Focus Fanatics Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
195 Posts
Discussion Starter #1
After dabbling in lemons and chumpcar for a few years with other teams, decided to try and build a team/car of my own with goals of going into now named champ as well as possibly wrl. Chose the SVT focus as I know the motor and car very well (owned a few over the years and run a zetec in a kit car). That said, I never really got much into race suspension setups on this car.

As it stands, the car is running tein springs, stock svt shocks and eibach sways (22/25mm).

After running the first race this spring, observed that the ~2.5deg of front camber wasn't nearly sufficient so got in on the cfm lca group buy. After some modifications, got that up to ~3.5-3.7deg. Ran a second race last week and the car now turns in phenomenally and wears tires much better, but lap times haven't really improved.

Even with the stiff sways, the car still dives considerably and is pretty soft. Now we do run on some pretty darn bumpy tracks (Harris Hill Raceway for example) so I don't want to go to something meant for F1 tracks only. But I am finding that the teins just feel too darn soft.

I am limited to non-adjustable rebound shocks as adjustables cost points, but I am willing to go to coilovers, or make my own coilovers. Was debating going either with something like h&r race springs or building coilovers on top of bilsteins with a high fixed rate spring, but would rather not keep throwing money at an unknown...

The question for the road racers really is, what do you feel is the best combination of shocks/springs and sways for enduro racing on tracks that aren't necessarily always baby smooth?
 

·
Registered
Joined
·
336 Posts
When you say "Dive", do you mean Dive under braking or Body Roll?
Springs will help the dive and sway bars will help the roll. Stiffer Springs and changing some geometry also help roll too.

What are your current spring rates?
Front Coilovers are not that hard to build yourself if you are handy. Opens up your spring options with 2.5" ID springs. I'm running 175lb 12" Eibachs on my SVT struts. Mine is more of a Rally style, but still way stiffer than stock and corners much better on pavement than stock. Takes the bumps great, which was my main goal.
Rear spring options are limited unless you modify the mounts to take coilover springs as well. I think Magus2727 is running something like 450lb springs in the stock location.
Moving the springs outboard (rear coilover) will let you accomplish the same thing with a lighter spring.
I have wagon springs that are cut down to get the height I want. They are 166lb originally, but after cutting 3 coils off them, they are now around 225ish. Cut more coils to get it lower and stiffer. Cheap to buy and play around with. Like $80 for a pair of Moog springs. Again, mine is higher than stock but still stiffer. But still works well on pavement
 

·
Registered
Joined
·
336 Posts
Changing the front end geometry will help too. Control arm mounting points, Spacing the lower balljoint/heim down in relation to the knuckle, adding more caster, etc.
 

·
Registered
Joined
·
369 Posts
A few of us play with road race setup here. I run Koni non adjustable front coil overs with spring rates that depending on track range from 450-700. The rears I am stuck within the rules to as remain like stock as for separate spring shock. We run H&R spring and shock. Spring rates in the rear start at 700 all the way to 1100 depending on track. Is 1100 to stiff, not on the track we run and the curbs become something to be aware of. The rear bar is big for our setup but it works. We use the JBR unit and have been very pleased.
 

·
Registered
Joined
·
336 Posts
A few of us play with road race setup here. I run Koni non adjustable front coil overs with spring rates that depending on track range from 450-700. The rears I am stuck within the rules to as remain like stock as for separate spring shock. We run H&R spring and shock. Spring rates in the rear start at 700 all the way to 1100 depending on track. Is 1100 to stiff, not on the track we run and the curbs become something to be aware of. The rear bar is big for our setup but it works. We use the JBR unit and have been very pleased.
Wow, I didn't know guys were running springs that stiff in the rear. I know with them mounted inboard the motion ratio is not ideal. That's a lot of stress on the control arm.
 

·
Registered
Joined
·
369 Posts
Inspection of everything every time is key, after 5 years no issues at all. We set it up for rear rotation and we do have a little more power than stock. We run R7 225 size so there is plenty of tire. Not much more than -3 in camber.
 

·
Registered
Joined
·
195 Posts
Discussion Starter #8
Great info, thanks guys. I should clarify a few things...

Dive - both under braking and roll in corners. the sways do help with the roll but springs are too soft even here.

I don't know the spring rate - the tein s springs are progressive - they're really street lowering springs. I used these largely because they were cheap and readily available and I had other things to worry about at that time.

Per champcar rules I am limited to what I can do with shocks/springs without incurring crazy points.

I have to stay under <2x factory cost for shocks, otherwise the point cost is obscene.
I would also love to keep the stock diameter to avoid paying points on that as well. If I can't, fine, I'll do it, but ideally only in the front.

----------

Relevant sections from the rule book:

- Shock absorbers / struts over the 2x cost limit and/or with damping adjustment, 25 pts per corner
- Springs, non-OE coil springs (including ‘coil-over’ kit):10 pts per corner
Exemption: Competition vehicles may replace OE coil springs for 0 pts provided that the replacement maintains the exact same ID/O

----------

Mike, for the Koni's up front, did you go with 2.5" springs or stock diameter? For the H&R rears are you able to get those spring rates in the factory sizes?

I can see how you wouldn't need as much static camber when running much stiffer springs. The mcphearson setup really bites when it comes to static camber and soft springs.

With the JBR unit, do you just run the race rear and leave the factory front alone?

Also note that in enduro we're tied to 200 treadwear tires, no R7s here!
 

·
Registered
Joined
·
369 Posts
Front is 2.5 as are the rear springs, we use a short 6” spring to get to the ride height min of 5” at the rocker panel. No front bar, we found that it lead to more understeer at the limit and with our spring rates the rotation was more important. I also have 4 piston front calibers so stopping isn’t an issue.
 

·
Registered
Joined
·
43 Posts
Inspection of everything every time is key, after 5 years no issues at all. We set it up for rear rotation and we do have a little more power than stock. We run R7 225 size so there is plenty of tire. Not much more than -3 in camber.
A little more power than stock = LOL!!
Good luck at the runoffs Michael. Sorry I've been so out of touch...
But I'll be monitoring your practice, qualifying and race via internet.
 

·
Registered
Joined
·
43 Posts
Petik knows my setup, as we have been texting about it.
For others interested, to get stiffer rates in the rear, we used the Moog catalog to find springs that are within 1/4" of the stock ID (0 points per Champ rules). The ones I am using now were about 360 lbs/in stock, but after cutting them to get the lowered ride height we wanted, they are now 460 lbs/in. I've tested them on a spring rate checker.
There are other springs that start out at a higher rate that will yield rates between 550- 650 once they are cut, but I haven't played with any of them yet.
So the current rear rate = 460 lbs.

We run Bilstein B8's all around. To achieve balance, and have adjustability up front, I've cut the stock spring seats off the Bilsteins, and slid coilovers sleeves over them to be able to use 2.5" ID Eibach springs. Currently, we are running 400 lbs front to go with the 460 rears.
We are running stock SVT sway bars front and rear. The car is pretty well balanced right now. We may have to adjust rates or bars once I get the Quaife LSD installed.
We've also redrilled the strut towers inboard and rearward to achieve more static camber (running -2.5 degrees), and also to add dynamic camber from the increased caster setting.

edit: Our previous setup used cut stock rear springs, which increased the rate from 159# to 213#, and used 175# 2.5" ID springs up front, but the car still had the excessive dive and roll that Petik described. One of my drivers characterized the car as having a "hop", meaning that at turn in, the front end rolled hard into jounce, and then rose again before taking a set. With the current rates, that tendency is gone. At turn in, the car rolls less and takes a set immediately.
 

·
Registered
Joined
·
369 Posts
A little more power than stock = LOL!!
Good luck at the runoffs Michael. Sorry I've been so out of touch...
But I'll be monitoring your practice, qualifying and race via internet.
I made it I have one fan.lol. Anything mike says on suspension set up works, I am just with a different race organization so our rules packages have set me a different direction. Don’t look for much in the way of performance I was speaking to a number of people and the top 8-10 cars are builds in excess of 100k. Yeah I thought I was crazy but there or those more nuts than me. I review the entry list 20 plus miatas, 7 Honda, 2 toyota, one Nissan and one Ford Focus. Hell I am the only domestic, I think I picked the wrong class to run in. Oh well.
 

·
Registered
Joined
·
195 Posts
Discussion Starter #13
So what I'm really curious about is how heavily does the stiff sway bar play into your spring selection.

Mike C, i think you're running the stock sways, right? That means the goal would be for the springs to be as stiff as possible to compensate. We've done the same with moving the upper strut tower mount inboard (diagonally) to gain both camber and caster.

Mike S, completely removing the front sway is definitely something I've considered and it sounds like it may be a reasonable way to go here. Plus it simplifies the math a bit (and gives me back 20 points!).
 

·
Registered
Joined
·
43 Posts
The way I've been taught (and the math agrees) is that roll needs more rate to control than dive. A sway bar is used to assist the springs with roll control, with each doing about half the work (roughly). However, for full blown race cars, I've seen very stiff spring rates controlling most of the roll, and some (like Mike S is doing) use no sway bar at all.

I've looked into building a Superlite Cars SLC, and have toured the build facility. Some of the cars that SLC builds do not use sway bars at all! The builder, who worked for some F1 teams years back, says that sway bars are a band aid for insufficient spring rates. They can be used for balancing a car, but are not entirely necessary if the car is sprung correctly. Just another opinion/experience to consider when looking at the function of springs and bars...
So in reality, the various sized (diameter) sway bars that are available for road/street cars are used to control roll without springing the car too stiff for comfortable street driving.
 

·
Registered
Joined
·
336 Posts
I agree with the above about more spring and less sway bar. Especially in the front of a fwd car. You don't want to unload your inside tire, especially without a LSD.
Soft springs and heavy sway bar is just going to pick up your inside tire. Ok on the rear, but not the front.
 

·
Registered
Joined
·
369 Posts
Are you allowed a better diff, I have run every one, including a custom made unit. Kaaz by far has been the best so far. Our 2580 lb 2 liter zx3 is set for the runoffs, no front bar, 600 front, 850 rear springs, jbr race bar, massive thing, lower front stay bar, 15” wheels running 225 section tires. R7 Small area mods, splitter rear wing. Lexan windows, carbon hatch, 2 liter built to the letter of the rules Focus Power motor, lots and lots and lots of dyno time. 4:25 final drive, quiafe gears, and away we go to see how it does. I like no front bar, it lets the front settle in especially in the bumpy areas over curbs.
 

·
Registered
Joined
·
195 Posts
Discussion Starter #17
diff is 25pts and i've been debating that. i have an mfactory helical sitting here on a bench ready to be dropped in. Tom mentioned the same thing about KAAZ but they only appear to make one for the mtx75 (and not the getrag), at least per their website. I have 3 getrags laying around so i'd prefer not to go dump more money into switching over to the mtx75. I think i need to pick your brain around springs so i get the right setup - what length springs did you end up going with to get a good ride height? Since you're running h&r rears i assume you're stuck with just clearing bump stops all around.
 

·
Registered
Joined
·
43 Posts
Champcar allows LSD (for 25 points.)
I have a Quaife unit that haven't installed yet.
Getrag 6 speed choices are more limited than the MTX-75.
….I know, why are we still running SVT stuff? LOL.
When you have 3 engines/trans for 1 car, it's hard to switch.
 

·
Registered
Joined
·
369 Posts
In SCCA f production I have a friend who is building svt for this class, using a zetec case for mtx75 trans. It allows for more interchange as opposed to the 6 sp unit, a little bit of work but zetec units are reasonable. Just a thought, with the ability to change final drive. 3:42/3.82/4:06/4:25/4:75
 

·
Registered
Joined
·
336 Posts
In SCCA f production I have a friend who is building svt for this class, using a zetec case for mtx75 trans. It allows for more interchange as opposed to the 6 sp unit, a little bit of work but zetec units are reasonable. Just a thought, with the ability to change final drive. 3:42/3.82/4:06/4:25/4:75
The 4.06 and 4.25 are pretty hard to come by it seems. I'd love to find a set for my 2006.
 
1 - 20 of 21 Posts
Top