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Author Topic: Lowering (for trackday use)  (Read 13308 times)
uberprutser
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« on: August 01, 2011, 08:18:02 pm »

I will be lowering my 2.2 for trackday use and I'm wondering how far I can go without running into problems using the original springs and custom made shocks. At some point the trailing arms are going to hit the chassis. Anyone experience this? I'm also considering cutting the original springs.

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krede
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« Reply #1 on: August 02, 2011, 10:40:50 am »

Dont cut the original springs. Get a set of proper lowering springs istead.
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uberprutser
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« Reply #2 on: August 02, 2011, 12:40:28 pm »

As far as I know there are no proper lowering springs for the Murena. (Spax set excluded)
But what's so wrong with cutting the spring? It will increase spring rate and reduce travel.
Together with my lighter engine and upfront fuel tank this should reduce body roll considerably.
Did you ever see a Murena on the track? They roll bigtime Smiley
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krede
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« Reply #3 on: August 02, 2011, 12:53:33 pm »

As far as I know there are no proper lowering springs for the Murena. (Spax set excluded)

Ohhh but there are :

http://www.simon-auto.de/matra/deutsch/mur_tuning.htm

I wouldn't go any lower than 35mm anyway.


Ps: yes.. Murena's roll big time.... GP from this forum race his Murena 2.2... perhaps he can help you out... though I think he uses the original springs
« Last Edit: August 02, 2011, 12:57:24 pm by krede » Logged
uberprutser
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« Reply #4 on: August 02, 2011, 01:59:30 pm »

That's good to know. I'll definitely investigate this option.
Looking at the picture I noticed that those springs have more coils. About 8 v.s 6.7 original. Or perhaps mine are allready cut. To bad they don't list any specs.
35 mm might be the max for a normal usable road car but I don't mind slowing down for a few speedbumps now and then. I don't think I'll be doing any cruising/posing around town aynyway. Thats more a thing for the boy racers with loud exhausts.
But how far can I lower without ending up with to little trailing arm travel and hitting the chassis.
How much travel do I need anyway? Guess this also depends on the sping rate.
The rear ride hight will have a great influence on the engine mounting position since I want to align the drive shafts as much as possible.




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uberprutser
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« Reply #5 on: August 03, 2011, 08:31:08 am »

I have another question. Did anyone ever try to mount the front torsion bars from a 1308, 1510 or Horizon? Since these are front engined cars I would expect that these come with stiffer springs. I'm also very interested in upgrading the front suspension spring rate. But do not like the spax coilover setup especially for track use.  A bit to fragile for my taste.
Another option would be to create inboard shocks replacing the upper wishbone with a rockerarm. But upfront is where my fuel tank will be so this might not be possible.
A big advantage of inboard shock will be that it will create space for bigger brakes.
No more hitting the shock absorber when in full lock.

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krede
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« Reply #6 on: August 03, 2011, 08:33:09 am »

I think the rally murena had inboard shocks... a guy once posted a pic of it here
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Jon Weywadt
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« Reply #7 on: August 03, 2011, 08:44:39 am »

I think the rally murena had inboard shocks... a guy once posted a pic of it here

The pictures of that car are in this post:

http://www.matrasport.dk/forum/index.php/topic,1432.0.html

Whatever happened to it, I wonder. Huh
Seem to remember a 4-wheel drive version also. Huh
« Last Edit: August 03, 2011, 08:54:14 am by Jon Weywadt » Logged

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uberprutser
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« Reply #8 on: August 03, 2011, 10:20:07 am »

Nice to know that it has been done before. Although this is a bit more radical then I had in mind. Did you notice the drive shafts laying on the ground? Seems to be a 4WD conversion.

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Laurens
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« Reply #9 on: August 13, 2011, 05:48:47 pm »

Don't cut the springs.

I have short 2.2 springs from carjoy on my 1.6. with spax. the raised the car 0,5 cm and the hitting the chassis problem seems to be gone.

hitting the chassis hasn't been a big problem, because the trailing arm bushes also can move a bit in the rubbers. nothing is bend or cracked.

my hight is around 5 cm i think. not sure.

Ik ben overigens CyberLaui op het nederlandse forum.
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uberprutser
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« Reply #10 on: August 13, 2011, 09:10:10 pm »

Don't worry Cyber, I have a spare set 2.2 springs laying around.  Wink
Although I might want to fit them to my 1.6 because it's sitting rather high at the back with the 2.2 shocks.
Did anyone ever modify 2.2 shocks? Should not be hard to do. Just machine a bit of and weld the bracket on again.
Heat might be a problem. How thick do you think the wall of a shockabsorber is?


1.6 (left) vs 2.2 (right)


Sitting pretty high.

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uberprutser
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« Reply #11 on: September 09, 2011, 09:28:52 pm »

Today I tried to modify a 2.2 shock absorber in an effort to lower the car.
Not a good Idea, because after a while I struck oil!
Apparently the absorber consists of tho halves that are welded together.



















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Bart_Maztra
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« Reply #12 on: September 10, 2011, 08:49:23 pm »

Have a look here on dismantling a rear koni shock.
KoniTeringVering
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