BIG Brake Kits Using OEM Calipers

[alexrex20]

Imo 1/2in is plenty. 4mm is pretty widely accepted as the minimum and that's about 3/16in. Wheels don't Flex

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[D1JL]

Imo 1/2in is plenty. 4mm is pretty widely accepted as the minimum and that's about 3/16in. Wheels don't Flex

I think you missed the point or excuse me, that might be your point.
With a 17" wheel there is only 1/2" clearance.
So with a 16" wheel there would be ZERO clearance.
This is why I said, if you use a 15mm wheel spacer, you may get enough clearance, depending on the wheel.




Dave

 

[alexrex20]

Yes, I completely missed your point. Lol carry on...

 

[kivnul]

Review

It has taken me a while but I have some time to put my review in for this kit.

All the parts are well machined and look nice. After I fit everything together I noticed that there was very little clearance between the bracket and the outside face of the brake disk. I double checked everything (hub was clean, spacer fit flush, lugs and other bolts nice and tight). Took it out for a spin on the streets and the setup worked great. (side note, I changed to Hawk HPS 5.0 pads. I do not like these and I feel that they lose all the gain from the bigger setup but I digress)

I took this setup out to the AutoX the next weekend. Dive breaking for a slalom and I was getting a horrible metal on metal sound. This went mostly away after a few runs.

After the weekend I took this kit off because it is winter and I need to run my 15's for snow tires and I discovered the below.



There was metal on metal contact between the bracket and the disk. I did not take a picture of the disk but it was apparent it had been rubbed on. On the passenger side I took out my feelers and I measured 0.068 on the inside and 0.030 on the outside between the disk and the brackets (this is after it had been ground away during AutoX). It would appear that the spacer provided in this kit is slightly too thick, pushing the disk to far outward. I had this happen to both left and right side brackets.

Next spring I am going to take out a small grinder and widen out the brackets so that they do not have a chance of rubbing any more. The disks are fine and will be able to be used in the future.

 

[SST]

you are referring to the front RX8 323mm adapter?

 

[kivnul]

you are referring to the front RX8 323mm adapter?

Yes sir. Specifically, the aluminum hub spacer/shim appears to be a tad thick (at least for my specific car)

 

[D1JL]

That hub centric spacer cannot be made any thinner as it is needed for clearance elsewhere.
I am looking into this.
I will be home from work in a couple of hours.


Dave

 

[D1JL]

@ kivnul,
This kit was tested on many FiST steering knuckles.
I don't do autoX but I did test doing a lot of spirited canyon driving and I had no issues.
We are still dealing with mass produced factory parts and very close tolerances.

First I would NOT do any grinding.
By your description above, you need to move the caliper bracket outboard.
I would split the difference and move the caliper bracket out about .018-.020, .018 would give you .050 clearance on both sides.
This can be done simply adding a shim (metal gasket) between the kit aluminum block and the caliper bracket.

You can buy shim stock from any GOOD auto parts store or online.
I would use stainless steel however, brass or aluminum would work just as well.
.020 shim stock can be cut with ordinary scissors.
The bolt holes should be punched or cut with a hobby knife, do NOT try to drill.

I hope this helps.



Dave

 

[alexrex20]

Empty Coke can or beer can is great shim stock.

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[kivnul]

First I would NOT do any grinding.
By your description above, you need to move the caliper bracket outboard.
I would split the difference and move the caliper bracket out about .018-.020, .018 would give you .050 clearance on both sides.
This can be done simply adding a shim (metal gasket) between the kit aluminum block and the caliper bracket...

Good idea, I will start with shims next spring and see where that gets me. Grinding should be the last option used.

Empty Coke can or beer can is great shim stock.

Heh, I use aluminum can bits for all sorts of stuff, no reason I can't here as well. Thanks.

 

[CSM]

Good idea, I will start with shims next spring and see where that gets me. Grinding should be the last option used.



Heh, I use aluminum can bits for all sorts of stuff, no reason I can't here as well. Thanks.

Did you ever sort out the grinding issues?

 

[kivnul]

Did you ever sort out the grinding issues?

I updated other posts but I forgot this one so I apologize.

I cut a aluminum can and used it as a shim in 2 layers. I did not measure the new clearances but between the new shims and the brackets getting worn down a bit from the rubbing last year I had no new grinding/rubbing during the latest autocross session a couple of weeks ago. I also swapped to new OEM pads (the high dust ones) and the braking overall feels better.

 

[CSM]

I updated other posts but I forgot this one so I apologize.

I cut a aluminum can and used it as a shim in 2 layers. I did not measure the new clearances but between the new shims and the brackets getting worn down a bit from the rubbing last year I had no new grinding/rubbing during the latest autocross session a couple of weeks ago. I also swapped to new OEM pads (the high dust ones) and the braking overall feels better.

That's awesome! I am considering doing this upgrade on all four corners vs. going with a big brake kit up front (like Wilwood). Is performance vs. stock highly noticeable?

 

[kivnul]

The car does seem to stop faster than before. With RE71R's it still does not brake hard enough to activate ABS. I think the added mass is somewhat counteracting the increased caliper distance from hub.

 

[D1JL]

The OEM brake calipers with the larger rotors do work just fine.
However, lighter peddle pressure is required to produce the same braking effect as OEM.
A heaver pressure on the peddle will lock the brakes as before and energize the ABS system.
It takes only a few minutes to learn the feel of the new brakes.
In actuality, you will realize much better control of the brakes.
I have been using this system for a number of years now with only positive results.

 

[kivnul]

An update after a full AutoX season and Daily driving. These brakes worked great all year. As D1JL stated they do react a bit differently than stock but it takes very little time to get used to it. Brake modulation is good, stopping power is good, never had a heat or fade issue (though I do not do any laps on a track so I am not pushing the heat issue). With OEM summer pads the bite is still strong. I just took them off for the winter (I run 15" wheels with snow tires) and the parts still look great. After my thin shims, I had no further problems.

I had a competitor shatter his 3rd gear 1/2 way through my last AutoX event and we dual-drove my car for the rest of the day. He exclaimed a love of my breaks and the ability to begin slowing down so close to an obstacle. Since he has 15 or so years experience racing (and he kicks my butt more often than not), I take that as a pretty big endorsement.

 

[D1JL]

I am certainly glad that you and your friend had a positive experience.
As I may have mentioned before, I have had setups like these on other cars before.
In the past, as in a very resent incident, the fact of having brakes with more stopping power has saved my butt.
The set that I use was primarily designed so that everyone could afford a bigger brake system.

 

[Adub]

@D1JL Do think these would fit the 16" Konig Dekagrams?

 

[kivnul]

@D1JL Do think these would fit the 16" Konig Dekagrams?

If you can make it over to Spokane we could do a test fit.

 

[D1JL]

If you can make it over to Spokane we could do a test fit.

Without a test fit, there is no way to tell.