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short strut inserts

Im just going for slammage here, as this is on my summer cruiser.. I can always redo it in the winter if it sucks..

I forgot to write that the only thing that needs doing to run the saab dampers at the rear is pressing over the metal bits of the bushings from the volvo ones..

Putting those short inserts in the long tubes doesn't do anything for slammage...
Think about it.
 
Putting those short inserts in the long tubes doesn't do anything for slammage...
Think about it.

Explain that one to me, or are you just talking about how it can possibly bottom out against the longer tube?
I would love to shorten the tubes too, but I don't have the time/skill/patience to do so..
 
Explain that one to me, or are you just talking about how it can possibly bottom out against the longer tube?
I would love to shorten the tubes too, but I don't have the time/skill/patience to do so..

What i am saying is you didn't gain anything by changing to shorter strut inserts when you have stock length housing except taking away total travel. You dont get the car any lower.
 
Well damnit, I obviously hadn't thought about it enough, had just been thinking about that they were 4" shorter than the stock ones and therefore = chopping more rings of the spring and still have preload (no preload/loose-ish springs = no numberplates, and no license over here)..

Well I'm gonna have to see when I let the car of the jackstands if theres any travel left, if there isn't I'll just have to stay car-less for a while longer, while I get some housings shortened.
Cops took the plates of my dd as I had swapped the engine in it, thats why I'm so decided on trying it this way, cause I need a car as fast as possible
 
"get" the housing shortened?

Dude you can use a hack saw if you want its not hard.... take it to an exhaust shop they can weld it back together take the old struts to make sure its all centered. Should not cost much.

Might as well order coilover sleeves and have them weld stop rings on at the same time you're like 150 bucks away from coilovers dude.
 
i would never ever hack saw it. a tubing cutter would work very well if your in a pinch, it has to be a straight cut.
 
Well I've been driving my low ass 240 around for a while now, and haven't bottomed anything out.
So spacing on top of the damper worked fine for me
 
Shortening strut tubes by cutting and rethread ?

this is some basic info about what strutcartridges can be used when shortening your 240 struts. low cost, so Koni race inserts are left out on purpose.
it's not complete, there are more cartridges that can be used and more information will be added when available.

please note this is general info that comes from websites across the internet, so make sure to double check any measurements before spending cash.

The strut cartridge used in 240's is a T4 cartridge.
T4 cartridges all share a few measurements, basically diameters of the housing.

stock 240 cartridge

this cartridge has monroe partnumber 73950.
Housing length: 40,64 cm
piston rod length: 20,6 cm
when fully compressed the piston rod sticks out of the housing: 1,27 cm

Saab 900 ('94-'98)

monroe partnumber: 73264
housing length: 34,9 cm
piston rod length: 17,15 cm
compressed: sticks out 2,54 cm

first thing to notice is the housing is 5,7 cm shorter.
if we use this cartridge in the 240 strut tube we have 3 options:
  1. shorten the strut tube by 5,7 cm and we have a 9,15 cm shorter piston rod compared to stock and gain a theoretical 5,7 cm extra compression travel.
    In reality we gain less travel, as it cant compress fully, the actual gain in compression travel will be 5,7+1,27 - 2,54 = 4,43 cm
  2. use a 5,7 cm spacer under the cartridge and we have a 3,45 cm shorter piston rod compared to stock. we gain no extra travel. this solution is nice if you want to lower a bit more than 40 mm and your -40mm lowering springs lose contact with the springperches at full droop. the downside to this solution is we also loose 2,54-1,27= 1,27 cm of compression travel compared to stock....not good i'd say.
  3. use a 5,7 cm spacer on top of the cartridge this solves the problem of the lost compression travel in option 2. the piston rod length will be 9,15 cm shorter than stock but we only gain 1,27 cm extra compression travel.


Saab 9.3 ('99-'02)

monroe partnumber: 73453
housing length: 34,9 cm (same as above)
piston rod length: 17,78 cm
compressed: piston rod does not stick out (yay)

  1. shorten the strut tube by 5,7 cm and have a 8,52 cm shorter piston rod compared to stock and gain a theoretical 5,7 cm extra compression travel.
    As the piston rod does not stick out at full compression we dont loose any compression travel...we gain 5,7 + 1,27 = 6,97 cm extra compression travel (yay again). so although the piston rod is a bit longer we gain more from this cartridge than we would gain from the Saab 900 cartridge above.
  2. use a 5,7 cm spacer under the cartridge and we have a 2,82 cm shorter piston rod compared to stock. we also gain 1,27 cm compression travel. this solution is nice if your -40mm lowering springs lose contact with the springperches at full droop. again this is better than the Saab 900 cartridge as with lowering we need more compression travel to not bottom out.
  3. use a 5,7 cm spacer on top of the cartridge the piston rod length will be 9,15 cm shorter than stock and we gain 1,27 cm extra compression travel.


Daewoo Lanos?

monroe partnumber: 73405
housing length: 34,9 cm (same as above)
piston rod length: 15,24 cm (freakin short)
compressed: piston rod sticks out 0,64 cm (yay)

  1. shorten the strut tube by 5,7 cm and have a 11,15 cm shorter piston rod compared to stock and gain a theoretical 5,7 cm extra compression travel.
    In reality we gain more travel, the actual gain in compression travel will be 5,7+1,27 - 0,64 = 6,33 cm ...not bad at all
  2. use a 5,7 cm spacer under the cartridge and we have a 5,36 cm shorter piston rod compared to stock. we also gain 0,63 cm compression travel. this solution is very nice if your -40mm lowering springs lose contact with the springperches at full droop. again this is better than the Saab 900 and Saab 9.3 cartridge if this is the case.
  3. use a 5,7 cm spacer on top of the cartridge the piston rod length will be 11,15 cm shorter than stock and we gain 0,64 cm extra compression travel.


thats it for now... 3 cartridges we can use, and 3 ways to use them depending on what we want to achieve.
option 1 is the typical coilover use, if the car has to be really low with sufficient travel left
option 2 is the typical "a bit more than -40mm lowering springs" use if we need to keep the springs in the perches at full droop.
option 3 is the typical "option 2 didnt do the trick"

ofcourse option 2 and 3 still give you the problem of not gaining much extra compression travel, but depending on how stiff your springs are and how low you want to go this isnt always a problem. putting more pretension on your spring actually raises the spring rate so again in some cases you wont need much extra travel.

for info about how to shorten your strut tubes here's some info written by Kyote:
http://forums.turbobricks.com/showthread.php?t=85793

and here's some p.s. stuff that i need to write down somewhere here:
  • the fact that a strut is a T4 size strut does not automatically means it fits. there are many housing lengths available and most of them are too long for the 240 struttubes and therefor useless.
  • make sure to check if the strut cartridges you want to use fit into your topmounts.
  • always use a bumpstop with sufficient length on the piston rod. the bumpstops that come with the cartridges dont automatically have the right length. unless you know what you're doing dont leave the bumpstop out.
  • the measurements above are taken from Monroe cartridges and dont neccesarily apply for other brands.
  • be carefull when using gas struts with an inverted design (Bilstein, DeCarbon, Volvo-R and others). these have an internal bumpstop which means the compressed length of the piston rod is often longer than the cartridges mentioned above. so you cant compress them all the way and have less travel than you would expect. to fix this you can remove the nut at the bottom of the strut cartridge and pull the actual damper out to shorten the internal bumpstop
  • watch out for cartridges like Bilstein B8 Sprint and Koni Yellow with additional shortened rebound as these have a shortened piston rod and then the measurements given above do not apply. normal Koni red and yellow are not shortened and therefor dont have this problem.

all typing errors or grammar mistakes are made on purpose :-P


As an alternative to cutting and rewelding my strut tubes can I cut then rethread? If so what is the thread measurements? Each thread is how many mm?
 
As an alternative to cutting and rewelding my strut tubes can I cut then rethread? If so what is the thread measurements? Each thread is how many mm?
Thats how we do it, we cut the strut tube down and machine the threads at the top of the tube. Factory Thread diameter and pitch for a 240 is m48x1.0


Personally I don't recommend cutting and welding it, If its just butt welded its not that strong, it would benefit from a reinforcement sleeve but there isn't much room for something like that.
 
Thats like putting an intercooler on a NA car.

Well it has worked for me, not bottomed out, and the spring isn't loose when I jack up the car..

Not that it matters, I'll be getting bags soon, would be nice to adjust the ride height by the flip of a switch, the roads up here aren't the best..
 
Well it has worked for me, not bottomed out, and the spring isn't loose when I jack up the car..

Not that it matters, I'll be getting bags soon, would be nice to adjust the ride height by the flip of a switch, the roads up here aren't the best..

That means your not low enough to need a shorter strut housing.
 
I know.
But I absolutely need pre load on the springs when jacked up, to have to car road legal/ passing check up, every two years
 
What is a good quality strut insert for front and socks for rear on 1991 240 that would not cost a lot of money? I am interested in keeping it close to stock.
Ken
 
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