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advise on time attack/ road course set up on a hard top egg
Hi all, I have done lots of searching. I am new to the forum. The majority of info that I have found for track set up is three years old. As you all know there are constant improvements. I am going to be putting in a roll cage and setting the car up for time attack mostly. Any insight as to preferred set up is appreciated.
The car is a 91 NX 2000 hard top completely stock for now.
I know that this is like asking for your secrets but I could use some guidance so that I am not spending a ton of money on trial and error, but more time and money on racing.
P.S I have started the process by purchasing Progress sways ft and rr
Most of the fundamentals have not changed in the last 3 years. The development work that was done by Mike Kojima between 2004 and 2006 was basically the pinnacle of FWD Nissan suspension development, much of that had to do with altering the front end geometry. Tim Rogers car (developed by Greg Amy) is probably the best developed stock geometry NX2000 out there.
What is your budget for suspension? Will it be used on the street or track only?
You will need camber plates, set them in the 3-3.5 degree range, don't lower the car more than an inch or so.
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Thanks for the advice. I will be driving the car on the street and tracking it as well. I was considering a set of progress coil overs with GC camber plates.
I am also going to be doing full poly bushings on the suspension and running a sub frame brace in the front White line or Progress. Not sure as to bolt in or weld in yet on the cage.
Thanks for the camber settings. I am also trying to figure out spring rates to use with the progress bars ft and rr.
Thoughts on either to go with the Progress coil overs or some thing else like Koni 8611.
Any quality advice is appreciated.
8611's or ground control advance designs if your going to race the car. Spring rates in the 1000lb range depending on your preference. IIRC Greg Amy was over 1000lbs I. Sprig rate on his custom valved 8611 setup (NX2000). Again if this is a race carthen these are serious setups. If it is a dual purpose car then the Progress is a great setup if you can get ahold of their race oriented setup. I thougt they offered a setup with valving to run stiffer springs.
Caster bushings, bump steer kit, are also required minimums.
Spring rates in the 1000lb range depending on your preference. IIRC Greg Amy was over 1000lbs
He also really, really knows how to drive. I wouldn't recommend those spring rates to a beginner (not sure what the experience level of the poster is) Also the higher rates make the car less able to work in the wet.
I have the Bits & Pieces 8611 setup with 600f/650r, it's very easy to drive but I can tell the car could benefit from more spring. I have bumpsteer, rollcentre and camber curve correcting geometry in my car, which helped immensely, but it's not exactly a 'bolt in' solution. For this reason I am able to run the car very low, with stock geometry you would run the ride height a good bit higher:
Thanks, Wes and Fast NX. This is just the type of information I was hoping to receive. I will look into both the Progress and the Bits and pieces setups.
I have done quite a few autocross events mainly in H stock. So this is a venture into a more track oriented project.
Fast NX, I do not think I am quite ready to step up to 1000lb springs so your set up sounds more my speed. You hinted at possibly wanting a bit more spring than what you have. Would you suggest your spring rates 600/650 as a good starting point or go higher?
Also Wes talked about caster bushings and bump steer kit, I will need to look into these. I am finding it interesting that race setup spring rates tend to go stiffer in the rear than the front, unlike a street kit that would favor more of a lighter spring in the rear. I am sure this is for liability reasons.
Fast NX are you running sway bars in conjunction with your high spring rates?
Not sure if I missed this but you said you are running Time Attack type events.
What tires are you planning to use? How much track time do you have? What sort of power are you making? Is this car 90% competition car only driving to and from events? Or is it really more of a trackable daily?
This will have a direct connection on what set up I would recommend
I recently spoke with Mike Kojima, Blair and a few others about this very thing.
I have a similar set up as you are asking about. Biggest difference is I have a bolt in 4 point rollbar.
I went with the Progress coilovers a couple of years ago. I have been extremly pleased with them so far. But As I progress I need something more aggressive.
The recomendation was to keep my rates under 500 because of my bolt in bar. The chassis will flex too much and not be all that good with much higher than that. If you do a cage, At least weld it in. If its in the budget I would get a proper custom made one built. Autopower will work but its not ideal. It will be so much stiffer that way. You can also run a much higer rate if you wish and the chassis will not negativaly affect your set up. As the chassis flexes it acts like its own undampend spring.
For a street/track car 600f 650r plus bars will be damn stiff. It will be near brutal on the street. The Progress coilovers will be at the upper limits to their available valving.
If you want to run higer than that, I suggest AdvanceDesign or Koni 8611's Since you are going to need Ground Control camber plates, in theory you could drop your coin in one place and be done. I havent priced their stuff lately so it could be up there.
Id only suggest 600+ if you are HPDE4/instructor level driver on At least R-compound tires. That is definatley not a novice cost/setup.
Fast NX, I do not think I am quite ready to step up to 1000lb springs so your set up sounds more my speed. You hinted at possibly wanting a bit more spring than what you have. Would you suggest your spring rates 600/650 as a good starting point or go higher?
Also Wes talked about caster bushings and bump steer kit, I will need to look into these. I am finding it interesting that race setup spring rates tend to go stiffer in the rear than the front, unlike a street kit that would favor more of a lighter spring in the rear. I am sure this is for liability reasons.
Fast NX are you running sway bars in conjunction with your high spring rates?
I think to run 1000+ spring rates you would need dozens of track days or races under your belt. I am running Progress front and rear sway bars, in the past I have run both on the medium setting. I wanted to run more bar, but the last few times I have run the car it has been wet, so I disconnected the bars. I am going to put them both to full stiff this year to see if that helps. I also have a splitter and adjustable wing so I can use that to tune high speed balance if need be.
My brother ran Progress coilovers on his old race car, the biggest problem we had with them was customer service and speed of delivery. If I'm not mistaken it took over a year to receive the coilovers since they had to wait for them to do a run of them. I have not dealt with Ground Control (Advance Design) directly, but I have heard bad things about their customer service and speed of delivery. With Bits and Pieces, Monty kept me in the loop through the whole process and I had the suspension within a few weeks.
I can't comment on what cage is required for what spring rates, but if the info is coming from Mike Kojima, it's pretty reliable. If your car can handle it, and you can afford it, I think Bits & Pieces is the way to go.
What tires are you planning to use? How much track time do you have? What sort of power are you making? Is this car 90% competition car only driving to and from events? Or is it really more of a trackable daily?
This will have a direct connection on what set up I would recommend
Autopower will work but its not ideal. It will be so much stiffer that way. You can also run a much higer rate if you wish and the chassis will not negativaly affect your set up. As the chassis flexes it acts like its own undampend spring.
For a street/track car 600f 650r plus bars will be damn stiff. It will be near brutal on the street. The Progress coilovers will be at the upper limits to their available valving.
If you want to run higer than that, I suggest AdvanceDesign or Koni 8611's Since you are going to need Ground Control camber plates, in theory you could drop your coin in one place and be done. I havent priced their stuff lately so it could be up there.
Id only suggest 600+ if you are HPDE4/instructor level driver on At least R-compound tires. That is definatley not a novice cost/setup.
I'm curious to hear the answer on this. This will make a big difference!
I'd go ever farther and say it's a waste. It really doesn't fit well since it's designed to fit with the interior in place. If I could afford it, I would replace mine with a custom one in a heartbeat. Mine is the original one from it's Showroom Stock days and you can tell it's an old design. I wish I could document and show you guys how much mine moves with my rates!
For a dual duty car I'd avoid the Progress coilovers. With enough rate to be good on track you're going to need alot of rebound to control it. Alot of rebound on the street is down right punishing. With 500f/600r the only change I make from track to street is to take the rebound out of the rear. I've forgotten to before and paid the price! The other nice thing about doing an 8611 type set up is that you can easily change the springs without having to have them revalved. You could start with a lower more forgiving rate ( note: you'll want to be careful not to bottom them out too much) and then up the rate as you feel the need.
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I'd go ever farther and say it's a waste. It really doesn't fit well since it's designed to fit with the interior in place. If I could afford it, I would replace mine with a custom one in a heartbeat. Mine is the original one from it's Showroom Stock days and you can tell it's an old design. I wish I could document and show you guys how much mine moves with my rates!
How can you tell the cage is moving? It must be hard to see when you are driving on the track, or is it that obvious driving around the paddock? My cage was originally a bolt in, I assume it's an Autopower, but it is currently a 6 point that has been extensively modified with MUCH better door bars, welded into the car with 20sq. inch base plates to pass tech (the cage originally had 9 sq inch base plates). Still sucks that it was designed to fit into the car without removing the dash, but I can't perceive the type of flex you are describing.
If I'm not mistaken Greg Amy's car started life with a budget bolt in roll cage that was modified and I think the whole thing was think replaced at one point. If this is in fact the case, it would be interesting to hear his views on how improving the cage affected the car.
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The other nice thing about doing an 8611 type set up is that you can easily change the springs without having to have them revalved. You could start with a lower more forgiving rate ( note: you'll want to be careful not to bottom them out too much) and then up the rate as you feel the need.
I was under the impression that with their 'out of the box' damping, the 8611s can't take too much more than 650 springs.
How can you tell the cage is moving? It must be hard to see when you are driving on the track, or is it that obvious driving around the paddock?
I was under the impression that with their 'out of the box' damping, the 8611s can't take too much more than 650 springs.
It's bad enough that you can put your hand on it and feel it (esp. in the area at the top of the a-pillar) just driving it around on the street.
This was true of the original 8611-SPORT valving. The new RACE valving is more aggressive (and IIRC digressive) and capable of higher rate. The internals are completely different and beefier in the RACE version.
Boy, this could turn into an epic...maybe I should write a book...
Simply put, you have a strut suspension car. Strut suspension geometry sucks. The more you lower it, either statically or dynamically, the worse it gets. So the general idea behind what we did was a take from the old Colin Chapman saw: "the best way to make a suspension work is to not let it."
Your budget limitation will be primarily shocks. Everything else you do - springs, camber plates, ride height, swaybars, rollcage, EVERYTHING - will be centered around whatever shock package you can afford to buy. Buy the best shocks you can afford. If that's 8-way adjustable remote-reservoir Motons, that's sweet; if that's KYB AGX, then so be it. I found that the best performance-to-value ratio came with Koni 86xx series (8611 2-ways or 8610 single-adjustable); in messing around with a lot of lower-cost ones I just never got no satisfaction, but that's just me. So do a budget analysis on shocks first, then we can help you figure out everything else.
By the way, to show you how important that mindset is, it took me nearly 3 years to develop a car that was as fast at Lime Rock Park when it was using KYB AGX, 300/400 springs, and Kumho tires. The reason was that by adding Hoosiers I was adding tire grip, but I was also increasing lateral G's which was compressing the suspension more, adding a need for higher spring which added a need for better shocks, and it was a death spiral and difficult to catch up. So take my word when I tell you buy the best shocks you can afford first and develop around that. And, if you can't afford 86xx series or better, then you're likely wasting your money on Hoosier tires.
Once you've picked the shocks, pick spring rates that are within 80% of their capabilities. These could be bolt-in HyperCo or they could be adjustable Eibach-type standard springs. Just stay within the capability of the shocks.
Buy the biggest rear swaybar you can. If you have madz fabrication skillz, build one of these:
(That's a 1.25 solid-steel torsion bar, as used in NASCAR. Works.) I never ran a front bar, but some folks like it. I think we actually may have been moving the direction of putting one back in, but never got there. We were also moving toward the direction of $1500-per-corner shocks; I am VERY glad we never got THERE, either...
Once you've got the shocks and springs, set the car up with a reasonable ride height. Remember, the lower you go, the worse the camber/roll height curve, and the worse the handling is going to be. You need a ride height that will keep the car off the bump stops, but also one that keeps the suspension geometry within its fat part of the curve. You may think that a low ride height is better, but with a strut car that's decisively and completely wrong. CG matters little when your roll centers are below the ground... Unless you can afford the shockage to control the springage to control the poor-geometry suspension movement, you're MUCH better off raising the car. Yeah, it doesn't look as hot, but that's not what we're after, right...?
A note on rollcages: they're important for safety, obviously, but they really don't come into the performance envelope until you have springs that exceed the natural spring rate of the chassis. I don't know where that is on the NX, but aside from building the rear legs of the cage to the rear strut towers to stiffen that, I don't see the value in going crazy with a cage until your spring rates start to exceed 400-500 in-lb or so. Purely a WAG on my part. And Frank is right that we started with a bolt-in rollcage initially, but that was because this is the same car I drove in Showroom Stock in the early 90's, when bolt-in cages were required. We later scrapped that and built one from scratch; look about halfway down this page: http://www.kakashiracing.com/2003.html
So, shocks, then springs, add a big rear bar, do a sane chassis setup. Go have fun.
I can offer more later, but I should do some work (it's what pays the bills!!!) If you have specific question I'll be glad to help as I can...after all, they're now Tim Rogers' secrets...
And Frank is right that we started with a bolt-in rollcage initially,
It's Jeff! As in Jeff with the black NX pictured above that met you at the 2006 SER Convention and still has your lanyard from the track day at Pocono (you gave it to me to hang onto while you suited up and I didn't see you again that day.) I'll try to remember to bring it to Mosport. Frank has the white NX1600 and is running that lapping day. Maybe when you see us at the same time you will see we are two different people
Regarding the low ride height, this is what my front end looks like:
I don't know of anyone besides Mike Kojima and myself that have done this. It allows you to lower the car agressively and still have it handle properly (or as properly as a B13 can handle....) It's not a bolt-on solution and definitely beyond the scope of what the original poster had in mind, but I wanted to show that I'm not a bone headed racer wannabe with a super low car because it looks cool.
Ugh! I knew that, Jeff :embarrassed: When I wrote that I had just responded to you via email about Frank's track day at Mosport we're doing next weekend so I guess I still had that in mind. (For reference, Jeff and I are attending Frank's open-track day the Friday of Memorial Day weekend. I'm taking my blue VVL-equipped street NX there. As a related aside, it has revalved Koni 8611 inserts with 400/300 springs, Progress rear bar and GA16 front bar, and I snagged some Spec Miata Toyo take-offs for it).
What you've done on the front end there is exactly what has to happen when you lower a strut-equipped car: lower the tie rod ends to decrease bump steer (the tendency of the car to change toe as the suspension moves vertically, a problem not unique to strut cars) but more importantly reducing the vertical angle of the lower control arm (to raise the roll center of the car, the imaginary point about which the center of gravity acts during lateral loads). Combine that with good springs and shocks to limit vertical movement of the suspension and the geometry can stay within reasonable areas.
Jeff did this by lowering the outer ball joint location. That's fine, but at some point you will be limited by wheel size (you can only go down so far before hitting the wheel) and/or ground clearance. The guys with the big bucks, like World Challenge GTS teams, will actually re-fabricate the inner pickup points to move them up into the chassis. You better have some serious fabrication skills to be doing that (we're actually considering it for the STU Integra).
Nissan, of course, considered all of this when they did their initial suspension geometry design, choosing between all the compromises of noise/vibration/harshness, economy of strut design, and where they needed to put the pickup points to make it all work. all we do when we change that if eff it up...
Thanks for all the input guys.
Blair: This car will be more of a trackable daily, that over time probably will become a track only car.
As of now the car is stock, but most likely will move up to a Neo VVL SR20VE
I was planning on running Nt01 or equivalent tire for now.
Was considering an Autopower 6 point bolt in roll cage but now am not sure.
Greg Amy: Thanks for the advice on buying the most shock I can afford, then springs then cage. I am trying to decide between the Koni 8611 or advance design any input would be great.
I just got off the phone with Monty of Bits and pieces and he told me that there are in fact two versions of the 8611 one for lighter cars like the B13 chassis, or there is one with firmer valving for Camaro and such. Which one would you suggest to go with?
Fast NX: I am digging your Control arm bump steer correction set up. I was wondering if you had to do anything similar to the rear as well?
I was poking around on MotoIQ and saw Mike Kojima's set up as well it looks great. For now I will be just doing a conservative 1" drop. Later I will look into building a similar set up as time amd money permit.
What you've done on the front end there is exactly what has to happen when you lower a strut-equipped car: lower the tie rod ends to decrease bump steer (the tendency of the car to change toe as the suspension moves vertically, a problem not unique to strut cars) but more importantly reducing the vertical angle of the lower control arm (to raise the roll center of the car, the imaginary point about which the center of gravity acts during lateral loads). Combine that with good springs and shocks to limit vertical movement of the suspension and the geometry can stay within reasonable areas.
Jeff did this by lowering the outer ball joint location. That's fine, but at some point you will be limited by wheel size (you can only go down so far before hitting the wheel) and/or ground clearance
It's about as far down as I can go with my Enkei wheels. Ironically my wet wheels (Rota Subzeroes) have more clearance, so if I were to committ myself to those wheels, I could make a longer stud, but I think I've done enough messing around with too little track time to show for it. One other thing I did was have the tubes that hold the rod ends welded at an angle further forward to increase caster. I have 4 degrees now, which my alignment guy says is safe to run without damaging the axles (too much caster can wreck the CV joints)
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Thanks for all the input guys.
Blair: This car will be more of a trackable daily, that over time probably will become a track only car.
As of now the car is stock, but most likely will move up to a Neo VVL SR20VE
I was planning on running Nt01 or equivalent tire for now.
I think you're on the right track. Keep in mind it can always be better. At some point you have to draw the line and be happy with what you have, but I think you will be more than happy with with your NX.
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Fast NX: I am digging your Control arm bump steer correction set up. I was wondering if you had to do anything similar to the rear as well?
My brother had an NX racecar and he went all out on the rear suspension geometry. He is a fabricator by trade, he used to work on Daytona Prototype cars so he borrowed a lot of knowledge from that. What he did was move the inner pickup points for the rear parallel links inward and further up, with longer links to keep the wheel in the same place. Moving the pickups higher did the same as lowering the balljoint, as Greg mentioned earlier, and making them longer meant less change in camber per inch of wheel travel. He also moved the pickup of the trailing link further forward, with a longer link to reduce rear bump steer.
In my opinion fixing the rear is less important than the front, and is considerably more expensive and difficult to do. I would completely reject the idea of playing with the rear geometry unless you have exhausted all other avenues of suspension tuning and still have money and energy to spend.
As mentioned earlier you can keep the geometry in a satisfactory working range just by not lowering the car much from stock ride height.
I just got off the phone with Monty of Bits and pieces and he told me that there are in fact two versions of the 8611 one for lighter cars like the B13 chassis, or there is one with firmer valving for Camaro and such. Which one would you suggest to go with?
I'm personal friends with Koni's North American Motorsports manager, and I am unaware of what Monty describes. I do know that - as Blair described above - there was a change in the product to a "-RACE" part number, and that's what's available off the shelf. However, after my experience with the 8611s in 2005/2006 I worked with Koni for a revalving of those inserts to handle higher spring rates, revalving that Koni to this day does not agree with (Gordon shakes his head every time we talk about it). But in the end, and despite all the spreadsheets and technical graphs, i found that my car needed that additional valving to handle the spring rates I was running in the car (IIRC, 800F/1200R). It's a long-standing joke, but you can send your 8611s to Koni and request "tGA valving" for them to get where I ended up.
As a related aside, I never found much need for a lot of compression on my struts. Plus, we usually found a sweet spot and never touched bump again, choosing to tune only with rebound changes. As a result, I suggest that were I to do it again I'd probably opt to save a few pennies and go with the single-adjustable 8610s instead of the 2-way 8611s; in fact I've got a set of 8610s in my garage waiting to install on my street NX (and those 8611s would be available if anyone wanted them).
As for Advanced Design, we ran those for a year. It was soon after that we fabricated our own struts based around the Koni 8611. We used GC's spring collars, GC upper spring perches, and Eibach springs, with modified (for more travel) GC upper camber plates on modified inner fenders.
eggman: I'd be happy to help out anyone working on such a project, but I suggest that anyone clever enough to make those changes probably doesn't need me bothering them...
Are you referring to any of the 8610 inserts? I am using 8610 Spec V inserts in the front of my B14. I am assuming I can have these re valved to run higher rates?
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