shanec

Getting ready to lower the car. I've had some FRPP K-springs in the garage for a while.

Plug: For sale here: https://mustangforums.com/forum/part...installed.html

Then I noticed my stock suspension on the front had already sagged and inch or two over the last 6 months, most likely from the weight of my E-Force supercharger (90 lbs). Would the FRPP's also drop over time under the weight of the supercharger in addition to the 1.5 inches that they're designed to drop vs stock?

Only one thing to do here. Call Sam Strano. :-)

So I called Sam to pick up some Koni SRT's and ask him what to do about springs. He advised me to go with Steeda Comp's. Said the drop in the rear is close to FRPP, but the drop in front would be less - on a normal car. Said the weight of the supercharger causing my stockers to sag so much would also bring the Steeda Comp's lower in time and I might end up with about the same front drop as FRPP would on a normal car.

So Steeda Comp's it is. Would like to hear from anyone else that has these. How much did it drop your front & rear? How's the ride and handling?

Sleeper_08

I'm running Steeda Comps with a Roush SC. Below are a couple of old pics of the car showing how it sits

The ride on my car is pretty stiff but mainly because in the rear there is only one rubber bushing left and everything else is either rod ends or poly

This video of my chasing a Porsche Cayman, also on R-comps is an indication of how well it handles

http://www.youtube.com/watch?v=NRb7GmWy5xo

The handling on my car is great but it has a lot more than just springs.

shanec

Dang. Awesome stuff.

F1Fan

I had Steeda Comp springs and measured them on a very high precision load cell spring tester. These are linear rate 225lb/in front and 185lb/in rear springs and they work very well compared to just about all the so called progressive rate sport springs. It is also much easier to get the damping right with a linear rate spring which is why I bought them not to mention that they are also about the highest rate springs for conventional struts available. The spring rates Steeda selected are nearly ideal for a street car that is moderately lowered.

I'm on 350lb/in fronts and 250lb/in rear springs and found that you can not go higher than about 225lb/in at the rear without the axle chattering over railroad tracks and the like so the conservative 185lb/in rate is an excellent choice by Steeda. I have an N/A GT and find that 350lb/in is not too stiff but I think you will start to run out of damping by 400lb/in on a set of D-Specs with stock valving. I think that 425lb/in is not unreasonable even here in the L.A. area but I tend to drive on the smoother L.A. area roads and rarely have to traverse the really bad pavement in the bad parts of L.A.'s surface streets.

The Steeda Comps installed on a N/A GT chassis do not lower the car much, maybe 3/4" initially. But with the extra weight of a blower may go a 1/4" to as much as 1/2" lower initially depending on the additional weight involved. This is as high a linear rate spring as is practical on the S197 GT chassis. If the spring rate is any higher there will be no drop in ride height. Steeda's springs won't sage over time though the spring isolators and stock strut bushings will compress quickly with this firmer spring.

The Steeda Comps handle and ride great on D-Specs and are noticeably less smooth riding on Koni Sport dampers but the Konis come into their own on long high speed corners. The Comps do not bottom out much at all compared to the popular progressive "sport" springs. In this way they are almost like stock springs. The spring rate is not really all that much higher than stock, about a 30% bump in spring rate vs. stock in front. But they reduce brake dive and body roll noticeably vs. stock springs on the same dampers.

I've tested all of the major brands and model "sport" springs over the years and finally had to go to Steeda's coilovers several years ago for the flexibility a coilover offers in terms of spring rates and ride heights. I have a complete set of Comps in like new condition sitting in a box out in my garage if you want to buy a set. Please email or PM if interested. I'm in SoCal but can ship most anywhere.

HTH!

Sleeper_08

It was because of F1Fan's recommendation that I put the Steeda Comp springs in my car. As you can see he still likes them.

geocomp

Sam recommend these for my Convertible w/ SC. I have not orded them yet but plan to before end of the summer. I am glad to hear such positive response about these.

F1Fan

Sleeper 08,

But what about your opinion? Do you still have the Steeda Comps installed in your car? How are they working for you? I think you have a blower too so was my description about right given your supercharger's extra weight?

Cheers!

F1Fan

Hey Sleeper 08,

I forgot to ask, what dampers were/are you are using with the Steeda Comp Springs? How do they work out for you in terms of handling and ride? any problems with any of your suspension parts? Forgot to ask how do you like having a Watt's link vs. Panhard bar?

Cheers!

Sleeper_08

F1Fan

I am now up to 15 track days with the car spread over 3 seasons and the springs seem fine to me. As I've not run anything else at the track I have no comparison. On the street the car rides like a truck but what would expect with only one rubber bushing left in the rear suspension

At TMP, a relatively slow short tight track I am getting understeer with the R-comps on some slow corners and am thinking about adding Sam's adjustable rear bar to go with my adjustable front Steeda bar.

Up to now I have been running the Tokico D-specs set to 5 f/r on the street and .5 f/r on the track. The tracks I run are pretty smooth so that is why the track setting is so stiff. However, in my dining room is a brand new set of Koni Sports (Yellows) which are going to be installed before my next track day on July 14. I hope my backside is sensitive enough to feel the difference. I've always wanted the Koni's as for someone of my vintage they epitomize a "race car".

I got the FAYS2 Watt's link after my first season and am much more satisfied with it than the panhard bar. It eliminated what to me felt like "jacking" of the rear end and uneven handling in left vs right turns.

This season I moved from the KDW2 to Nitto NT01 R-comps and they are a blast.

The main improvement has been in my skill level as each time on the track my times are getting better. Last Monday I got down to a 1:44.5 at Mosport which is my best lap there. My brother set the standard in my car at the end of May when he did a combined segment time of 1:38.4 so I still have a ways to go.

F1Fan

Hey Sleeper 08,

You seem to be having fun driving your Mustang which is what really matters IMO. The choice between wrenching and driving for me is a difficult choice. I can't squeeze much play time at the moment until I get my M3 off the stands and out of the garage. I'm doing a complete (really complete!) suspension rebuild with welded chassis reinforcements, all new bushings, hardware, TC Kline D/A coilovers etc. The M3 should be a blast to drive and hopefully still ride pretty well when I get it done.

Where did your bushings go? Do you have rough roads there? Anyway what are you running for UCA and LCAs? Did you relocate your front and/or rear control arms? What anti-roll bars are you running? How much static camber are you running? did you install a bumpsteer kit? Are you one a square (same size wheels and tires all around) tire setup? If not don't make any changes before you try a square tire setup. If your car only pushes on slow speed turns and you have a staggered wheel/tire setup go to a square setup may fix the problem for these tracks while the staggered setup may work fine on the high speed tracks.

You say your car is pushing in slow speed turns, where is the push in the turn, at the very beginning, middle or after you hit your apex? You may want to try tuning down your front D-Specs to let the suspension work better sooner in the turn. A lot of folks crank up their dampers too much and this can cause the car to feel more responsive but actually go slower.

How do you have your front alignment setup? For a small track with lots of slow turns you really need to optimize much front grip as possible with that blower in the nose. Do not try to trade off rear grip to achieve more neutral handling balance by using a bigger rear bar. There are a lot of possibilities you might want to consider before going there and many of them have to do with maximizing your front tire contact patch by looking at your tire temps across the tread and optimizing front suspension geometry.

First consider alignment, static camber, toe and bumpsteer. These items can make big improvements to initial turn-in and front grip through a turn. But alignment can only go so far if the outside tire is not flat throughout the turn so once changes to your alignment stops helping lower lap times you need to look at the mechanical issues that can help improve your tire temps. The S197 likes a lot of front spring rate or failing that lots of front bar to keep the front outside tire on the ground with about 1/2+ degree negative camber.

But of course you can only go so far with static camber on a strut suspension like the S197 has without starting to hurt braking. When you get past maybe -3.5 degrees negative camber or so the braking trade off starts to show up depending on the tire, track and chassis. So what you have to do is try to limit the amount of chassis roll first with geometry, then with spring rate and last anti-roll bar rate. The S197 chassis seems to work very well with a higher front roll center. When you reduce the ride height you are also lowering the front roll center height. When you set your front ride height do not go lower than having the front control arms level to the ground or the roll center will be too low and fall even faster once they are past level to the ground.

You can improve this by relocating the inner control arm pick-up points and or the outer ball joints on the control arms. This works really well and the car will corner much flatter with just these changes. You can also crank up the front roll bar rate by moving the linkage farther away from the end of the bar but this is not ideal. Pay attention to the details here, if your car is lowered too much you may need to use a set of adjustable end-links to keep the anti-roll bar links from going negative on the rate due to having altered the geometry of the links. You want the end-links set so the anti-roll bar is parallel with the axis of the front control arm pick-up points and as perpendicular as possible to the bar and control arm pivot axis. I know this is hard to do with what we have to use but just keep this stuff in mind.

With a conventional strut we cannot pick our spring rates anymore than you already have so the only other options are at the rear of the car. We also need to not forget rear axle geometry tuning by changing LCA angles and the possibility of changing your UCA and UCA pick-up point. This stuff is getting sort of out there but if the car is lowered too much the rear axle geometry may be doing you in by steering the car out of the turn. If the static LCA angle is not set parallel or slightly (no more than 1 degree) up hill toward the rear axle your rear axle may be causing your car to feel like it is pushing in slow turns. If you have done all of the front end stuff I posted above and are still pushing in slow turns look at your LCA angles first. They may be out of wack or your car may benefit from tuning them to invoke a bit of rear axle oversteer. With a Fays Watt's link you can also easily raise the rear roll center by moving the chassis side pivot up but don't do this unless you have done all of the front stuff and the LCA stuff.

I don't know how much of this stuff you know but have a look at it and see what your chassis looks like and get back to me here.

You're in Canada?

Nitto NT01 R-comps are a whole lot faster than KDW2s but of course you cannot drive on them for long without trashing them on the street. It's all trade offs eh? It seems like if your brother is in the high 1:30's at Mosport he is going fairly fast for a nose heavy and relatively untuned street chassis like your blown S197 Mustang. You can see that the chassis is doing something right even as it is. Smooth is fast. ride with him to see what he is doing differently than you are.

HTH!