Thread: Coil over rebuilding?

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2011-01-28 03:26:07

#11

iczer200sx Online/offline status of iczer200sx is unknown

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mr2 board!!!

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2011-01-28 03:37:45

#12

BlueRB240

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took forever to get my membership on that forum.

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2011-01-28 03:49:35

#13

wnwright

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Does he have dyno plots of his work?

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2011-01-28 03:54:32

#14

BlueRB240

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Yeah I'll find it and post it later.

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2011-01-28 09:58:27

#15

Cozzm0_AU

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Interested to see plots too.

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2011-01-29 01:47:35

#16

BlueRB240

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I looked over the thread and couldn't find the graph after just the before for the V1 and V2 D2 coil overs. He documented the parts he found the V1 and V2, I'll quote his post.

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2011-01-29 21:50:50

#17

Cozzm0_AU

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Still interested to see a 'real' graph of them in the before state. can you link to the thread?

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2011-01-29 22:04:10

#18

BlueRB240

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Originally Posted by aszilagyi

D2 racing struts for the MR2_ MK1 Up-date #1

I received the used set of 4 coil-over assemblies from MicaCeli.
With the intent of running them on the shock dyno.
And investigate if there is any possibility of re-valving (re-calibrating).
For a more suitable ride, targeting autocross and performance street driving.

And from the start there were a few challenges to over come.
Not a big deal this is quite normal in the shock Biz.

# 1 D2 racing deviated from the production MR2 strut tab offset.
So I need to make a new dyno fixture to run them.

#2 the corrosion that accumulated from normal street usage.
Has become a minor inconviance. As water had collected inside the drilled shaft.
And had completely locked-up one of the adjusters with rust.
Also the steel threaded main body also seems to corrode to the threaded on aluminum fixtures.

I would suggest the other owners of D2 (and similar struts). Do some corrosion prevention work. To keep there struts in fine working order.
I would not leave the adjuster hex keys in place. As this is where the water enters.
I would remove them and instill an easy to remove plug to seal the opening.
Also I would take the time to remove the threaded on hardware and lubricate with anti-seize. So in the future spring seats and clevis hardware will move freely.
The best bet would be to send them to a racing shock expert for service.
And while there an oil change will keep things on track. Please remember. A racing shock can be quite dangerous. If the untrained attempt to service them!!!

As far as the quality of the product, it is better than expected.

I grade racing shocks like this. Based on quality and value for your dollar.
Penske Racing #1 value, flexibility and ease of use – (made in the USA)
Ohlins #2 a bit pricy, Excellent fit and finish,
Bilstein #3 nice value for the price. And a nice conservative approach to racing.
Koni #4 good value for the price.

D2 is not main stream here in the USA. But if it was I would place it as comparable to Bilstein. This set uses good quality racing internal components (Better than the low tech street stuff found in some)

There a few flaws but at this price I would call it a good value.

And when tuned properly will be a great performer.

It is a true mono-tube race shock with a single (no check) needle and seat adjuster.
Meaning the single adjuster changes both the Compression and Rebound low speed forces.

It is a true high pressure gas shock with an inline separating piston. Dividing the gas charge and the hydraulic shock oil.

Like I said, D2 Racing struts have a few design flaws. But at this price, is a nice value.
But do not forget. Just like any racing shock will require service to stay in top condition.

Next time I post I will supply dyno data from the as built struts.
And a bit of insight about a re-valve direction.

Originally Posted by aszilagyi

Well I have disassembled one of the struts.

And found a few surprises. The working piston is an Ohlins copy (knock-off)
It is 42 mm & I have no knowledge of a 42mm Ohlins ever being used.

The aluminum parts from D2 Racing are quite soft and easy to damage.

And after a brief conversation with the salesman @ D2, they have little in the way of spare parts. No one is servicing them in the USA. And do not wish to repair or service the struts here in the states as they feel they are so inexpensive. It would be easier to just buy new parts.

The good news:

I have sources lined up for most of the seals. And re-valve parts.
And there should be no problem tuning this unit.

I also see the limited support from D2 racing as an opportunity.
Time will tell, but I feel we will be able to make this low buck monotube in to a winner.

Any one want to sell me a used set for my car?

.....................

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2011-01-29 22:08:27

#19

BlueRB240

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Originally Posted by aszilagyi

D2 racing struts for the MR2_ MK1 Review _Up-date #2

Just the facts:

D2 Spring rates as delivered –

Front rate is 225 #/inch
Rear rate is 360 #/inch

D2 Spring package is a standard race size - 2.5 in. I.D. x 7 in. free length Front and Rear.

Stock Aw11 spring rates I have measured in the past-
Front is 85 #/inch (first inch, don’t have the installed preload length)
Rear is 178 #/ inch (first inch, don’t have the installed preload length)
AW16 Rear spring rate is 183#/inch

D2 strut total shaft travel is 4.75 in. stroke length.
But a droop spacer inside could be removed to increase that slightly.

The struts system friction is higher than I like. And is not consistent in the 4 units.
This friction is measured as seal friction on the shock dyno. But I feel it is not the shaft seal that is the largest contributor of the friction.
We have a plan to reduce this force.

The adjusters on the D2 struts tested have no effect on the damping forces. Twisting the knobs in all positions (full hard to full soft) showed no change on the shock dyno.
Sadly there appears to be a slight design problem that keeps the adjuster from actually working. I feel this can be easily corrected. And will up-date when it is fixed.

As you will see in the as delivered dyno curves they are as we thought.
Very stiff in rebound.
The right to left forces differ more than I prefer or are miss-built.

Will let you know more as we start the actual re-valve process.

Originally Posted by aszilagyi

TheD2 Aw11 front strut Rebound Force is stupid high?

The Rear Rebound force is not as high as the front.
And Right to left also needs work.

I will keep you up to date

Originally Posted by aszilagyi

Did a bit more work Saturday, and will be back at tonight.

Found a few items of interest.

#1 - A portion of the high system friction. Is caused by the clamped on sway bar tabs. They are actually distorting the strut body tube. Actually causing the working piston. As well as the separating piston to stick in the housing.

This is a big deal that needs to be addressed.

I was able to change the force curves on the dyno by simply tighten the pinch bolts.
We will need a new or modified sway bar link bracket. On the strut to correct this problem. (I was unable to tighten the pinch bolts enough to keep the clamp from spinning)(without impacting the struts performance).

But once corrected - this will add consistence. And increase the life of the unit.

Called D2 Racing NA this afternoon. And they now have a revised larger version of the Sway-Bar clamp bracket (currently out of stock). But it still uses a pinch bolt to lock it in place.

I am sure we can modify the clamps we have as well.

Item # 2

Work to make the adjuster functional, looks quite promising.

Will post adjuster force curves when I am become happy with the results.

All I all things look good!

......................

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2011-01-29 22:16:59

#20

BlueRB240

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Gen 2 D2's now, those click when u turn the adjusters vs Gen 1's that didn't

Originally Posted by aszilagyi

D2 update

I ran a set of D2 struts for Jason Lee.
That are new and improved over the older set I worked on for MicaCeli.

The good news:
There was an adjuster design change. And it is completely functional.
And the range of adjustment (mostly rebound) is large. (a good thing)
Also they added a detent system. Making it easy to count out the adjuster clicks.

The not so good:
The force curves are still craze stiff in compression.
And the seal force is still too high. And has a weird effect seen in the low speed area of the shock plots.

The body cap and bearing has been changed. So I need to make new tools to disassemble the strut. So this slows the repair slightly.

But overall the design changes are positive!

Originally Posted by aszilagyi

D2 update
Jason Lee’s LF D2 struts

Shown are runs as delivered from D2
With the adjuster set @:

Full hard
-6 clicks
-12
-18
-24

Originally Posted by aszilagyi

FYI D2 update

Sadly I am disappointed in the changes made by D2.
After working on a newer set for MRSUPERTWO.

The revisions made to this newer version corrected the non-working adjuster from the earlier version. But for some reason they changed the shaft seal and bearing.

This new shaft seal may add to the durability?
But it also exhibits’ a low speed stick-tion problem. That can not be corrected with out a design change.

I did my best to fix the other problems and re-valve them for Mr. Lee (MRSUPERTWO). And elected not to send him a bill. I feel they will perform better than as delivered new. But I am not happy with the results.

And after a few calls to D2 USA.
I have little confidence they care enough to help fix or even understand the problem.
Its quite sad, they are not interested in using coustomer feedback or support. To better there products.

Link to the OG thread MR2 Owners Club Message Board
You need to be a member to even see it so I quoted the good stuff from the thread.

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