fpvteg0681

Hi everyone. I have a '00 ITR that I am blurry on for my next steps. Any thoughts and comments are much appreciated. This season I've setup my car with the following specs:

-K20A2 w/ 5.1 FD
-Koni/GC 14kf/16kr
-15x8 +40 w/ 5mm spacer front, 3mm spacer rear
-225/45/15 Toyo R888 on all 4
-Camber: -3f/-2.5r (no camber kit in rear currently)
-Stock ITR Sways front and rear
-35psi front / 32psi rear hot

Essentially my car handles very well in higher speed turns (mid to top of 4th). The rear drops, plants and stays there while I work the throttle. My problem is the turns I take in top of 2nd to 3rd. My car seems to turn in with good response, but it's that time before the apex that I feel it push (understeer). Any thoughts on what I can do? (Besides adjust driving habits, for which I try and improve everytime I go out.)

My thoughts are either:
-0 camber in the rear
-24mm ASR Rear Sway Bar
-No front sway bar

Any thoughts? Thanks!

Black R

Toe settings front and rear?

You have a couple of options, but bigger rear bar might be the easiest to adjust easily when at an hpde.

What are your tire temps like?

What are the damping / rebound settings on your shocks?

Does the car see any street time?

fpvteg0681

Thanks for the response!

Toe settings front and rear? 0 toe rear, .1 toe out front

What are your tire temps like? Front's seem to heat up quite easily while the rear doesn't heat up much

What are the damping / rebound settings on your shocks? Running full soft damper front and full stiff rear

Does the car see any street time? Car is a DD

Black R

Ok, personally I have a similar setup on my autox car with a couple of notable exceptions:

I have 11k up front and 16k rear.
I set my rear dampers on soft.
I have an adjustable bar on full stiff in the rear.
I still run a front bar.
I run 275f and 225r Hoosiers.
I run zero toe all around.
-2.5 up front and -2 rear.

This would likely scare the crap out of me on a road course.

If I were to go back and redo my setup, I'd run heavier springs up front and softer rear.
(something like 1100f / 550r)
I'd run an even bigger hollow adjustable rear bar.
I would run a square setup for hpde and adjust rear bar accordingly.

Easy button for you is asr 32 hollow rear bar.

fpvteg0681

Thanks for your input. I've always had an eye on the 32mm rear sway, but always thought of it as overkill for me. But perhaps it's something I need. I'll definitely consider it, thanks again. If anyone else has any comment or suggestion, it's definitely welcomed!

10cjennings

iTrader: (1)

You DD 780/900 lb springs?
Also, are those standard yellows? They will have a hard time (ie: they can't) dampen that much spring.

0 Rear camber is extreme. Try taking out .5 degrees, so -2.0 deg, and see what that does, made a big difference for me.

Calif_Kid

Have you searched similar threads in the Road Racing/Autocross & Time Attack forum? You might get more responses by posting the question in that forum also. You probably could fine tune the front vs rear spring rates if the car was track only, but since the car is a DD, then going with an adjustable and larger rear bar seems a reasonable way to go to me.

There was a post https://honda-tech.com/forums/road-racing-autocross-time-attack-19/swaybar-rates-common-setups-3157965/ in the Road Racing/Autocross & Time Attack forum, and I posted the info below. If you really do decide to go with the 32mm rear bar, then starting with the thinnest one seems good to me. I'm not sure if your current rear sway bar is 22mm or 23mm, but I recently went from 22mm non adjustable rear bar to the 24mm adjustable ASR bar, and the intermediate setting seems good on it so far. - Jim

***************
I was looking into going from a 22mm non adjustable rear sway bar to either the solid ASR 24mm adjustable one, or possibly their 32mm hollow bar. The ASR website mentions that the 32mm hollow bar comes in thicknesses of 0.095, 0.120, 0.188, and 0.250", so I was wondering about how those compared to the solid 24mm vs the 22mm bar, so ASR replied with the info below. I ended up getting the 24mm ASR rear sway. - Jim

***************
Hello Jim,

We didn’t do any formal lbs/in stiffness testing on our swaybar. We base our stiffness recommendations on experience we have on our cars and customers feedback.

But I can tell you that a solid 26mm swaybar feels the same as the 0.095 bar. The stiffness of the 22mm to 24mm is about 40%.

Here is the stiffness calculations on Speedway engineering’s website, they supply our swaybars.

http://www.1speedway.com/swaybar39.htm

Thank you!
Charleston Ong

fpvteg0681

Thanks for the responses guys.

10cjennings - Yes I DD these springs. It's a lot more tolerable than one might think, and yes I do have bumpy roads here. Rain driving isn't scary either, but more alertness is definitely required - just in case. Agreed that OTS Koni Yellow (that came with the kit) does not have enough dampening for my spring rates, the plan is to revalve over the winter for next season. I'll try the camber adjustment with a little more bar in the rear and see what happens.

Jim - Thank you for the great info, I've found that same information as well from a different source but thank you for confirming the same data. Currently I am on the OEM USDM 22mm RSB. I know the effectiveness of changes to the sway bars changes when you run higher spring rates, so I wasn't sure if the 24mm ASR would be as effective, if I were running say lower spring rates - in the 400lb range. If I run with the 32mm, I'd definitely take your advice as well and run the thinnest version first since it's for RR/TA setup.

After further consideration, I wonder what would yield the best rotation (without overdoing it), as I'd like to run with a loose rear end with my current spring rate setup:

1) Remove OEM front sway bar and run ASR 24mm rear sway bar, or
2) Keep OEM front sway bar and run ASR 32mm (0.095) rear sway bar.

Any comments on these choices?

10cjennings

iTrader: (1)

Disconnecting front sway is really a personal preference. It may help with rotation but imo it makes the front end feel very sloppy. Some fast people like it though and it's free to try out. Getting the asr 24 alone should be plenty, between that and taking out a little rear camber (.5deg) if the car is still not rotating something is wrong. 32mm bar is overkill imo for an already very rear biased car.

I also can't even imagine what the yellows are doing with that much spring, I'm running 550 on the OTS, work well but you can tell they are near the limit for the shock.

I'm going to SPSS this week, from my research, looking at the prices even Koni will recommend you sell your yellows and just buy new SPSS, it is much cheaper. It's about 250 a shock for re valving, and new SPSS's /w GC and whatever springs you want are $1329 from Redshift.

FlewByU352

You could always reduce rear tire size and run a 205 width. Or introduce oversteer by getting light on the throttle and steady controlling it through the turn. Orrrrrrrr run a front splitter

Libertariat

The first thing I would do is try running 30lbs in the front. I usually run 30F/32R. I daily the car on 40lbs, and never run more than 32lbs in the front for autocross.

With the rates you running, I agree that the front swaybar is probably hurting you. I would at least loosen it up and run it that way or remove it to see if you like it better without.

FlewByU352

There is always the JDM 23MM rear bar. I see them new for $130 with bushings and the 22MM can always be sold for some cash. While it may not seem like a lot, coupled with decreasing rear camber a half degree might be perfect to your liking.

Design

There is a lot of good advice in this thread. I also agree that an adjustable rear bar/camber should be the next step. After that, if you're still looking to transfer weight to the rear, I'd recommend reducing the front spring rate over removing the bar on a DD (assuming that's financially feasible). GL.

STOCK_SOHC_DX

Camber, 205, softer front rate. That's pretty much all covered here.