[2006Pony]

I have a 2006 GT with power adder (KB 2.6 twin screw), Ford Racing handling pack and BMR frame connectors and upper/lower control arms. I put Roush big brake kit up front (14" rotors and 4 piston calipers). I was out on road track for first time recently and under heavy braking nose tends to dive. Someone at track recommended a brake proportioning valve but said it might mess up ABS. I called Ford tech line and they said don't mess with it, it will 'confuse' ABS.

Anyone out there know how I can get car to sit down flatter during heavy braking on track without messing up ABS?

[TheKurgan]

The FRPP pack sits very low in the front already. Is the front of your car scraping the ground or something ? I don't see how it can be moving very much if it's not...

[limp1969]

The back of the car is too high. A valve can not be used on an abs set up.
You can change the master cylinder to a balance bar set up, but if this is not a track car only I would say stiffer in the front and bring the rear down suspension wise

[2006Pony]

Thanks Kurgan. No the front isn't scraping. When out on the road track for the first time my instructor ( a road racing guy for a long time) said that a proportioning valve can be put in that will lessen how much the car dips in the front under heavy braking.

[TheKurgan]

Yeah I would not mess with the brakes. I am assuming the proportioning valve would apply more brake in the rear which would then cause the ass end of the car to get loose. You can control bite with different pads in front/back.

Like limp said, lowering the car more is about all you can do and some stiffer springs. FRPP kit is 1.5" and Griggs kit is 2.5" which is as low as you can go. You've added quite a bit of weight up front with the 14" brakes and supercharger. Good for tracks with wide turns and long straightaways, but will bite you on the smaller road courses.

Also do you have brake ducts in the front ? That is going to help also since not as much pressure will need to be applied resulting in less nose dive.

[TheKurgan]

Just found this while browing the ford racing site. You might want to call them just to confirm:

Ford Racing Performance Parts [M-2328-C*]

[RedMosesSC]

You prolly dont want to swap your springs but Steeda's springs are lower in the rear than the front, lowred 1" front / 1.25" rear.

[Garyalpusa]

Anti dive is combination of spring rate and geometry. Also when you brake you are transferring weight to the front.. The way to counter that is by heal and toeing. Adding a bit of power to transfer the weight towards the rear as you turn into the apex is what separates the men from the boys. That is why you are going to the track. To learn these techniques. After a bunch of practice you can feel the weight shift and learn the limits of your cars suspension. Pretty soon your spending big bucks to get better suspension and tires. Early in my road course education I felt that tires were the biggest mod I made to my car. A good R rated tire allowed me to feel the suspension and improve. The other street tires or harder rubber compounds would slide before the suspension was really stressed. Have fun...GA

[billf]

I believe that the problem with the Prop. Valve and ABS is this: When under braking, the amount of weight transfer depends on the degree of pedal pressure...more pedal pressure, more transfer. More transfer, more weight taken off the rear wheels.

Basically, the proportioning valve can't increase rear wheel braking, only lessen it, thereby causing the ABS to engage to keep the wheels from locking (under less line pressure conditions...see above). A Proportioning Valve will decrease the pressure from the original (base line), to the restricted pressure.

Therefore, it will increase the problem, not solve it. Your answer might be in pad material (more grab), or increasing the caliper size to increase the clamping force for the same line pressure/pad combination. (If we were discussing drum brakes, for example, you would want to change the piston size to accomplish the increase in force.)

I hope this helps to clarify the problem.

Good racing.

Bill

[limp1969]

Everyone has some good advice. The tire mod being the best.The tires are all the money. Get your self an extra set of wheels with some toyo 888r or slicks for track days.

Here is what I would do. Remove the rear spring iso this will lower the car a 1/2 or so. Then I would use a more aggressive pad in the rear. If that does not help get coil overs, feel much better than stock style springs. You can then adjust how high or low at all four corners. Cross scale it and then your talking . Also a balance bar brake set up. It uses two master cylinder bores 1 for the front 1 for the rear. There is a bar in the center of the pedal that has a remote for adjustment between front and rear bores. This is more of a race set up. The heel to toe would help for coming in fast , braking hard and down shifting, so the engine rpm matches the transmission therefor less transfer but I thing the car is simply to high in the rear. Or both front and rear. Do you have a picture of the car sitting flat we could see? By the way I have a 94 gt that I have started setting up for the track . I just got MM coil overs but what is in it now is ford racing springs and its way to hi in the back and sat even higher until I removed the spring isolators it made it sit way better but still to high in the rear. I hope this helps. If you are looking at the brake set up check out wilwood brakes

[SportsPix]

Originally Posted by 2006Pony

I have a 2006 GT with power adder (KB 2.6 twin screw), Ford Racing handling pack and BMR frame connectors and upper/lower control arms. I put Roush big brake kit up front (14" rotors and 4 piston calipers). I was out on road track for first time recently and under heavy braking nose tends to dive. Someone at track recommended a brake proportioning valve but said it might mess up ABS. I called Ford tech line and they said don't mess with it, it will 'confuse' ABS.

Anyone out there know how I can get car to sit down flatter during heavy braking on track without messing up ABS?

2006Pony,

I know this finds you late but your brakes are fine assuming you did the usual stuff. BBK, spindle ducts, nose mounted brake ducts and 3" hoses, SS lines, Motul RBF600 and more aggressive pads for your rear calipers. Do not mess with your brakes any more than this.

Your real problem is probably just that you need to replace your springs with something appropriate for the track. Your now much more nose heavy S197 is going to need a lot more spring than you can buy for a conventional McPherson strut on the S197. The best solution if you are serious about running on the track regularly is to go with coilovers. There are many different ways to go and the best are pretty pricey. If you are made of money just call up FRPP and order a set of FR500S dampers and the matching rear upper damper mount and front strut mounts. They come with 500lb/in front springs and 300lb/in rear springs both linear rate. These are 2-way dampers with reservoirs and are well setup for these cars. Short of this you can just call up the usual suspects, Griggs, Maximum Motorsports, Ground Control etc. and order their coilover setup and appropriate springs.

There is nothing you can really do geometry wise to reduce brake dive without messing up everything else about the front end. You just need more spring rate to solve this problem.

HTH!

[TravisCadello]

I think to help with that I put Stiffer springs up front.

[TheKurgan]

Originally Posted by SportsPix

2006Pony,

I know this finds you late but your brakes are fine assuming you did the usual stuff. BBK, spindle ducts, nose mounted brake ducts and 3" hoses, SS lines, Motul RBF600 and more aggressive pads for your rear calipers. Do not mess with your brakes any more than this.

Your real problem is probably just that you need to replace your springs with something appropriate for the track. Your now much more nose heavy S197 is going to need a lot more spring than you can buy for a conventional McPherson strut on the S197. The best solution if you are serious about running on the track regularly is to go with coilovers. There are many different ways to go and the best are pretty pricey. If you are made of money just call up FRPP and order a set of FR500S dampers and the matching rear upper damper mount and front strut mounts. They come with 500lb/in front springs and 300lb/in rear springs both linear rate. These are 2-way dampers with reservoirs and are well setup for these cars. Short of this you can just call up the usual suspects, Griggs, Maximum Motorsports, Ground Control etc. and order their coilover setup and appropriate springs.

There is nothing you can really do geometry wise to reduce brake dive without messing up everything else about the front end. You just need more spring rate to solve this problem.

HTH!

The FR500S dampers don't come with the springs. They are sold seperately. This might be overkill for his needs. The FRPP spring rate is one of the highest out there iirc...should be enough for the little bit of added weight he has at the front. A better solution might be removing some of the weight in the front.

[SportsPix]

Originally Posted by TheKurgan

The FR500S dampers don't come with the springs. They are sold seperately. This might be overkill for his needs. The FRPP spring rate is one of the highest out there iirc...should be enough for the little bit of added weight he has at the front. A better solution might be removing some of the weight in the front.

Hi Kurgan,

The FR500S damper kits do not include the springs but the spec. springs are 500lb./300lb. rate springs. Hyperco springs are some of the best most precise springs available and cost the same as FRPP sells them for.

Who is to say what is overkill, the guy has a 2.6l KB blower on his motor! The FRPP springs are progressive rate springs and top out at a 235lb. and at that point the struts are resting on the bumpstops and bottoming out. The Eibach springs are just not very well designed for the real world. This is why I said he would need a coilover suspension to get enough spring rate to help reduce brake dive and get a rear spring that he would be happy with. This has not changed.

I've measured the stock Ford S197 GT, FRPP M-5300-K springs, Eibach ProKit and Sportline springs along with all three Steeda Sport and Competition springs and H&R OEM, Sport and Super Sport springs. Yes the Eibach ProKit springs have the highest ending rate but they are already going into the bumpstops and coilbind by that point. The effectively stiffest conventional strut springs are Steeda's Competition springs which are 225lb. linear rate springs in front and 185lb. linear rate in the rear.

But I do agree with you that he should remove some of the weight from the nose of his car to be happier on the track. He could pull off that 2.6l KB blower and send it to me! I already have a complete coilover suspension so swaping springs is not big deal to me! BTW a lot of us running coilovers are running 2-3 times the stock GT front spring rate on the street no problem and brake dive is not so much an issue.

HTH!

[TheKurgan]

Hi

I've seen your posts and they are good reading. He already has coil overs in the front with the FRPP kit and switching to the FR500S dampers are very pricey. I also have the FRPP kit and mine only hits the bump stops on hard bumps like it's supposed to..I don't have the nose diving problem on mine. I would be interested to see if it changes his car. I can't imagine springs changing hitting the stops if you want to stay low. The Griggs kit lowers the car 2.5 inches. Are there even stops on the front ? I only seen them on the back...