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Discussion Starter #1
I recently converted from a SM FWD Honda into my IS300, and while the Honda was setup quite well and there was loads of info on them, that doesn't seem to be the case with the IS.

What I am hoping to get out of this post is wheel and tire sizes which fit the IS's suspension and are class legal.
What would also be nice is to add in is alignment settings, ride heights (which could affect the amount of negative camber one gets, and we know the IS is begging for more) and spring rates.

I am looking for STS/STX specific info but it will also cover SP, to an extent.

Since my car is equipped with an LSD I am dropped into STX immediately. That leaves me with a 17 x 8 inch wheel max and a 245 tread width. That leaves me with a question, are there any 17x8's on the market which can handle a nice 245 and will fit the IS's wheelwells/suspension?
Another question is what is the max width tire you could run on the stock 17x7's without rubbing?

The tires which I see working fairly well are the Kumho MX and the Yok ES100, both are available for a good price and should provide good grip too.

Currently my only suspension mod are Tein FLEX with standard rates. Unfortunately they aren't as stiff as anticipated, not even on full hard damping. So TRD Yellows will be a must have.

Lastly, the standard alignment seems to be 0 toe to 1/16 total toe out in the front and 0 toe to 1/16 toe in for the rears. All the camber talk I hear is for stock ride heights so I have only seen -.9 frt and -1.4 rr. Has anyone gained more from lowering the car and working with the adjusters?, specifically to gain more front camber. Caster I assume is not adjustable, but more is better from what I hear.

I realize this is quite long, but any info is appreciated, and is needed on this forum. I found nothing in searches or in the sticky.

Thanks,
John
 

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congrats on getting the IS.

from what i know, you shouldnt be dropped to STX b/c the car actually came w/ LSD.

on 17x7 wheel, you could to 225/45/17.
since IS sportcross comes with 225/45/17 on the rear, you could use 225/45/17 all around for D stock.

w/ my understanding Kumho MX is classified as "max performance", and ES100 as "ultra high performance". so MX perfroms better(?)
you could also use Falken azenis, but they dont come in anything higher than 17".

yes, you could gain more negative camber by lowering, but you should check the tire temp with a pyrometer to see temps are equal all around.

here are few links you might be interested...
http://www.is300.net/forum/viewtopic.php?t=13316831&highlight
http://www.is300.net/forum/viewtopic.php?t=13315157
 

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Sorry for the delayed response John, I was out racing my IS this weekend.

STX advice:

You can run 17x8 SSR competitions with a +38mm offset. You'll be hard pressed to find a better option. Tire choices would either be Kumho MX's or Falken Azenis in the 245/45 size. I currently have 245/45 Kumho V700's on these wheels and they fit fine.

Sway Bars:
Don't jump on the TRD yellows just yet. Your better off playing with spring rates on the Teins instead. I run 950lbs front and 750lbs rear springs on my Ground Controls. Probably too much for the street. Try the L-Tuned (eibach) sway bars - cheaper and the rears are adjustable. If it doesn't work then try the harder to get and more expensive TRD race bars.

Camber:

Max out whatever you can get in the front - the lower you go the more camber you'll get. My advice is to corner weight the car which will give you some significant rake (front to rear) in the car. You'll probably get 2.3-2.5 degrees in the front with a fairly low setting. Rear camber should be 1.0 to 1.5 degrees less than the front to aid in rotation (dial some more toe in to compensate for oversteer). Street tires may be slightly different so adjust accordingly.

Stock Wheel Sizes:

Back when I ran stock I was able to fit a 245/45/17 Hoosier on a 17x7 inch rim. I found that stuffing such a large tire was useless as the tire bulged around the rim and the contact patch was reduced. 225/45's are a much better choice for a 7 inch rim. On an 8 inch rim the 245 should work.

Good luck

-Derek
 

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good advice derek.
I can vouch for the l-tuned sways having started with the TRD's and then selling them for l-tuned (I didn't listen to derek the first time around). The stopwatch says that the l-tuned are noteably faster.

The only thing I would like to add to his comments are that with lower spring rates that you and I are running, you are likely to bottom out the car if you lower it too much. I have 14/10kg (750/550) for spring rates and I scrape the front end feelers on hard corners and have hit my bumpstops on the street when going over bumps at freeway speeds. I'm lowered about 1 inch btw. -I'm willing to live with this rather than up my spring rates since it's my daily driver and don't think my backside can tollerate much higher spring rates.

My camber is set to the full positive range which has my camber at about -1.6 front and 1.7 rear. This gets me a fairly flat contact patch up front but the rear is running much hotter on the inside. I may end up raising the rear to get more pos camber. I think I may need more negative in front like derek suggests. I'm just beginning to tune with a pyrometer so I'm still in the process of tinkering.

Post back with your results and findings.

Dave
 

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"I can vouch for the l-tuned sways having started with the TRD's and then selling them for l-tuned (I didn't listen to derek the first time around). The stopwatch says that the l-tuned are noteably faster."

Dude you got to be careful. You don't test IS300 suspension parts with a stop watch. Why would TRD call the bars "Race Bars" if they weren't the best bars for racing? You had better hope the unwashed IS300 masses don't flame you for this transgression :D
 

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jmess,

"TRD race bars" are built specifically for track/road racing. Autocrossing requires a much different setup than track/road racing.

Road racing IS300's are setup "tight" to understeer at the limit so the race bar will work well - even with 1200 lbs front springs. They also require high levels of constant roll control where higher swaybar rates are needed.

Autocrossing requires a combination of high speed stability along with the ability to oversteer in tight sections. TRD race sways along with higher spring rates will induce terminal understeer in the tight stuff. Running significant toe out in the front will aid in turn-in but this setup will most often cause mid-corner understeer (push). Autocrossing requires a swaybar that can handle fast transitions and allow the front end to bite in the corners.

Having setup and driven three stock IS300's, one street prepared IS300 and one track IS300 I have learned many valuable lessons.
 

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Discussion Starter #9
Wow! All of a sudden all my questions have been answered.

After 2 events I'm starting to feel out the car and the RWD. The balance isn't bad sometimes, but any tight slow stuff and it plows real bad. Throttle on oversteer is pretty prevalent, especially in low/mid speed corners. My general feeling is lack of all the things below is killing me, or at least preventing the car from doing what I want!

After mulling over all of this info and running a few events I will probably try the following:

1) Stock wheels w/Kumho MX 225/45 (my wife doesn't want an extra set of wheels in the house yet!!) I'm opting for the MX b/c I hear the Azenis lose grip when hot, and the IS is kinda portly.

2) Leave the car at its current height. The Tein manual says their stock settings give a 90mm road clearance (13.03" from wheel center to fender lip at the front and 12.95 rear.). I have dropped it an extra 1/4", the front now measures 12.875 and the rear is 12.625. With these settings I have not felt the car bottom out(suspension or shock), even with the shocks on full soft for my commute.

3) for spring rates I am trying to keep these (10K, 8K), I know they are soft, but this is a street car and I'm trying to keep some comfort in it (mostly so my wife doesn't smack me upside the head!)

4) Get an alignment. Max out front camber. Set rear camber as Derek suggests (which actually worked well in my Honda which had 2.5 frt and 1.5 rr).

5) Purchase some L-tuned sway bars. Who is a good supplier for these? I have only dealt with Carson Toyota for parts thus far, with good results. A reputable East coast supplier would be a plus.


I am really hoping some added camber and grip in the front will help low speed corners while the sway bars and alignment should make it possible to coax the car into some beneficial yaw angles for the longer, larger radius corners.


Dave,
How are the Porterfields? I am assuming they are the R4S. I am also curious how you like the PLP intake, I've been eyeing that.

Derek,
I was out racing mine too! Did I mean steering with the throttle is fun?


Thanks everyone for their input, it is very much appreciated. It's tough going from a very competitive car that can set FTD to another car which needs to start from the ground up.

John
 

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John,
I'm happy with the porterfields. I've got both the R4S's and the R4's. The R4S's work well for street and autox. There are more aggressive pads out there, but for me they offer up a good balance of stopping power and rotor wear. They're a definate improvement over the stock pads and they won't fade on you in an autox or street situation. They even worked well for me on the track until I upgraded my tires and suspension, but as my skill level improved, I noticed that by the end of my sessions they were starting to glaze. Hence the purchase of the R4's, which are an awsome dedicated track pad by the way. I think Axxis makes pads for us now too which might be worth looking into.

I just got the PLP intake last week. So far I like it. The sound is nice, not much louder than stock, but it has that slight intake growl when you hit the upper rev range. Don't expect much power from just an intake though. I'm not sure if you can really feel a 9hp gain or not. Still deciding if I feel any more power or not. Only a dyno can tell I suppose.

As far as where to purchase, a lot of us have had good luck with Carson Toyota. You can't go wrong purchasing from a large dealership and they've got great prices to boot. I got my brakes from bulletproofautomotive.com. I heard of them through word of mouth. Products were delivered as promised and the staff is knowledgable.

hope that helps, it sounds like you're well on your way.

Have you also considered steel braided brake lines and a Schroth harness? They're both worth while mods as well.
 

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what is a shroth harness?

also do any of you have experience with endless pads? im looking at the VN2 for my car with a set of straight slot (6) rotors.

derek: how do you convert your spring rates into kg/mm? im running 12/9 right now and im not too happy. a friend suggested to save money for me to buy a set of 16's for the front and move the 12's to the rear. imo that sounds a little extreme. do you think i should go with a 16/12 setup? or keep the 16/9? or all together buy new rear springs as well?

btw im running with a51 sways. i get the slightest bit of oversteer but its fun :)

this is great info.. thanks so much derek and dave!!
 

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Oops. spelled it wrong. The Schroth Harness is one of the better 3 or 4 pt harnesses out there. It is street legal and really helps hold you in your seat better. This link has some good info on it.

http://is300.net/forum/viewtopic.php?t=13340414



kg can be converted to lbs roughly by dividing by .018 . I think teins web site has conversions listed somewhere too.
 
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