belizelittle39439

iTrader: (4)

I've seen numerous posts (none of which I could find using the search button) make mention that the front ride height of the Evo should be higher than that rear ride height. Most of these posts agreed that the relative ratio should be about an inch in difference.

This is all fine and dandy and I was planning on maintaining that ratio, however after installing a set of Zeals (using the prepackaged settings) the car now sits with a positive rake (I.E. front lower than the rear) -- and I like the way the car handles better than the previous setup. The current setup allows for a bit more downforce in the front and a bit less in the rear which seems to promote a bit more oversteer.

The front measurement from top of lip of the stock BBS rim to the innermost edge of the fenderwell is about 10 15/16.

The rear measurement from the top of the lip of the stock BBS rim to the outer edge (where it rolls up) of the fenderwell is 11 1/8. (Which is actually an 8th higher than the stock measurement).

So ratio front to rear is - 1 1/16 and + 1/8 (from the stock measurements).

Are there any drawbacks to having the positive rake? I thought I read somewhere on here that the purpose for the higher front end was so as to not "overwork" the front suspension -- but now that I'm running a 10kg spring on new coilovers, would that really "overwork" them? Additionally, I wouldn't think the + / - an inch would make that much of a difference in the lifespan of the coilover...but I'm no expert.

Thoughts?

19psi

iTrader: (6)

I see you finally installed them zeals.

Like I suggested before, let the springs settle and re-adjust your height.
I slightly adjusted mine this past weekend.
The car is sitting at :
14 inch front and a hair under 13 1/4 inch.
The distance was measured from center of hub to fender lip on a level surface.

IMO, a slight positive rake (front is lower) is good but too much will put that much stress on the front suspension components which is not good IMO.

I am sure some suspension gurus can chime in on this subject.

coolnick

iTrader: (9)

Get the car corner weighted.

19psi

iTrader: (6)

ultimately yes, this is how a car with coilovers should be set up.

madmax199

iTrader: (20)

The evo suspension was designed and works better with the negative rake( front higher than rear). Remember the car already have a bad weight distribution and by giving it that positive rake you are accentuating the problem. The evo's biggest handling problem is understeer because of several reasons, one being a lack of front grip due to loss of camber in hard turns also not enough front track and rubber to support the load put on that poor inside front tire. Now, in your post you said that you are experimenting some oversteer with your new set up and that's because you are taking away weight and traction off the rear wheel and adding that unwanted weight to the already overloaded front. So what you are doing is making the rear brake away before the front, it might feel like a solution because you can steer with the gas pedal but you have not done anything for that understeer but mask it by some oversteer wich take away the evo's incredible ability to come out of corners. Another thing to take in consideration is the front roll center that by lowering the front more than you should makes the car roll too easily. My suggestion to you while it might be conter intuitive is to raise the front about and inch or so higher than the rear and attack the front lack of grip by adding spacers to the front(wider track), putting more rim and rubber on the front,more negative camber(camber plates), raise the front roll center(roll center correction kit). By doing all that you will increase the front grip considerably and cure most if not all understeer demons and the car will become much more neutral and faster. When you are all done, find an empty parking lot and turn your steering wheel a 1/4 of a turn and slowly increase speed without adding any steering input; if the front start to brake away before the rear you have natural understeer and vice versa, if you start drifting to the opposite side of your circle with both front and rear wheels your car is neutral and you've achieve your goal.

Evotech8

iTrader: (4)

^Good advice.

I concur with your experience.


.

nothere

iTrader: (23)

n.m.

belizelittle39439

iTrader: (4)

Your response is probably the most well put together I've seen on here. I appreciate the information. I had the car corner balanced actually, and it was sitting 61/39 front to rear weight distribution (with the positive rake). It corner balanced at 50.1/49.9.

What's your take on that? I read in another thread https://www.evolutionm.net/forums/sh...d.php?t=272581 that our cars are all around 60/40 front to rear normally. Should I still raise the front end up a bit you think? I'll try the parking lot test when it stops raining and see how she handles. So far she sticks like glue on all four, no slippage front or rear in any of the corners I've hit around town.

madmax199

iTrader: (20)

Yes our cars sits naturally around 60/40 front to rear and since you got it corner balanced at almost 50/50, I would not suggest touching the rake at all. On the other hand, assuming that you are sitting lower than stock, the front geometry is most likely screwed up as your roll center is sitting lower than it should and accentuating natural understeer. It becomes important for you to raise the roll center back up, a roll center correction kit should be your next mod and will transform the car (neutral with no understeer unless driver induced). I did the parking lot test after installing the roll center correction kit and was amazed with the results: I was able to carry much higher speed than before, the car turned flatter and did not brake the inside front loose before the rear. I hope this helps.

belizelittle39439

iTrader: (4)

Hmmm...I've already lowered the rear of the car (the same amount on both sides), and lowered the right rear 2mm lower than it was to compensate for that final .1 percent to get it right at 50/50. The front end is a bit higher now relative to the rear. I've already ordered a set of corner balancing scales (which is what I should have done in the first place since the guy I took it to didn't even know the equations, only what the electronic scale told him). I'll double check my work to make sure it's right where it needs to be. Where would I get the roll center mod from? Robi?

Vicious1

iTrader: (5)

If you add some camber plates, and Whiteline Roll Center Adjustment kit, i think you can counteract much of the negatives of having the negative rake (um, er, forgive the double negative, or triple now O.O). I am currently running KW Variant 3 Coilovers, with Tien Top Mount Camber plates front/rear and Whiteline Roll Center Adjustment Kit and it rides great thus far on the street, with the front lower than the rear (by about 1/16"- It's pretty level really). Haven't been on track yet, but going Thunderhill in Nov. so will see how it does.

Something else to consider for everyone who has posted. Beware of measuring from hub center to fender. When my car was getting corner weighted, the mechanic had a tough time at first because the cross weights were hugely off. After repeated measuring, he asked me if the car had been in an accident. I was like, wtf mate? The car is brand new, and only had 2500 miles on it since I bought it with 10 miles on. Turns out that from hub center to fender, the drivers side rear fender is 3/8" higher off the ground than the passenger rear fender. He had to measure from scale to frame to adjust ride height accordingly. Got it cross balanced 50/50 dead this way, with 62% front, 38% rear.

Bottom line: Be cautious when measuring to fenders. Apparently Mitsu's build quality is almost as lacking as their paint quality on some things.

belizelittle39439

iTrader: (4)

Thanks for the heads up! I wonder if that was just your car or all our cars! The good thing is that shouldn't be too much of an issue when corner balancing, because you're not using reference points to establish ride height, you're using the distribution of the weight as the guiding reference.

Corners could very well be at different heights (a few mm here and there) but the distribution of weight would be proper.

madmax199

iTrader: (20)

You can get the roll center correction kit from whiteline, kit # KCA395.

belizelittle39439

iTrader: (4)

I did some more research on what you were talking about.

http://e46m3performance.com/tech/transfer/pg-2.htm

It's because we have Macpherson struts right? the design is done in such a way that when the vehicle is lowered it also lengthens the roll couple thereby increasing the tendency to roll!

I also found that the reason it may not be as apparent is because with the addition of higher spring rates and/or torsion bars the increased tendency to roll can be nuetralized.

Steiner

iTrader: (3)

subscribed!