECHNOTOYTUNING.COM gabe tyler makes some parts for the z cars, like rca's "ROLL CENTER ADJUSTERS, "AKA" BUMP STEER SPACERS. some one mentioned the spacers, hes got great products and is pretty reasonably priced...

nice of you to bring that topic up by the way....