Coilover Question (Differences)

[totta Crolla]

As MK2 Escort turreted rear dampers will fit an AE86 what about these:
http://www.peterlloydrallying.co.uk/inde...cts_id=462
not sure about the damper ratings though

[SekiguchiUeno]

Nohachi i dont want to disrespect you, you posts have technical background.

stock rear shocks have 35N compresion force,
Stock spring has 22N/mm compresion ratio,(on stock car at static load it gives around 2000N+ while the schock force is still 35N at the most of his stroke). Things change at the bumps on higher loads.When the body deceleration occure.
I cannot calculate it now out from the head, later i find formulas.
Now imagine to have 60N/mm rear springs paired with very stiff shock takes the whole load on shock tower and shock mount.

I had seen seen hachi with 35N/mm rear springs in normal place and bilstein rally shocks (they are really stiff 100N) and the perch on the axle was presed down to axle body, you can image what would hapen with this tiny sheet that holds shock on the axle if this would be coilover spec (thats probably what apolan talks about).

Stock rear towers are not made for this kind of loads for the long run and roads. Its better to direct the force over the chassis rails and axle body.
You have Miata if i remember and this is different story.

[nmwisima]

NoHachi Wrote:Ah, ... ...understand.

OMG!!!

Is it true NoHachi????
You re still here????

[Apolan]

lol, you have to go all the way to greece for something so offtopic, yet perfectly on cue

[NoHachi]

SekiguchiUeno Wrote:Nohachi i dont want to disrespect you

..while the schock force is still 35N at the most of his stroke)

You have Miata if i remember and this is different story.

Hi, no worries about disrespecting anyone. I'm not 100% sure myself and wrote down some ideas to get some other opinions. Hopefully, we all learn something in the end

Back to your idea: 35N seems a bit low? Do you know at which pistonspeed that is? For 86's ive only seen HTS shockdyno's and those ramped up to 300-400lbs at high pistonspeeds.. That would be closer to 1400N..even the turreted escort billsteins above are rated at 220lbs, or close to 1000N. Am I mixing something up?

My intuition says: cornering introduces a force that is counteracted or "stored" in the springs. After the corner, you take away the cornering force and are left with the potential energy stored in the spring.
Leave the spring and body alone, and the spring will launch the body. Pogo-ing and much laughter and joy will follow. So you slow things down by a counterforce from a damper. You're just slowing things, so the force certainly isn't equal. But I do think that the resulting force is near the force of the spring..certainly not a ratio worse then 35N vs 2000+N
What do you think? Just throwing up ideas.

Oh and by the way..I haven't had a miata for 2 years now :wink: Been driving a Trueno, just like most others here. Mine is street driven on 9/7kg springs and rear coilovers. No cage, no damage to shocktowers (so far..). I'd like to keep it that way, so that explains my interest in the subject :-)

[NoHachi]

nmwisima Wrote:

NoHachi Wrote:Ah, ... ...understand.

OMG!!!

[video=youtube]http://www.youtube.com/watch?v=bPmVhyHBRAM[video=youtube]


Is it true NoHachi????
You re still here????

I'm still here..just not posting anything if I don't have anything usefull to say..unlike some people here :wink:



(kidding offcourse, you old greek keyboardtiger! How's the miata? We're building a cheap one to do a sub 8min lap of the ring..always new that girly cars rock..god I miss mine).

[nmwisima]

NoHachi Wrote:I'm still here..just not posting anything if I don't have anything usefull to say...

Shame you have so little to say then...

Check the project thread

[SekiguchiUeno]

Hehe.

Well explained, i dont know for sure for myself, also your words makes much senze. I have not such great gift to explain this at english.

I hope this parametrs are ok, a recieved this from my mate in one telefon call, he had measured his all shocks at KW. Stock shock was probably worn out. And maybe it was not in N but in Kg, not sure now.
This was compresion valving i think at low speed. rebound was 120N (kg?) on stock old and 220N (kg?) at bilstein rallies. All rears. I know more as i visit him and looks at the graphs. Have you some dynos from HTS? I am curious now, but rumours are they are overdamped at compresion.
I have greedy type S and they are also prety stiff much stifer at compresion in oposite to bilstein sports B6 as i tried it to compress with my hands.
I dismounted it after year, have small cracks on the turets. There is maybe difference where you drive at most.

As you well explained springs accumulate the impact energy and shock is holding it back and release it slowly as spring decompres. But the worst thing is the first impact that should be accumulate and this is better to do with the spring(softer is better here) not with the shock. Shock should only control engagement and small high frequency shaking.

The turret is made in his shape to widstand rebound forces better in my opinion(konkave shape) not to take bumps from underside.
With coilovers you pair the bump forces in one point on the shock turret over one small damper rod washer and 10mm rubber bushing, but you lower the rebound forces as you said because the shock is sloving the spring down directly not over the body and turret dome.

Maybe i am wrong but thats what i have logically figured out. It depends how you drive and where you drive and what for shocks you have.

p.s.Hey i remember you have bought this flat black trueno from germany. have you some news?

[NoHachi]

Hi,
You can see the (sales) shockdyno here: http://www.ziptied.com/forums/index.php?topic=5537.45
(X-axis probably m/s, Y in lbs)

120kg sound more reasonable..about 250lbs whoch would put them in line with dampers from similar cars.

I agree about the forces from the shock probably being smaller. Both shocks counteract the return off the body to its normal angle. And, as you say, bump forces are significantly smaller then rebound ones.


Oh well, doesn't matter much. If she cracks I will be the first one to photograph it and put it on the internet. Just hasn't happened yet and haven't seen any other users have these problems. Maybe it will be ok. We'll see.

PS: not much news on the trueno..most of the stuff on the car was up to spec. Powerfull engine, top notch suspension etc. Just correcting small faults around the car and tuning towards a personal spec. Will update if anything worth photographing turns up.