Following the advice of many on this site, I've been attending every driver's ed and autocross school I find (and could afford...). So I've tightened the nut behind the wheel some already. I'm starting to think about what I want to do suspension wise and would appreciate some advice.

Here's the starting point: '04 MCS with performance, sport and winter packages. (About 56k miles). Mods: CAI with cowl mod; 15% pulley; 22mm 3-way adjustable rear sway bar; Kosei K1 Racing 16x7.5 wheels; 215/40-16 V710's; and MTH (the old version before the Tuner/Standard thing) which I'm not sure is doing much for me. Brakes: EBC Greenstuff + slotted rotors; SS brakelines; high-temp fluid. No LSD.

Use: 4-6 HPDE track days per year. 40-50 autocross runs @ 60 sec each. Class: Street-Mod (or Mod-till-you-drop).

Challenges: Still has to be used as daily driver, 15-20k miles per year, mixture of twisties and highway use. I'm never going to win my class (especially in this mega region). I just want to be competitive with the JCW guys as a benchmark. If I had to pick between auto-x and track, I'd lean toward the track set-up as a priority.

Here's what I'm thinking: The car currently is very well balanced on the track. I'm thinking about adding fixed camber plates to the front (Ireland engineering 1.25 degree) to help with tire wear. I want some camber but I don't want to wear out my street tires either so I thought fixed might be a good choice. I'd like to lower the car about 1 inch all around, especially with the shorter Kumhos it looks a bit 4x4 ish. But I can't go much lower and still get in my garage. If I'm only going for a 1 inch drop, can I keep my stock shocks? I'm thinking of the H&R sport springs with 1 inch and .75 inch drop. What are the trade-offs in doing that? Anyone have a better recommendation? Thanks for the advice. Next up: header and exhaust....

 

The H&R springs are *definitely* more than an inch drop in the front an 3/4 in the rear. Turner is just wrong about those measurements, especially the drop in the rear. Helix lists the H&R's as a 1.2" drop in front and 1.3" in the rear. That jives a lot more closely with what most people that have installed them have seen. When I had the h&r springs on my MCS, the rear drop was closer to 1.5" so the car is using up more of the available suspension travel and is closer to riding on the bump stops.

For my spring money though, I would get the h-sport springs (which I have also owned). They lower an inch front and rear and come with replacement bumpstops.

 

I can't give you any advice on the suspension setup, but I'd advise doing a cat-back exhaust mod of some kind (many threads on that topic!) and not to worry about the header--it will provide little HP increase at best, and a hell of a lot of heat, fitting and noise problems at worst.

good luck,

 

I've gotten to the point that I hate to see anyone go to just a lowering spring. Do the springs and shocks or just the shocks. Consider the 11.75" Wilwood BBK with easily changeable pads you could go from street pads to track pads in just a few extra minutes. You will want more negative camber, get the Helix/RDR plates and run -2.0 to -2.5 but keep the toe near zero, it's toe and lack of camber that kills the tires. The 215/40/16 710's are a great autocross tire but for the track you might want to consider something both a little bigger and more durable. What, will depend on the length of your track sessions and how hot everything is.

 

I've never considered doing just the shocks. How does that work? I thought ride height was a function of the springs not the shocks...

 

If you have the balance of your car in a happy place now, I can highly recommend the JCW suspension upgrade - just do the springs and dampers (shocks) only, don't touch the swaybars.

I put the JCW suspension springs and dampers on my car, and the balance in terms of oversteer / understeer stayed the same imho, but the limits increased. The ride height drop is negligable, and it is still comfortable enough for daily driving. Sounds like it might be something worth looking into for what you want.

 

Snid,

I have lowered my MINI about 3/4 to 1" with H&R sport springs. It's been 25,000 miles and am considering replacing my stock struts with the JCW units. Have the suspension oriented toward track use. Do you know if or how the JCW struts differ from my stock ones?

A problem that I have had with the stock shocks is that in the track environment, the front struts are hitting the bump stops under super heavy braking. Trimmed the bumpstops with a great improvement. But this has left me thinking that I lost too much strut travel when I lowered the car. Are the JCW struts constructed to function better with a lowered car?????

Thanks in advance,

John Petrich in Seattle

 

The JCW suspension is a bit of a technical "black hole". This is very uppsetting to the "tweakers" who want to know all the details. For me, I don't care because it works.

The JCW dampers work great with the JCW springs. I wouldn't bother trying to break that pair up by using the springs with different dampers or the dampers with different springs.

I'd look someplace else for struts / dampers to go with aftermarket springs. The JCW springs are so minimal a drop that I'd guess that the JCW struts / dampers would be sub-optimal with a drop of around an inch.

 

John Petrich did some measurements, and the roll coupling you get when you lower the car goes up A LOT! This means for a given turn the car leans MORE when lowered. You can negate this a bit by running a different spring, but then you loose compliance and the street ride suffers. There's a lot in the suspension geometry that is ignored by those that lower the car a lot, and you end up making compramises all over the place to get the center of gravity down one inch. Running out of strut travel is just one of the items you'll run into. FWIW, when I corner balanced my car, I actually raised the car up to about 1/2" lower than stock (the shocks had been set lower when I did the rough set-up in my driveway). Helps with bottoming out as well.

I like the idea of the camber plates, I added them to my car first (before the rear bar) and loved the difference. Tire life is greatly improved, and getting the front camber a bit more negative also helps the understeer a bit.

I had the Dinan demo car for a couple of days. The don't lower aggressively (about 1/2" I think, but I'm not sure), they run some custom valved Koni's and some custom springs, and the set up is sweet! And they did do the geometry analysis in designing the system.

FWIW.... Matt

 

Snid,

I was afraid that you'd say that. Do appreciate your input. Am wary of some of the aftermarket struts. Don't want an overly damped ride. I feel that the stock struts are very very well balanced for track use.

A friend of mine has a bone stock JCW and is an absolute terror on the track. He seriously challenges M3's and Boxsters at will. His secrets are excellent driving skills and driving a MINI. I aspire to get to that place and don't want to muck up the suspension with ill considered strut changes.

Happy motoring,
John Petrich in Seattle

 

Changing the shocks only PROBABLY wouldn't lower the car. The only reason it MIGHT is the MINI shocks are gas filled if you put a non gas filled shock on the car, the height will drop a LITTLE. The reason I suggested the possibility, of shocks only, is I think shocks only is probably a better choice than springs only, for improving handling. Some of the top stock class autocrossers run de-gassed Koni adjustable shocks and I'd rather see a good adjustable shock on a car to improve handling than just a lowering spring. Springs aren't stock legal but this isn't about that.

 

promini sells the bilstein sp's as a kit with the h&r's. my vogtland springs are supposed to lower 30mm. the drop had me easily scraping the driveway unless i was careful. i have now added bilstein sp's and i dont scrape hardly at all.look-up scobib's post on his h&r/bilstein combo. good description.

 

Definitely go with a performance damper if you are increasing the spring rate. Adjustable damping is also useful. My problem with most of the aftermarket drop in springs is that the spring rate is not high enough for the amount of lowering. For this reason I would recommend coilovers, since that is the only way to get a high enough spring rate. Plus you can set the ride height exactly where you want it. If you lower the car, don't forget to get a pair of rear control arms to "fix" the camber.

I have the IE fixed camber plates and I am very happy with them. If you don't need to adjust/fine tune the front camber, then I'd highly recommend them, especially for a street car.

 

matma92ser,

Your post has got me thinking.

I am using the stock dampers with H&R sport springs. The springs are advertised as having 20% increased spring rate over stock and provide a little less than 1" lowering. I like the spring compliance for street and track, but I think that I am dangerously close to the limit on strut travel on bump. Would do better with struts designed for lowered suspensions.

If I were to go coilovers, what spring rate should I choose for starters? Is there a formula or rule of thumb that would help guide me?

Regards,
John Petrich in Seattle

 

...John, in a word or two, cpm, roll rate, and, roll couple.

cpm - cycles per second. About 180cpm +/- is a very sporting spring rate. If roll couple is increased, then a portion of a heavier springs potential will be absorbed controlling larger roll couple.

Linear rate springs around 300lb/in are not bad for street/track use...for starters.

 

Spring rates are only part of the story -- valving is another. It's why you cannot compare spring rates easily. It's the package that matters!

 

Yes Don, the package always matters. However, any setup must begin with some discussion about spring rates as these fundamentally determine the character of the car. Spring rates, damping rates second - because the damping required has much to do with the character of the spring, then swaybar and geometry fine tuning. In my opinion that's the correct order. But, get the damping wrong and the springs won't work well and so on and so forth.

So like so many things in life, this is a forward and backward relationship. But ya gotta begin with some fundamental assumption about ride and roll rates. And my reply above is somewhat primitive in that it suggests a known sporting value for a car weighing about 2,600lbs.

 

Since this is an advice column, I'll offer this: Unless you are club racing and bringing along a shock engineer (which high budget racers do) use the KISS method. The less adjustability you have the better.

 

Yup! Agreed. We spoke about this over the phone. Remember?

I'm going to the Glen with the car the way it is. I'll catch up with you in Jersey at some point in October before my last four events.

 

Sounds like a (good) plan.