Ride height: Positive Rake vs. Negative Rake
Jun 12, 2007, 12:38 PM
#31
A nice set of 10-15MM hubcentric spacers for the front end balances the set up quite a bit. I was also reluctant on doing them because of potential wear on bearings but unless you go overboard the evo seems to be fine. Make sure you do it right, as the ones that bolt to the existing studs are nothing but trouble; go with longer studs and hubcentric spacers like the 10-15mm H&R kit you won't regret it. How is the green spool up, compared to stock, at part throtle coming off a slow corner? Do you find your self waiting for power out of hairpins?
Jun 12, 2007, 12:55 PM
#32
It's a figure of speech man. By saying "you won't regret it" one is implying that they had a positive experience with whatever it is they're talking about.
I've just always stayed clear of spacers because as he stated--the excess wear on affiliated parts, mainly the bearings. I always think of the cars back in the early 90's that had spacers making the wheels stick out past the wheel wells--the car's literally sagging because the spacers are causing a tremendous amount of strain on the suspension that wouldn't have otherwise been there.
However, a few mm here and there shouldn't be too bad since what we're trying to do is correct a handling deficiency. He already said to check out the H & R set--perhaps you could read up on that at their website?
Edit:
I just looked it up...here's the text:
Now Max...here's something I've got a question on. Under normal circumstances, widening the stance and lowering the roll center is fine. However what you and I have been discussing is getting the roll center correction kit--a kit that is designed to RAISE the roll center to reduce the roll couple "lever". Wouldn't these spacers be counterproductive in terms of our cars?
I've just always stayed clear of spacers because as he stated--the excess wear on affiliated parts, mainly the bearings. I always think of the cars back in the early 90's that had spacers making the wheels stick out past the wheel wells--the car's literally sagging because the spacers are causing a tremendous amount of strain on the suspension that wouldn't have otherwise been there.
However, a few mm here and there shouldn't be too bad since what we're trying to do is correct a handling deficiency. He already said to check out the H & R set--perhaps you could read up on that at their website?
Edit:
I just looked it up...here's the text:
Originally Posted by http://www.optionimports.com/h-r-spacer.html
If you've ever seen a sleek, European sedan with that oh-so-low street stance and a bulging wheel/ tire combo that just barely tucked under the wheel wells, chances are that car was fitted with H&R TRAK+ wheel spacers. TRAK+ wheel spacers move the wheel out from the hub, effectively widening the stance of the vehicle and lowering its roll center. This simple modification increases lateral stability, which in turn provides improved handling, greater safety and of course, the sleek style you've been looking for.
TRAK+ wheel spacers are made from a proprietary aluminum/magnesium alloy which is not only incredibly strong, but also very light weight (up to 70% lighter than a comparable steel product). TRAK+ wheel spacers are then hard anodized to ensure a tough, durable finish that is resistant to chipping, scratching and oxidation. Hub centric for the highest level of accuracy, TRAK+ wheel spacers are 100% made in Germany under ISO 9001 Quality Assurance standards, and meet the rigid safety criteria of the German TÜV.
Whether you want improved handling, increased safety or simply want your car to make a statement about your individual style, TRAK+ wheel spacers can help you accomplish your goal.
TRAK+ wheel spacers are made from a proprietary aluminum/magnesium alloy which is not only incredibly strong, but also very light weight (up to 70% lighter than a comparable steel product). TRAK+ wheel spacers are then hard anodized to ensure a tough, durable finish that is resistant to chipping, scratching and oxidation. Hub centric for the highest level of accuracy, TRAK+ wheel spacers are 100% made in Germany under ISO 9001 Quality Assurance standards, and meet the rigid safety criteria of the German TÜV.
Whether you want improved handling, increased safety or simply want your car to make a statement about your individual style, TRAK+ wheel spacers can help you accomplish your goal.
Last edited by belizelittle39439; Jun 12, 2007 at 01:02 PM.
Jun 12, 2007, 01:50 PM
#33
It's a compromise like most things you loose some you gain some. In our case: 1) we lower the car and it's center of gravity (good) but we lowered roll center (Bad)
2)We widen the front track (really good because of added front grip especially for a front heavy AWD with relentless tendency to push or understeer) we slightly lower roll center again(not as bad because up to 15mm is negligeable in terms of lowering the roll center)
3) We put the roll center correction kit wich, not only fixes and compensates for what we have lost, but put the roll center higher than it was stock and gives us ultra flat cornering and a lot less understeer while allowing us to really take advantage of the other grip-enhencing mods.
Conclusion: if you do it right it gets rewarding but if you don't you might end up helping something and hurting another cancelling the whole point of upgrading the already superb evo platform.
2)We widen the front track (really good because of added front grip especially for a front heavy AWD with relentless tendency to push or understeer) we slightly lower roll center again(not as bad because up to 15mm is negligeable in terms of lowering the roll center)
3) We put the roll center correction kit wich, not only fixes and compensates for what we have lost, but put the roll center higher than it was stock and gives us ultra flat cornering and a lot less understeer while allowing us to really take advantage of the other grip-enhencing mods.
Conclusion: if you do it right it gets rewarding but if you don't you might end up helping something and hurting another cancelling the whole point of upgrading the already superb evo platform.
Jun 12, 2007, 02:04 PM
#34
It's a figure of speech man. By saying "you won't regret it" one is implying that they had a positive experience with whatever it is they're talking about.
I've just always stayed clear of spacers because as he stated--the excess wear on affiliated parts, mainly the bearings. I always think of the cars back in the early 90's that had spacers making the wheels stick out past the wheel wells--the car's literally sagging because the spacers are causing a tremendous amount of strain on the suspension that wouldn't have otherwise been there.
However, a few mm here and there shouldn't be too bad since what we're trying to do is correct a handling deficiency. He already said to check out the H & R set--perhaps you could read up on that at their website?
Edit:
I just looked it up...here's the text:
Now Max...here's something I've got a question on. Under normal circumstances, widening the stance and lowering the roll center is fine. However what you and I have been discussing is getting the roll center correction kit--a kit that is designed to RAISE the roll center to reduce the roll couple "lever". Wouldn't these spacers be counterproductive in terms of our cars?
I've just always stayed clear of spacers because as he stated--the excess wear on affiliated parts, mainly the bearings. I always think of the cars back in the early 90's that had spacers making the wheels stick out past the wheel wells--the car's literally sagging because the spacers are causing a tremendous amount of strain on the suspension that wouldn't have otherwise been there.
However, a few mm here and there shouldn't be too bad since what we're trying to do is correct a handling deficiency. He already said to check out the H & R set--perhaps you could read up on that at their website?
Edit:
I just looked it up...here's the text:
Now Max...here's something I've got a question on. Under normal circumstances, widening the stance and lowering the roll center is fine. However what you and I have been discussing is getting the roll center correction kit--a kit that is designed to RAISE the roll center to reduce the roll couple "lever". Wouldn't these spacers be counterproductive in terms of our cars?
Last edited by trinydex; Jun 12, 2007 at 02:07 PM.
Jun 12, 2007, 02:06 PM
#35
What pretty much guaranty that you won't regret such a mod if the fact that it's totally reversible ont he fly.You can run the spacers at the track and take them off for normal daily driving(releiving possible stress on bearings) and if for some reason you don't like the positive effect of taking turns at greater speed you can always not put them and keep the upgraded longer studs that they came with.
Jun 12, 2007, 02:24 PM
#37
Dangerous like, running non factory tested coilovers that runs 3-4 times the the spring rates the system was designed for, agressive alignments that most consider unsafe for any type of street driving, raising your rev limit, messing with your fuel/ignition maps, turning your boost up, removing your cat converter, running non factory recommended fuel etc. Spacers are not what I would call dangerous in any evo owners book. They, however potentially increase stress levels on wheel bearings when you start really pushing the wheel out and that's why I recommended running up to 15mm while many other evo owners have being running more at the track without any higher failure rates. To each their own, you pick your poison.
Jun 12, 2007, 08:17 PM
#41
So then you're repeating something I already said...thanks for the input.
OH and the definition you were looking for goes as follows:
However, the connotation on a message board is someone who is posting rhetoric simply to get responses. All of your posts but the last one were little quips offering nothing in terms of intellectual property. Even the last one technically doesn't count since I've already stated getting wider tires was my preferred method.
OH and the definition you were looking for goes as follows:
To fish for by trailing a baited line from behind a slowly moving boat.
Last edited by belizelittle39439; Jun 12, 2007 at 10:19 PM.
Jun 13, 2007, 05:20 AM
#45
Evolving Member
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.
The car looked great with the front nicely lowered but I noticed more understeer going into corners and the car handled worse than when I was running on the MR Bilsteins.
I was advised several years back by my suspension tuner back in Singapore that positive rake does exactly what madmax has explained above, and I asked the local garage here to raise the front by 5 mm.
Then I got corner weighted and found that the cross-weight balance was 49.3%, and was advised that this was not going to be significantly noticeable on the track (it worked out to a 2kg difference) due to the other stuff I had in my car anyway.
In the last track day, running on Yokohama ADVAN Sport tires in stock 235/45/17, I put the new setup through its paces and here's my feedback:
The front now gently pushes into understeer when I push the car hard into the corner with later braking. Applying just a tad too much throttle puts the car slightly wide of the apex and just 10 feet before the apex, I can easily induce enough lift-off oversteer to precisely clip the apex, 9 out of 10 times.
The car looks less than ideal (everyone LOVES the look of a car with positive rake), but handles the way I like it. The same understeer-into-oversteer precision can also be manifested on street on-demand, within full control.
The next step of the suspension tuning would be to get the rear fenders rolled, and have the car lowered another 10 mm to improve CG. My Whiteline front and rear sway bars, along with the endlinks and a roll centre adjustment kit are almost here and will be installed next week.
Just my experience with rake adjustment and how it performed on track. Hope someone finds this useful
