ITRCA

While researching for available coil-overs for use at the track with an ITR, it seems that those with a separate adjuster ring for ride height and spring pre-load are well regarded. Models include Tein RE and Zeal B6. However these shocks are only provided with a single adjustment means for both bump and rebound changed simultaneously. While reviewing options from Truechoice for the track, they provide Koni's with independant bump and rebound adjustment, along with Koni's recommended procedure for track tuning of these adjustments. However I do not know how easy it is to access both the Koni adjusters. I was wondering what other shocks there are with independant adjustment that anyone has tried. I found Leda's which are available with external reservoirs for separate bump and rebound, but they are a little pricey. Moton too but way too expensive. One brand I found was http://www.advance-design.com which seems to fit the requirement (sold by Ground Control I think), but I know nothing about these products.

My First thought is why do you need that much adjustability? Look at how high end the TEIN RE and Zeal B6/S6 are and they only have the single adjsutability. I have never felt that i needed seperate adjustment for them rebound and compression on any of my setups although I have felt the overall valving didn't always fit the situation.

I currently havd the Zeal B6's and can't say enough good things about how nice this setup is on the streets and the track. They handle well and ride reasonbably comfortable.

I don't think you will find double adjustable shocks for under $2000 and that will likely be a good deal. the Zeal B6's can be had for around $1400 or less shipped. Check with Leo at http://www.jdmspecperf.com for other options if you are hell bent on the double adjustability.

FWIW I have been racing for 5 years from National Auto-X's to the first ITR Expo to other track days and have never sen an integra with double adjustable shocks and have only seen 2 cars that were using them (BS Porsche boxster and BSP Corvette).

Trey

Trey, it's good to see that you really like the Zeal B-6, as these were the coil-overs I was thinking of getting. However I noticed that King Motorsports for example are using the Moton shocks with separate reservoirs on their racing ITR, and all high end racing shocks tend to have independant bump and rebound adjustement. In particular most of the racing shocks from Koni like the 2812 and 2816 ($995 each shock) provide independant adjustment for bump and rebound, as do Penske's, Dynamic Suspensions, Quantum and other very expensive shocks. I spoke to Benoit Theedge at Watkins Glen and he upgraded to Dynamic Supensions shocks on his Grand-Am NSX, and P.D. Cunninham upgraded to Moton shocks for his NSX. Therefore there are obviously a lot of racers who believe the extra adjustability is worth paying for.

The bump damping controls the unsprung weight, and thus needs to be adjusted for the weight of the tires/wheels/suspension, while the rebound damping controls the release of energy stored in the compressed spring, as well as the speed at which the car transitions to roll in cornering. Rebound can be used to control the balance front to rear in terms of corner entry understeer or oversteer. Thus bump gets adjusted for one thing, and rebound gets adjusted for another. Rebound is changed based on spring rate and balance adjustment. Since the springs are selected based on the mass of the car to get a particular resonant frequency, one could say that bump is adjusted for unsprung weight control while rebound is for sprung weight control. Low speed bump and rebound adjust how the car feels when transitioning into roll, while high speed bump and rebound adjust response to small road irregularities and bigger ones like curbs where the shock piston is moving really fast, controlling how well the tires stays stuck to the track on bumps. Low speed to high speed damping ratios need shock revalving, unless you get some really trick 3 or 4 way adjustable shocks.

The benefits of Tein vs. Zeal vs. others have been discussed extensively on many boards, but I have not seen any discussion relating to higher-end coil-overs more in the tune with what the some of the racing world seems to be using.

When I noticed that Truechoice offered double adjustable shocks as part of their coil-overs for both Phase III (~$1880) and IV (~$2020), I wondered who else had some in the $2k range, and if anybody had had good results with them. The Advance-Design ones are about $1600 for a set (plus springs and seats I think) and they have the two adjustment wheels at one end like a true Koni racing shock, appearing to make it very easy to adjust one or the other by opening the hood or hatch. I wanted to know if anyone had ever tried either the Truechoice or the Advance and what they thought.

I don't disagree with you one bit. But like you mentioned $995 per shock. Is it worth it? Maybe if there is a purse to be won at the end of the race but for enthusiasts that track and drive their Type-R's on the street I don't feel the cost si worth it. I think $2000 for a set of shocks and springs is pretty much the top dollar that makes sense on a double/triple duty car.

What are you doing with the car and what is the budget are probably better questions? Wil it see wheel to wheel races?

That being said I suppose I dodn't really answer your question and unfortunately can't. I have seen a few sets of Moutons and Olihns on different cars and even a set of penskes. Shocktek (sp?) costom valves stuff but last I heard they were not open for business. THis may have changed though.

Trey,

with all the posts I have been reading on various forums about coil-overs for ITR's, there just hasn't been much actual info about real tuning for the track. It is like only the guys who race know and most everyone else is just guessing. Before I buy, I want to educate myself on suspension tuning and make the best choice. At the track I have often heard guys saying they wish they had waited and bought another mod instead of the one they did. There have been a lot of posts discussing North American preference for stiffer springs in the rear and the Japanese bias for stiffer springs in the front (and it seems that all the Japanese made coil-overs I have looked at come with higher stiffness front springs), plus many of opinions on why someone prefers this coil-over over that coil-over. For instance I know from speaking with Tein that flipping the springs front to back from their standard supplied RA or RE systems requires the shock to be re-valved as the adjustemnt range will not accomodate such a radical change in spring rate (according to them). I am sure you can still drive around the track and have fun if you flip the springs front to back and don't revalve the shocks, but your car will not be as good as it could be.

At a World Challenge event at Mosport, when Mike Galati was running his own team with an ITR (and won the championship), I spoke with his crew chief in the paddock. He told me that the place they spent the most money after the motor was the shocks. They were using Mugen racing shocks, which are stiffer and more expensive than what I want. I want to track my ITR for lapping days, not wheel to wheel racing. I will drive it to the track, but I won't use it much on the street, as I have another car. No prizes to be won. My budget is about $3000 to $3500 for tires/wheels/coilovers and say bar. I just thought that it would be fun to learn about really tuning the car while at the same time improving my driving skills. (Mostly how do go flat out on those high speed sweepers!). Thus adjustable shocks in bump and rebound seem like a good idea for that extra tuning freedom, if they can be had at a reasonable cost (not at $995 each) although for more than Tein's of Zeal's I am sure. And since Truechoice supplies the Konis and Advance-Design has theirs, I was hoping to find out if anybody had tried these products.

I spoke to lee grimes of koni, NA about this. he said that for most cases in amature racing/autox, the single adjustable would be more then enough but u had to make sure that the shock was valved for the spring that u were using with it. H also said that the adjustable compression was used mostly on vehicles in classes wher u couldnt change springs(stock classes) to esentially trick the car into thinking that u were using either a softer or harder spring . he also said that the difference between single adj correctly valved, and double adjustable was 1% on track time

Thanks, I appreciate the info. I think I will also call your contact at Koni since they obviously know a great deal about shocks. One of the problems with single adjustables is that you don't actually know if they are set right for your car. For example, since many ITR users seem to put springs with combinations like 600 lbs/in. ratings at the front and 900 lbs/in. at the rear for "serious" track driving (or 400f/600r for more streetable and 800f/1200r for racing), and they are exchanging the springs front to back from the as supplied Tein or Zeal values, a lot of people are not running shocks matched to the springs. Almost all the ITR aftermarket coil-overs are set for higher front than rear spring rates. Also the weight of the wheel/tire/brake/suspension can vary a fair bit which changes the shock's bump requirement, and who knows if the supplied values are correct? Being able to adjust them in both bump and rebound would let you know what the correct value is, and maybe this is why Truechoice supplies both their Phase III and IV kits as independantly adjustable. As for the 1% improvement you mention, that's 1.1 seconds for a 106 second lap at Mosport. That might be quite a lot for some people! I will consider whether the extra $400 or $500 for the Truechoice option is worth it above the Zeal B6's after I talk to Koni.