If you've ever raced a car with an open differential, you know how frustrating it is to run around the course with that inside tire loosing its mind. You focus on the braking zone, execute the set-up, hit the apex, then mash the accelerator and....nothing. Ok well not "nothing", you car is doing the best it can with its original basic hardware. You have to time your inputs perfectly, be conscious of the surface condition, and wait.....for what seems like forever to go full throttle again. Not only is this slower, but it wears down the tires faster from all the wheel-spin. Super lame.
Now what if I told you it doesn't have to be this way, WHAT IF all you had to do was plant your right foot and steer? Let me share with you a genius product from CuscoUSA.
The RS Model has small coil springs between the pressure rings, constantly applying some pressure to the clutches. This results in a lower break away torque and minimal loss of this initail torque over time due to wear. The benefit of a lower(51-65ftlb) initial torque is a gradual and quicker clutch activation, smoother turn-in, an overal stable operation.
Not only is the RS completely rebuildable, they are also fully customizable! You have the regular options of 1-way, 2-way, or 1.5-way....but there is more! You can have custom ramp-up angles, preload springs, clutch discs, and even have them WPC treat the gears inside! Don't feel like you need to make all of these decisions on your own either, the crew at Cusco is more than willing to evaluate your situation and make suggestions. I've always felt super grateful for their amazing motorsports support, and I let them decide on my settings every time. Not once have I received anything less than a perfect product from them. You will have to re-tune your suspension once you switch from an open diff to the LSD.
The difference between an open differential and the this Cusco clutch-type LSD is like night and day. The first time you drive the car after the install you need to do the break-in procedure, then change the fluid. There is a definative difference in how the car turns while accelerating, you will feel the LSD lock and pull the car in the desired direction. If you decide to stab the accelerator with the wheels turned you better be prepared and have both hands on the wheel, in dry conditions the grip is INSANE! However in icy conditions you will still need to be careful, because you now will spin both front tires...and that means zero front grip.
Autocross is the perfect way to test a car, you have many different elements to master and usually not the most ideal surface. You need to accelerate at full blast through the first element, then a slalomn, throw in some turns and another slalomn...you really NEED both front tires to do their job. Iv'e raced this car the longest with an open differential, and it teaches you to give up throttle in places where the front starts stepping out. Its extremely frustrating, but there is a solution. The Cusco unit is best described as magical, since it effectively eliminates all of these traction issues. You no longer have to be gentle with the throttle, just set the arc and keep the throttle down...seriously. This is why we jokingly say "just mash the gas and steer", because now the LSD is HELPING the car turn.
The grip on a racetrack is a bit easier to manage, with an open differential you can expect to start spinning that inside wheel when trying to drive off the corners. The only thing to do is just make sure you have a good line and be patient, momentum and precision are the game plan. Once you have the Cusco LSD things change a LOT, you still need to set the arc in the turn but this time you get on the throttle right after braking. You no longer need to worry about the front losing grip and sliding, that doesnt exist anymore. Now you can hold the gas down and it actully keeps pulling the front of the car in the desired direction. The game has now changed to " whats the fastest I can enter the turn and not fly off?", because now you wont have to give up speed anywhere else but the entry!
There are many things you can do to a vehicle to make it faster; more power, weight reduction, fine-tuning the suspension....but all of these upgrades will still leave you with a incomplete build. A ton of power doesnt help much if youre spinning a tire the whole time. This is why I am such a gearhead, I've learned how much of a difference gear ratios and a winning LSD make. If you want to know my opinion on what makes the biggest improvement in a race car; hands-down it's having a Cusco LSD. Check out the comparison video below!
You guys may know by now that I performed a C60 swap into my 2zrVios last December, and have done a bunch of highway and autocross testing for the past 5 months. On the street the 6 speed was awesome, the only time it ever had traction issues was in the rain. Autocrossing with this gearbox was quite frustrating though, the 4.5 final drive and short ratios resulted in a ton of wheelspin. We knew we needed an LSD badly, so I contacted my friend Kenji at CuscoUSA and placed an order. Once the LSD arrived, we did an unboxing video HERE and pulled the gearbox from the Yaris to start the install.
During the disassembly process (VIDEO) is when we do a majority of the inspection and take measurements, this way we know what parts need to be ordered while the gearbox is completely torn down. I created a thorough blueprint booklet with images where you can log all of your measurements and gearbox details. If you want a copy just send me a message. Once you place the order for bearings and synchronizers, now is the perfect time to send parts to be WPC treated as well.
Now that you're waiting on parts, take this opportunity to strip the case down completely and clean it. You want to de-grease it and clean all of the tiny areas where metal debris and tarnish may accumulate. Once the case is completely clean of oils, you can scrape off the old sealant and chase the case bolts/threads with an 8mmx1.25 tap and die. This is to clean the threads providing consistent fastener torque. Next, I blow all of the debris out of the case with shop air then cover it to prevent dirt intrusion before assembly. Check out the video HERE
If you remember 2 years ago when I shared my C50 build, then the Cusco Type-RS LSD will sound familiar. Again I did a ton of research on every type and brand of LSD to make sure the right decision is made. The TRD helical LSD and the Quaife are nearly identical in design, and I passed on these after many reports of wheelspin and an "unloading" in race applications. So it came down to KAZZ and Cusco, and with how awesome the unit in the C50 did I went for the RS again. This time, however, Cusco and I agreed to increase the ramp to 45 degrees and try the 1.5 way. ALL THE GRIP!
The AR-Differential Install Kit
Since I've built several of these boxes now, I figured it would be easier for everyone else if I put together a kit including the bearings, seals, and instructions. This way you guys won't need to go to the dealership and point out the parts you need on a diagram(and likely the counter guys make a mistake), you'll have the correct Toyota part numbers! (VIDEO) Once you transfer the ring gear and speedometer drive, install new bearings, put the assembly in the case, torque the bolts, and check preload (VIDEO). Then if your preload measurement is out of specifications, this kit will have the numbers for the shims as well! Easy Peasy. I also recommend investing in one of these high-quality magnetic plugs from Mishimoto, I didn't want to risk buying a cheap part and have my gearbox destroyed if it detaches. Make sure to put the plug in the FILL port only, since there is not enough differential clearance at the drain port. The link is to this part is HERE.
There have been many instances where C60's have suffered a broken 3rd gear under drag racing conditions. I'm not the type that enjoys this straight line racing, but in the Pro-Solo environment we do have a drag-style start. I measured all of the gears and sent out the 3rd and 4th gearsets based on their tooth width being the lowest. I also decided to have the output shaft treated due to rare instances of tooth breakage. If you want to learn more about WPC treatment and see the friction test video check out my write-up here: leave nothing to chance.
Now it's time to put it all back together, make sure you pay close attention to the install direction of every single part. Gears, Synchros, shift hubs, and even clips must be installed in a specific orientation. One mistake during the assembly process and you could be missing a shift or even have an immediate failure. Pre-lubricate all of the parts and take your time, feel free to use my videos of the assembly process here:
Input Shaft Assembly
Output Shaft Assembly
Final Transmission Assembly
Fluid And The Break-in Procedure
Once you have the transmission back in the car, special attention needs to be given to the fluid you use. All clutch-type LSD's require a unique formula of friction modifiers in the fluid to prevent disc sticking and chatter. I know you can take the risk and use whatever fluid you want and add a modifier to it, but that's outside of my comfort zone. I always just pay more for the recommended Cusco Mission Oil. If you installed a Quaife or Torsion differential then no special fluid is required, since these differentials only contain gears. Once the gearbox is full of the correct oil, it's time to perform the break-in procedure. Break-in for clutch-type differentials is a process similar to breaking in your clutch or bedding brakes. You want to slip the friction surfaces in a manner that results in a surface conformity of the discs, while also maintaining optimum temperature. After the process you replace the fluid and carry on, as usual, you can watch my video on the whole process below.
I was scrolling through the "poor" section of Craigslist autos one day helping a friend look for a cheap car, in the $1000 or less ads. Most of the cars in this range either don't run, don't drive, or have been crashed. This is the perfect place for someone like me to find a ride since I've become proficient at sourcing cheap parts and performing the required repairs. I've bought and fixed many cars by now in this manner, but usually regular sedans and small SUV's. When I saw the ad for this Celica I knew right away I had to save this one too. It had a blown engine and something wrong with 2nd gear, serious issues but nothing I can't handle. I e-mailed the owner and we agreed on a price, so I called my buddy Rubin at JDTE Towing and we made the hour long drive to pick up the car.
We arrived at the owner's gated community around 9am to pick up the car, after getting buzzed in we spotted the car right away. Dan(the owner) met us on the driveway and we introduced ourselves, after a brief talk I asked to look at the car. They brought out the only key and unlocked the door, I popped the hood and looked around inside noticing several trim pieces missing. It was obvious this car had been dead for a while, there were plenty of spiderwebs and a good amount of dirt inside and out. I finally go check out the engine and notice right away that someone had tried to fix this car, several broken plastic parts, oil residue everywhere, and things out of place. We were able to find some of the interior parts in the garage and then decided to settle the purchase.
Dan and Andrew were really honest and pleasant to do business with, that's always refreshing given the atmosphere of Craigslist. Turns out that Dan is an author and actually signed one of his books for us, its always cool meeting creative people. We made the hour long drive back to SD and dropped the car off at the shop, I paid Rubin and we went home. I didn't look the car over again until the following Monday.
The first thing I did was buy a composition book to log every issue I find along the way. I looked over the interior and exterior and wrote down everything missing or broken, later that night I looked up the prices on all of these repairs. Next, I decided to verify the issues with the drivetrain, I put the battery booster on and started the engine for the first time. Right away everyone in the shop knew for sure this engine had rod-knock, and sadly it hadn't just started. This knock was pretty bad and the engine struggled to idle, soon stalling out. So I fired it back up and checked the clutch and gearbox, it has reverse and first and moves fine in those gears. Second gear, however, is completely gone. No matter how hard I hold the shifter in position, once the clutch is released it just grinds and grinds.
Now that I'm fully aware of all issues and know exactly what I need to fix, I removed the drivetrain. I've never owned a Celica before, so all of this is a learning experience for me even though its similar to my Yaris. I will continue to provide updates as we progress on this car, stay tuned for the results of the engine and transmission dissasembly.
If you're not familiar with the WPC process, I'll describe it based on what I've learned from their website:
WPC treatment is not a coating that can wear off, the process results in a micro-dimple surface that reduces friction and strengthens the product. They "fire" an extremely small media at parts extremely fast, to compact the surface at a microscopic level. These dimples then serve as oil reservoirs that hold oil in place when the equipment is not in use. This process is similar to shot peening, but instead of using beads, the media resembles a fine powder. This results in a surface treatment that increases strength through thermal discharge, sealing up minor surface cracks and tool marks from machining...without a resulting dimension change. The surface becomes condensed with improved density, and this overcomes the issue of brittleness associated with "hardened" parts.
One of the things I was really surprised by was the packaging, individually sealed and branded parts bags! Now I had seen some pictures of this packaging on the internet before, but only for a new set of treated gears. I had no idea they gave every product this special treatment, however, it's completely necessary to protect the gears after treatment from corrosion since they're now bare metal. Make sure you package your gears well when you send them to WPC because they send the finished product back to you within the same materials.
Once you open the packaging, the first thing you'll notice is superior cleanliness. WPC does mention that you need to thoroughly clean the components yourself to remove any possibility of leftover media. After cleaning the parts you also need to apply a layer of lubricant so that no surface corrosion can form. This is really no different than handling untreated parts, any bare metal part will corrode if left unprotected.
I did a lot of research on what commonly fails in the C60 6-speed transmission before finishing up the Cusco LSD install. The last thing I wanted was to put a new differential and bearings in this box, then have to worry about launching or adding power and having a failure. After posting my first few C60 videos the comments started rolling in, and they all had a similar context. Google, YouTube, Facebook....they all yielded the answers I was looking for; 3rd and 4th gear. Most people break third gear in drag racing situations, apparently wheel-hop causes these kinds of breakages. I measured all of the gears in my WPC prep video and found that the third and fourth gears were thinner than all of the other gears. The 5th gear set was 15mm whereas 3rd and 4th were 13mm, so I skipped treating 5th since 1st and 2nd are also 15mm yet never have an issue.
When I was searching the far corners of the internet for every possible C60 failure, I came across a few images of broken output shafts. All of these instances again involved drag racing. I believe the issue is due to the physical size of the pinion teeth since the C60 has the most aggressive final drive ratio of all the C-transmissions. The easiest way to distinguish a 3.9FD from a 4.5 is to simply look at the teeth, the tooth profile in the above image may look identical but did you notice the 4.5 on the right has the bearing race removed? The 3.9 shafts have 8mm of tooth vs the 4.5 shafts only having 5mm(refer back to the first image also).
I chose to only have the known weaknesses of my transmission treated since I'm not wealthy, but you can have all of your components done. To get the 3rd and 4th gearset, and output shaft serviced, with shipping, tax, and insurance it cost me $182. To me, that was a steal for all of the benefits you will gain. WPC advised me beforehand that it would be "about" $500 for all of the gears, both shafts, and the ring gear. Keep in mind though that shipping will be more due to the increased weight.
I don't know anyone personally that has had any gears treated by WPC, nor do I know anyone that has broken a C transmission. Like I mentioned, I wanted to feel at ease that I've done everything possible to ensure this gearbox survives abuse. I was also excited to see the WPC results myself and run my own test. Overall I am extremely happy with the whole experience, customer service, attention to detail, and an awesome end product. Huge thanks to Izumi Ogawa for streamlining the process. You can see my video below:
The DR-Type coilovers from BC Racing use digressive valving, this means they rely on high flow pistons and preloaded shim stacks in order to get high, low speed damping forces(~2 in/sec). The pistons flow enough oil that the shims control the valving profile, and at high shaft speeds oil flow through the piston is not restricted. This provides decent force ramp up from about 20 in/s and higher, but less than linear and progressive valves. "Cornering" happens at ~2 in/sec so the digressive shock will have better feel and control in most road racing applications. Refer to the comparison below:
With the technical points out of the way, lets talk about my experience with these on the Toyota Yaris. When you order a set of Yaris DR-Type coilovers from BC Racing you can get the standard 5K front/ 3K rear spring rates, custom BC rates, or the SWIFT spring upgrade with custom spring rates. The INSTALL for this suspension upgrade is straight-forward and only requires basic set-up for most. We tested the standard spring rates first to see how they perform, then made changes. Check out the DR damper dyno graph below:
On The Street...
On the street these spring rates were perfect. We started with the dampers right in the middle at 16 clicks, but the ride was very harsh. I turned them down to 10 clicks and the ride quality was nearly identical to my previous Tokico damper feel. If you want coilovers just to slam your car and maybe attend an occasional autocross, the BR-Type and standard rates may be more suitable for you
At autocross these rates were not so great. The 5K front was fine, but the 3K rear had us completely maxed out on the dampers to get some rotation. We went to a 5K rear swift spring to try a square setup, and the car starts rotating perfectly around 5 clicks front/16 clicks rear. Then we tried adding a UR BRACE to the rear of the car to be sure we weren't losing spring performance due to chassis flex. There was just a bit more rotation after the brace so we decided to stay with the square 5K spring set-up.
At the track this square setup felt amazeballs, but I turned all of the dampers down to 5 clicks to be sure the car stayed nice and predictable. Even at this low setting the car did great and you could still get some rotation with a little flick of the wheel. I have no doubt a more talented or fearless driver could crank up the damping and toss the car around this course faster than I did.
Why Swift Springs?
When you order a set of coilovers from BC Racing, you will have the choice of; Standard spring rates, Custom BC spring rates, or the Swift spring upgrade. Now I can imagine you are curious like me as to what the difference is between the BC and Swift springs, so I'll drop in a description from the Swift website below:
...So you see, It's about getting the absolute best performance out of your suspension. The Swift springs are extremely light, holding them in comparison to the BC springs will make you wonder how they hold the weight of the car. The evenly spaced coils and linear spring design results in more predictability and control through transitions, unlike the increasing rate of a progressive spring. If you're like me and do an excessive amount of research and planning, you will always have the thought in your head that your leaving time on the course because of that "one last thing". For me it was not having Swift springs or corner balancing, but now we're finally there. For the front you need the 8", 60mm ID. The rear is a 6", 60mm ID.
Do you really need to corner balance?
The answer to this question is based on how you use your vehicle. If your're never going to do any type of racing, then odds are you dont need it. But if youre racing like me and want to ensure the suspension is operation at its absolute best, to squeeze every tenth out of your tires requires a properly balanced car. A drivers weight ballast is placed in the car with the race tires on and fluids at their normal levels, then the spring perches are adjusted to achieve an optimum 50/50 cross weight balance. Suspension geometry, ride heights, and rake are all verified at the same time. Once this procedure is complete, a wheel alignment is performed, resulting in a 100% optimized suspension. I was able to notice the difference right away after the corner balancing, a smoother ride and easier slide recovery being the main benefits.
The main take-away here is that you should consider the intended use and future plans for your vehicle before deciding on a suspension system. I thought I never really "needed" coilovers until I started doing WEIGHT REDUCTION and changing the cars balance, but I'll tell you you...that was a miscalculation. The ability to fine tune the suspension has been one of the most beneficial upgrades to this car, and I'm still impressed to this day. BC Racing Coilovers AND Swift springs....highly recommended. Then when you're ready to get serious, get that corner balancing done.
Connect with me