oem Civic Si front brakes on my LX!! -impressions...(pics)

[Andrei'sCivic]

Originally Posted by CZ-75

Makes your stops longer. I'd rather have installed rear discs than 11.8" front rotors.

What this wouldn't have had the same effect as getting the front larger rotors? Wouldn't the ABS detect the same thing if I swapped my rear drums for rotors, since I will assume that the brake pads clamp harder than the brake shoes.
What would you recomend I do change out my ABS modulator assembly? Even the Civic EX shows a different part number for their modulator compared to the LX, all three are different it would seem...(LX,EX,Si) even though they look the same in the pic.

[CZ-75]

I'm sure all three modulators are different, probably because of the differences of the fluid capacity required for each brake caliper or drum. Too much rear brake can be worse than too much front brake, because it destabilizes the car under braking. However, let's think this through. Your OEM front brake was the same as the brakes found on the EX, which uses rear discs, so it is highly doubtful that the rear discs are too much for the car to handle with regard to brake balance. You, OTOH, have the crappiest rear brakes used on the Civic with the best front brakes.

[Andrei'sCivic]

CZ-75, so what do you suggest I do in order to make my new brakes work properly or more efficient, like you said they did before? How do you propose I decrease my braking distance with these new front brakes? - I'm still skeptical.

[CZ-75]

A) take them off or B) install rear discs.

[Andrei'sCivic]

Originally Posted by CZ-75

A) take them off or B) install rear discs.

Are you implying that I would have the shortest braking distance with my oem front brakes and swapped discs in the rear?
-Or with Si brakes up front and rear discs swapped in?

[BillyB]

For what you paid for those volks, couldnt you have upgraded to the si? Just a thought.
BillyB

[CZ-75]

Originally Posted by Andrei'sCivic

Are you implying that I would have the shortest braking distance with my oem front brakes and swapped discs in the rear?
-Or with Si brakes up front and rear discs swapped in?

I'd try Si front brakes + rear discs first before I went back to OEM fronts. If you drive up and down hills and canyons a lot, it might not be the shortest stopping distance you want, but fade resistance, and the Si fronts will give you more of that.

[cappykd]

Nice job.

[rmfa]

Originally Posted by aki

Hate to say this, but your braking distance will be longer with that mod.

First off, it will feel like it's braking better, because of the stronger brake torque up front, which gives an initially stronger bite.

BUT

1) The ABS computer will detect that the car is decelerating too rapidly, and will continually modulate (in other words weaken) the braking force. When the ABS cuts out for a moment, it again detects that the car is decelerating too fast, and compensate again. This happens continuously over your braking, and it stretches out the braking distance of your car. The ABS computer was programmed to expect a certain deceleration rate, calculated by the stock LX brake torque. Since you've increased brake torque up front by adding bigger rotors, the ABS will be overcompensating.

2) You've significantly increased the brake bias up front, which reduces the overall efficiency of your braking. The reason being that Honda engineers specifically chose the front and rear brake rotors sizes to work with each other. You can't simply add stronger brakes up front and expect better braking, as it throws off the brake balance with respect to the rear. A more front-heavy brake bias means that the front brakes are doing more work than needed, and the rear brakes are doing less than they should. Hence, irrespective of ABS, your braking distance would increase. The only benefit for this new setup would be less brake fade, but that comes at cost of greater braking distance.

+1 rep. This is very clear but still there are questions??

[CZ-75]

Originally Posted by rmfa

+1 rep. This is very clear but still there are questions??

Stoptech has the answers.

However, #1 is certainly clear and #2 ought to be clear if you're familiar with the traction circle that divides up the total potential traction of the tires amongst the various tasks they must do like cornering/steering, motive traction, and braking. Sooner or later, you will experience enough braking force to exceed the tire's traction and lock it up (but only briefly for an ABS car, which then cuts the brake pressure to that wheel). This is the issue at hand - exceeding your tire's ability to provide frictional traction at the front while grossly underutilizing that ability at the rear. The best braking scenario would be ever so slightly front biased to provide maximum control with near-optimum use of available traction; OEM brakes are more front-biased than they need to be so Honda (etc.) doesn't get sued by dumbasses who overdrive their vehicles.

[aki]

Compensating by adding rear disc brakes may or may not improve braking. It depends on 1) whether ABS computer is optimized to handle the different brake torque and possibly slightly different brake bias (more than likely it's not), and 2) whether the LX brake master cylinder is up to task for those changes.

Adding rear disc brakes would reduce the front brake bias, but if you're using OEM you'd still have brakes that are more front-biased than they'd need to be, as CZ-75 said. If you're going to go through the trouble of upgrading the rears, I'd wait for some aftermarket application (eg stoptech) that optimizes brake bias balance.

[Andrei'sCivic]

Originally Posted by aki

Compensating by adding rear disc brakes may or may not improve braking. It depends on 1) whether ABS computer is optimized to handle the different brake torque and possibly slightly different brake bias (more than likely it's not), and 2) whether the LX brake master cylinder is up to task for those changes.

Adding rear disc brakes would reduce the front brake bias, but if you're using OEM you'd still have brakes that are more front-biased than they'd need to be, as CZ-75 said. If you're going to go through the trouble of upgrading the rears, I'd wait for some aftermarket application (eg stoptech) that optimizes brake bias balance.

Get rear disc brakes from an Acura they measure 11.1" in diameter.

[Way2Short]

^^ any pictures?

[Andrei'sCivic]

Originally Posted by CZ-75

Stoptech has the answers.

However, #1 is certainly clear and #2 ought to be clear if you're familiar with the traction circle that divides up the total potential traction of the tires amongst the various tasks they must do like cornering/steering, motive traction, and braking. Sooner or later, you will experience enough braking force to exceed the tire's traction and lock it up (but only briefly for an ABS car, which then cuts the brake pressure to that wheel). This is the issue at hand - exceeding your tire's ability to provide frictional traction at the front while grossly underutilizing that ability at the rear. The best braking scenario would be ever so slightly front biased to provide maximum control with near-optimum use of available traction; OEM brakes are more front-biased than they need to be so Honda (etc.) doesn't get sued by dumbasses who overdrive their vehicles.

Listen, the car brakes better. I don't know what kind of tires you have but my 225/40/18 Toyo Proxies tires are very good, they have excellent traction.
I talked to a mechanic I know fairly well, who is SAE certified, he said what you stated is true but only when ABS is kicking in, which in my case is practically never.
He basically said your braking will be better, until ABS kicks in. When your car is braking very hard and ABS is kickin in to prevent lockup this is when my car's stopping distance is a bit longer. I guess I should give my tires a lot of credit.

[Andrei'sCivic]

Originally Posted by Way2Short

^^ any pictures?

From www.acuraautomotiveparts.org:
-07 Acura RDX, the RDX actually has:
Front Discs
11.7 inch (296 mm) diameter ventilated (w/ dual piston caliper)
Rear Discs
12 inch (305 mm) diameter drum in disc

07 Acura MDX:

Front Discs 13.0 inch (330 mm) diameter ventilated (w/ dual piston caliper)
Rear Discs 13.2 inch (334 mm) diameter drum in disc

07 Acura TL:

Front Discs TL - Ventilated, 11.8 in (300 mm) diameter; 1.1 in (28 mm) rotor thickness
TL Type-S - Ventilated Brembo, 12.2 in (310 mm) diameter, 0.98 in (25 mm) rotor thickness
Rear Discs Solid, 11.1 in (282 mm) diameter; 0.35 in (9 mm) rotor thickness

07 Acura TL :

[Andrei'sCivic]

Originally Posted by BillyB

For what you paid for those volks, couldnt you have upgraded to the si? Just a thought.
BillyB

Why do people like you continue to exist your comments do not help at all. How dare you... you have no idea what my situation is or how much I paid for the Volks. You are assuming I paid so much money for the Volks that I could have instead bought the Si. Stop making assumptions.
-Here's the story:
I had a crappy car ,and my parents wanted to get me a new one. I was being picky so they just bought me this Civic one night and showed up in it.
The Volks with tires were only $1000, and the markup on the new Civic Si was rediculous.
So please refrain from posting comments like that. Next time just let it be a "thought."

[Way2Short]

Dude, don't worry about what they say. Just keep up the good work.

[aki]

Originally Posted by Andrei'sCivic

Listen, the car brakes better. I don't know what kind of tires you have but my 225/40/18 Toyo Proxies tires are very good, they have excellent traction.
I talked to a mechanic I know fairly well, who is SAE certified, he said what you stated is true but only when ABS is kicking in, which in my case is practically never.
He basically said your braking will be better, until ABS kicks in. When your car is braking very hard and ABS is kickin in to prevent lockup this is when my car's stopping distance is a bit longer. I guess I should give my tires a lot of credit.

Yes, when you're not braking hard your braking will be better. But your minimum braking distance hasn't improved--all that changed is how much pedal you need to apply. In essence, you've changed the feel of the brakes.

ABS kicks in when you're braking at the car's calculated limit. That doesn't change regardless of the tires, brakes. If ABS detects X g's of deceleration, it automatically activates.

[Andrei'sCivic]

Originally Posted by aki

ABS kicks in when you're braking at the car's calculated limit. That doesn't change regardless of the tires, brakes. If ABS detects X g's of deceleration, it automatically activates.

ABS doesn't kick in anymore, I really mean its SO RARE. As before it did so more often. For some reason it feels it doesn't need to pump the brakes 16 times per second or however much it is.
-I swear, I just might test the braking distance with the Si brakes on then again with the oem ones back on.

[06RREX]

Ok time to revive a dead thread (better than wasting space on a new one) I just read through this whole thread and here are my questions:

I am looking at the new HFP brakes on my EX. In order to do that, I should ONLY need the Si calipers. So my brake setup would be entirely new with the HFP kit. I would have invested appx. 800 dollars in a brake setup. Bigger and slotted rotors, Bigger calipers, bigger everything it seems. So, after reading this thread I am under the impression that I would invest 800 dollars in a braking system that is actually WORSE than before, due to the ABS? If I changed EVERYTHING (like I am planning to do) with my brakes, (Not just the front like Andrei'sCivic did) would it be better?

So questions are:
1. Would my braking system (stopping distance and that stuff) get worse with the new brake setup?
2. I would be changing all 4 brakes, not just the front two, so shouldnt that make up the difference between the two? (Andrei'sCivic only changed the front two)
3. How would my braking effectiveness differ between lighter braking (non-ABS braking) and heavy braking (ABS engaged)
4. Would I need anything else other than buying the Si brake calipers to complete this HFP brake setup on my EX?