2007 Jaguar STR Brakes Confirmed

[Kumba]

Anyways, I still think the upgrade is great. Got plans to do it myself and will start collecting parts in the garage (again).

I am just trying to make sure no one spends $1000 with the wrong expectations. I've never once commented about the looks or bragging rights. That's all up to you and what floats your boat. I just don't want someone doing this upgrade thinking they will knock 50-feet off their stopping distance. Even with the stock LS brakes and tires an M5 only stops 14 feet shorter at 70mph. That's 1 car length. And the difference gets even smaller the slower you go.

 

[LS4me]

IIRC, the Stoptech kit reduced stopping distance by a whopping 5' over stock. It WILL reduce fade considerably. IMHO, unless the LS is tracked regularly this change just helps the looks. The big complaint about the LSes brakes is the pedal feel, not stopping distance.

 

[05 LS8]

except for the fact that the OEM brakes already have more stopping power than the tires can handle, as proved by the fact that if you go out and brake from 60mph as hard as you can, the ABS will constantly be activated because the tire already cant keep up with the braking force, now your adding more stopping power to the same situation, and the ABS is STILL going to be activated the whole time because nothing was done to give the car more traction to be able to utilize the extra stopping power. sure it may be a lot easier to lock up those tire now, but the same tire and the same ABS system are actually what is deciding the stopping distance.

Back to locking up brakes i see.

now take a other wise stock LS with damn good tire where the OEM brakes cant lock up the tires (the tires are no longer the weak link in stopping distance) then doing anything to increase braking force will for sure make a difference in distance.

Thank you! Now, we are agreeing!!

I do have high performance tires on my car and if i was going to upgrade to larger brakes, it would improve the stopping distance.

Instead of saying (not necessarly you) larger brakes do not improve stopping power, which is a wrong statment, it can be said larger brakes do improve it with the right tires.

Driven an STR and an XF. Have not driven an E550. I think you are looking at pedal feel more then the actual stopping power.

Ok good! You should understand what i mean then, since we have both driven the same cars.
How would you compare the STR or the XF to the LS under normal driving conditions?

My experience? When i touched the brake pedal in the XF, the car actually stopped where i want it to. Where the LS takes extra second or two to actually stop.

Exactly! The idea that bigger brakes stop your car faster when you are not repeatedly locking them up is wrong. You may have increased pedal feel, generate more braking force earlier in the pedal, have a quicker initial bite, which all translates into the car feeling better for you, but the actual performance of the car will have changed very little. If I was going to attribute something to bigger brakes without changing anything else it would be that they let you stop easier not faster. Your reaction time to move your foot and hit the brakes is going to be a bigger factor in stopping distance in most cases. I am not alone in this. It's not so much opinion as a fact. The car as a whole has to be looked at. If you disagree with me then just type "do bigger brakes stop faster" into google and read what others say.

I understand where you are coming from and what you mean. But, you have to look at the larger picture.
You even said it in your post above that larger brakes translate into the car feeling better, which means stopping better, on the dime as they say.

 

[dwiggy]

OP, thank you for taking the time doing this upgrade. It's been a long time coming. Just know you are appreciated!

Thanks for the props. My goal is to answer as many unanswered questions about one of the most underrated but well engineered cars out there.

 

[BlackLS06]

I can see the look on the techs faces at the stealership when you come in for service and they see the big ass brakes.....

 

[2002_lincolnLS]

I can see the look on the techs faces at the stealership when you come in for service and they see the big ass brakes.....

it would be funny if you had them do the brake pads for you, just for the fun factor of them going, well the pads we have for an LS don't look like these....

 

[1LoudLS]

Back to locking up brakes i see.

well that is the exact point where you find out at what point your tires are not good enough, so yeah, i believe that is the easiest factor to pay attention to when you dont have a test track with all the goodies that the dudes at motor trend have at their disposal.

now if your talking about feel, thats a horse of a different color, feel is subjective, performance is quantitative. i have agreed that this would make a difference in feel no matter what the tires. and i do think these would make a nice difference in actual performance, as long as all of the other factors are also considered. you already have great rubber, so this would be a great upgrade for you. i just want to make sure that if any of the young guns on here that might not know any better to go out and drop this kind of coin expecting the sh!tty braking on his car to be fixed when the real root of his problem could be that he is cheaping out on tires.

 

[TooManyToys]

...

 

[TooManyToys]

IIRC, the Stoptech kit reduced stopping distance by a whopping 5' over stock. It WILL reduce fade considerably. IMHO, unless the LS is tracked regularly this change just helps the looks. The big complaint about the LSes brakes is the pedal feel, not stopping distance.

The pedal issue is an issue with the tapered wear of the pads that develop because of the two different sized pistons used in the front calipers. Many people notice a softer pedal travel by 25% of the front pads wear life.

 

[n8bachelor]

Toys: I am an Engineer and love a good graph or two. I agree with most of what you have stated: Tires, brakes, suspension, and driver all play into the final stopping distance of a given vehicle. Increase the performance of any one of these items and you can increase the overall braking performance of the vehicle (not necessarily stopping distance).

As you may know, increasing the unsprung weight (rotating mass) of the wheels/tires/brakes alone will have a negative affect on stopping distance. This is generally offset by the increase in friction area of the larger size tires (recall that drag slicks are very wide) but not always. While friction force is a function of pressure and frictional coefficient, there can be no dispute that the larger area of wide, slick tires has an advantage over smaller, similarly slick tires even though the sum of pressure and area is the same. I recall several tests of large new SUVs where the factory wheels were replaced with larger, heavier ones (using the same width & type of tires) produced longer stopping distances. In addition to the weight of the wheels, the inertial moment (I) was also increased by moving more of the weight to the outside of the rotating wheel. The brake must overcome the weight of the vehicle in addition to the inertia of the rotating mass. The effect was exaggerated by multiple, frequent stopping events due to the FACT of brake fade.

It stands to reason that an increase in rotor size alone with all other elements remaining constant (rotating mass and brake pads specifically) would produce NO decrease in distanced distance of a single stopping event. It is the combination of many factors that determine stopping distance, not the least of which is the material characteristics of the brake elements. Larger rotors AND pads will produce a shorter stopping distance (maximum stopping force of the tire can be reached faster with the larger brake elements), all other things remaining equal. Keep in mind that a non-ABS stop can be shorter than a full-on ABS event, theoretically.

For someone with 16" tires like me to increase to 18" and larger pads and rotors there would be multiple factors involved so no one element could be pointed as the deciding factor. Lowering the vehicle would also improve the stopping distance of the vehicle by reducing nose dive and subsequent load transfer to the front tires (allowing the rear tires to take on more of the stopping force).

With all that said.... the OP has done us all a favor by demonstrating this retrofit works with the LS. Yes, it is cosmetic (as many are after with larger wheels) and yes it does improve stopping distance (all other things being equal). The upgrade is very welcome.
Cheers :Beer

 

[Kumba]

As you may know, increasing the unsprung weight (rotating mass) of the wheels/tires/brakes alone will have a negative affect on stopping distance. This is generally offset by the increase in friction area of the larger size tires (recall that drag slicks are very wide) but not always. While friction force is a function of pressure and frictional coefficient, there can be no dispute that the larger area of wide, slick tires has an advantage over smaller, similarly slick tires even though the sum of pressure and area is the same. I recall several tests of large new SUVs where the factory wheels were replaced with larger, heavier ones (using the same width & type of tires) produced longer stopping distances. In addition to the weight of the wheels, the inertial moment (I) was also increased by moving more of the weight to the outside of the rotating wheel. The brake must overcome the weight of the vehicle in addition to the inertia of the rotating mass. The effect was exaggerated by multiple, frequent stopping events due to the FACT of brake fade.

This is why I only run an 18" rim. Big enough to fit over big brakes while being smaller to limit the unsprung weight and rotational inertia. This also lets me run a higher-profile tire which acts as an extension of the suspension absorbing and dampening small road changes. Reducing the unsprung weight also allow the suspension to react quicker as well.

Larger rotors AND pads will produce a shorter stopping distance (maximum stopping force of the tire can be reached faster with the larger brake elements), all other things remaining equal. Keep in mind that a non-ABS stop can be shorter than a full-on ABS event, theoretically.

For the extra time it takes the pedal to travel to the skid point of the tires you might shave 2-3 feet off the stopping distance at high speed. That gap closes the slower you are going. At 70 mph a 0.2 second reaction time is something like 20 feet. It is also not a universal thing that the pedal will engage firmer at the top. That gets into the whole pedal feel thing and people have all their own subjective standards to that. I know some people who like the pedal to firm up half-way through the travel so that they can get better feathering on the brakes. I would be one of those people. I don't want a big initial bite or an overly aggressive braking setup because sudden changes to the car cause a lot of weight transfer which can unstable it. So I like the pedal to be lighter at the top and to start getting firm about a third of the way down and to start getting to my skid point about half way through the travel. I also know of guys who will disconnect the booster and pull the ABS fuse making the pedal as hard as can be so they get more feedback from the wheels. Plus, once you get into the ABS you are increasing the stopping distance anyway due to the releasing of the calipers to prevent skidding.

With all that said.... the OP has done us all a favor by demonstrating this retrofit works with the LS. Yes, it is cosmetic (as many are after with larger wheels) and yes it does improve stopping distance (all other things being equal). The upgrade is very welcome.
Cheers :Beer

Never once disagreed with that


My complaint with the stock brakes on my LS was the inconsistency I felt in the pedal. I would get engagement then the pedal would sink a little. I would also start running into fade going around a track. The pedal feel really didn't become consistent for me until I put the stainless braided lines on. Once I did that it was predictable. Changing to Akebono Euro pads also gave me the rest of the feel I was looking for.

 

[dwiggy]

Last comment...

You know if you guys want larger brakes under those factory 17"s you could always do the 320MM on the front like K. and then put the STR's on the rears...

Just saying. That would be a really Cheap upgrade over stock.


Plus, these brakes rock!

 

[mlara1129]

awesome! Again thanks so much for this, Dwiggy.

I know you don't seem like the "take many pics" kinda guy, but please more pics!

 

[dwiggy]

Some Pics...

awesome! ...please more pics!

I'm not a great photographer...

 

[Elemino]

Correct me if I'm wrong guys... but isn't the reason for having bigger brakes to have the ability to apply more braking with less force? (among the many other benefits)...

I mean, the brakes on a civic could likely lock up the wheels on my Navigator, but that doesn't mean they're the best ones for it...

Why are there so many ppl even arguing about this? Better brakes are better.. period. Add some wider tires, get some more rubber on the ground, and call it a day.

 

[1LoudLS]

I mean, the brakes on a civic could likely lock up the wheels on my Navigator, but that doesn't mean they're the best ones for it...

No, they wouldn't even come close to locking them up, let alone stop the truck from 60 mph in under a mile and a half.

 

[dwiggy]

LMAO!! You guys are funny!

These brakes still kick @$$!!!

Peace!

 

[tbird6]

Great job! A few errors about the STR in this thread. I have a 2005 STR and a 2003 LS V-8 sport. It is amazing how much stuff is the same or very close!!

The STR came out in 2003. Only had the 4.2L super charged V-8. The 2003-2005 cars had the best equipment with the great fixed caliper Brembo 4 piston brakes up front. As with the LS Jaguar (Ford) started to decontent the cars as production started winding down. The rear brakes were 2 piston with a separate caliper for the E-brake. Has the same electric parking brake motor as the LS.

The 2006-2008 STR (there were no 2009 STR's) went back down to a more common floating caliper design very similar to the stock LS setup. It was a cost cutting measure. No seperate parking caliper on the rear.

Most definitely use the 2006-2008 STR brake setup if upgrading the LS. The Brembo's will be a whole bunch more expensive to do. Not a bolt on deal!!
.
.
.

 

[dwiggy]

I am not so sure about this statement...

"The rear brakes were 2 piston"

A couple of pirated rear caliper pictures:





It looks like anyone is capable of making misguided statements. Even the people on this forum who don't spend thousands of dollars and countless hours modifying their cars only to share all of that useful information with the rest of us.

 

[HyeLifeLS]

I might be doing this upgrade for my fronts as i am in need of new brakes. OP Any updates? Do you still like the brakes?

I have the S-type R wheels already so might as well get the brakes too.

 

[dwiggy]

I might be doing this upgrade for my fronts as i am in need of new brakes. OP Any updates? Do you still like the brakes?

I have the S-type R wheels already so might as well get the brakes too.

Do the upgrade. These brakes work perfectly on the car.

I would suggest the EBC Red Stuff pads. I have these pads and they are excellent.

After driving a few miles I had a small screeching noise which required me to flatten the backing plates more. They were touching the rotors slightly. This is a very easy job.

Now, I'm just being extraneous here. The Gen I STR wheels are really close to the front calipers. They don't touch but if you have Gen I STR wheels be aware that they are extremely close.

Now to the fun stuff...

Stock LS:
60-0 braking distance : 130 ft
Curb Weight : 3755 lbs
http://www.modernracer.com/lincolnlsv8.html

2010 Jaguar XKR (Same Brakes)
60-0 braking distance : 111 ft
Curb Weight : 3,968
http://www.edmunds.com/jaguar/xk/2010/road-test-specs.html

Drop a couple hundred pounds off of the XKR's weight and the stopping distance will probably lose a couple of feet.

I couldn't find an apples-to-apples (same-source) brake test for the Jaguar and the Lincoln but you get the point.

Hope this helps!

 

[M4rk]

Stock LS:
60-0 braking distance : 130 ft
Curb Weight : 3755 lbs
http://www.modernracer.com/lincolnlsv8.html

2010 Jaguar XKR (Same Brakes)
60-0 braking distance : 111 ft
Curb Weight : 3,968
http://www.edmunds.com/jaguar/xk/2010/road-test-specs.html

Drop a couple hundred pounds off of the XKR's weight and the stopping distance will probably lose a couple of feet.

I couldn't find an apples-to-apples (same-source) brake test for the Jaguar and the Lincoln but you get the point.

Hope this helps!

Tires. High-perf, sticky, wide-ass tires, vs narrow all-seasons on the LS.

 

[05 LS8]

Mark's points are very valid.

Not to appear very pugnacious, there is much more to stopping power/brake performance than just calipers. But, Jaguar's brakes being the in the industry, i am sure, the upgrade will significantly improve the braking on the DEW 98 platform.

Also, i wouldn't go with the posted numbers, they aren't accurate.

NA XF 60-0 is 107ft. A lighter, more agile XKR with bigger brakes along with stiffer supportive suspension can't possibly take longer to stop.
XJSC is equipped with the same brakes as the XKR i believe and it being much heavier, it's 60-0 is 103ft.

 

[HyeLifeLS]

[QUOTE=dwiggy;2037274999]Do the upgrade. These brakes work perfectly on the car.

I would suggest the EBC Red Stuff pads. I have these pads and they are excellent.

After driving a few miles I had a small screeching noise which required me to flatten the backing plates more. They were touching the rotors slightly. This is a very easy job.

Now, I'm just being extraneous here. The Gen I STR wheels are really close to the front calipers. They don't touch but if you have Gen I STR wheels be aware that they are extremely close.

Now to the fun stuff...

Stock LS:
60-0 braking distance : 130 ft
Curb Weight : 3755 lbs
http://www.modernracer.com/lincolnlsv8.html

2010 Jaguar XKR (Same Brakes)
60-0 braking distance : 111 ft
Curb Weight : 3,968
http://www.edmunds.com/jaguar/xk/2010/road-test-specs.html

Drop a couple hundred pounds off of the XKR's weight and the stopping distance will probably lose a couple of feet.

I couldn't find an apples-to-apples (same-source) brake test for the Jaguar and the Lincoln but you get the point.

Hope this helps![/QUOTE]

Thanks for the reply. I will see how money goes and will try to get em.

 

[mlara1129]

I'm going do this mod just for the looks. Hate how small the LS brakes look with bigger wheels, especially when I was rocking my Sentas...

and hey if performance improves, or at least the pedal feel is better, that'll just be a plus for me.


Dwiggy, any more pics, man?!