TBK's Time Attack Build: MK-BRX

[TBK]

Love those aerodisc, where did you get them? Are they universal?

From trackparts in Europe. They're specific to my wheel not universal.

Some users on their experience with their racebred front splitter

Thanks, appreciate it

What would you get instead with what you now know? I was leaning racebred and using pro awesome in lieu of the cables.
OP, what do you plan to replace the racebred with?

Personally, i am using racebred+proawe for now until this splitter blade dies. If i could go back in time, i would have told myself to wait for AJ hartman.

This one's actually on me. @i3igpete actually warned me about the rods in the past, and i actually did buy them (pic below!), but brain fart/oversight on my part i actually forgot to use them. The blade, quick release, and endplates are great. Racebred have been nice to deal with in general too. I'll notify them of this, but i don't expect anything to come out of it.

Here's a vid where you can hear the shudder. Wait for it at the end of the straight. Sorry about the derpy vid, i forgot to calibrate the camera on the Catalyst so it was just pointing upwards. Anyway doesn't matter as you wouldn't have been able to see the splitter anyway, so just listen to the shudder

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[TBK]

Some shots from the last race @ Yas Marina

I've also done some logs with the revised map from Sameh where he addressed the boost issue (in the sense that i wasn't making any before). I do not like these maps at all though. I feel like i have no corner exit control. Basically the throttle mapping is horrible. At 45% throttle, i'm requesting all the torque. We've asked for some revisions, so hopefully this gets addressed.


https://www.bootmod3.net/log?id=696d2c1947f2f4594c8260f7 (low boost map)
https://www.bootmod3.net/log?id=696d2c1a47f2f4594c8260f8 (this starts as high boost then switch to low boost 2nd pull)
https://www.bootmod3.net/log?id=696d2c1a735c9735399f78ae (high boost map)

@razorlab penny for your hypercritical thoughts kind sir?

if anyone else wants to chime in as well, i'd appreciate the extra eyes and minds.

 

[TBK]

Response from Racebred

I've already picked up another Racebred splitter kit (tunnels/endplates). Same 5" stickout. Yeah what happened really sucked, but i really do like the kit otherwise. Will be using the PA rods instead of the cables that come with the kit.

The question i asked them though is should i also reinforce with additional support near the leading edge of the splitter. Either by using 2 of the 4 rods as such, or going overboard and using an additional 2 rods. Or using 2 of the cables, rather, since i only have 4 rods atm. That's what they initially recommended, but that could be while using the cables instead of rods they're now outright recommending.

The Boss Boss Supra does have rods (or cables?) near the leading edge for better leverage.

 

[razorlab]

Some shots from the last race @ Yas Marina


I've also done some logs with the revised map from Sameh where he addressed the boost issue (in the sense that i wasn't making any before). I do not like these maps at all though. I feel like i have no corner exit control. Basically the throttle mapping is horrible. At 45% throttle, i'm requesting all the torque. We've asked for some revisions, so hopefully this gets addressed.


https://www.bootmod3.net/log?id=696d2c1947f2f4594c8260f7 (low boost map)
https://www.bootmod3.net/log?id=696d2c1a47f2f4594c8260f8 (this starts as high boost then switch to low boost 2nd pull)
https://www.bootmod3.net/log?id=696d2c1a735c9735399f78ae (high boost map)

@razorlab penny for your hypercritical thoughts kind sir?

if anyone else wants to chime in as well, i'd appreciate the extra eyes and minds.

Car looks awesome. Tune still looks like ass.

This boost control man, Sameh def has a "Signature" lightning bolt in his tunes. Not to mention a ton of throttle closure, etc. He is probably phoning it in, like usual. When I had his "tune" I could literally hear the WGA cycling like a lightning bolt at WOT at one track with a lot of walls. The sound would bounce off the walls.

P-gain tuning is the culprit, atrocious:

 

[Phlizza]

Great build thread!

 

[TBK]

Car looks awesome. Tune still looks like ass.

This boost control man, Sameh def has a "Signature" lightning bolt in his tunes. Not to mention a ton of throttle closure, etc. He is probably phoning it in, like usual. When I had his "tune" I could literally hear the WGA cycling like a lightning bolt at WOT at one track with a lot of walls. The sound would bounce off the walls.

P-gain tuning is the culprit, atrocious:

Hard to explain how difficult it is to manage anything partial throttle related. Basically i struggle a lot more than i should in both sweepers and corner exit.

I looked at pedal vs throttle, but more importantly pedal vs torque request to try and see what's going on at partial throttle

Great build thread!

Thank man!

 

[razorlab]

Ask Sameh for a more linear throttle mapping. To be fair, that was the one thing he got right on mine years back.

 

[TBK]

Ask Sameh for a more linear throttle mapping. To be fair, that was the one thing he got right on mine years back.

Yer, i'm just really confused as to how Sameh could even let my throttle mapping be this bad.... Here's a strong tell..... the the pedal pressure distribution. Sameh handed me drag-style maps with shit throttle mapping. The OTS tune, which we all know is garbage and non-linear, is a lot more linear. You can see just from the pedal distribution, where i was using a lot more of the 30-70% pressure range in the OTS map vs their maps, almost double. And also a lot more in the 0-30% range. Basically i was doing a lot more modulation in the shitty OTS maps than i was in the custom tunes.

I don't want to move away from Sameh now, because i have all the PI parts on standby ready to go. Need to move to Rev2. And so it's pointless paying for a tune now, and then again in a couple of months. Might as well try to get him to deliver a proper tune and then potentially move to someone who can deliver a proper track map

 

[razorlab]

Yer, i'm just really confused as to how Sameh could even let my throttle mapping be this bad.... Here's a strong tell..... the the pedal pressure distribution. Both Sameh and Sam handed me drag-style maps with shit throttle mapping. The OTS tune, which we all know is garbage and non-linear, is a lot more linear. You can see just from the pedal distribution, where i was using a lot more of the 30-70% pressure range in the OTS map vs their maps, almost double. And also a lot more in the 0-30% range. Basically i was doing a lot more modulation in the shitty OTS maps than i was in the custom tunes.

I don't want to move away from Sameh now, because i have all the PI parts on standby ready to go. Need to move to Rev2. And so it's pointless paying for a tune now, and then again in a couple of months. Might as well try to get him to deliver a proper tune and then potentially move to someone who can deliver a proper track map

Just wait until he uses the crap BM3 compare and update feature, then doesn't care to check his work and almost blows up your engine. That was fun.

 

[TBK]

Track day coming up tomorrow. Should have a revised map by then, hopefully something more linear and consistent. It's always been such a mad rush that i've never really had time to take a race-ready setup for testing. Tomorrow should be the day i get to do that.

Game plan will be to gather data to optimize the tune, suspension/alignment settings and aero. Will not be pushing beyond 9/10ths.

On the aero front, i think i need to run a bit more than the almost 0 degrees i was running at the last race. Even though the splitter only made it for an outlap and another lap before breaking off, it was clear that i was making a fair bit more downforce up front than i was in the back....despite the addition of the bigger wing endplates and the gurney flap. The 67" APR wing + Verus diffuser in the back needs a bit more help. So going up in angle. The only reason i initially reduced it anyway was because of the addition of the endplates and the gurney flap while the APR splitter was still on. Back up to probably around 5 degrees for now.

Also raising the car another 10mm tomorrow before the track day. Will bring it back down when the 35 sidewall tires are on next month.

 

[TBK]

Yesterday's track day was a success. I set out to with the intention of logging, and testing aero/suspension/alignment.

Conditions: I was on dead 295/30 CRS tires, and it was day after it rained, so was very dusty and slippery. No rubber on the track. Way too much traffic, so couldn't get any proper clean laps.

Despite that, and not really trying to put down the fastest time, i did actually (surprisingly) set a faster time that the winning lap at the time attack event that the same layout. Silly fast car.

Front aero setup of Racebred splitter/tunnels/endplates/louvers/vents overpowered my rear of APR 67" wing + singular endplates + gurney flap and verus diffuser. That was when the wing was basically flat. So i went back up to around 6 degrees (hard to measure accurately now with the gurney flap). Much better.

Starting tire pressures were 26, and that worked out beautifully for me. Settled at around 31-32. Temps, taken with probe pyro, were not where i wanted them to be. Inner and middle were close, and outer was lower.

The tune is a lot better, but still needs work. Looking at the pedal usage distribution, it's hilarious how much more time i spent in the 30-70% range compared to before. Current map is in blue, other colors are previous ones.

Boost control is still all over the place, and i'm seeing too many throttle closures. High and low boost maps charted below


Some extrapolation.....and it seems i'm getting 3-4 cuts on an 8 second pull.

Will get another revised map, esp as this is my first full fat logging session on the track. But will probably stop at that even if it's nowhere near perfect, because all this becomes a thing of the past when i move to rev2 and PI.

 

[TBK]

Expanding on the tune side of things a bit. Comparison between the old tune and the latest revised one

The old log wasn't great, or long (and was on the street vs the new one being at the track). Hence low number of frames for example, but should still be at least somewhat representative.

Less p-gain noise, but bigger swing.

The 86% avg throttle during the cut is not the worst, but the throttle closure density should be improved. Basically, 26% of the time, my throttle is being cut by about 13%.

 

[skatheeri]

Yesterday's track day was a success. I set out to with the intention of logging, and testing aero/suspension/alignment.

Conditions: I was on dead 295/30 CRS tires, and it was day after it rained, so was very dusty and slippery. No rubber on the track. Way too much traffic, so couldn't get any proper clean laps.

Despite that, and not really trying to put down the fastest time, i did actually (surprisingly) set a faster time that the winning lap at the time attack event that the same layout. Silly fast car.

Front aero setup of Racebred splitter/tunnels/endplates/louvers/vents overpowered my rear of APR 67" wing + singular endplates + gurney flap and verus diffuser. That was when the wing was basically flat. So i went back up to around 6 degrees (hard to measure accurately now with the gurney flap). Much better.

Starting tire pressures were 26, and that worked out beautifully for me. Settled at around 31-32. Temps, taken with probe pyro, were not where i wanted them to be. Inner and middle were close, and outer was lower.

The tune is a lot better, but still needs work. Looking at the pedal usage distribution, it's hilarious how much more time i spent in the 30-70% range compared to before. Current map is in blue, other colors are previous ones.

Boost control is still all over the place, and i'm seeing too many throttle closures. High and low boost maps charted below


Some extrapolation.....and it seems i'm getting 3-4 cuts on an 8 second pull.

Will get another revised map, esp as this is my first full fat logging session on the track. But will probably stop at that even if it's nowhere near perfect, because all this becomes a thing of the past when i move to rev2 and PI.

Did you film your session? just enjoy watching those POVs especially in our beloved Yas Marina

 

[TBK]

Did you film your session? just enjoy watching those POVs especially in our beloved Yas Marina

Unfortunately i don't. I keep forgetting to set up the camera on the Garmin. It's there, i just need to calibrate it. Takes a second, so will get to it.

The Sector:One guys have a lot of good vids on yas.

Here's Jack in a 488 (Corkscrew Layout)



Yash in a stock Supra (GP Layout)

 

[razorlab]

Expanding on the tune side of things a bit. Comparison between the old tune and the latest revised one

The old log wasn't great, or long (and was on the street vs the new one being at the track). Hence low number of frames for example, but should still be at least somewhat representative.

Less p-gain noise, but bigger swing.

The 86% avg throttle during the cut is not the worst, but the throttle closure density should be improved. Basically, 26% of the time, my throttle is being cut by about 13%.

MegaLogViewer has great Scatter plot tools:

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