Basic Rules (again adapted from material from elsewhere - edited for content)

Here are some general basic rules if you want to improve your cars handling:

If you race in sanctioned competition, <u>read your rule book</u> before performing any modifications at all to your vehicle. It would be a pity to buy a fortune in trick parts only to have them declared illegal by an official. Beware of SCCA’s Street Prepared rules as many hot and popular street car mods would put you out of this class.

<u>Do not lower your car too much!</u> This perhaps is the number one no no. It is a symbol of a truly ignorant person with regards to suspension dynamics. Lowering looks really cool and can make a significant improvement to a cars cornering capability but going too low is detrimental to both handling and even safety. Going too low can cause bumpsteer, where the tie rods and control arms are traveling different arcs resulting in the wheels steering themselves with no steering wheel input. When a car is so low that the suspension bottoms under cornering loads, the end of the car that bottoms first will violently slide out. Super low guys are convinced that they are driving super touring cars but if you take them out on the track they will suck incredibly. Our Type Rs have a short travel suspension as it is and cannot take being lowered more than 1.5-2 inches at the most. So install some good springs such as Eibach, H&R or Ground Control and DO NOT CUT THEM MORE TO MAKE YOUR CAR LOWER. If you have the Ground Control springs do not adjust them to lower your car more than two inches except if you are going to compete in car shows where the car will be a stationary display. You want to maintain at least 1-3/4" of travel.

<u>Buy and install matched components from a single manufacture.</u> For instance do not put H&R front springs in with Eibach rear or a Suspension Techniques front bar with a TMC rear. Suspension manufactures usually offer these parts as a tuned set with rates, etc. made to match each other. So unless you really know what you are doing don’t mix and match. Good stuff for our cars is made by Eibach, H&R, Mugen, Spoon, TEIN, Ground Control and Comptech.
If you are using high performance springs, try to wait until you can afford the shocks also. Performance springs store more potential energy when they are compressed. They need a shock with more rebound damping to keep the car from bouncing all over the place after you hit a bump. Really good shocks like Koni or GAB’s are adjustable so you can tune your shocks to the springs. Performance springs with stock shocks usually feel floaty on high speed undulations. I find that that feels a little spooky. Performance spring’s quicker rebound characteristics also seems to wear out stock shocks quickly making them get super floaty. I prefer Bilsteins because of their auto adjustability and durability.

Limiting body roll is good. Our Type R’s sit high, and have fairly soft springs from the factory. They roll quite a bit. Install stiff springs and swaybars with matching shocks, and lower the car to a reasonable level. Limiting roll keeps the weight from transferring excessively, allowing the inside tires to work more in a turn. Limiting roll also helps keep the car from bottoming in a turn and keeps the car out of the bumpsteer zone. Type Rs like ours do gain some negative camber under roll either so limiting roll helps keep the tires from folding over.

<u>Having adjustably is good.</u> Having the ability to adjust shocks, camber and toe is very useful when trying to extract G’s from your car. On a showroom stock racer optimizing the alignment and tire pressures alone can make the car corner a lot better and have faster lap times. As front camber is not adjustable on our cars (unless you purchase a kit) it is important to make it so. Mugen and Skunk make high quality camber kits. These will slightly harshen your ride but will sharpen turn in due to the elimination of squishy rubber with metal bearings. Rear camber adjustably is not critical on most FWD cars. If you are racing Solo II stock class or Showroom stock and don’t want to cheat, you can get about ½ degree more negative camber by loosening all of the suspension bolts and having someone hold the wheel in the negative position while you retighten everything. No one currently makes an adjustable set of antisway bars for our cars but Ground Control can make you some custom ones if you are willing to send them your car for a few weeks. In fact, it would be no problem for just about any decent race shop to whip some up.

<u>Align your suspension and optimize your tire pressures.</u> In the previous paragraph, I said that alignment and tire pressures can make a huge difference. IT IS TRUE! If you are poor, you can still make big improvements in your cars grip by just playing with tires pressures and the car’s alignment. Try the poor boy technique and dial in some front negative camber, increase the front tire pressure, decrease the rear and set your toe. Boy will you see a difference. Try to find a place that does racing alignments near your house as alignment is where people really get ripped off as it is almost never done correctly. Most hacks just throw a car on the rack and if it falls somewhere within in the wide factory specs, don’t touch a thing. What you need is a blueprint type alignment where the suspension is adjusted exactly to spec. Most repair shop dorks don’t understand this and will argue and tell you that that is not necessary. A race prep shop will understand. When your car is aligned, it should be done with your weight in the drivers seat and with the technician bouncing the car after every adjustment to settle the suspension. Set your tire pressure before you take the car in. Remember that you must realign the car if you lower it!

<u>Cut your bumpstops</u>. It is important to cut the rubber bumpstops on your shock shafts to get a little more wheel travel out of lowered suspensions. Cut an inch or one segment out of the front and rear ones. Do not go crazy and remove the bumpstops or cut off more than half of them away. That can cause the suspension to bottom out possibly breaking it. If the car suddenly gets real bouncy, that is what probably happened. The only solution is to get new shocks.

If you are racing, <u>run R compound tires on the widest wheels that will fit.</u> These tires can get more that 2 seconds for every 30 seconds on a slalom course or 3 seconds for every minute on a road course. These tires usually have a vestigial tread and a really short tread life so you don’t want to run these as a daily driver tire. Also R type tires only have about 10 good heat cycles in them so their stickiness will decline quickly in daily use, leaving you with a fast wearing, not so sticky tire.

<u>Don’t over tire or wheel your car.</u> Our cars will go the fastest and handle best with the widest, lightest 15 inch wheel that will fit. 16, 17 and 18 inch wheels which look radical, really slow the car down because they are heavy and the bigger diameter screws up the gear ratio. There are few R type tires out yet in these big plus sizes to my knowledge yet either. The widest tire that you should run unless you have a turbo or some other ungodly power is a 205. Wider tires will result in more drag that our relatively low power engines can accelerate. A 205/50-15 works well in most cases and a wide variety of R compound tires are available in this size. The maximum rim width that the Type R can run is 7 inches with a 43-50 mm offset. Since this always comes up, the bolt circle measurement on our wheels is 5x114.3 mm. The competition wheels that impress me the most are the Spoon and Mugen wheels. These wheel are forged so it can be much thinner than a cast type wheel. It weighs like 11 lbs which is twice as light as a regular wheel. Any forged or semi-forged wheel under 13 lbs is great. Remember that 1 lb on the wheel is worth about 10 on the car due to the wheels rotational inertia.

<u>Tire pressures rise considerably during a run/race.</u> Take notes of your tire pressures before and after every run so you can start with a cold pressure that will increase to your desired hot pressure during a run. Bleed your tire pressure down after every run to keep it constant.

 

i love reading these

tj

 

daym g00t posts BPR

yoshi - who gives it

 

Nice

 

Mugen makes camber kits?

HAhaha..... I just had to be the ***** of this post.... KING makes 'em!



Nevertheless, good post....particularly about lowering the car TOO much.... low is no GO....

 

For autocross, a good tip for tires is a not so wide hot tire will grip better than a big wide cold tire. You have to find the perfect compromise between the two.

Just what I have learned over the years...
nate

 

hrm, looks different from Andrew's kit


-y

 

nice post!!

 

Aren't these the Skunk arms? (nice photoshop job on the sticker btw)

 

Thanks!!! Just added this to my notepad.

Just to clarify, spoon and mugen wheels weight 11 pounds less which equals out to the equilevant to 110 pounds of unsprung weight, which is equal to ruffly 7.7 WHP right? If so, that beats out just about every bolt-on mods you can do.

 

great post
I love reading about suspension

 

So the ITR tends to understeer in its stock form. What can someone do to make it neutral? I'm talking bout specific mods (IE. mugen rear sway bar, jdm rear sway bar)