TBK's Time Attack Build: MK-BRX

[TBK]

Can't believe i forgot to post this part....considering how important it is



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[TBK]

Are they the calipers that take 25mm thick pads? If so, it looks like the same kit I'm running. But I use Ferodo DS3.12 in the front and DS2500 rear.

Back to this again. OEM data is a bit tricky, but i'm fairly certain the numbers are either accurate, or close enough to be representative

Here's the progression of my braking setup

So with my new setup, i'm dropping another 3.4kgs (7.5lbs). That's 5.6kgs (12.3lbs) less than OEM. Unsprung of course.

And in the process i'm increasing pad surface area and volume significantly. The downside of course is the thinner pad than something like the 25mm in yours. Mine will heat soak sooner. That's something i can live with though, because i don't do 30 mins of continuous driving. Or 20 even. I'll do a few hard laps and a cool down lap or 2 and back on it for a few more etc...I'll occasionally break that rule and do 4-5 hard laps before cooling down, but almost never more.

 

[razorlab]

I think your pad thickness between OEM pattern pads is incorrect. All FMSI D1867 pad shapes are the same thickness, 18.8mm, or less.

20mm wouldn't fit.

 

[TBK]

I think your pad thickness between OEM pattern pads is incorrect. All FMSI D1867 pad shapes are the same thickness, 18.8mm, or less.

20mm wouldn't fit.

That's what i thought as well. But for whatever reason Endless for example list their pad thickness for the Supra @ 20mm. Are there different ways of measuring pad thickness? Maybe they cheekily include the backing plate?

 

[razorlab]

That's what i thought as well. But for whatever reason Endless for example list their pad thickness for the Supra @ 20mm. Are there different ways of measuring pad thickness? Maybe they cheekily include the backing plate?

Manufactures publish incorrect stats all the time. Looking at you Toyota.

 

[TBK]

I have multiple sets of springs on the way for the Nitrons, and so will be trying a few combinations.

First set going on:
60/140 (343/800)

Second set:
80/160 (457/914)

Third set:
120/160 (685/914)

Let's see how that plays out. Will be looking at both lap times and subjective feel. I think the feel component is just as important as lap times, because ultimately the different spring rates will also require different suspension setups, and i might not be able to get that done properly right off the bat for obvious reasons.

What is the shaft diameter and canister prefill pressure that you're running? I can calculate the gas contribution to spring rate at full droop for you.

Shaft/rod diameter: 16mm front and 14mm rear

canister prefill pressure (range): 11–12 bar front 9–10 bar rear


Another update:

I've put in an order for a stage 1 Dodson trans kit (superstock). includes the full clutch pack (frictions + steels + seals). Uses the Dodson carbon/kevlar composite. On paper torque rating is about 700wtq. But Dodson themselves would tell you that the number is very conservative. That's good enough for my use case.

Not as good as something like a stage 1 Pure kit... e.g. reuses the OEM pressure plates and drums. For half the price, i'm fine with that. The pure kit is rated for a looot higher than i'd ever need. There's headroom and then there's headroom.

 

[razorlab]

I have multiple sets of springs on the way for the Nitrons, and so will be trying a few combinations.

First set going on:
60/140 (343/800)

Second set:
80/160 (457/914)

Third set:
120/160 (685/914)

Let's see how that plays out. Will be looking at both lap times and subjective feel. I think the feel component is just as important as lap times, because ultimately the different spring rates will also require different suspension setups, and i might not be able to get that done properly right off the bat for obvious reasons.

Nice, that will be a fun test!

 

[i3igpete]

ok, I'm calculating about ~50 lbf/in rate from the gas pressure with those specs, so the coil spring still dominates.

 

[TBK]

ok, I'm calculating about ~50 lbf/in rate from the gas pressure with those specs, so the coil spring still dominates.

That's very interesting. So as we're talking about the front shocks here, does that mean the "true" spring rate is whatever i have + 50lb/f because of the canister? Is that would it works?

So then these would be the "true" rates:

First set going on:
343/800 ---> 393/800

Second set:
457/914 ---> 507/914

Third set:
685/914 ---> 735/914

 

[i3igpete]

Correct. There is a slight nuance because gas pressure rises non-linearly, but in a nutshell, yes.

Recall springs in parallel add keff = (k1+k2), but if you look at the spreadsheet, the tire stiffness is a spring in series keff = (1/k1+1/k2)^-1 = (k1*k2/(k1+k2))

 

[TBK]

Correct. There is a slight nuance because gas pressure rises non-linearly, but in a nutshell, yes.

Thanks. Learned something new today. I'll take it

 

[Z4m40i]

I have multiple sets of springs on the way for the Nitrons, and so will be trying a few combinations.

First set going on:
60/140 (343/800)

Second set:
80/160 (457/914)

Third set:
120/160 (685/914)

Let's see how that plays out. Will be looking at both lap times and subjective feel. I think the feel component is just as important as lap times, because ultimately the different spring rates will also require different suspension setups, and i might not be able to get that done properly right off the bat for obvious reasons.



Shaft/rod diameter: 16mm front and 14mm rear

canister prefill pressure (range): 11–12 bar front 9–10 bar rear


Another update:

I've put in an order for a stage 1 Dodson trans kit (superstock). includes the full clutch pack (frictions + steels + seals). Uses the Dodson carbon/kevlar composite. On paper torque rating is about 700wtq. But Dodson themselves would tell you that the number is very conservative. That's good enough for my use case.

Not as good as something like a stage 1 Pure kit... e.g. reuses the OEM pressure plates and drums. For half the price, i'm fine with that. The pure kit is rated for a looot higher than i'd ever need. There's headroom and then there's headroom.

Best to stay away from Pure anyway.

 

[TBK]

Best to stay away from Pure anyway.

Damn. I'm sorry that happened to you. has to be a fluke though, right? I do like the fact that Dodson is, well, Dodson. Strong name in the business and they often stand behind their product.

That said....

Pure just shipped me the replacement parts for the wastegate. Should have them by Saturday or so. Won't go on until mid next week, so i'm hoping the current patch job lasts the 2 trackdays i have lined up on Saturday and Monday. Chris has been very cool and easy to deal with, and sent me the parts even though i didn't send them the turbo itself to inspect (since i'm halfway across the world). So that was a lot better than expected.

Edit: OK, i was today years old when i found out that Pure Turbos and Pure Drivetrain Solutions are not owned by the same company. Shirley i can't be the only one.....shirley.....please?

 

[FLtrackdays]

Be interested to see what you think of the Winmax R7 / Paragon R7. I have yet to meet someone that had a good review of them.

They didn’t hold up for me. Especially if comparing to the P mu 999s. Didn’t last as long or have the stopping power. They reminded me of EBC blue stuff I tried long ago. Soft pedal feel as well.

Project mu Racing999 pads. I'm hoping these pads last a bit longer than they should. Until the end of November, when the Alcons arrive.

You’re gonna love em!! The car is looking sick btw

 

[TBK]

They didn’t hold up for me. Especially if comparing to the P mu 999s. Didn’t last as long or have the stopping power. They reminded me of EBC blue stuff I tried long ago. Soft pedal feel as well.

Identical setups, including tires? I'm not sure how much brake pad friction material does as far as outright stopping power vs things like tire compound/width/temp. Imo pads are about being repeatable, controllable, and heat resistant.

How long they last of course is something else entirely, and i guess that's not comforting at all. i guess that's also relative. How long did they last, approximately. Would then also factor in the cost, which is reasonable. Not the cheapest, but not CSG level expensive either.

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