Back on Track

[Victorofhavoc]

So turns out motive didn't have an acura specific adapter for their power bleeder. Instead I bought a top off Amazon, then some tubing and a barb to threaded fitting at the home depot racing. This will work just fine, but sadly the tubing is only vinyl and that is not great for passing brake fluid through. I only used my power bleeder for pressure anyway, so not a problem for me.

First time I pumped it up, it didn't seat properly and it blew off, throwing fluid everywhere. Yuck! Second time I tightened it up a bit more and it held 15psi fine. Should do the trick!

For anyone else planning on doing brake fluid, the clutch shares the same reservoir, so you have to flush and bleed both. I hate these kind of designs.

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[Victorofhavoc]

I'm going to be playing with mounting soon, actually. I've thought about the back glass with a greater focal length, but it won't capture enough of the driver. The most ideal place is like 3" behind the driver's ear. I might rig up a pvc pipe with some zip ties on the passenger headrest.

My roll cage in the racecar is 1.5" and that's where my gopro mount is sitting today, so I bought some 1.5" pvc. It should zip tie up fine to the passenger headrest, and then I can use it to mount the gopro to.

 

[StingertimeNC]

Crap, bleed the clutch fluid too? This is the first I'm hearing of this. Is that easy to get to?

Also, back to heat cycles on tires, I assume they only really go through the cycle on a track session, and not on the street, right? Typically driving around town I see about a 2 psi pickup in pressure vs track of say 5-7psi pickup. My plan is to eventually switch to 200TW and just drive on those even around town. I do not need to drive the car daily, or have a commute or anything, but it is my get around town car. Bad rain and low temps can be avoided. If running errands would count as a heat cycle then that's going to speed up the useful life.

 

[Victorofhavoc]

Crap, bleed the clutch fluid too? This is the first I'm hearing of this. Is that easy to get to?

Also, back to heat cycles on tires, I assume they only really go through the cycle on a track session, and not on the street, right? Typically driving around town I see about a 2 psi pickup in pressure vs track of say 5-7psi pickup. My plan is to eventually switch to 200TW and just drive on those even around town. I do not need to drive the car daily, or have a commute or anything, but it is my get around town car. Bad rain and low temps can be avoided. If running errands would count as a heat cycle then that's going to speed up the useful life.

Yeah, it's part of the same fluid system, but north of the abs pump. Clutch fluid won't move as much as brake fluid, but if it boils the bubble will go up and they often carry contaminants from the superheated fluid with them. They will travel up through the system and can get to the reservoir. If you're doing minor track side bleeds, I wouldn't worry about it, but if you're doing a yearly flush it matters.

It's a bleed valve on the bell housing and not hard to get to, but I wouldn't do it while hot because you have to go past the downpipe and elbow deep. You need a much longer drain hose for the nipple than you'd typically use for the brakes. Look past the DP and you'll see a little black nipple coming up and forward, right on the housing. After you see it, you'll never miss it.

There's a lot of theory around how street miles effect high performance tires. If you're competing, you just don't mix. If you're just doing it for fun, then you have to do what's easiest for you. Basically, those micro heat cycles you're rarely going above 170F, and typically a highway drive is like 140F. It's not quite hot enough where it produces that higher grip and faster wear, but the rubber is still being effected. Each time it heats up and cools the rubber molecules "resettle". The rubber still gets less grippy over time, but not quite at the pace of a full heat cycle impact. The weird part is the sidewall. While it gets the biggest brunt of flex/Heat on track, especially under braking, it takes a lot more punishment on the street with potholes, ruts, curbs, etc. It won't heat cycle out like the compound will, but it will "wear" out and become softer faster with a lot of heavy street miles.

Doing 1 or 2 days per year, tires like the ps4s really shine. They give up high heat resistance and a lot of sidewall stiffness for being a comfier and grippier street tire, but this also lends well to playing in their optimal operating range without tremendous fall off longer term. Meaning you can hit the track 5k miles in on the tire and still get to 1G in corners, as long as you're not overheating them on every short drive either. You can treat every 250-300 miles on the street like a "heat cycle" with a 300tw tire. 200tw tires are not as kind. They're more 150-200mi being like a heat cycle, and after 2-3k miles they'll perform the same as a ps4s.

 

[StingertimeNC]

Awesome, thanks for the input. I haven't forgotten about the other message I sent you by the way, just haven't had time to respond appropriately.

 

[RamVA]

For anyone else planning on doing brake fluid, the clutch shares the same reservoir, so you have to flush and bleed both. I hate these kind of designs.

It's quite dumb and annoying to set it up this way. Are you sure the clutch must be bled if you change the brake fluid? In concept you could leave it alone, and live with some DOT3 fluid in the system (as long as it hasn't boiled). I don't think there's much fluid in the clutch line.

I can't think of a good reason to run high temp fluid in the clutch line. It only increases maintenance cost, and possibly shortens the life of the slave cylinder. I'm sure they had their reasons, but it's not a great setup to have the brakes and clutch share fluid.

 

[Victorofhavoc]

It's quite dumb and annoying to set it up this way. Are you sure the clutch must be bled if you change the brake fluid? In concept you could leave it alone, and live with some DOT3 fluid in the system (as long as it hasn't boiled). I don't think there's much fluid in the clutch line.

There's not much fluid in it, no. If you're just driving around town it's not a big deal. If you take the car on track with stock fluid, it will boil. Mixing fluids is just no good though. It's not like they stabilize between the two, they just contaminate each other.

 

[RamVA]

There's not much fluid in it, no. If you're just driving around town it's not a big deal. If you take the car on track with stock fluid, it will boil. Mixing fluids is just no good though. It's not like they stabilize between the two, they just contaminate each other.

Ugh. I guess I'll leave it alone, then. This car might see one or two track days. Would you agree that the clutch line doesn't need high temp fluid? It's just a consequence of the design choice?

We have two dedicated track cars with DOT4 fluid, and keeping on top of it is not fun. We flush them at least once a year, depending on how much action they've had.

 

[Victorofhavoc]

Ugh. I guess I'll leave it alone, then. This car might see one or two track days. Would you agree that the clutch line doesn't need high temp fluid? It's just a consequence of the design choice?

We have two dedicated track cars with DOT4 fluid, and keeping on top of it is not fun. We flush them at least once a year, depending on how much action they've had.

It depends on how much shifting and wot you're doing. The clutch slipping causes heat in the fluid, but the clutch gets hot from constant wot abuse as well. Clutch fluid doesn't boil as fast as brake usually but it certainly can depending on how much you're using it. These cars do make decent torque after all.

Once a year flush is probably about right.

I agree with you, though. It "shouldn't" boil. You can ignore it and see how it does, but if you have experience and you take it out you won't be satisfied pushing it 60% so you know you might boil stock fluid. Thankfully if you've already got pressure on the master for bleeding your brakes, what's another bleeder to touch? There's already 6 so 7 isn't so bad.

It won't make any appreciable difference on the street.

 

[RamVA]

It depends on how much shifting and wot you're doing. The clutch slipping causes heat in the fluid, but the clutch gets hot from constant wot abuse as well. Clutch fluid doesn't boil as fast as brake usually but it certainly can depending on how much you're using it. These cars do make decent torque after all.

Once a year flush is probably about right.

I agree with you, though. It "shouldn't" boil. You can ignore it and see how it does, but if you have experience and you take it out you won't be satisfied pushing it 60% so you know you might boil stock fluid. Thankfully if you've already got pressure on the master for bleeding your brakes, what's another bleeder to touch? There's already 6 so 7 isn't so bad.

It won't make any appreciable difference on the street.

I get what you're saying, I just don't put a lot of heat in the clutch on track. If the systems were separate I would not expect to touch the clutch fluid until the clutch comes out. It's just an annoying extra step for a brake bleed. No shade, I appreciate your input.

 

[Victorofhavoc]

I get what you're saying, I just don't put a lot of heat in the clutch on track. If the systems were separate I would not expect to touch the clutch fluid until the clutch comes out. It's just an annoying extra step for a brake bleed. No shade, I appreciate your input.

It is definitely an annoying step.

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