To boost/improve Yaris, or move on....?

[ROCKLANDTOYOTA]

Originally Posted by Jason@SportsCar

Only you know what will make you happy... But I would start with the basics and work up.

First, better suspension. Get a set of quality coil-overs. The Tokicos are not track worthy, they are an OK street shock - hint, stay away from any adjustable shock that combines compression and rebound adjustments, you will never get the damping curve where you want it. Stick with rebound adjustable shocks unless you really know what you are doing, you can really screw up a car playing with the compression settings.

Swaybars: if you get the springs and shocks right you wont need to bolt a 15lb weight to your rear axle.

Brakes: the stock brakes are overkill for the weight of the Yaris. Upgrade the front pads and leave the rest alone. If your car has a lot of miles, or the lines look suspect, get the stainless ones. We only added brake cooling ducts when we went to the 13" wheels because the airflow is so restricted, we have still never had fade - and this is with a 40min race, not a few hot laps.

Trans: this makes the car, you must get an LSD. If you have the money get the OS Giken, if you want to go cheaper get the TRD unit. BUT while you are in there install the xB 4.312 final drive, it really wakes the car up. You will already be paying the labor (or doing the work) to pull the stock gears when you install the LSD, it is not much more work to swap the gears.

Tires/wheels: 13" wheels make the car a rocket. They give you an even shorter final drive, lower the cg (and help get the roof down out of the air), they are also a lot lighter than the big stuff. Another advantage is you can run a wide 13" tire without it bashing the fenders, no need to cut or roll.

Bolt-ons: Get the header, intake and ecu. You can really unlock some power.

That alone should be enough to take out any stockish Cooper S. If you are not satisfied at that point you have all the basics covered, and now you add the FI.

As far as a radiator, the Mishimoto xB unit pretty much drops right in (you have to drill two holes in the core support), and we used the xB hose set.

what ECU are we to use for just BOLT-ONS???

[Jason@SportsCar]

Originally Posted by ROCKLANDTOYOTA

what ECU are we to use for just BOLT-ONS???

Anything that will let you past the rev limiter, and control the VVTi.

We had a custom harness made that allows us to piggy back an AEM EMS series 2.

There are other options out there, none of which are cheap. But without ECU control any mods, including FI, are compromised.

[Blown_xa]

Good advice was given for sure. If you go boost, keep it at a 40whp gain and no more if you want it reliable on a stock motor for track abuse. I say 40whp gain instead of a specific number because dynos vary. Get a baseline number, and use that same dyno later for reference. I popped rods many times at 150whp (our dyno) and it is never fun to invest $500 entry fee and go home on a tow truck. I must have done 6 Time Attacks at 130whp and never had issues. It was enough power to podium many times in street fwd, as long as you are a decent driver and you have everything else dialed in.

[mazilla]

Great thread.

[TRD.RiC]

Brakes are a must thats for sure. If i can put my input into this id say get braces as a 1st suspension mod. IMO is prolly the best mods done that ive done yet. without them i felt that the body was working too much. i got the 3 underbody brace from UltraRacing and it really feels good now. Just going over a speed bump you feel that the body of the car doesnt wobble as much. The car feels a lot stiffer and when i push it I like the feel that Im into a solid car. I got coilovers and RSB as well but my 1st mod was the braces and I can defenitly say that i got better benefit from those mods that the shitty tein basic coilovers i got

I starting doing some laps in the car fully stock except for advan a032r tires. In a way I am building the car to what my track sessions tells me can be improved. So my setup was the braces ---- RSB ---- Coilover(which I really really really dislike) and alignment at same time. The car is tail happy with me driving but I am really rough on it when doing my inputs. I have to improve that a lot (my racing instructors loves to ride with me but say ill kill the direction of the car really fast.) The front bushing where torn at 33000km?.

Anyway. Go out there do some laps and build it from there is what I would say more than try this try that. We all drive differently and you build it for your driving habits not some other person. It's ur money!

[ilikerice]

I like braces. But I think if you wanna track a car the first thing you should invest in is a roll cage an fire extinguishing system. But I am a little confused what the OP goals are for.
Just simple PDX track events are great and fun and you dont need all the safty equipment.
Then you mentioned autocross which those braces will put you in SM class.
IF you run track events and build it to a specific class there. You may end up in a non competitive class in autocross. Most of the guys who run track events use autocross to dial in thier cars a bit more and just fill in the gap between track events. They usually run Prepared class's.

Depends what type of racing you wanna do to be competitive in.

[cali yaris]

I think if you wanna track a car the first thing you should invest in is a roll cage an fire extinguishing system.

I tracked my car a month after I bought it on stock tires and Tanabe springs. I didn't put a cage in until two months ago. So I will respectfully disagree; you can go have a lot of fun before installing all that stuff.

[why?]

Originally Posted by Jason@SportsCar

The stock setup (flywheel/clutch/pressure plate) is 26lbs, our lightened setup is 18lbs. While it is a significant difference, it is totally street-able. The problem with most race setups on the street is to aggressive of a pressure plate/clutch combo, some of them are an on/off switch. We used a 3-puck solid hub clutch (weighs 1lb), but a very mild pressure plate - its not like we are trying to hold back 300hp - so it is easy to drive. The flywheel alone wont have much impact on how the car drives, it just lets it rev more freely.

1 pound! Do I even want to know how rare and expensive it is before I get my hopes up? Is it something that can last on a daily driver?

[Jason@SportsCar]

Originally Posted by why?

1 pound! Do I even want to know how rare and expensive it is before I get my hopes up? Is it something that can last on a daily driver?

Nothing exotic at all, its right off the shelf from SPEC. The stock clutch disc is only 2lbs, and it is a full disc with a sprung hub.

I can't think of any reason it would not work for a daily driver. The solid hub is not as smooth as a sprung one, but you really only feel it in 1st gear.

[why?]

Originally Posted by Jason@SportsCar

Nothing exotic at all, its right off the shelf from SPEC. The stock clutch disc is only 2lbs, and it is a full disc with a sprung hub.

I can't think of any reason it would not work for a daily driver. The solid hub is not as smooth as a sprung one, but you really only feel it in 1st gear.

Oh, you made it sound like it was significantly less than stock. I go a little crazy with weight reduction. I hate the stock Yaris clutch with a passion, I am pretty sure Garm sells SPEC too. Thank You.

[OTB]

Originally Posted by Blown_xa

Good advice was given for sure. If you go boost, keep it at a 40whp gain and no more if you want it reliable on a stock motor for track abuse. I say 40whp gain instead of a specific number because dynos vary. Get a baseline number, and use that same dyno later for reference. I popped rods many times at 150whp (our dyno) and it is never fun to invest $500 entry fee and go home on a tow truck. I must have done 6 Time Attacks at 130whp and never had issues. It was enough power to podium many times in street fwd, as long as you are a decent driver and you have everything else dialed in.

thanks! I think alot of us wanted this info

[CrankyOldMan]

Originally Posted by Jason@SportsCar

Trans: this makes the car, you must get an LSD. If you have the money get the OS Giken, if you want to go cheaper get the TRD unit. BUT while you are in there install the xB 4.312 final drive, it really wakes the car up. You will already be paying the labor (or doing the work) to pull the stock gears when you install the LSD, it is not much more work to swap the gears.

What parts would have to be swapped out for this? I'm assuming that it's not just the drive/driven pair for 5th gear (circled in red), but a different gear that mates to the LSD or driveshafts? I'm having a hard time getting a good picture of the gearbox from these parts diagrams.



Looking at the C50 repair manual gives much better illustrations, so I'm thinking it's actually the gear that attaches to the differential? If so, then wouldn't the entire output shaft also have to be replaced?

[Bluevitz-rs]

Originally Posted by CrankyOldMan

Looking at the C50 repair manual gives much better illustrations, so I'm thinking it's actually the gear that attaches to the differential? If so, then wouldn't the entire output shaft also have to be replaced?

Yes.

[cali yaris]

+1, the final drive + the output shaft.

[fnkngrv]

This is an awesome thread and giving me much more useful info than I knew about this car. It could greatly shift my plans. Great way for the OP to start things.

[CrankyOldMan]

So after poking around for part numbers with the xB transmission, it looks like in '07 they went with the E351 instead of the C50 (due to engine change). This would mean that only an '06 or older xB/xA tranny would have the desired output shaft and gear ring? (I looked into the part numbers and they match for xA/xB).

How can it be the same transmission (C50) if it has different gear ratios inside? Seems like that would warrant a sub-designation or something to make it apparent, especially if I were to go to a junk yard and try to find one.

[cali yaris]

Jason posted the xB part numbers needed:

If anyone is interested in the parts needed to do the xB final drive (4.312) swap:

33321-52110, output shaft
41221-52270, ring gear
90105-11040, ring gear bolts (8)

[CrankyOldMan]

Originally Posted by cali yaris

Jason posted the xB part numbers needed:

Is there a difference between the old/new parts? Some sites don't have the new numbers, so here's the old ones:

33321-17011, output shaft
51221-12340, ring gear
90105-11040, ring gear bolts (8) (no change)

At this point, I'm going to either make a new thread or keep chasing these ideas on the xB final drive swap thread