Mazdaspeed 6 KSport Big Brakes! Posted on 18 Apr 19:44
Trying out K Sport's big brake kit, install and first impressions!
Trying out K Sport's big brake kit, install and first impressions!
If you've been following Chicago Car Life's social media feeds, you may have seen my RX-7 pop up a few times. I did an impromptu photo shoot with it a while back, and while it is not as in depth a shoot as I would normally want for a feature car, I wanted to get the back story of the car on the blog. I owned a couple of modified Honda Civics previous to this car, and the modding/go fast bug bit me hard. After I was forced to sell my 00 Civic for need of more doors (new little additions to the family), and my more heavily modded 92 Civic HB was stolen, I was on the hunt for the "next thing". As much as I really enjoyed the Civic's, I did not want to go back to one for fear of having another one stolen, and I was determined to have something that was a purpose built sports car. This eventually led me down the rabbit hole of RX-7's, mostly lured in by the odd yet fascinating rotary engine. The first generation FB seemed too old tech, the third generation FD seemed too complex and costly, so the FC fit the Goldilocks model perfectly, just right.
My searches turned up this TII model in Connecticut, and having an inspection I set up come back good, I decided to make the deal. It was late April, and I decided I would fly out on a one way ticket and drive the car back home to Chicago. I flew out, inspected the car (poorly I might add), drove it through some winding, sandy roads in the rolling hills of a CT suburb and I was immediately smitten, and bad. I began the long trek home with a huge grin on my face. The weather started off as a cool, gray and misty rain in Connecticut but as I crossed into NY, progressed to a heavier rain, and a fairly heavy wind. About halfway through NY, it was now a downpour with flooding in the area, and heavy winds that had put at least one truck in a ditch. A bit unforeseen, but I soldiered on. As I transitioned into Pennsylvania I had some...concerns. It had begun to snow lightly. It was at this point during a fuel stop, that I realized my tires were a summer compound, and also not at all the amount of tread the inspection said they were. Unfortunately I was dealing with somewhat worn front tires, and nearly bald rears, all summer tires. A bit worrying, but being late April I assured myself this would be a light snow that blows over quickly and I could manage. I was wrong, and hours later I would find myself crawling at a snails pace behind a plow truck in Pennsylvania high country, with very little of anything around. Snow was accumulating by several inches on the road at this point, and traction was nearly non-existent. I found the value of fog lights in the now heavy snow fall that also cut visibility dramatically. I found the value, because I didn't have any fog lights at the time, and it was like driving through a series of white curtains, hoping there was nothing to hit on the other side. Traveling at about the pace of a bicycle now, it had gotten into the wee hours of the morning and I resolved to stay overnight somewhere in OH, hoping the storm would blow over and the April morning sun would erase all evidence of it happening.
I was awakened the following morning by the familiar and at this point, horrifying sound of plow trucks clearing the motel lot. Yep, still snowing, and with over a foot on the ground I had no idea if this thing would get me home. I spent about 30 minutes trying to find a clean enough path with no incline to fight against, and managed to somehow get out of the lot and onto the interstate highway again. The snow let up and visibility was better, but the road was a slushy mess so I was still moving pretty slowly. I struggled on, and the road conditions gradually improved, and when I was greeted by sunny skies in Indiana, I knew I would make it home. I did, and having survived this journey, made my bond to this car that much stronger. It washed away any regret about the condition of the tires, or many imperfections I would later find. I just loved that it felt like nothing else I had ever owned before.
I would continue to drive it and enjoy it for the next year or so, and that would begin a second chapter of it's life... Eventually a small coolant leak that I was negligent in fixing, led to the engine running a bit too hot on a couple of occasions. I started noticing starting the car became more difficult, idling a bit more erratic, and it would stall at times. This led me to test engine compression and unfortunately the numbers weren't great. I probably could have run it for a while as it was, but I decided to pull the engine and rebuild it. I got as far as removal and tear-down, but life circumstances intervened and I had little time and no money to continue the rebuild. The car sat for two years before I could begin thinking about rebuilding it again. Of course at this point, I was now thinking it was going to need more than just a fresh engine, and project escalation began. What proceeded was several more years of amassing new parts, stock and aftermarket, upgrades wherever possible, all with the goal of building a completely refreshed and "OE plus" version of my TII FC. After seven years of sitting, I now had enough parts amassed and some time to allow me to start the process of restoring it. Everything came off the car, I removed some rust and repainted where an ABS module leaked brake fluid, new OE brake calipers went on, all of the mods in the list were almost entirely during this time, all at once. The work moved slowly, and many of the hours spent were on the engine rebuilding itself. I had gotten closer to completion, but now was faced with having to move to a new home, but the car was not ready. In a rush, I cobbled everything I stockpiled for the car onto it or in it and ended up shipping it off to Banzai Racing. It was a three quarters complete basket case when they got it, and they did an amazing job of piecing the remainder together and sorting some issues that I had not realized were there. I would get the call that it was ready, on my birthday fittingly enough. Thus began it's second chapter in life, and my second favorite road trip home in the old FC.
Since then, I have had to sort a variety of issues that have popped up along the way, mostly brought on by mistakes I had made installing the engine to the transmission. As it sits now, it is finally sorted well enough to get it tuned. I had been running it very gingerly on a base map tune for the last two years while breaking in the engine extremely slowly (it was tricky getting many miles on it for various reasons). It is due for it's dyno tuning session soon, and I will have an update in the very near future. It has been an extremely long journey for this car, but completion is near. I am now looking forward to putting it to track and autocross duty, as well as the occasional joy ride, everything I spent all the time and effort building it for.
1989 Mazda RX-7 Turbo II
13B-T engine rebuilt with new OE Mazda seals and bearings
APEXi power intake filter on custom intake
BNR Turbo stage 2
Top Speed single exit 3" turbo back exhaust
Injector Dynamics 725cc primaries and 1000cc secondaries
Deatschwerks fuel pump
APEXi dual chamber blow off valve
GM 3 bar MAP sensor
AP Engineering APEXi Power FC w/ commander
Mazdaspeed competition engine & transmission mount bushings
Mazdatrix short shifter
Ground Control coilovers
Bilstein custom valved struts and shocks
Mazdatrix DTSS delete
Infini IV front strut bar
RE Sugiyama three point rear strut bar
Custom front suspension lower tie bar
Mazdaspeed competition lower control arm bushings
Goodrigde stainless braided brake lines
OE replica front lip spoiler
Carbon Fiber sun roof
Carbon Fiber radiator panel
Mazdaspeed steering wheel and horn
Sparco racing seat
-photos and writing: Robert Sixto
I realize I left this topic hanging, and never really had a complete conclusion to this piece, so here is my updated revision on the topic:
In this installment, I will cover the major task of removing the rear subframe and differential assembly on my Mazdaspeed6. The complete removal of the rear subframe makes replacing many of the parts easier as an individual job, but even more so when replacing several of them at once.
Nothing like a box stuffed with automotive goodies!
Most of the parts being installed will be employed to replace old worn out original components. The Corksport rear differential mount, replaces the old and very worn original OE Mazda mount; a DriveShaft Shop rear passenger side axle to replace the original factory axle that had torn boots and worn joints (the driver rear has already been replaced with a DriveShaft Shop axle for the same reason); a pair of Corksport front upper control arms to replace the worn factory originals; and a Whiteline rear sway bar as an upgrade to the OE Mazda bar since everything would be apart and easy to access. Finally, some Prothane sway bar bushing brackets would eventually go in place as well, an important step with this combination of parts. More on that later. The front upper control arms from Corksport, are some great looking pieces, they offer some additional camber adjustment, and increased rigidity in the bushings they employ. Install was a snap, with no real mishaps in the process. Long term, I had noticed the adjusting bolts develop some surface rust rather quickly, but they appear to be holding up OK.
Looks so nice and pretty before install...
On to the real meat of the job, the rear subframe removal. I must credit the great resource that is this post on nemotorsport.com. It is a fantastic, step by step guide, that I used throughout the project. I moved slowly and deliberately through each and every step, which was really a necessity for a job of this scope on my first attempt. Also bear in mind, this car is now over 10 years old with over 100,000 miles on the clock and many winters worth of salted streets. The rust is plentiful! Patience is essential in avoiding any broken bolts along the way (which still ended up happening to one bolt). The how-to from the forum is really as thorough as it gets, and made the whole process relatively easy. I was able to have the subframe removed and on the ground within a few hours, even with a relatively slow and cautious pace.
After a few hours of battling rust and grimy bolts, the subframe was out!
With the entire rear end assembly removed, this was to be a good opportunity to replace the rear differential mount, the rear sway bar, and the rear passenger side axle. Since all these components are anchored to this assembly in some form, in theory at least, the install would be a breeze. It is worth noting, my H&R sport springs, which have been on the car for at least 70,000 miles and probably about 7 years now, are holding up incredibly well. The paint on the springs shows no signs of age other than dirt, and I don't see any corrosion setting in as of yet. That's no small feat for a car driven in Chicago winters with all the slush and road salt it sees annually.
You can see apparent here, lots of rust and lots of CV joint grease spattered on the assembly
Onward with the install which was easier with the entire rear subframe removed, but there were definitely challenges. Really one challenge, the passenger side axle replacement. I had not mentioned earlier, but this was actually my second attempt at replacing this same axle. A previous effort fell short when simply hammering the axle would not free it from the hub. Being pressed for time, I simply left the job for another day. So for this go around, the hammering continued, with copious amounts of fire, several rounds of PB Blaster spraying, and lots more hammering (with the help of a friend to basically tag team the damn axle!). The axle was quite stubborn, and literally moved fractions of milimeters at a time, for a long time the progress was imperceptible to the eye. The amount of hammering needed, caused the end of the axle to mushroom out so severely that I needed to grind the excess metal in order for it to clear through the hub once freed. We lost easily an hour and a half to this axle alone.
Eventually everything was removed that needed to be, and replaced with the new upgraded parts. Fitment of all the aftermarket parts was spot on, and went together with ease. I even did a bit of rust removal on the under body and sprayed on a couple coats of 3M Rubberized undercoating for both it's sound deadening and rust preventative properties. I also repeated this on the subframe, giving it a healthy coating of Rust Bullet. After all the paint and undercoat dried, the process of lifting the rear subframe back into place went ahead slowly and carefully. The theme of taking my time was once again at play, as I wanted to be sure nothing was left loose, pinched, cracked or otherwise broken in some way in the act of sandwiching everything back into the underbody of the car. Once all the work was completed, it was time for the test drive. This test would reveal a critical issue that is key to having both the Drive Shaft Shop axles and the Whiteline rear sway bar. What you might not notice in the photos above is just how close the axles sit to the sway bar, the bar essentially wraps around the axle. When you have these beefed up versions together, the clearances become almost zero, to the point where the axles will bump against the original factory sway bar brackets. Luckily the bumping merely tore a CV boot and caused no catastrophic damage. The remedy is simple, Prothane makes a universal sway bar bracket and bushing set that fits perfectly and restores factory like clearance. I have been trouble free for over 15,000 miles since.
Long term driving impressions:
I have really no complaints with almost a year and 15,000 miles of driving, everything has held up well. As for performance, nothing in my opinion took away from the performance or comfort. Little, if any, noise or vibration was created with the addition of these parts. The real performance stand out, is the Whiteline rear sway bar. I can say emphatically, that this is how it should have been delivered from the factory. The cornering grip and the way it rotates now is better than I would have imagined it could be simply from replacing the rear sway bar. I would consider this modification a must if you really want to extract the best handling from this car, even if you already have lowered and stiffened it via springs/shocks or coilovers. The customer service stand out, was definitely Drive Shaft Shop. You may have picked up on the fact that I was not aware my new sway bar would rub against the Drive Shaft Shop axles, and sure enough I tore open a CV boot as a result. A call to Drive Shaft Shop, just to price out the replacement boot and ask about how to replace it, was met with courteous and eager help from the staff. Not only that, but they even ended up sending me that replacement boot kit free of charge! I never asked for even a discount, as I took full blame for the mishap, but they made the gesture anyway. That is something that really makes an impression for me, and I would never hesitate to use their products and services in the future. Be sure to check out more Mazdaspeed 6 modifications, like my big brake upgrade!
-photos and writing: Robert Sixto