edfc???

 

Guys - don;t be fooled into thinking you can comapre the stock spring rates to those of any coilover - you cannot. Coilovers such as the Cusco, JIC, Tein, HKS are not just springs, they are new dampers (shocks) as well. As such, manufacturers, especially ones with a longstanding reputation such as Cusco, have spent tons of time matching the srpuing rates to the dampers. Not only that, but shock design (twin tube, monotube) also afects whatt he "right" spring rate is for the car. Having driven a 350 with the Zero 2's for example, I can tell you its defiantely not softer than stock - in fact it is a bit stiffer but much better dampened overall, and very well controlled.

As for the Tein Flex, it also is a good unit, particularly for a street car. Howver, its downside is it uses a twin tube, and the piston diamter is a bit on the small side for truly exceptional handling. But it is a very capable unit, and we have been huge Tein fans (not to mention dealers) for years now - very good company to deal with.

Any questions, let me know - we are well versed in all the units, as we have been selling and isntalling coilovers for years - just don't want to see people get confused by what is largely marketing information.

 

what do you recommend for me then

 

How much track racing are you planning on? How capable are you at making the adjustments yourself, and how often do you think you'll make those adjustments?

Also, where do you live? What are road conditions like? Realize that your ride quality is going to go down the tunes with those 20's no matte how you stack it.........I;d err on the side of a milder setup, especially if comfort is anywhere in the roster of important factors to you. We sell them all, from HKs to Tanabe to Tein to JIC to Cusco, and are authorized dealers of all as well (so no need to push one vs another) - there are lots of options, so want to try and steer you to the ones that best suit your needs.

adam

 

Well, I am moving to hawaii and have no idea how the roads are. Also who knows if I am going to race, I have been saving for a TT but now I am spending all my money on a body kit, wheels/tires, and coilovers so my car looks good. I guess I really cant go with an all around coil over (incase I went to race only) This is my daily driver so maybe ride quality will be better because of the 20s and lose of performance....or ride quality and some performance....i realize 20 ride is gonna suck

 

oh I am very mechanically inclined, and can get access to a lift....adjustments should be no problem

 

I'd be interested in a more detailed account of your impressions from the Zero 2 as it's one of the systems I've been considering. Particularly do you think it would be a good choice for a daily driver that sees the track once a month?

As for the Cusco website it's www.cusco.co.jp

 

Personally I love the Zero 2's on this car - very controllled ride (subject car had 18's, Toyo Proxes T1S), and Cusco sways - a bit stiffer than stock, but well damepend (drove the car in upstate NY). I don't have coilovers on my own Z (roads are too rougth near us) , but if I were to get them , these would be them - very good blend of performance, adjustability and comfort.

Gerr - but do you think you'll actually make the adjustments? Reason I ask is that I find most of our customers who buy coilovers end up finding a combination of rideheight and dampening settings they like, and sticking with it. Some guys like to fiddle with camber, dampening settings, etc, others just want to set it and forget it. Given the price you would be paying for the Cusco, they are impossble to beat IMHO

 

Thanks Adam.

 

apsilon - any pics of that exhaust - one of the ones I am considering

 

It's interesting that the Tanabe GF210 springs outhandled the other cars in the recent 350z tuner car challenge, beating out other Z's that were equipped with adjustable coilovers.

adjustable coilover suspensions are cool, but I would not underestimate spring and strut upgrades

a lot of people want 'coilovers' but many are misinformed as far as their function

 

1. Don't be fooled into thing thinking that should not use the stock spring rates as a base line. Go out and find what you like and or don't like with the stock car's handling. Do the research you need to do to find out how you would best change or NOT alter the stock car's spring rate balance. "Deciding on spring rates is one of the most important decisions you have to make about your race car set up." Quote Smithees Race Car Technologies. Start with setting your spring rate quotient first, then buy the coilover system that has the dampener system you believe in the most.

2&3. True and thank god, most all of them do not use progressive springs. Yet the need to follow tunning rule number one, setting your spring rates applies. Does your choice in coilovers obey the tunning rules you know to be true and unwavering concerning spirng rate balance or neutrality? Do not follow a name brand in blind faith, that the unlogical is somehow ok, cause they couldn't possibly be wrong. Know your fact's and know better.

4. How does mono tube or twin tube design factor's actually show up in the market place. You have jic's mono tube and teins twin tube, yet they us very simular spring rates. So the manufactures are not "springing" their coilvovers in regards to twin-tube or mono. Yet they are different, We need to reveal how the 2 are different.

Mono Tube
Very wide damping rates can be achieved through bigger diameter pistons and shims designs Cools faster and more reliable because they can withstand higher pressures and temperatures without aeration or foaming of the oil. Bigger diameter piston rods can be used because of bigger internal chambers with sufficient oil. Mono tube design's are said to be more stiffer/more responsive/better feedback vs twin tube design's.

Twin Tube
cheaper to manufacture and said to offer greater ride comfort and less tendency to bouce. On other term that come up is that the twin tube design's are not a durable as the mono tube's.

5. Don't doubt a word, makes perfect sense. But with 62% greater roll stiffness and softer rear springs, car will push more and be slower around the track for it. Not something Cusco's sway bars can compensate for. Let's do the math. Say you set the front Cusco bars at their softest setting 12% stiffer. And of course the rear bar offer's 73% greater bar stiffness over stock.
You'd think your 74% greater front roll stiffness is washed out with the rear bars 73% greater stiffness. Well remember, these car's understeer from the start, being equal, won't change that. It took a transfer of 36% transfer of roll stiffness on my car to net neutral handling and that's NOT with running softer rear springs. This is where it get's back to knowing what your stock setup is, so you know the proper direction to follow and what to avoid.

6. Theirs are ton's of extreamly positive flex reviews on this board, what is debateable is how much does one have to push a twin tube design, before it's performance fades. Will that point ever be reached with aggresive street driving, or will it only occur in a track event only?

7&8. Having been in sales in my life time, I can read bewteen the lines on that one. Theirs a difference between what your feed by the companies sales staff and what training event's they tend to put on that you might attend, and their's what you have adjusted your thinking to as to push the more profitable item's and the reality of what is really and truely rightious, devoid of any profit motive. Being that you know how good the Jic's factualy are, I see hope. Turning a blind eye to Cusco's bewilderingly low rear spring rates, something's not right on the rightiousness part. Their's way to much info out thier that point's to how wrong those low rates are.

 

Consider this...

The average driver is much better off with a car that pushes, it is MUCH safer.

The fastest car is typically on the knife edge of loose. If I were going to spend every weekend at the track I'd want the JIC product simply because it is probably closest to that balance. However, if I was an average driver and did not spend much time on the track improving my skills I am better of with other products.

How many of us really can say we drive over 8/10 anyway...

 

I just wanted to throw one thing in on the spring rates topic...

If you are discussing spring rates of linear springs, you also have to consider spring length. By definition, a linear spring increases it's force for every inch of travel.

What does this mean? well, it means that if the Cusco spring is 1" longer than the JIC, when it is compressed by the cars own weight, what seems like a soft spring becomes much harder...

392bs x 2" = 784lb spring installed.

Now, the math isn't quite this simple, but you have to compare installed compressed spring height for the springs as well...
so: (orig height - compressed height) * rate = effective rate

One last thing.... If you consider this info, the Cusco spring will actually provide a much smoother ride. Consider this..
672 JIC rear spring
392 Cusco rear spring
For every 1/16" of travel this is how much force must be applied to the spring:
JIC: 42 lbs
CUSCO: 24.5lbs

This means that the dampener has to control that much weight for every 1/16", and it also means that it will ride that much harsher...

Just some info to think about...

Does any one have the orig/compressed spring heights?

Edit: corrected spring rates based on numbers from previous posts

 

G35 - good post, bt we;ll go round and round on the spring rate issue forever it seems The book you quoted is an excellent source, except you are leaving out one thing (which we apparantly disagree on, but no biggie) - that while spring rates are a VERY critical choice for a race or street car, once you alter the valving of the shock, shock length, and other aspects, you are no longer comparing apples to apples. What that book refers to is having to choice from an array of spring rates while retaining the same dampeners - your example of changing spring rates is fair for say, people selecting which aftermarket lowering springs to buy, since for the time, being, we are pretty much limited to the stock units (or the NISMO ones). So, you have a wide array, from eibach, H&R, RSR and many many others. However, once you change the shock portion, its a different ballgame. Your example is also a good one if someone already has JIC's and are now looking into playing around with different spring rates...

You also talk about inducing a neutral feel with sway bas, etc, but as you well know, tires have the biigest overall influence on how the car turns in, behaves in a corner, and grips overall - unles you keep the tire completely static and alter only sway bar settings, its not a fair comparison (you did not make mention of this in your post above).

I was not quoting sales jargon at all - frankly,t he profit margin on each one of the brands is the same for us, so I have no axe to grind there at all. All I can speak from is my experience with a variety of coilovers on this car that I ahve personally driven in to date - none have been in a track environment yet, though that may come in the future with my own car. These different cars I ahve driven have also have different wheel/tire combinations, which greatly affects things as well (from width to offset to tire pressure, tire brand, etc.). I cannot say which is faster or slower around "a" track, as that requires too many constants that frankly none of us here will ever likely get to test out.

 

Adam, did you feel any bit of understeer when you test drove the Z with all the Cusco parts.

 

And is all the spring rates the installed effective rates or are they the rates for the loose spring outside of the car? Because the Mechanical leverage changes due to the location on the suspension and a great deal of other geometry involved.
Apples and oranges can't be compared.

 

My $.02...coming from a road racer. For optimum handling, I would stay away from the Cusco's based on the spring rates they advertise. You can always change springs later on and dial it in to some extent, but I'd rather not buy one of these coilover sets then turn around and spend more money on the "correct" springs.

Now, there still is a question I have about the Cuscos though, and this might change my opinion of them. Are the rear's a coil over setup, or does it use the stock setup (not coilover). If it is actually a coilover in the rear, then you truly are comparing apples to oranges when you look at the spring rates. Something called "motion ratio" comes into play here, and in order to compare the two you have to know the motion ratio, which will allow you to calculate the wheel rates. The wheel rates, once known, can be compared.

 

Ok, I just did a quick search and it appears that the Cusco set is actually a coilover in the rear. That would explain the use of springs that are a relatively low rate in comparison to the front. Since the spring is on the shock instead of in the stock seats, it can be a lower rate while maintaining the same rate at the wheel. In the case of the Cuscos, the spring rate is slightly less than stock but the wheel rate is probably a good bit higher.

The front is already a coilover configuration from the factory, so when going to a true coilover, a higher spring rate will actually increase the apparent stiffness of the suspension. I don't have time to measure and do the calcs, but I would guess that the Cusco setup actually ends up with a fairly even increase in wheel rates front and rear.

I take back what I said about getting another setup rather than the Cusco

 

I'm with you 100% on where the rear springs are (leverage principles and all) and what that means if the Cusco coilovers use a on the dampener location, that would explain the low rates. However, how did you verify the location of the rear coils on the Cusco's? Tein's and Jics use the stock location for their rear springs, but on other applications they mount the rear springs on the dampener itself.