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Part Deux
2001 WRXed Caged L
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OK, you already acknowledged you didn't know that drilled rotors were on so many DD's from Mercedes and Porsche (both built for speed and safety). So, they are present for more then bling and weight loss, although as I mentioned before, saving rotating mass weight (unsprung) is ALWAYS a good thing and yet another of their benefits.

Now go figure this, if the drilled rotors don't evacuate water better, ask yourself why Mercedes would spend this money on R&D and technology? Every car that MBZ makes with drilled rotors has this function > When you are driving in the rain (determined by your wipers being on) the calipers automatically and intermittently press against the drilled rotors to dry the brakes in case an emergency stop is needed!

Is there any argument that MBZ makes one of the safest cars on the road?

I guess they have been duped too...? :facepalm:
But on a daily driven car, weight loss should be second to braking. I couldn't tell you any differences regarding weather, however as it has already been pointed out... rally car teams do not use drilled rotors. They depend on their brakes even more than daily driving billionaire grandmothers.

I have already clearly presented enough information to know the truth.

I changed mine old drilled/slotteds rotors last week, no cracks or anything besides rust, I never had a problem with them and I drive everyday.
We don't need pictures of your drilled rotors, there are going to be drilled rotors that don't crack. It all depends on how hard you drive on them, how big the rotor is, etc. The entire point is that they do not benefit over blank rotors except for weight loss.
 

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Registered
99 Impreza RS , Silver.
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446 Posts
But on a daily driven car, weight loss should be second to braking. I couldn't tell you any differences regarding weather, however as it has already been pointed out... rally car teams do not use drilled rotors. They depend on their brakes even more than daily driving billionaire grandmothers.

I have already clearly presented enough information to know the truth.



We don't need pictures of your drilled rotors, there are going to be drilled rotors that don't crack. It all depends on how hard you drive on them, how big the rotor is, etc. The entire point is that they do not benefit over blank rotors except for weight loss.
Okay well that's just your opinion and we respect it..
 

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L On Roids.
98L 2.2
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1,365 Posts
If blanks are really the way to go, how come so many suby guys run DBA rotors? Everyone I've talked to say they swear by them.
 

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Banned
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4,588 Posts
Because it is a top of the line system for a car wanting to shed weight. Also, this gets all of the riceboys to buy their super small thin cross drilled rotors. They probably cost $15-20 to produce and sell them for $100-120 each. $80 profit. However, real race teams needing to save this weight and lose a tiny bit of braking performance over blanks want it.

I already have posted enough information to easily prove it. Racing engineers who have real experience with braking systems will tell you the same thing.

I have to agree with you that drilled rotors are for saving weight. The stock R35 GTR has drilled holes in their rotors to eliminate weight but the braking area when the pad to the rotor meets is increased due to their very big brakes.

Also if you drive in the winter and get water/ice/snow in the holes of the rotor and you brake this can cause your chances of cracking to increase due to the different temperatures on the rotor.
 

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If blanks are really the way to go, how come so many suby guys run DBA rotors? Everyone I've talked to say they swear by them.
because usually when you upgrade your brake system you upgrade the pad as well.. but alot of people dismiss pads and focus more on the number of pistons and the size of the rotor

also two-piece rotors are pretty neat, and there are certain benefits to them that i would love to have, but its $$$, and would only be felt on the 10th lap of a full blown race.


the other factor is that people that spend 250 bucks on a rotor will never admit to it not being an improvement.. that would just make them look stupid.
 

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The Silverback Mod
05 Black OBS
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8,896 Posts
Discussion Starter #49
safe is a very, very, very broad term.
Hmm? OK. MY wife was hit in a new C Class in '94 while six months pregnant. T-boned in fact by a double tanker semi, who blew through the light (according to the CHP at 55 mph-65 mph).

Fortunately, he hit the passenger side of the Merc and there were no other occupants but my wife. After the hit (and being moved 150 ft across the intersection) the car was bent in a V.

She was able to open her own door (no jaws of life) laid on the ground and told a witness, "I am pregnant, call an ambulance..." then passed out.

My daughter is 14 years old and my ex-wife is alive as well. Yep. SAFE!
 

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find me a car where the pads are larger than the rotor from factory :rolleyes4
Unlike previous generations of the GTR where they used 4 piston front calipers they went to upgrade the R35 GTR with 6 piston front calipers. You are getting more clamping between pads and rotors with 6 piston calipers.
 

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Unlike previous generations of the GTR where they used 4 piston front calipers they went to upgrade the R35 GTR with 6 piston front calipers. You are getting more clamping between pads and rotors with 6 piston calipers.
okay now we are talking about calipers, thats a different avenue

lets get back to rotors.

you said a larger rotor with holes in it provides more surface area for pad contact.. which is absurd, unless the OEM rotor was smaller than the pad.

not to mention the holes, which means at any given moment the pad has less contact with metal than it did OEM.
 

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Premium Member
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the other factor is that people that spend 250 bucks on a rotor will never admit to it not being an improvement.. that would just make them look stupid.
Ummm I see your point as I admitted it a few posts back but a blank rotor for an STi brembo setup is $425 from the dealer... each.
 

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yep. you heard me.
03 Legacy GT wagon
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6,471 Posts
i havent read every word of this thread but i read most of it and skimmed the rest. i dont think you guys are even considering what the original purpose of using drilled and slotted rotors was. its safe to say that TODAY and in recent years, theres really no practical purpose for having drilled or slotted rotors other than looks and less rotating mass. however they definitely used to have a strong purpose when brake pads were made with material that would powder up and/or offgas during use. the junk needed some place to go and so with a slot that extended across a length of the rotating arc and over the radius of the rotor, it would allow it whatever was building up to escape somewhere (into the slot and out the part of the slot that was not being covered by the pad at that moment, and the slots were overlapping to make sure there was always 1 or more points of escape). drilling works the same except it just escapes into the brake vents or for non-vented rotors, it would collect in the holes and then hopefully escape once the holes werent covered by the pad again.

but today brake pads arent made from that kind of material anymore, so its not an issue. its for show, and the very minor decrease in mass.

i really think the first post of this thread is the only useful post, everything else is just you guys bickering. use of braided brake lines, a good fluid, brake vent ducts if possible, and perhaps a MC brace will all greatly increase your braking ability. using a different kind of brake rotor will do practically nothing, especially in comparison to using any of the aforementioned upgrades, or simply going to a larger brake caliper/rotor

/thread
 

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Meany Head
2000 RSC
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10,230 Posts
Ok... how's this for an attempted summary.

- Cracking Drilled rotors are the domain of cheap eBay rotors.
- drilled and slotted doesn't increase breaking power, nor added cooling.
- drilled reduces un-sprung weight thus increases performance.
- off-gassing is no longer an issue with todays pads

Thus, if you get larger diameter than stock high quality rotors, with drilled or slotted and better pads.
Your braking capability is going to be an improvement over stock.
= Not a waste of time and money as some have suggested.

Take the above conclusion and go with Slotted or Blanked rotors, and increase braking power, at the expense of performance.
= If Braking is critical to you, get blank rotors and address the un-sprung weight issue elsewhere.

Seems to me that one can simply weigh the pros and cons of Acceleration & Braking performance by choosing various combinations, and still come out on top.

Seems to me that the minor sacrifice in braking capability with drilled, when compared to the weight savings, and your ability to offset it with larger diameter, makes it well worth looking at.

P.S.
I'm cheap, and totally sticking with blanks and good pads.
Been working fine for me so far!
 

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Part Deux
2001 WRXed Caged L
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3,025 Posts
i dont think you guys are even considering what the original purpose of using drilled and slotted rotors was.
Yes, I already added this information to the bottom of this post: http://www.rs25.com/forums/f9/2060785-post16.html

Also, this thread is specifically giving facts about rotors. There is already a thread on the other brake parts that can be upgraded that Geran created (aka Carisma, aka The Reason).
 

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you said a larger rotor with holes in it provides more surface area for pad contact.. which is absurd, unless the OEM rotor was smaller than the pad.
.
I did not say that. That is what you thought I meant to say. I tried to make my point clear that the 6 piston calipers would require a bigger pad design compared to a 4 piston design previously used on older GTR models. I love using the GTR as an example. That car is just sex and I would take that anyday over my GF4 wagon.

 

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The Silverback Mod
05 Black OBS
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8,896 Posts
Discussion Starter #57
not to mention the holes, which means at any given moment the pad has less contact with metal than it did OEM.
Those holes give up contact area and increase the friction coefficient from the beveled edges = a wash. That is the reason you say they eat pads, those very same holes... same happens with slotted, the shape does not matter, they both do the same job.
 

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yep. you heard me.
03 Legacy GT wagon
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6,471 Posts
Yes, I already added this information to the bottom of this post: http://www.rs25.com/forums/f9/2060785-post16.html

Also, this thread is specifically giving facts about rotors. There is already a thread on the other brake parts that can be upgraded that Geran created (aka Carisma, aka The Reason).
ah ok i missed that small part. i think in your quote i focuses on the part you bolded lol

between what me and Skidd just said, this thread should be locked and possibly stickied for others
 

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Premium Member
06 Lexus Rx400h
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1,661 Posts
I can agree with skidd!

but people will fight till the death to prove someone else is wrong and they are right. if not they will nit pick every little word and try and twist things around to make you look dumb even though you were right in your comment :)


and ha ha obs \/ two posts down (not to make another post off topic)

it will never be closed "muahahah"
 

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Cpt. Pontiac
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5,290 Posts
The Pontiac Aztec Rally addition came with drilled and slotted rotors up front, but out back it still had drums.:screwy:

I think Skidd hit the nail on the head, a +1 will go to that crazy Canadian.
 
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