2007 Jaguar STR Brakes Confirmed
- Thread starter dwiggy
- Start date
Hmmm... Guess us 20 inch wheel owners can smile just a little bit.
Until you need snow tires, if that applies
This really puts the stoptech kit to shame. The front stoptech kit is a four piston 355mm rotor design but it costs $2500. With this you can get front and rear for around a grand and still get the 355mm fronts.
Everyone should invest in this if they run aftermarket wheels.
Everyone should invest in this if they run aftermarket wheels.
JoshMcMadMac
Dedicated LVC Member
Have you seen the stock 16" wheel clearance on the calipers? It probably measures in the hundredths of an inch. There is no way the 320mm upgrade could ever clear 16" wheels.
The action on a 4-piston caliper is better I think. Doubt anyone would really notice though. A lot of the benefit of the bigger brakes and all doesn't really show up under regular daily driving. Not until you go to do an emergency stop does it pop up and say hello. Even then you are limited by the rubber meeting the pavement. So if you can lock up all 4 wheels with the stock brakes, then a big brake kit won't do anything other then lock them up earlier in the pedal. That is from the mechanical standpoint. As far as the brake feel to the driver all bets are off. You might as well be arguing body kits and rims at that point. It's going to very from person to person.
For instance, say you take two identical LS. Same year, engine, trim, rims, street tires, weight, everything. You then equip one with a 6-piston caliper and a 15" composite floating rotor and stainless braided lines with some high-grade carbon metallic pads. If you were to now take these two cars and do a 60-0mph test on a dry day they would show almost identical stopping times and distances on the initial pass. A locked up tire is a locked up tire regardless of what is applying the braking force.
Now, in the same scenario, if you were doing this repeatedly in short succession you would see the bigger brakes having less fade. That's really where the big brakes shine in terms of performance. Repeated use and/or abuse.
There are two caveats to big brakes though. That being the unsprung weight and rotational inertia. I understand how those work in theory but I have never made a clear real-world connection of just how they effect things. But then again, I've never run a heat and then changed brakes before the next one. I would imagine the big thing to stand out would be the suspension reacting slower from slinging around an extra 10-pounds per wheel. I'm not sure exactly how it would translate into acceleration or stopping times from the rotational intertia. I would think that would be minimal considering the weight of the car.
Like TooManyToys stated you can actually have too much brake. I don't think that's as much of a problem with the LS since it's a pretty good size car. But a 355mm brake kit on something like a Chevy Aveo would make the brakes so finicky they would be almost unusable.
However, I think most people will do this upgrade to fill in the gap between their stock brakes and their 18"+ rims personally. They'll certainly work for that
I will probably run my current set-up until I either wear them out or start having issues with them. Then that will be my justification to spend more money
Nope, my LS had 17" rims stock. That's why I said it was unverified. The caliper would be approximately 1/2" higher then the stock. So if you can fit your pointer finger between the rim and caliper it would more then likely fit. If you can't, then probably not. I based that assumption (with warning) on the fact that there was about 5/8" clearance between the stock 17" rims and the back of the caliper. The smallest rim available with the S-Type "Sport" that it was based off of was a 17" rim so no verification there either. Someone just has to try or measure it to know for sure.
I am almost positive that there is more then a few hundredths of an inch in clearance between the stock brake set-up and a 16" rim. The rim will flex more then that when you are driving. That's why hubcaps would fly off of a steel rim although they would flex a lot more then aluminum rims.
Like with anything when going outside of the box there is always the possibility it will be an amazing failure.
mlara1129
Dedicated LVC Member
Kumba quit being a party pooper! Lol
I think most, including myself, just want to do this upgrade for the looks. Whether braking performance is improved is secondary, although it would be nice. Even the stoptech "big brake kit" offered very little improvement over stock.
I think most, including myself, just want to do this upgrade for the looks. Whether braking performance is improved is secondary, although it would be nice. Even the stoptech "big brake kit" offered very little improvement over stock.
dwiggy
Active LVC Member
...they look nice and the car f'n stops on a dime. Big improvement!
1LoudLS
Dedicated LVC Member
i would say that the tire are going to make a huge difference with this up-grade.
with most of the tires i have ran on my LS, the OEM brakes have more than enough stopping power where the tire will actually lose grip before the brakes do, for instance, the cheap falcons i have on there now will definitely lock up and put the ABS to work on dry pavement, but they are a hard tire so they last forever, and bigger brakes would probably help a lot with the feel of them, but would likely not do much of anything for stopping distance. but a couple of sets ago i had a set of F1's that where amazing, they where hard to lock up on wet pavement, and i dont think i ever could get them to lock up for more than a fraction of a second on good clean pavement(i guess a better way of putting it would be that the ABS would never stay activated for more than a fraction of a second because with the ABS the tire would never actually lock up for more than a fraction of a sec).
long story short, make sure to spend enough on the rubber to be able to take advantage of the added stopping power!
with most of the tires i have ran on my LS, the OEM brakes have more than enough stopping power where the tire will actually lose grip before the brakes do, for instance, the cheap falcons i have on there now will definitely lock up and put the ABS to work on dry pavement, but they are a hard tire so they last forever, and bigger brakes would probably help a lot with the feel of them, but would likely not do much of anything for stopping distance. but a couple of sets ago i had a set of F1's that where amazing, they where hard to lock up on wet pavement, and i dont think i ever could get them to lock up for more than a fraction of a second on good clean pavement(i guess a better way of putting it would be that the ABS would never stay activated for more than a fraction of a second because with the ABS the tire would never actually lock up for more than a fraction of a sec).
long story short, make sure to spend enough on the rubber to be able to take advantage of the added stopping power!
1LoudLS
Dedicated LVC Member
BTW: the should be a mandatory requirement for everybody running 20"s and larger.
the stock brakes no matter how clean or painted just look like they where taken off of a focus or a mongoose with wheels that big. just makes the car look unhealthy or malnourished.
the stock brakes no matter how clean or painted just look like they where taken off of a focus or a mongoose with wheels that big. just makes the car look unhealthy or malnourished.
LOL, not trying to rain on the parade. Just making sure someone doesn't get the wrong idea about the upgrade making the car stop better. That's all tire related first, brake related second
Everything on a car ends with the rubber meeting the road. That should always be the first thing you fix when looking at the performance aspect of a car. The only other things that makes a bigger difference is the driver.
Elemino
Dedicated LVC Member
Damn, I really like my factory (2006) 17s. I have yet to find an 18 or 19 that I like enough to give them up. I wish I could have a custom 19" version of my wheels made.
lol, not trying to rain on the parade. Just making sure someone doesn't get the wrong idea about the upgrade making the car stop better. That's all tire related first, brake related second
everything on a car ends with the rubber meeting the road. That should always be the first thing you fix when looking at the performance aspect of a car. The only other things that makes a bigger difference is the driver.
+1...
TooManyToys
Well-Known LVC Member
With all the NHTSA FMVSS tests we ran, it would be extremely rare for us to not to be tire skid limited on any of the tests with OE materials.
05 LS8
Dedicated LVC Member
The action on a 4-piston caliper is better I think. Doubt anyone would really notice though. A lot of the benefit of the bigger brakes and all doesn't really show up under regular daily driving. Not until you go to do an emergency stop does it pop up and say hello. Even then you are limited by the rubber meeting the pavement. So if you can lock up all 4 wheels with the stock brakes, then a big brake kit won't do anything other then lock them up earlier in the pedal. That is from the mechanical standpoint. As far as the brake feel to the driver all bets are off. You might as well be arguing body kits and rims at that point. It's going to very from person to person.
For instance, say you take two identical LS. Same year, engine, trim, rims, street tires, weight, everything. You then equip one with a 6-piston caliper and a 15" composite floating rotor and stainless braided lines with some high-grade carbon metallic pads. If you were to now take these two cars and do a 60-0mph test on a dry day they would show almost identical stopping times and distances on the initial pass. A locked up tire is a locked up tire regardless of what is applying the braking force.
Now, in the same scenario, if you were doing this repeatedly in short succession you would see the bigger brakes having less fade. That's really where the big brakes shine in terms of performance. Repeated use and/or abuse.
There are two caveats to big brakes though. That being the unsprung weight and rotational inertia. I understand how those work in theory but I have never made a clear real-world connection of just how they effect things. But then again, I've never run a heat and then changed brakes before the next one. I would imagine the big thing to stand out would be the suspension reacting slower from slinging around an extra 10-pounds per wheel. I'm not sure exactly how it would translate into acceleration or stopping times from the rotational intertia. I would think that would be minimal considering the weight of the car.
Like TooManyToys stated you can actually have too much brake. I don't think that's as much of a problem with the LS since it's a pretty good size car. But a 355mm brake kit on something like a Chevy Aveo would make the brakes so finicky they would be almost unusable.
However, I think most people will do this upgrade to fill in the gap between their stock brakes and their 18"+ rims personally. They'll certainly work for that
I will probably run my current set-up until I either wear them out or start having issues with them. Then that will be my justification to spend more money
Test drive a STR/XF, E550 and see what you said about bigger brakes having nothing to do with better stopping power, still has any merit to it.
TooManyToys
Well-Known LVC Member
So if you can lock up all 4 wheels with the stock brakes, then a big brake kit won't do anything other then lock them up earlier in the pedal. - Kumba
You highlighted his point then stated about the STR having better stopping power.
What is your definition?
If it's lower pedal effort, then you are agreeing with him. As long as the vehicle is tire skid limited, under any pedal effort within law, you are not going to improve it's stopping distance with the exception of a few milliseconds it takes to get deeper in the pedal.
You highlighted his point then stated about the STR having better stopping power.
What is your definition?
If it's lower pedal effort, then you are agreeing with him. As long as the vehicle is tire skid limited, under any pedal effort within law, you are not going to improve it's stopping distance with the exception of a few milliseconds it takes to get deeper in the pedal.
Stopsign002
Dedicated LVC Member
I'm guessing he means it wont help 'unless' you get better tires that dont lock up with stock brakes.
05 LS8
Dedicated LVC Member
My point was that, i disagree with what Kumba said about bigger brakes not helping out a car stop shorter. I know about the whole heat thing bla bla bla.....
The fact is , you will stop in a shorter distance with larger rotors and bigger pads.
Smaller surface area of clamping on small brakes will not be able to generate the same amount of stopping force in the same amount of time as a larger one. Yes, it's that simple.
Tires are a very important component in performance of a vehicle. Extremely important. But, not as important where you make it sound like Toyota Corolla with the best performance tires in the market will stop as good as M5 with the factory tires.
I think both of you guys are looking into this brake upgrade a little too much and picking it apart. You are talking extreme conditions here, when most people don't drive around locking up their brakes every time they come to a stop.
OP, thank you for taking the time doing this upgrade. It's been a long time coming. Just know you are appreciated!
1LoudLS
Dedicated LVC Member
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.
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.
well mostly because the M5 already has some of the best tires in the world for the factory, so you would just be putting as good of tires on it, not to mention that the M5's tires are twice as wide.
it will also come down to a huge difference in weight, it is easily possible for a small import with amazing tires and stock brakes to out stop a heavy ass M5 with the best brakes in the world if it has some cheap sh!tty tires on it.
no one part of a car can account for great performance, every part has to work great together. I
'm not saying that the brake upgrade doesn't have a huge potential for making a large improvement, but with out rubber that can make the difference, the mod cant see any improvement.
how good would your car stop if you had nascar brakes and plastic tires?? It wouldn't stop at all!
Stopsign002
Dedicated LVC Member
Yeah, the weakest link is what determines the power of the breaks. If the tires cant keep up adding more wont help one bit. If you want these breaks for performance you better be spending some money on tires also. Everything your car does is relayed through the tires. Bad tires = bad performance regardless of any upgrades.
RodLS
Dedicated LVC Member
Will an upgrade like this reduce brake fade? My current setup has incredible braking power, but after a couple of hard stops they start fading like crazy.
If these brakes stop the same but don't fade as much, they would be the ideal cheap good looking brakes for the LS.
If these brakes stop the same but don't fade as much, they would be the ideal cheap good looking brakes for the LS.
The STR would have less fade over repeated use. That would make it better then stock all other things being equal. There would be more potential braking effort in the STR setup which would be usable with better tires. But if the tires are all the same and you can lock them all up then there is no real gain on the initial stop. Once the ABS kicks in you have reached the end of your tires traction. That was what I was trying to say.
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.
Take your LS out, get up to about 45mph, then smash the brakes hard like an emergency stop. If the tires skid then that means you have more braking force then you have traction. How will increasing the braking force even more increase the traction?
That is like saying you stomp the gas the rear tires spin, so you put a super charger under the hood to solve it. More power, either pushing or stopping the car, does not help the tires generate traction.
Considering an M5 came with Michelin Pilot Sport PS2 from the factory there really isn't much to improve with the tires short of using some racing compound tires.
If you take two identical cars, one with small brakes and one with big brakes, they will have an almost identical 60-0mph time on the initial stop. If you take the car with the smaller brakes and put race compound tires on it then it will stop quicker due to less skidding. A BMW M5, by just changing from the Michelin PS2s to Goodyear Eagle RC AS will stop shorter. There is no more braking force being generated by the brakes, so why is it stopping shorter?
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.