andrewhake

EVERYONE GET READY TO GET EXCITED! I GOT a new air filter for my Mugen intake.

Mugen air filter:







It looks like at some point Mugen switched suppliers from a company that makes yellowish green filters to K&N which makes red-ish air filters. Annoying that this filter is made by K&N in the U.S. and is likely an exclusive design for Mugen so it can't simply be sold to me in the U.S. but has to be shipped to Japan and put in a Mugen box and shipped back to me. All well. Both which appear to be pretty much identical in terms of design and filter medium. I got this second one so I can clean/oil/dry the other (drying can take quite awhile), and always have a fresh one available when I want to swap them over.

blueprint

I love the arms!! Im seriously debating on getting a set however i told myself to start investing in safety equipment and gear for the track...

Great posts andrew!

adrs2k

No one ever said, drastically alter suspension balance. Springs can only do so much, and in the end, their main purpose is not to limit roll. A springs main purpose is, to keep the chassis off the ground. Springs other purposes are to absorb road imperfections and then lastly, to limit roll. A spring allows the wheels to deflect in reaction to accelerations. The spring is what is supposed to keep your tire planted to the ground and maintain contact patch as much as possible. The shock controls the spring and the springs stored energy. You want the spring and spring rate to be such that it allows the spring to focus on its primary goals, keep the chassis off the ground and absorb bumps. Springs must be soft enough to give good tire compliance and allow both effective damping and sufficient vertical wheel movement to absorb the shocks of road surface irregularities.

You need an anti-roll bar because, if the springs are stiff enough to limit roll to our desired maximum, the wheel rate will become too high for tire compliance. Therefore, negatively impacting the wheels ability to stay planted to the ground and remain in contact with the ground. Trying to use a spring to limit roll is in some cases asking the spring to do more than it is intended to do and it will then become a compromise. Enter, anti-rollbar. While its primary objective is to limit roll, it also helps control camber during cornering and impacts a cars balance without impacting ride rate. The best part of anti-roll bars is they allow us to quickly and easily change the understeer/oversteer balance of the vehicle. Something a spring cannot do. An anti-rollbar also helps control camber while cornering .

Obviously its easy to go too far with a anti-rollbar and negatively impact the cars balance, ride comfort, and suspension independence. Everything is a balance, compromise, and trade-off.

My whole point was, questioning why one would buy the ASM bars because they are not the best tool for the job. They offer very little over stock, don't have the most usable range,and are probably stupid expensive for what you get. There are MUCH better options out there and I suspect to achieve proper roll resistance, balance, and camber control you are now going to need A LOT more spring than you should be using. Let springs do their job, let anti-rollbars do their job, and the car will be happy. I also think you are putting ASM bars on your car, because, well, ASM.

That is my short story on the topic.

Glad you like the new lens too. Its pretty awesome and I find myself shooting at f22 a lot to capture full details.

andrewhake

I think you are just trying to justify your own setup, which is fine, but I will oblige. They are the right tool for the job. They have the absolute perfect usable range for my intended spring rate. There isn't any better option available for my purposes. I completely disagree with what you have said. Having driven both types of setups, I am extremely confident I could drive my setup much faster than I could drive one with much stiffer sway bars. Overly stiff sway bars are a silly compromise to make in my opinion. Particularly if it's completely unbalanced front and rear. I have been in many cars with this type of setup, I don't like it. It is terrible. I can happily drive around these compromise, still drive quickly, and still enjoy it, but I don't want it on my car. Nothing you have said has convinced me otherwise. I have been in cars with setups more similar to what I am after, and the difference is very obvious to me. Subtle changes and improvements has been the goal with this car from the day I got it. If that still surprises anyone at this point I am not sure what to say.

[if you don't care to hear full thoughts on this, it's time to punch out now]

Balancing the car's roll and pitch together is extremely important. It's pretty standard suspension tuning theory. A properly balanced car can minimize the time in-between braking, entry, the car settling and exit. It can do all of this as one smooth motion if driven well. If the car isn't inherently balanced using the geometry and springs, the setup is already compromised, and it is just being compromised more adding sway bars that are too stiff. If you are only considering roll stiffness and not pitch in how a car is balanced, your understanding is compromised. The way the car transitions from left to front to right to rear and everything in between is what needs to be considered, not just left to right. And just like with springs that are too stiff, sway bars that are too stiff will compromise ride and grip, as well as the cars ability to utilize all available grip under turn in and traction on exit. Especially if they are used with poorly matched spring rates. Cars with poor suspension designs rely on extra stiff roll bars and springs to control body roll because they have no other option. Their inherent imbalance from their poor geometry can not be completely corrected with geometry adjustment or spring rate alone, so stiff sway bars are required to further try to correct that poor balance. A compromise to try to correct an already compromised design. These types of cars are terrible over curbs and particularly terrible on roads with aggressively changing camber and elevation mid corner. The S2000 is not one of those cars. The inherent balance is good because of the considered suspension design doesn't allow for a huge amount of roll, spring rates are chosen to compliment that design, and sway bars are chosen to further compliment that design.

I am already very happy with the current setup, I just know there are advantages and improvements in both slightly stiffer springs and slightly stiffer sway bars without really compromising balance or ride. In fact it should allow me to better use the amount of grip available from the tires I use. At the moment I feel that my current sway bars are are too soft for my spring rate. I think the ASM bars will not only work better for my current setup, but will be ideal with my upgraded rates. ASM designed these rates around the 12.5kg/12.5kg (700lb) rates they include with all of their damper setups. 12.5kg/700lb will likely be the rate I use because HyperCo doesn't offer metric rates. I am not and don't plan on only using springs to limit roll to my desired amount, I am/will be using slightly stiffer springs and slightly sway bars that will work together to limit roll and pitch to my desired amount. The tires I use have enough grip that I feel my car is under sprung slightly to best take advantage of them. The springs will absolutely still do their intended job, and the sway bars will contribute to the roll resistance more and are 3-way adjustable giving me the fine tuning range I am after with out being overly aggressive, and still allow me useful tuning options when driving on low grip surfaces and in the rain. I don't need to drastically increase the the sway bar rate to get the desired effect I am after, a small change can still have a very useful effect. All the other options I considered were all stiffer than I would want, and didn't offer useful ranges of adjustment. I didn't even consider a blade style bar because they offer way more adjustment than I am after, and have other compromises in complication and fitment. Not to mention being just as expensive if not more expensive.

adrs2k

It's funny that you disagree. I would expect that from you. It's funny because it's directly out of one of the most widely referenced and used setup books in the world, tune to win. Since you are smarter then everyone else I can understand why you think it's rubbish.

Of course I need to use your thread to justify my setup. You are a genius!

Ricky_Flowers_

QFT

andrewhake

I don't think I am smarter than anyone (except Ricky, everyone is smarter than Ricky), I am just not going to hold your hand while explaining why I disagree on something. Especially something that simply comes down to driver preference. I am easily convinced by testing real world examples, which I have, and come to this particular conclusion with the S2000. I'm not sure what is funny about it, but your interpretation of that book is drastically different from mine. I think you are over simplifying what was written about roll bars and ignoring what was written about geometry, roll-center, spring rates, ride height, and so on, and how they all relate to each other.

"The amount of chassis roll resulting from a given lateral acceleration is dependent on a multitude of factors: vehicle weight, c.g. height, roll center height, track width and the resistance in roll of the suspension springs and anti-roll bars."

"So we want to restrict chassis roll. We can do so either by increasing the roll resistance of the suspension springs, and/or anti-roll bars, or by reducing the roll moment by raising the roll center."

"We can modify this roll couple distribution with the rates of the anti-roll bar and suspensions springs."

I am guessing this is the particular point are you are referring to, which I agree with:

"Long before we reach the point where lack of independence or load transfer under bumps becomes a real factor we will achieve the situation where we have too much roll resistance and the car gets very slidy due to the suspension being too stiff in roll and losing its sensitivity.
So anti-roll bars restrict the rolling tendency of the unsprung mass without increasing the ride rate of the suspension, which is good. They also detract from the independence of the suspension and laterally transfer load, both of which are bad but not terribly so. They do one other thing of great interest-they allow us to change the understeer/oversteer balance of the vehicle quickly and easily. If we make the rear anti-roll bar softer, either by lengthening its actuating arm or by decreasing its effective diameter, then relatively less load will be transferred laterally at the rear of the vehicle, the rear wheels will be able to generate more traction and we will achieve reduced oversteer. It's a hell of a lot quicker and easier than changing springs and every bit as valid."

However, as the surface you are driving on becomes less and less like a race track, this particular bit becomes much more important. – "They also detract from the independence of the suspension and laterally transfer load, both of which are bad but not terribly so." Skipping across a road surface due to springs that are too stiff is one thing, skipping across the surface due to roll bars that are too stiff is much worse. I have experienced both. There is good reason a stock S2000 or CR doesn't come with swaybars as stiff as something like the Eibach setup. It's all well and good to say very stiff roll bars have few compromises on a race track with extremely grippy tires, that changes drastically when you are dealing with a completely different road surface, driven in many conditions. I fully understand the benefits stiffer roll bars can provide, which is why I am increasing my roll bar rates slightly. I also fully understand the benefits of fine tuning suspension balance using roll bars, which is why I got 3-way adjustable roll bars instead of 2-way.

In regards to the balance of the car. I simply think that spring rate and geometry should always be considered before considering roll bar rates. But more importantly they should all be considered as part of a whole package. Saying the ONLY valid way of reducing roll is by using significantly stiffer roll bars just isn't true. It is perfectly possible to achieve the ideal amount of roll you are after by making incremental changes in geometry, spring rate, and roll bar rate. I think using ONLY geometry, or spring rate, or roll bar rate is the wrong approach. And I think the rates ASM chose for their sway bars will be the most beneficial to me without any compromise. If that for some reason upsets you or you think my reasoning isn't valid, so be it. I am hardly using some wacky setup that disregards everything mentioned in that book as you suggest.

adrs2k

I am very much aware of how a car works and all variables are interrelated. So thank you for not holding my hand. I am not a child so don't be condescending. Yes I did oversimplify because we were only talking about springs and anti-rollbars.

Yes obviously the full package has to be taken into consideration. Never argued that. You just posted that you think using anti-rollbars to control balance was silly, I was saying that you are in fact silly. The ASM bars aren't made from unicorns just because they were made by ASM.

Eibach bar is only 50lbs/in stiffer than the factory CR bar...not a big difference imo. Just enough to slightly change the cars balance. Notice I don't say drastic change like you.

Everyone is entitled to their own opinion. We can quote books all night and present facts to prove points but we both are smart enough to know it all really comes down to one thing. Personal preference. I suppose it's your thread so you can preach, pretend, and be the all mighty in here, so with that, I respectfully bow out and have no more interest in discussing anything further.

Enjoy justifying your car and mods and I will do the same.

andrewhake

I didn't post that using anti-rollbars to control balance was silly, I posted that using anti-rollbars to compensate for a compromised overall balance is silly. I am well aware the ASM bars aren't made from unicorns. In fact they are likely just made by whoever manufactured the OEM swaybars, which is another thing I like about them. They also use regular rubber bushings instead of urethane, which I also like about them. I don't think they hold any magical properties because they are sold by ASM, I just think they have rates that will better suit my setup than the much stiffer Eibach rates. Particularly the rates Eibach uses in the rear. In regards to the price, a front and rear set of Eibach swaybars lists for around $600. Probably even around $500 if you hunt around for a deal. The ASM roll bars list for 64800 yen (~$535, figure $600 with fees,etc), unfortunately due to the size of the package the shipping cost bumps up the price quite a bit. But it is far from the $900 or whatever that they are listed at on GoTuning's site. That extra importing/shipping cost sucks but if it gets me what I actually want I am willing to pay it. If Eibach made a setup even remotely close to to what I was after I would have purchased it without hesitation.

You have gone from saying a +43lb change (ASM front bar vs. my AP2 front bar) isn't enough to make a difference, to saying a +50lb change (Eibach vs. CR bar) is enough to make a useful difference. Do you see where I cam coming from now?

The Eibach front bar is 368lbs and 416lbs, my car has a ~233lb front roll bar (according to ASM and Eibachs data, which is much lower than that popular thread with the various spring and roll bar rates. I am more inclined to believe ASM/Eibachs data), so forgive me if I think that a bar that is +135lb/+183lb is too stiff and not a useful range for me. The rear Eibach bar is listed as 515lb/605lb compared to the ~280lb rear bar on my car (based off ASM/Eibach data). So again, forgive me for stating that a +235lb/+325lb setup wouldn't be useful to me. I didn't just want to run a front adjustable bar I want to have the option for adjusting the front and rear and with the rear Eibach bar being that stiff it is hard to see as a useful option. I agree that a small change in sway bar rate can have a useful effect, so I am increasing my sway bar rates slightly.

Having driven a stock CR back to back with my own car, I believe they purposely intended to make the car understeer more than the previous models which seems to be preferred in auto-x setups, which I wasn't a fan of at all. Again this is personal preference, but I think it is pretty clear that a car with the same size front tires, larger rear tires, the same alignment and a stiffer front to rear spring and roll bar ratio is going to understeer more. If I had a CR I would still opt for the same setup I am using for my car.

andrewhake

For anyone who hates reading here is a guy that thoroughly explains everything I have mentioned here in a soothing Australian accent:

http://www.youtube.com/watch?v=JxOBw78DXBQ