Some people on this board is not quite familiar with how race cars are set up in the JDM land, especially spring rate bias. Here are some pics to show what they have over there, all of those are all-out track/race car (spring rate conversion factor to lbs/in = 56):

My favorite *privately tuned* DC2R. 210hp, 870kg (1920 lbs). Anyone who is familiar with Tsukuba would know how fast 1'01" is. This is the time that this car pulled:



Spring rate: F26K, R20K




Here's another DC2R (this one has Spoon brakes, the previous one doesn't) with F20K, R14K:



B18C powered EF. F14K, R12K:



B16 EG with F16K, R14K:



EK9 F20K, R18K:



EF with F16K, R14K:



EK4 with F22K, R18K:



VERY nice J's Racing CRX (F18K, R16K):



All of the shocks they used on the above cars are all short stroke, large diameter valve, single tube design that are available to the general public.

In that same magazine, there are pages of setups for those "Sunday racers" that are not quite as hardcore as the ones posted above. But I still haven't seen a FF car YET that uses stiffer rear springs. Maybe there are some out there, but sure is a very rarity. Again, I'm not saying whatever they do over there is the only way to go. Just want to point out the different world that is outside of ours.

And hopefully I wouldn't get accused of pulling stuff out of my ess again.

 

Did you also happen to see that some of those cars mention they run wider front tires.

F215 / R195
F205 / R195


[Modified by StageOne, 3:23 PM 2/21/2002]

 

Yeah, I'm playing with a setup of 205/195 f/r right now and it seems to be pretty good. A bit more oversteer, but a LOT more oversteer if the tire pressure at the back isn't set properly; needs to be a little higher than equal-size front/rears.


[Modified by SnyperSiR, 12:30 PM 2/21/2002]

 

*shrug*

 

I've been using my autox setup on the track:

F:225/50/15 V700
R:205/50/15 V700

I like it better than the 205 V700s all the way around, which was my previous setup. The only part that may bother some is how loose the car gets when you drive it through a quick chicane. Watch your entrance speed and turn-in, keep your foot planted and you're fine. The increased tendency for oversteer has yielded better lap times.

 

Looks like they're running HUGE camber up front.

 

Yeah I saw that. Some of them run 4 identical tires too.

 

They didn't list out the camber settings. But they're around -2.5 to -3 based on what my friend told me.

 

1'01" around tsukuba

to put it perspective, I think a stock 98 spec does one lap around there in ~1'09". Option vdo has a monthly competition among tuners of various brands to see who can break the 1'00" barrier. I know a bunch of highly mod'd turbo cars have done this but not sure about any NA cars.

 

KEEWWWWW!

 

Half those cars are running the Kosei K1's (Or BuddyClub rebadges)

And I love those EF's. Glad to see people aren't getting rid of them, because parts will still be available.

However, their use of more spring in the front in JDM land and our Realtime/motorola cup cars over here run waaay higher in the rear still boggles me. Two sides of a coin I guess.

 

Interesting... Well it looks like they're using a few different methods for combating understeer. Just looking at the first one it's obvious they're using very different tire sizes front and rear. Plus with rates that high they're probably going to get next to no compression, which would explain the massive amount of front camber. I'm sure they're using quite a thick rear bar too. It also looks like the rear is substantially higher than the front.

For the cars with the same wheels f/r you can see their spring rates are much closer to being even. I can't speak about what kind of rear bars they're using, but I'm going to have to assume they're not stock.

It's hard to read into exactly what those cars have going on, but it seems like they would make pretty hardcore track cars but I wouldn't do it that way. I'm not a fan of different tire sizes. I know someone who does it successfully, but it was more of a cost cutting method for him. The excessive camber gives less of a contact patch when braking too. Hrm. Interesting though...

 

I was flipping thru some old mag and found something quite interesting. Before this brace became available to the public as a "bolt-on":

(this pic is in courtesy of spoonek9)


This is what the Japanese did to their car to achieve the same result:




[Modified by Wai, 9:20 PM 2/21/2002]

 

Wow! 1:01 is very impressive at Tsukuba. I remember Spoon 2liter's time attack is only 1:06

 

Auto-X setup is totally different to circuit.

Very good idea to show ppl on this board for the Japanese professional setup

These A-Sport bars are excellent and chassis feels much more rigid.

 

If this comment was directed towards me (I'd assume so since I'm the only other one who even said auto-x), it should be noted that my car is completely stock so playing with changes in tire size is the only "adjustable" feature on my car.

 

Good observation but not exactly right. The ones that have close f/r spring ratio are the hatchbacks. They do that because of different weight distribution, not because of same size f/r tires.

This can also be attested by the Mugen Lowdown kit, where the DC2R kit has F6.8K, R4.5K while the EK9 kit has F5K R4.6K. The ratio for the EK9 is much closer to being even.