FivesIS

iTrader: (1)

Kind of curious if anyone on here is autocrossing their ISx50s. I use my IS250 for long commutes, but plan on autocrossing on a monthly basis, if my schedule allows for it. I think I have a decent set up, but have not touched the springs or shocks yet. My future plan is to get a set of coilovers. I will use what I have until it needs replacing. My question is regarding H&R springs. I've searched and read reviews based on street driving. There is almost no info regarding track use. I have a set of h&r springs laying around, so my question is...

Would it be of any benefit, besides aesthetic, to use the h&r springs or would it be better to continue with stock springs?

knguyenk

The main benefit that you will get by lowering the car with the H&R springs is that you'll have a lower center of gravity, which often translates to better handling. However, H&R springs are progressively wound so the springs will get much stiffer as it compresses in comparison to the stock spring. The stock spring keeps the stiffness even as it compresses, as stock springs are linearly wound.

So, if you don't mind to re-dabble with the car's handling after installing the H&R springs (to feel for the car's new limits), you'll find that you'll be able to handle the car better and possibly take corners quicker with the lowered ride height and stiffer rate of the H&R springs.

FivesIS

iTrader: (1)

I was planning on installing them soon with the intentions of getting the benefits you mentioned. It just seems that people who autox seem so opposed to them. I read, somewhere on here, that the h&r kind of act as singular, but only one way to find out right. I guess I could write a review with more aggressive driving in mind. Thanks for your quick response. If anyone else has any input, all advice will be appreciated.

pmanliu

iTrader: (4)

I have tein s-techs on mine and autocross. HOWEVER there was still a fair amount of body row but for the most part a huge improvement over stock. I'd go coilovers if your budget permits, paired up with some upgraded sways and it should handle like a beast...

Gville350

iTrader: (10)

If you have the springs already, go for it! Just save up for true coilovers in the meantime.

An2ny

Will you be running with the SCCA? If your car is stock; springs will bump you to a higher class where you will need a lot more than springs.
If you are just running other local event or don’t care about being competitive, just install them since you already have them.
Any benefits, at an AutoX? Yes… your car will look better.

albertgoq

You can add sports shocks like F-sport shocks, it can give you better grip and less sway on your turns

FSportIS

iTrader: (13)

I don't have H&R springs but I do have the F Sport springs/shocks/rear sway bar combo and it is very fun to drive. I can initiate oversteering easily and power slide. Recently last weekend, I even drift my IS350 with the traction control off during an autocross.

You can find more of my experience here:
https://www.clublexus.com/forums/is-...b-for-fun.html

Also, F Sport suspension components have been tested by professional racer in Willow Springs track and tuned by Lexus team together with the parts provided from Eibach, Bilstein and other companies so F Sport have been proven. Here is a brief video

FivesIS

iTrader: (1)

I run with the scca locally. I already embraced the idea of running in stx sometime ago. The car isn't classed all that great in stock or for any level of modification, not to mention I still need to improve on my own skills. Haven't really played with engine mods for two reasons 1. I like that the IS is quiet on my long commutes 2. The 250 will not produce much horsepower, especially for the price tag at times very tempting. I have upgraded my sway bars, my brakes have been upgraded from ss lines to 350 calipers and slotted rotors all around, and a torsen lsd as of a few hrs ago. Hopefully the springs will be in this weekend, time permitting. I'm pretty much going to wait until my current shocks go out before upgrading to coilovers, if not go fsport. I really like the fsport products. I'm on the fence about any further upgrades for now but an isf steering ecu sounds nice.

I appreciate everyone's input, it was very insightful. Those videos were really good. I can't wait for the next event to try out my new mod.

FSportIS

iTrader: (13)

Congrats man, you have almost all the right mods for handling

IS350 brake calipers and slotted rotors: You gonna love that initial hard bite!
Torsen LSD: Your car can rotate/dance better with better corner exit.
ISF ECU: Power mode on, the transmission will be kicking in more aggressively and the steering wheel feels a lot more accurate, better acceleration but got to be smooth with the power mode on.
Rear sway bar (i assume F Sport): Understeering is greatly reduced and your car will be way more tail happy. Use that as your advantage to for rotation during cornering.

With all your current upgrades, you really need to pair them with Fsport spring/shocks or decent coilover such as BC Racing or even KWv3. Stock suspension will definitely be the bottleneck of your system.

I would suggest F Sport Under Chassis Brace which will stiffen up your car rigidity so even less body roll for better turning.

Gville350

iTrader: (10)

What additional mods might you could do to your ride to bump it out of STX to the next class? Wider tires? Suspension? Engine mods?

FSportIS

iTrader: (13)

For autocross, you should focus more on better tires, wider tires, stickier tires, and just tires first. With higher g-force, you gain more time than anything else. Then follow up with stiffen suspension. Engine mod should be last. Again this is for autocross only.

FivesIS

iTrader: (1)

Here's a link to give you a basic run down on some of the classes. It's an old list but it looks like most of the rules still apply.

http://www.azsolo.com/backup/classes/car_class_worksheet_2009.pdf

I'm keeping my stock set of wheels to run in for now. Can only go so wide in stx, 265 tire or 9" wide wheel I think. Stock rears are 8.5". Stx does allow most basic bolt-ons. The chasis brace would be awesome, but I think it'll but me to another. This is if I am interpreting the rules correctly.

There's plenty of room for upgrades and as I said before improving my own driving skills. I just needed to decide whether or not to use my springs. My plan is to upgrade when parts need replacing or if time and money permits me to do them in advance.

Gville350

iTrader: (10)

I also agree that besides a "driver-mod", tires are your next best investment! I believe 140 treadwear tires are the MAX you can run in ST in the '14 season without being bumped up to another group. In '15, I think they're raising it up to 200 treadwear. Someone correct me if I'm remembering this wrong.

Looks like I can still add headers and a catback and still be in the ST class.

An2ny

Yes, those F-sports braces are illegal in STX.

I am glad to see more people autocrossing these cars; I have been slowly building my IS for STX (just for fun, I don’t see this car being competitive)

The rules are very extensive; of the top of my head here is a basic short list…
All parts must be bolt on parts, you cannot change/modify/ fabricate different mounting locations etc

STX is a street tire class.
Tires max: STX (2WD) – 265 mm 140+ UG Tread wear for Y2014 & 200+ for Y2015
WHEELS max: STX (2WD )– 9.0”
Suspension: basic bolt ons; coilovers, sway bars, “some” camber adjuster etc.
Power: basic bolt ons: intake, exhaust, header, HFC at the same location as stock. Tune.
Body: OEM parts only-No updates/ backdates , no pulling fenders etc
Differential: can be upgraded to a LSD etc.
Brakes: You can upgrade to any pads and replace calipers and rotors. (Some restrictions apply)