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Yes, the M2/ Wilwood 13" brake kit actually fits under stock 16" FD wheels!

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Old 04-24-04, 05:41 PM
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Yes, the M2/ Wilwood 13" brake kit actually fits under stock 16" FD wheels!

After I burned up my stock 1993 RX7 brakes in 2 lapping sessions at Laguna Seca Raceway last October I decided it was finally time to do something about the brakes. However, the last thing I want to do is buy a bunch of larger wheels and tires. My opinion is that the stock wheels and stock tire size is a great combination.

The only larger brake kit I found advertised that said it still fits under the stock wheels was the one put together by M2performance using Wilwood 6 Piston Front Calipers and 13" Brake Rotors.

I order this kit (with thermolock caliper piston and heat treated rotor option) from M2 Performance in late October. I finally got the last of the components (the front brake lines) last week. Yes, six months is absurd but that's another story...

On the plus side the quality of the kit looks great. But by eyeballing it I thought, "NO WAY this fits under the stock 16" rims!".

I finally test fitted the brakes today and amazingly they do fit with about 1mm to spare. Picture:



As you can see the 13" rotor is also much wider with a much greater vented area than the stock rotors. The caliper and pads are also much larger. I'm still suprised they fit under the stock wheel. M2 Performance says the whole kit weighs the same as the stock brakes. I havn't weighed them yet but judging by feel I'd say they're about the same weight. Pictures:



I decided it would be prudent to install some larger rear brakes also to try to balance things out. Since I still drive my car on the street I wanted to keep the stock parking brake so I decided to just go with the larger RZ '99 Model Brakes. Nobody seemed to have a clear answer if these fit under the stock 16" wheels. Some said yes and some said no. So I bought them and figured I'd take a gamble. The answer is yes, but with a minor modification. The knuckles on the back of the caliper barely drag against the inside of the stock wheel. I had to use the shadetree mechanic's favorite fabrication tool - the hand file - to take off a couple millimeters of metal on the end of the knuckles. Now it seems to barely fit. Pictures:



I'm going to a three day track day and time trial at California Speedway in the middle of May so I'll let everyone know how they do on the track.

I am still waiting on some front brake ducts from the N-Tech group buy. I know Nick had some family emergencies that delayed things. Anyone know when he plans to ship them out?

I figure once I have this all done I should have the ultimate brakes that still fit under the stock wheels.

-John Magnuson
rx73rdgen@aol.com
Old 04-24-04, 05:44 PM
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Hey guys, Geocities won't let the links to the pictures above work but if you cut and paste the links into your web browser it will work.
Old 04-24-04, 08:18 PM
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What were you doing that you burn the stock brakes? Did you use DOT 4? and Performance Pads?
Old 04-24-04, 08:55 PM
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I was using Motul Brake Fluid and Porterfield R4 pads. I've had no problems with the combination on other tighter tracks. I think I just got over zealous braking into turn 2. Riding the ABS from 130 down to about 55 does wonders on your brakes. Of course I had no dedicated brake ducting. The the "ducts" from the R1 model lip.
Old 04-24-04, 09:45 PM
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Originally posted by John Magnuson
I was using Motul Brake Fluid and Porterfield R4 pads. I've had no problems with the combination on other tighter tracks. I think I just got over zealous braking into turn 2. Riding the ABS from 130 down to about 55 does wonders on your brakes. Of course I had no dedicated brake ducting. The the "ducts" from the R1 model lip.
You think if you had a brake duct and maybe some cool air going in that would have happened? BTW Whatd you kill the rotors or the caliper?
Old 04-24-04, 10:35 PM
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Originally posted by Fatman0203
You think if you had a brake duct and maybe some cool air going in that would have happened? BTW Whatd you kill the rotors or the caliper?
My guess is he was melting pads and cracking rotors. I've never used dedicated ducts on with stock rotors so I would be interested to hear how effective it is from someone who has. If you continually brake from 140 plus down to 55 with stock brakes my guess is your looking at some brake troubles no matter what kind of duct setup you have.

Last edited by Fritz Flynn; 04-24-04 at 10:43 PM.
Old 04-24-04, 10:45 PM
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Originally posted by Fritz Flynn
My guess is he was melting pads and cracking rotors. I've never used dedicated ducts on with stock rotors so I would be interested to hear how effective it is from someone who has. If you continually brake from 140 plus down to 55 with stock brakes my guess is your looking at some brake troubles no matter what kind of duct setup you have.
Why not? Calipers not big enough to disipitate the heat? Caliper not have enough grip?
Old 04-24-04, 10:51 PM
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Originally posted by Fritz Flynn
My guess is he was melting pads and cracking rotors. I've never used dedicated ducts on with stock rotors so I would be interested to hear how effective it is from someone who has. If you continually brake from 140 plus down to 55 with stock brakes my guess is your looking at some brake troubles no matter what kind of duct setup you have.
Why not? Calipers not big enough to disipitate the heat? Caliper not have enough grip?
Old 04-25-04, 01:48 AM
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Well, to begin with my brakes started fading after just a couple of hard laps. During the third lapping session the brake fluid boiled over and I had massive fade. I also had about 1mm of brake pad material left on NEW PADS after 60 minutes of lapping. I didn't do a "break in" on the pad that time so that may be the cause of it. The rotors did not crack but the front rotors had some serious grooves and scoring.

May the Porterfield R1 pads aren't the way to go... who knows... I loved them on my Miata.

Like I said before this combo worked very well for me at Spring Mountain and Streets of Willows... but these tracks are easy on brakes.

But that's all beside the point now. We'll see how the M2 kit does!

-John
Old 04-25-04, 02:12 AM
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Well would a DOT 5 (non-silicone based) fix the boil over? Im doing Sebring at the end of July, and I heard that track is very tough on brakes, but I dont have the cash for upgrade.
Old 04-25-04, 09:37 AM
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John i thought you were selling your car? Its good to see that your not. I remember your outting with the Porsche club out in Nevada good luck and post your results with your new setup at Laguna Seca.
Old 04-25-04, 07:35 PM
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Yeah, I did intend to sell my car. I even got some nice offers. But I decided to keep it for a number of reasons. Plus, it's just so damn fun on a racetrack.

The stock FD are really quite nice. I'm not trying to say that they're bad or won't work fine in most situations if you prepare them right.

Anyway, I justed wanted everyone to know that the M2 13" brake kits does fit under the stock wheels. I'm going to a three day even in Fontana at California Speedway with the Porshe Club so I'll give a full report when it's done.
Old 04-26-04, 08:28 AM
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Originally posted by Fatman0203
Why not? Calipers not big enough to disipitate the heat? Caliper not have enough grip?
Everything about Brakes by Grassroots Motorsports
Old 04-26-04, 09:47 AM
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Ok so I wont post for a while, so I can read that whole thing . Thanks very interesting, halfway done with it. Probably will read it twice to make sure I understand it.
Old 04-27-04, 09:06 AM
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Too bad about M2. No way i'm waiting even six weeks for anyone's stuff. Think about how much money they're loosing from people who WANT to buy their stuff but won't put up with that. Sad.

Nice looking setup, and kudos to you for making the '99s work out back!
Old 04-28-04, 02:13 PM
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The GRM article is a decent summary of a variety of topics, but does not answer Fatman's "DOT 5?" question.

As I understand it, DOT 5 is silicone based, does not absorb water, and therefore may be a good choice for a restored classic or show car that is rarely driven. However, DOT 5 is not compatible with DOT 3 and/or 4, and can degrade seals, hoses, etc. In other words, you should bench flush your calipers, and perhaps rebuild them, if changing from DOT 3/4 to DOT 5 or vice versa.

Most OEM and race cars use DOT 3 or 4 brake fluid - these are petroleum-based, do absorb water, but are compatible with each other. The specs for the different fluids typically show their "dry" boiling point - their "wet" boiling point will obviously be lower. The main difference between DOT 3 and 4 is the boiling point - DOT 4 is higher. If you are putting your car on the track, you should be changing your brake fluid at least every 3 months anyway, so it's reasonable to just go with the highest "dry" boiling point you can find at a reasonable price. Beyond that, personal preference varies - Motul, ATE (clear or "Superblue"), Castrol SRF, Wilwood, AP, PFC - all have their proponents. I like the ATE fluids - I alternate between the clear and blue versions to make sure I've gotten a fairly complete flush.
Here's a nice comparison chart from Pegasus Racing: http://www.pegasusautoracing.com/pdfs/127.pdf
Old 04-28-04, 02:28 PM
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Originally posted by macdaddy
The GRM article is a decent summary of a variety of topics, but does not answer Fatman's "DOT 5?" question.

As I understand it, DOT 5 is silicone based, does not absorb water, and therefore may be a good choice for a restored classic or show car that is rarely driven. However, DOT 5 is not compatible with DOT 3 and/or 4, and can degrade seals, hoses, etc. In other words, you should bench flush your calipers, and perhaps rebuild them, if changing from DOT 3/4 to DOT 5 or vice versa.

Most OEM and race cars use DOT 3 or 4 brake fluid - these are petroleum-based, do absorb water, but are compatible with each other. The specs for the different fluids typically show their "dry" boiling point - their "wet" boiling point will obviously be lower. The main difference between DOT 3 and 4 is the boiling point - DOT 4 is higher. If you are putting your car on the track, you should be changing your brake fluid at least every 3 months anyway, so it's reasonable to just go with the highest "dry" boiling point you can find at a reasonable price. Beyond that, personal preference varies - Motul, ATE (clear or "Superblue"), Castrol SRF, Wilwood, AP, PFC - all have their proponents. I like the ATE fluids - I alternate between the clear and blue versions to make sure I've gotten a fairly complete flush.
Here's a nice comparison chart from Pegasus Racing: http://www.pegasusautoracing.com/pdfs/127.pdf
Mac daddy thanks that was a very helpful site. Actually I have found DOT 5 that are NOT silicone base MOTUL being one of them. I highly appreacite your input helps alot.
Old 04-28-04, 03:50 PM
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Hmmmm... the Motul Racing Brake Fluid bottle that I'm looking at right now which I purchased last weeks says DOT 4.

Typical Dry Boiling Point: 594 F (312 C)
Typical Wet Boiling Point: 421 F (216 C)

My understanding is that DOT 5 fluid is silicone based as a definintion? Does Motul make anther brake fluid that is DOT 5?
Old 04-28-04, 04:52 PM
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Originally posted by John Magnuson

My understanding is that DOT 5 fluid is silicone based as a definintion? Does Motul make anther brake fluid that is DOT 5?
I think so, they make two though one silicone one not. Yet I may be off and maybe it wasnt Motul, cause I was looking into fluids since I will have to bleed mine anyways when I remove the ABS system to install the Garfinkle brace.
Old 04-29-04, 11:39 PM
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Since when do you have to remove the ABS to install the Garfinkle brace?
Old 04-30-04, 07:16 AM
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Originally posted by clayne
Since when do you have to remove the ABS to install the Garfinkle brace?
Thats what he told me =/
Old 04-30-04, 01:57 PM
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A thought about safety...

I was thinking about how I have about 3mm clearance between my brake calipers the insides of my wheels now. If I dent my wheel even slightly I think this could cause the wheel to hit the caliper and lock up the wheel? Or would it probably just break the caliper off? What do you think? Is this a dangerous set up?

-John Magnuson
Old 04-30-04, 02:01 PM
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Originally posted by John Magnuson
If I dent my wheel even slightly I think this could cause the wheel to hit the caliper and lock up the wheel? Or would it probably just break the caliper off? What do you think? Is this a dangerous set up?
I think you're fine. If you hit something hard enough to dent anything but the lip of the wheel (it's much harder to dent the entire wheel) then I think it would be the least of your worries as to whether the wheel locks due to striking the caliper.
Old 04-30-04, 03:29 PM
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should be more concerned with things heating up and rubbing. caliper gets hot and expands...wheel gets hot and expands...gap gets real small.

it won't ever jam...imho...but you could very well get some rubbing(grinding).

clearancing the calipers a TINY bit is usually ok...

john
Old 04-30-04, 04:31 PM
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Isnt the Brembos on the STI just about the same? Just like a few mm's away?


Quick Reply: Yes, the M2/ Wilwood 13" brake kit actually fits under stock 16" FD wheels!



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