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#51

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - December 01, 2015, 10:38:11 PM

Laguna Seca for you! I'm heading to Maui!!

They don't have any paved tracks on Maui!

Sux



The long summer gave me plenty of time to think about the car. By early Sept. Mike and I had set the date for Laguna Seca to be December 13. I knew I was still busy for a bit longer with weekend work events and wanted to have time to improve the car.

The two biggest issues I had at Thunderhill was:
1. Brakes.
and
2. Front traction.

Brakes. Oh my brakes. At Thunderhill I felt like I had either too much horsepower or too much weight for the brakes. They would stop me well enough, but I was nervous to really squeeze them hard. I kept trying to accelerate for longer a duration before braking at each corner but I found myself timid or not able to trust the brakes.

Nevertheless, I did hammer them a few times and wow those Porterfield pads are NO JOKE. With the tires and brakes warmed up WOW the car can stop. But sure enough it wasn't long until I was getting a ton of modulation from the brake pedal and returning to the pits each time I could feel the brakes had warped. It wasn't until the next day driving to work that I really realized just how bad they were.

So as shown on the previous page I did indeed replace all four rotors. I had to. The car would chatter like crazy every time I slowed down from any speed. But it got me thinking about my brake setup....

Back in 1999 or 2000 when I was 19 or 20 I installed front brake components at the rear. I've always known that as a result I have a greater rear brake balance but it didn't take much pondering to understand just how out of balance they were.

Consider the following.

Stock 1987 front caliper bore diameter: 50.8 mm
Stock 1987 rear caliper bore diameter: 36.5 mm
Front to rear ratio: 1.39:1

Now consider the surface areas:
Front stock caliper: 2026.8 mm^2
Rear stock caliper: 1046.3 mm^2
This is a stock front to rear pressure ratio of 1.94:1

By running front calipers in the rear I've effectively increase my rear brake balance by 48.5% (all things equal; yes I know there is a progressive rate factory proportioning valve). This is crazy. So I started looking into a larger front brake setup.

Doing some research there are a few ways to do this, but I don't have a big budget and prefer to use easy to service/replace OEM components so I went for the ST185 Celica Turbo Alltrac single piston front brakes.

Sept 4, 2015: Front Brake Upgrade

ST185 front calipers are a single 57 mm diameter caliper, which is a surface area increase over stock 87-89 fronts of 25.9%. There is a twin piston ST165 caliper, twin piston providing a better spread of the forces across the pad and better pad wear and performance, but with each piston being 38mm, it's increase over stock is only 11.9%. Calculating the piston surface area ratio of ST165 front to AW11b fronts-installed-to-rear, it is only a 6.2% improvement over front AW11b caliper + front AW11b caliper.

For these reasons I went with the ST185 and WOW am I ever glad I did this. The car has noticeable more front brake dive and stopping power and brake response has definitely increased. Temperature readings of front and rear still show the rear rotors having a slightly higher reading, but at this time it's unknown how much of this is from the larger rear brake bias or warmer ambient air due to close proximity to the engine.

Sorry for rambling, here comes the pics!!

Side by side comparison. ST185 rotor dimension is 278 mm compared to stock AW11b which is 258 mm. This is a diameter increase of 7.8%. Torque or in this case braking force is measured by the force acting on each brake pad by the caliper times the distance from the center of the rotor (radius). And we've got two rotors and four brake pads. So any increase in rotor diameter is a nice compounded benefit!

Various thicknesses. Keep in mind that the AW11b front rotors shown are used and therefore worn from stock. I love the extra thickness, the extra meat. It's gonna take a lot more heat to warp these puppies and I'm reducing the amount of brake force to my rear rotors so it's a big win-win.

#52

Projects and Build-Ups / Re: The Rebirth

Last post by Sirdeuce - December 01, 2015, 07:59:42 PM

Dirt oval

#53

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - December 01, 2015, 06:54:08 AM

Oh well

Go to "Maui Motor Speedway" http://www.racingin.com/track/details.aspx?s=HI&Address_ID=0411

#54

Projects and Build-Ups / Re: The Rebirth

Last post by Sirdeuce - November 30, 2015, 10:50:24 PM

Oh well

#55

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - November 30, 2015, 07:44:30 PM

Laguna Seca for you! I'm heading to Maui!!

They don't have any paved tracks on Maui!

#56

Projects and Build-Ups / Re: The Rebirth

Last post by Sirdeuce - November 30, 2015, 08:48:28 AM

Laguna Seca for you! I'm heading to Maui!!

[LAGUNA SECA DEC 13, 2015!!!!!!!]

#57

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - November 29, 2015, 10:45:09 PM

Went on a lot of wheeling trips for work and did a ton of marketing.

During this time however I knew I could not go on much longer without getting back on a race track.

So Mike and I talked about it and decided to schedule our next track event for LAGUNA SECA DEC 13, 2015!!!!!!!

Ohhh man this thread is about to get REAL SERIOUS REAL QUICK LET ME TELL YOU!!!

#58

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - November 29, 2015, 10:43:46 PM

And some of this

#59

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - November 29, 2015, 10:42:44 PM

And some of this:

#60

Projects and Build-Ups / Re: The Rebirth

Last post by BigMike - November 29, 2015, 10:40:39 PM

Between May and Sept I didn't have time to do much of anything with the MR2. It even was parked for a few weeks at a time during the summer while I was out doing this: