TravisJB Journal

Boost_lee

Love the diffuser. I hope the results are good!

travisjb

So, long interesting weekend is over... some of the highs/lows

- diffuser doesn't add much value as far as times at this particular 1.6 mile ROVAL track... on the OVAL I was drifting constantly and not getting much aero download vs. running the wing, if any at all... bottom line, save your money on diffusers and put $ into more wing - at least until someone comes up with a more proven design

- more details on diffuser... best time with it on and no wing was in mid 1:11's... best time with no diffuser and wing only was 1:09.29... best time with both on was low 10's... as for driver feel, I couldn't tell it was on... just a theory but I think one error we may have made is the steep angle where we made it taper to the rear fascia, as opposed to just having a flat diffuser that dumps air off the back directly

- my time of 1:09.29 was my best yet at this track on Nitto's, and in fact beats my previous best time on Hoosiers!... this time should be the winning time in my class for the weekend, but unfortunately I achieved this time on the same session that I had an off, and thus DQ'd

- why are my times improving?... If the Hoosiers are worth 1.5 seconds or so, I think that means I picked up 2.0 seconds at the track through a combination of weight reduction and the MOTORDYNE intake manifold... special thanks to Tony at Motordyne for becoming a part of my build and creating the part that Nissan should have included from the factory... I'm seeing/feeling a noticeable improvement over the 3-7k rpm range

- another off? lol... I had several incidents of icing mode today... two of them could have put me into a concrete wall on turn 9 of PIR... the third DID in fact put me into the tire wall... so, there is no structural damage, no driver damage, but the front fascia is cracked in two places... strictly cosmetic... time to replace the fascia - will need to chose between a Stillen version or picking up an OEM fascia from our friend Lou Fusz

- brakes... overall, still v happy with the AP Racing brakes... bad on me for not replacing the pads sooner - I think that contributed to the icing mode today... the air cooling is helping but I had some smoke coming out of the front right given we were going counter clockwise... I need to check in with Chris at AP/Stillen about the new pads they have for the kit

- brakes continued... very seriously thinking about disabling ABS! maybe I can install a switch to defeat / restore it in the cabin? any thoughts on the best way to do that?

- traqmate... no data logging or video this weekend - got an error message of "No SU" from the display unit... and the power light is not coming on... possible I fried the unit during battery disconnect/reconnect - will send to mfgr

- rear diff... it could be in my head but I think I'm detecting some slight movement from the rear diff/axle... contemplating getting some stiffer mounts for the diff, but not sure if those are available... also, anyone know off-hand how many hours one should expect to get out of a carbonetics diff?

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2009 370Z #104
*For Sale*

travisjb

one more thought... the car is still 120 pounds heavy for the class... might be worth another 0.5 second... and I think I can dig out another 1.0-1.5 seconds by going absolutely flat out in the oval... so in theory that means low 1:07s in "TTA trim"... not going to hold my breath, but think that's a good goal and if I get there I will then move 'up' to TTS again

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2009 370Z #104
*For Sale*

Jamaica

any pics of the exhaust?

ChrisSlicks

Travis are you running the DS3000 all around? My guess is that you were overheating the front pads or even just the front right corner which was causing the rear to lock up and send you into ice/crash mode. My recommendation is to run a slightly lesser pad in the rear. I only run the Mintex Extreme in the rear and ice mode has never returned.

Congrats on the times, too bad about the diffuser. It is pretty difficult to get those kind of parts right the first time without simulation or a wind tunnel.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

travisjb

Hey Chris, that makes sense... Yes, have been running that same compound on all four corners... I will discuss with AP Chris and likely will try an approach similar to yours

Re diffuser, I haven't totally given up on it... possible that the design will work with some tweaks and proper supporting aero... e.g., I wasn't running the front splitter this weekend

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2009 370Z #104
*For Sale*

RCZ

I really thought that diffuser was going to make a difference. It looks exactly as I pictured it in my mind. You may be right that the angle is too much and is causing separation.. I have my doubts that that's the issue though because from looking at some other examples of diffusers, your angle, although sharp, doesn't seem too extreme.

Any chance there's a pocket of air collecting under it and air pressure keeping flow away from it? Most race cars have a completely flat bottom that does not allow for this. Maybe if you extend the plate forward more to keep that from happening?

I would maybe try a combination of both...

travisjb

Raul! re air flow to the diffuser, have been discussing exactly that theory with a few folks off-line. Common wisdom is that a diffuser becomes effective when you direct air at a high velocity to the diffuser and minimize surfaces that could cause turbulence leading to diffuser... also having a front splitter to minimize airflow under the car is supposed to help... all i can say right now is that this particular design, without all the accompanying aero, has proven ineffective. I will try again when I put this car back in "TTS" where aero is unlimited

Another update... ordering from Stillen tonight... their front fascia, mintex f3r front pads, mintex xtreme rear pads... will use the stillen fascia with canards and splitter for any event that outside of NASA TTA

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2009 370Z #104
*For Sale*

Mike

I think you can just pull the ABS fuse to disable it. I know thats how it worked on my 350.

I would go with the stillen bumper, much more cooling airflow available, and whether you wait for their brake cooling kit or make your own (which you seriously need to do), it will be easier to fit with theirs.

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NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z
Porsche: 93 968 / 23 Macan GTS / 93 968

travisjb

Question on brakes for AP Chris or anyone else...

What is your experience with the effectiveness of brake pads as they wear / heat cycle? have you seen any data on the capacity of pads to deal with heat build up and how that changes over the life of the pad?

Another theory on why I may have experienced more 'ice mode' this weekend... I changed my suspension setup... dropped the front down by 0.5 inch... that typically results in more oversteer in trail braking and changes the braking balance front/rear... possible the back end picked up just a bit under braking and caused ice mode... just a thought, nothing to substantiate

Things I need to fix for braking:

1. less aggressive pads in back
2. lower back of car 0.25 inch, raise front 0.25 inch
3. add some stiffer mounts for rear diff... I suspect it is moving under braking and creating momentum / lifting rear - just a theory
4. add ABS kill switch/toggle

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2009 370Z #104
*For Sale*

travisjb

I think I will try to hook up a switch in the cabin where I can bypass the ABS fuse from there, good idea... wonder if that requires an ECU reset or if it can just be switched in real time

Agree on the fascia

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2009 370Z #104
*For Sale*

ChrisSlicks

It requires a engine restart, but not a full ECU reset as I understand it.

As for the height change that will have definitely moved your weight balance forward a bit which would increase the likelyhood of the rear locking up. Worn pads also do tend to overheat more quickly (less mass to absorb the thermal energy), so you may have inadvertently created the perfect storm.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

travisjb

I think you're right Chris... have any data / seen any charts on the thermal capacity of pads as they heat cycle and wear? just curious how big a deal this is, as input to how often I should replace my pads

thanks for the tip on engine restart for abs disable/enable

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2009 370Z #104
*For Sale*

travisjb

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2009 370Z #104
*For Sale*

ChrisSlicks

Haven't seen anything about heat cycles affecting them, but I've seen my overheated pads crumble after being removed due to the bonding agent being cooked out of them. I usually throw my track pads away when they are about 1/2 to 2/3's gone as the more worn they are the more heat gets transferred to the caliper (the pad material is a moderate insulator). I'll see if I can find any data that shows the correlation.

__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms