How my new suspension feels

[wheelhopper]

So I installed MM3 struts/shocks with coilovers on my fox with IRS, 400lb front and 650lb rear spring rates. This change caused my car to develop a slight bit of over steer, but I am making a few small changes to try to dial it out. I have to say that I was not expecting the way my car feels now. I went from having the car lean some in the corners and shift weight forward when braking to feeling like a go-kart. My car previously felt balanced and I selected the spring rates based on MM's recommendation as well as simply moving the wheel rate up about 100 points in the front and rear to increase spring rate while maintaining the same balance. I had also tracked an '03 Cobra with 375 front and 575 rear springs. My new set up completely screwed up my brake points. Now that my car does not dive at all when I brake I have to find a way to relearn how my car feels at the braking limit. I almost can not feel my car braking since there is absolutely no dive. Did those of you who made this change yourself feel this way? I feel like I am taking one step back learning a new set up to take 2 steps forward once I get it figured out.

 

[racebronco2]

Part of the reason is that the foxbody is so much lighter than the cobra, the front roll center is several inches lower too since you don't have the blower on top of the engine.

 

[cobra-boss]

.

 

[darreng505]

Of course you will need to relearn the car now. Dont panic. But experiment with your suspension settings.
You were used to brake dive and how it felt as cues for brake zones etc. Gonna have to feel for new cues.

I'm sure ill have this same experience after my coil overs get installed and I've been thinking about it.

 

[Greensix]

Yep. Very similar feeling. I have a 2900# V6 with an IRS and the same spring rates. It is a very different feeling than the old "sport" springs I had. Don't worry too much, from what I gather that was a very very big change so you should absolutely have to relearn things. Otherwise you would have wasted your money right ;-)

 

[99COBRA2881]

Same spring rates here too 400/600. I also was used to the brake dive from my 99 cobra with h&r race springs. My race car is like you said driving a go kart. Very little brake dive/ weight transfer to the front of the car. It's made me have to adjust how I drive the car especially in brake zones. I still need to compress my braking zones and try to make the car brake harder in some corners.

The next item you'll find is the rears carry more weight under braking and can be utilized more. A proportioning valve will be the next thing you start looking at if you haven't already.

 

[MFE]

Very little brake dive/ weight transfer to the front of the car. It's made me have to adjust how I drive the car especially in brake zones.

You're still getting plenty of weight transfer, it's a function of deceleration rate, traction, and CG

 

[darreng505]

You're still getting plenty of weight transfer, it's a function of deceleration rate, traction, and CG

You beat me to it. I was about to say that...

 

[gregscott]

...>

 

[gregscott]

So I installed MM3 struts/shocks with coilovers on my fox with IRS, 400lb front and 650lb rear spring rates. This change caused my car to develop a slight bit of over steer, but I am making a few small changes to try to dial it out. I have to say that I was not expecting the way my car feels now. I went from having the car lean some in the corners and shift weight forward when braking to feeling like a go-kart. My car previously felt balanced and I selected the spring rates based on MM's recommendation as well as simply moving the wheel rate up about 100 points in the front and rear to increase spring rate while maintaining the same balance. I had also tracked an '03 Cobra with 375 front and 575 rear springs. My new set up completely screwed up my brake points. Now that my car does not dive at all when I brake I have to find a way to relearn how my car feels at the braking limit. I almost can not feel my car braking since there is absolutely no dive. Did those of you who made this change yourself feel this way? I feel like I am taking one step back learning a new set up to take 2 steps forward once I get it figured out.

Summit Point Oct 5,6 are you going ?

 

[darreng505]

If my ASTs come in on time ill be at summit then as well.

 

[99COBRA2881]

You're still getting plenty of weight transfer, it's a function of deceleration rate, traction, and CG

It must all be in my head then. Seems with the nose dropping under braking it made the other car feel like it was braking harder than my race car does now.

 

[MFE]

We've been trained to associate nose dive with braking force. Even a car with no suspension travel at all transfers lots of weight (load) to the front tires during braking. Any acceleration along any vector shifts load whether it shows in body movement or not.

 

[wheelhopper]

I understand that weight is still transferring to the front. With the new springs it just does not feel like the back end is coming off the ground anymore. Even though I did not think it was before, but after the new coilovers that is what I imagine now. Anyway I did plenty of research on my spring rates prior, so I am sure that the car will handle better. I just need to get used to it. I even got lucky with the install and had a pretty good corner balance.

I won't be at Summit in Oct. The weekend before I'll be at Watkins Glenn and then running TT at VIR 2 weeks later. I don't think the Queen would approve 3 weekends gone in a row.

 

[darreng505]

It must all be in my head then. Seems with the nose dropping under braking it made the other car feel like it was braking harder than my race car does now.

It is. With the car more level during braking the tires (specifically the rears) have more even weight on them and bigger contact patch which means more traction. So you can brake more, but without the sensation of the car lurching forward your mind might be holding back on the brake and thinking it doesn't brake as well.

 

[DocB]

wheelhopper,
Just to clarify for me:
Are your rears coil-overs or are they shocks and springs?

 

[gcassidy]

Doug, were you using trailbraking before?

 

[wheelhopper]

wheelhopper,
Just to clarify for me:
Are your rears coil-overs or are they shocks and springs?

The rears are coilovers as well.

Doug, were you using trailbraking before?

It depended on who I was chasing.

 

[Goindeafonmtx]

Off topic question: what does the IRS do as far as points assessment in NASA TT?

 

[wheelhopper]

You end up taking points for everything that it basically replaces. So when I first put it in, and the rest of the car was factory, I was taking points for arms, sway bars, springs, shocks, brakes, etc.