E46 M3 springs
Discussion
Hiya
Right, I'm wondering if anyone can help me with stock numbers for the springs on the E46 M3...
I'm trying to build a very accurate M3 model for a car simulation, and have been sourcing data from all over the place, however, the spring rate has been hard to get.
Currently, I'm using "guessed" US rates for the springs, 150 lb/in front, and 450 lb/in rear. These equate to pretty soft wheel rates.
I've set an appropriately long front wheel bump length, and still manage to be bottoming the front out when braking over bumps alot.
I've heard and read that the front of US M3's is quite soft compared with Euro spec M3 suspension, but can't find any detailed information on the rates.
I have the motion ratio of the rear control arms and everything, just no real spring rates to put in unfortunately.
This US rates equate to a *wheel* rate (seen at the tyre) of ~ 25800 N/m front, and ~ 34500 N/m at the rear... Seems setup so the rear travel is less effected by passengers or heavy boot loads!?
It's interesting to note that the adaptive suspension in the US for the 3 series, including M3, Pentax or something, gives stock 330Ci rates of 150lb/in front, and 410lb/in rear. Almost identical to the US M3 figures i found posted of 150lb/in f/450lb/in rear.
I'm quite sure the Euro rates for an E46 M3 are considerably higher than the US spec 330Ci at least!
Just want these numbers as accurate as possible...
Any help would be greatly appreciated!
Picture of my model so far, most of the technical details are in now, just tweaking different brand tyres and the suspension needs finalising...
Again, and help or numbers at all that you know for Euro spec E46 M3's would be great!
Thanks
Dave
Right, I'm wondering if anyone can help me with stock numbers for the springs on the E46 M3...
I'm trying to build a very accurate M3 model for a car simulation, and have been sourcing data from all over the place, however, the spring rate has been hard to get.
Currently, I'm using "guessed" US rates for the springs, 150 lb/in front, and 450 lb/in rear. These equate to pretty soft wheel rates.
I've set an appropriately long front wheel bump length, and still manage to be bottoming the front out when braking over bumps alot.
I've heard and read that the front of US M3's is quite soft compared with Euro spec M3 suspension, but can't find any detailed information on the rates.
I have the motion ratio of the rear control arms and everything, just no real spring rates to put in unfortunately.
This US rates equate to a *wheel* rate (seen at the tyre) of ~ 25800 N/m front, and ~ 34500 N/m at the rear... Seems setup so the rear travel is less effected by passengers or heavy boot loads!?
It's interesting to note that the adaptive suspension in the US for the 3 series, including M3, Pentax or something, gives stock 330Ci rates of 150lb/in front, and 410lb/in rear. Almost identical to the US M3 figures i found posted of 150lb/in f/450lb/in rear.
I'm quite sure the Euro rates for an E46 M3 are considerably higher than the US spec 330Ci at least!
Just want these numbers as accurate as possible...
Any help would be greatly appreciated!
Picture of my model so far, most of the technical details are in now, just tweaking different brand tyres and the suspension needs finalising...
Again, and help or numbers at all that you know for Euro spec E46 M3's would be great!
Thanks
Dave
www.bm3w.co.uk/ubbthreads/showflat.php?Cat=0&Board=UBB31&Number=108167
E46 M3 Coupe OEM springs
Part Number Front 31 33 2 282 330
Part Number Rear 33 53 2 229 490
spring rate Front 25 N/mm (143 lbs/inch)
spring rate Rear 60 - 120 N/mm (345 - 685 lbs/inch)
"The OEM and eibach rear springs are progressive but they are linear for a very long way in the compression until the spring rate increases in the end."
Car gets stiffer rear springs if you spec it up with options (sunroof, satnav etc).
What's the simulation for? Would be interested to see it when it's done.
>> Edited by john_p on Wednesday 5th January 15:09
>> Edited by john_p on Wednesday 5th January 15:14
E46 M3 Coupe OEM springs
Part Number Front 31 33 2 282 330
Part Number Rear 33 53 2 229 490
spring rate Front 25 N/mm (143 lbs/inch)
spring rate Rear 60 - 120 N/mm (345 - 685 lbs/inch)
"The OEM and eibach rear springs are progressive but they are linear for a very long way in the compression until the spring rate increases in the end."
Car gets stiffer rear springs if you spec it up with options (sunroof, satnav etc).
What's the simulation for? Would be interested to see it when it's done.
>> Edited by john_p on Wednesday 5th January 15:09
>> Edited by john_p on Wednesday 5th January 15:14
Wow, well I didn't believe the low front numbers at first...
I'm sure when I did the wheel rate for my Pug 405 Tdi a while back I got a figure of 21,000 N/m, and it seems to bottom out more than I like with a bit more travel than an M3... mind, the M3 being more 50:50 weight distribution means the mass over the front is about the same!
Erm, well, those figures must be right then... I'll have to try get realistic anti-pitch values for the front and rear.
The simulator is from www.racer.nl
The official forum for it is down right now, and thats where most of the interesting stuff goes on, the website is updated rarely.
There is plenty of trash out there, lots of young people like to rice up badly modelled badly setup cars with surreal numbers though.
I've been working on this M3 for almost two years, and been searching for numbers and data for ages to get it as accurate to real life as possible.
Biggest problem now is the rear progressives, since the simulation doesn't support them yet, but I can probably extrapolate a good intermediate value, say 20% ontop of the initial spring rate.
Thanks for the data anyway, it'll hopefully make some other values fall into place...
If I ask for some other values, such as hub centre to wheel arch top, and rolling radius at standard tyre pressures, would you be able to provide them?
Thanks for the help!
Dave
I'm sure when I did the wheel rate for my Pug 405 Tdi a while back I got a figure of 21,000 N/m, and it seems to bottom out more than I like with a bit more travel than an M3... mind, the M3 being more 50:50 weight distribution means the mass over the front is about the same!
Erm, well, those figures must be right then... I'll have to try get realistic anti-pitch values for the front and rear.
The simulator is from www.racer.nl
The official forum for it is down right now, and thats where most of the interesting stuff goes on, the website is updated rarely.
There is plenty of trash out there, lots of young people like to rice up badly modelled badly setup cars with surreal numbers though.
I've been working on this M3 for almost two years, and been searching for numbers and data for ages to get it as accurate to real life as possible.
Biggest problem now is the rear progressives, since the simulation doesn't support them yet, but I can probably extrapolate a good intermediate value, say 20% ontop of the initial spring rate.
Thanks for the data anyway, it'll hopefully make some other values fall into place...
If I ask for some other values, such as hub centre to wheel arch top, and rolling radius at standard tyre pressures, would you be able to provide them?
Thanks for the help!
Dave
I was surprised by the low rate too. Happy to help if you need anything else!
Not sure if my rolling radius measurment will be useful as I'm using odd sized tyres
but tyres are
225/45R18
255/40R18
or
225/40R19
255/35R19 if you spec 19" wheels
Ask over at BM3W if you have any more tech questions, I'm sure someone will be able to help.
Not sure if my rolling radius measurment will be useful as I'm using odd sized tyres
but tyres are
225/45R18
255/40R18
or
225/40R19
255/35R19 if you spec 19" wheels
Ask over at BM3W if you have any more tech questions, I'm sure someone will be able to help.
Well, I got the wheel rates all right and in, then finished the model graphically and got some more real data.
Right now it has all the wheel geometry correct, the wheel rates are correct, the mass is correct, the engine torque is from a superchips dyno, callibrated to get 0-100 and 0-200 km/h times and lots of in-gear times within 5% of real. www.track-challenge.com
Also has lots of other little bits and pieces extrapolated from the real car, like engine inertia from blipping speed and such.
Thanks for your help John with those spring rates, it's helped to make it as real as I care to make it...
Just getting them dampers setup right now though... I need a damper dyno and someones M3 for a day
A pic
http://forum.rscnet.org/attachment.php?attachmentid=254631
and you can get it from here
http://forum.rscnet.org/showthread.php?t=191287
You'll need the simulation too of course if you wanna have a drive too John. Contact me as it takes some setting up if you want to have a go.
Thanks again
Dave
Right now it has all the wheel geometry correct, the wheel rates are correct, the mass is correct, the engine torque is from a superchips dyno, callibrated to get 0-100 and 0-200 km/h times and lots of in-gear times within 5% of real. www.track-challenge.com
Also has lots of other little bits and pieces extrapolated from the real car, like engine inertia from blipping speed and such.
Thanks for your help John with those spring rates, it's helped to make it as real as I care to make it...
Just getting them dampers setup right now though... I need a damper dyno and someones M3 for a day
A pic
http://forum.rscnet.org/attachment.php?attachmentid=254631
and you can get it from here
http://forum.rscnet.org/showthread.php?t=191287
You'll need the simulation too of course if you wanna have a drive too John. Contact me as it takes some setting up if you want to have a go.
Thanks again
Dave
john_p said:
www.bm3w.co.uk/ubbthreads/showflat
E46 M3 Coupe OEM springs
Part Number Front 31 33 2 282 330
Part Number Rear 33 53 2 229 490
spring rate Front 25 N/mm (143 lbs/inch)
spring rate Rear 60 - 120 N/mm (345 - 685 lbs/inch)
"The OEM and eibach rear springs are progressive but they are linear for a very long way in the compression until the spring rate increases in the end."
Car gets stiffer rear springs if you spec it up with options (sunroof, satnav etc).
What's the simulation for? Would be interested to see it when it's done.
>> Edited by john_p on Wednesday 5th January 15:09
>> Edited by john_p on Wednesday 5th January 15:14
E46 M3 Coupe OEM springs
Part Number Front 31 33 2 282 330
Part Number Rear 33 53 2 229 490
spring rate Front 25 N/mm (143 lbs/inch)
spring rate Rear 60 - 120 N/mm (345 - 685 lbs/inch)
"The OEM and eibach rear springs are progressive but they are linear for a very long way in the compression until the spring rate increases in the end."
Car gets stiffer rear springs if you spec it up with options (sunroof, satnav etc).
What's the simulation for? Would be interested to see it when it's done.
>> Edited by john_p on Wednesday 5th January 15:09
>> Edited by john_p on Wednesday 5th January 15:14
Not wishing to start a new thread and go over old ground, but has anyone got the spring rates for the CSL by any chance? I guess the motion ratio's (main geometry) is the same, just with new castor/kpi and camber etc...
I'm building the CSL version now in line to working towards a Loaded M3 CSL for release in a few of the PC sims like rFactor and Racer... any numbers like the above would be a great help as I've not had much luck finding them so far!
Thanks for any help.
Dave
Edited by Mr Whippy on Monday 15th January 23:16
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