Cars 2002 Toyota MR-S C Stock/ E Street Spec (suspension mod) 0.7

[Tennisbiki]

Tennisbiki submitted a new resource:

2002 Toyota MR-S C Stock/ E Street Spec (suspension mod) - MR2, physics, C stock, E street, OE spec

The 3rd and last generation Toyota MR2, AKA MR-S or MR-S Spyder was known as a baby Porsche Boxster or a poor man's Lotus Elise. In the C Stock autoX or SCCA it was often outclassed, now it is placed in E Street class.

These files are the result of my attempt to produce a stock spec Toyota MRS using realistic suspension data as much as I can from Velo's 2002 MR-S mod. This is tuned for forgiving but spirited handling characteristics. There is enough tuning options for a typical AutoX...

Read more about this resource...

 

[Jim Carvalho]

I currently own and drive a stock 2003. I'll give this a try and provide feedback as appropriate.

Thank you.

 

[hachikid]

I've got an ES '03. The part that jumped out to me is the part where you mentioned the spring rates. The stock front spring rates are 75 lb/in, and the rears are 125 lb/in, and the typical ES-spec front sway bar rates range from around 500-800lb/in. I'll try it in the game, though.

 

[Tennisbiki]

The stock front spring rates are 75 lb/in, and the rears are 125 lb/in,

I used 13,000/21,000 N/mmm (1.4/1.6Hz ride frequency) , that is converted from 75/120 lb/in. Let me know if that feels too stiff, because there should be a motion ratio square in the calculation, which will drop about 10% in wheel rate. But the balance should be pretty close. Most mod cars out there use very stiff wheel rates.

and the typical ES-spec front sway bar rates range from around 500-800lb/in. I'll try it in the game, though.

Any idea what the original equipment's front and rear sway bar rates are?

 

[hachikid]

I used 13,000/21,000 N/mmm (1.4/1.6Hz ride frequency) , that is converted from 75/120 lb/in. Let me know if that feels too stiff, because there should be a motion ratio square in the calculation, which will drop about 10% in wheel rate. But the balance should be pretty close. Most mod cars out there use very stiff wheel rates.

Any idea what the original equipment's front and rear sway bar rates are?

I'll get some measurements later today and do the math on it. As for the suspension motion ratios, I believe it's around 0.97-0.98 for the Spyder. I didn't check it out last night, but I'm about to jump in and try the mod, though. I'll edit this post with general thoughts after. The one thing I did notice is that the dampers are 4-way adjustable. Street class rules only allow for 2 way dampers.

:EDIT: the car feels really good, but honestly, it's really hard for me to get a feel for what the car is doing with the camera riding in the passenger seat. I know the person who made the mod is trying to simulate a LHD position, but I'm in VR and seeing my virtual body, hands, and steering wheel all on the other side moving in my peripheral is making it really difficult for me. Is there an easy way to re-center the camera on the right side? Or is it possible to make the interior LHD?

 

[hachikid]

I just got the rear sway bar measurements. It's right around 45 lbs/in thanks to this SB calculator. This rate is static and does not change as the fast setup with these cars is leaving the rear OEM bar in and moving to a beefy fsb. So, removing the in-game adjustment, or at least adding an "OEM" setting hard coded to a 45 lbs/in rate would be a good move. As for the front bar rates, I'd say use increments of around 500-950 lbs/in with increments of 50. This is roughly what I've calculated the various spring rates are with the different bars that are out there. If you'd like more specific measurements of the various bar options, I'll ask some friends for what they're running. I'm using a hollow 1.25" front bar, but I believe there's also solid 1" and 1-1/8" bars out there, too.

 

[hachikid]

Also, is it possible to add different bump stop choices, adjustable length, and packers? I could also provide bump stop lengths to make sure the total bump stop/packer combination doesn't exceed OEM length. This is also a big part of ES setup. You mentioned wheels as well. I could send measurements of those, too, if it's possible to replace them.

 

[Tennisbiki]

I just got the rear sway bar measurements. It's right around 45 lbs/in thanks to this SB calculator. This rate is static and does not change as the fast setup with these cars is leaving the rear OEM bar in and moving to a beefy fsb. So, removing the in-game adjustment, or at least adding an "OEM" setting hard coded to a 45 lbs/in rate would be a good move. As for the front bar rates, I'd say use increments of around 500-950 lbs/in with increments of 50. This is roughly what I've calculated the various spring rates are with the different bars that are out there. If you'd like more specific measurements of the various bar options, I'll ask some friends for what they're running. I'm using a hollow 1.25" front bar, but I believe there's also solid 1" and 1-1/8" bars out there, too.
View attachment 669994

Thank you for the data.
I am going to test the rear ARB value using the 45 lb/s with 0.95 motion ratio, 7.8K *.95^2=.7.1K N/m.
Re: Front ARB:

I am wondering about the motion ratio of the f ARB. Is there a good picture of the wishbone from the top? Or a front view of the front suspension? Estimate from the above pictures, the motion ratio is less than 50%.
Do you think the OEM front bar is at about 500 lb/in (87.55K N/m)?. Assuming motion ratio about 0.50, that makes 21.88 K N/m. (For comparison only, Kuno's Alfa 4C 26680/10880, Elise: 21000/0, Arch's Elise: 2840/0)

 

[Tennisbiki]

Currently there is sufficient adjustment range in the setup.ini to allow driver's preferences. I can also include another setup files that enables wheel rate and ride height adjustment, that is for prepared and modified classes. For my purpose, I am able to set the suspension.ini to a pretty reasonable default value. And I would be happy to make changes to this default setting based on driver's feedback and real world value.

There is a way to make setting into choosing say discrete sets of spring or sway bars, but that means getting into creating lut files. Another way of doing this would be creating different setup files.

Again the kind of feedback that I really like is how the car drives compare to your stock MRS. The car I think is probably 10% too stiff in wheel rate, but I think it felt pretty close, what do you think? Any quirk in transition? Turns ok? It is pretty stable, more so than the AW11 entering a turn. AW11 seems to snap a bit more easily.
I do hope that more people likes real cars like this, that is a bit softer, has a bit more movement, more dive, more roll.. Maybe it is not so quick nor razor sharp, but .. I think it is a bit more nuanced.

 

[hachikid]

Currently there is sufficient adjustment range in the setup.ini to allow driver's preferences. I can also include another setup files that enables wheel rate and ride height adjustment, that is for prepared and modified classes. For my purpose, I am able to set the suspension.ini to a pretty reasonable default value. And I would be happy to make changes to this default setting based on driver's feedback and real world value.

There is a way to make setting into choosing say discrete sets of spring or sway bars, but that means getting into creating lut files. Another way of doing this would be creating different setup files.

Again the kind of feedback that I really like is how the car drives compare to your stock MRS. The car I think is probably 10% too stiff in wheel rate, but I think it felt pretty close, what do you think? Any quirk in transition? Turns ok? It is pretty stable, more so than the AW11 entering a turn. AW11 seems to snap a bit more easily.
I do hope that more people likes real cars like this, that is a bit softer, has a bit more movement, more dive, more roll.. Maybe it is not so quick nor razor sharp, but .. I think it is a bit more nuanced.

I'll shoot you a dm.

 

[Tennisbiki]

Tennisbiki updated 2002 Toyota MR-S C Stock/ E Street Spec (suspension mod) with a new update entry:

0.71 Edited Suspension.ini

Minor adjustment on suspension travel, in suspension.ini

Includes:
car.ini
setup.ini
drivetrain.ini
suspensio.ini

and optional setup file
OED4_7

Read the rest of this update entry...

 

[Tennisbiki]

Tennisbiki updated 2002 Toyota MR-S C Stock/ E Street Spec (suspension mod) with a new update entry:

0.71 Edited Suspension travel for 2002 Toyota MR-S

Minor correction/edit for front and rear suspension travel.

Read the rest of this update entry...

 

[Tennisbiki]

I am going to post my change here, since I have not figured out how to post update in RD.

Open Suspension.ini, edit the following two lines and save file.

[FRONT]
BUMPSTOP_DN=0.6 ;0.08
BUMPSTOP_DN=0.06
[REAR]
BUMPSTOP_DN=0.06 ;0.095
BUMPSTOP_DN=0.08

Thanks to UnofficialMotorsport for bringing this to my attention.

 

[Craigscave]

thanks for this man, getting one soon and need a little practiced before i hit the track with it