mitch_f1's mariner NA6

[evil_weevil]

glad to hear/see you got it back home all good and I could have helped out mate.

I think you are right, save up and get the better diff!

[hks_kansei]

What oil were you using in the diff when it went bang?
Open diffs use the same oil as the gearbox.

It's blue?
IT wasn't ATF fluid was it!?

[Black_Penguin]

Redline Lightweight Shockproof is blue.

[Apu]

Different kind of blue though - the Redline one is like squashed / blended Smurfs. The blue fluid from Mitch's car looks like its still "clear".

[hks_kansei]

Either way.

Open diff = Gearbox oil

ATF fluid is a fair bit thinner than gearbox oil, so it probably isn't able to lubricate as well.


(worth noting, Torsen T2 also uses gearbox oil just like an open diff, T1 I think needs to use gearbox oil with extreme pressure additives)
Don't quote me on the T1 info, I never looked too much into the T1




I would really recommend the T2 over the T1, from a function point of view they both feel the same.
BUT!
T2 is stronger, the T1's worm gears cop a lot of force, and are held in with basically a split pin and a fairly open casing.
The T2 has less open space on the casing, and the gears are located inside specially machined sections.


To show:
T1:



T2:


T2 insides:

Not an MX5 diff, but the same concept.

[mitch_f1]

Car is an import, so has a VLSD, so it is Penrite Limslip, which others were using for the same diff, so I thought okay this is fine. I am open to people telling me otherwise though?

That is interesting what you say about the T2 using gearbox oil though? I had never heard that before?

For me it depends on cost; if I can get a T1 cheaper than a T2 then I will. I am not too worried about toughness, as it only has to handle a massive 70kW of power, and as mentioned in my other thread, no one has ever complained of a failure (again, happy to be proven wrong).

[mitch_f1]

Not many words, just pictures. Long story short, got a Torsen diff (not 100% sure which kind, but looks like a T2) with a 4.3FD (I think...yet to drive it).





















Fun fact: the wrecker couldn't remove the half-shafts from the upright, so sent them attached. I tried with a puller and they wouldn't budge. Took it to one of dad's friends place who has a hydaulics place in Brookvale, and he applied 12tonnes of pressure to it, and it didn't budge. Then he applied 12tonnes of pressure AND an oxy torch, and it released with the sound of a gunshot!!!





This spacer was damaged in transit, so I replaced it with the one off of my diff



















Then I tried to fit the seat which I sold a while back and then bought back off of the new owner. Took about 20 times longer than I thought, so duckling sick of the car at the end of this ordeal!!





Shorter hardware made it easier to fit this time
















Proof my car went from Japan to New Zealand to Australia. All found under the carpet















All said and done the seat sits about 1fingers-width higher, despite the fact that it cannot go lower at all. I think this may be because the red seat had an open bottom, so with my weight on it, i sat below the mounting points.

So the car isn't yet driveable, I just need to find a torque wrench to go to 250nM for the hub nut, then I am sorted.

[Jeo]

I love 8 hour seat fitting sessions!

[mitch_f1]

I dont, I really really do not

[Hjt]

I am glad your car is nearly fixed mate

[mitch_f1]

Thanks Hayden

[mitch_f1]

Soo now it would appear that either a wheel bearing or a diff bearing has died as i am getting that kind of speed sensitive grinding noise. Gonna take it to someone now; i am getting quite sick of this car to be honest. Taking it to Daniel Deckers as he has been suggested by a few people.

But even with a dead bearing i can now say that the car goes sideways very efficiently!!

[mitch_f1]

So I got the rear wheel bearings replaced on the weekend by Deckspeed...but that wasn't the source of the noise. It is now determined to be the front pinion bearing. After a long conversation with the guys there we came to the consensus that the car can be dríven for a while before it actually becomes an issue, and that when it does become an issue I will know because it will be incredibly loud. So now I just need to save my pennies to get it rebuilt.

In the mean time I have an updated mods list:
Exterior:
-SSR Reverse mesh 14x6.5 +8, 14x7.5 +7 with cheapie Hankook tyres
-No name 15x7 +40 wheels with 205/50/15 R888 for track
-Headlight intake duct
-Custom made offset number plate bracket
-Garage Vary front lip
-Project G hard top wing
-RyokuRob tow hooks front and rear
-Shaved lights

Suspension/body
-Tein Flex coilovers
-Rear lower control arm chassis brace (racing beat style)
-Garage arrive front lower control arm/chassis brace
-Carbing front strut tower brace with brake master cylinder brace
-949racing adjustable end-links front, stock rear

Brakes
-RS Factory Stage S500 pads
-NA8 rotors, calipers
-RDA slotted fronts
-949 racing braided lines on all corners

Performance/gearbox
-ARC intake chamber with K&N panel filter and ducting
-HKS Super Header 4-2-1 headers, heat wrapped
-RS Factory Stage catback exhaust in mild steel
-F1 Racing Chromoloy flywheel (4.5kg)
-Exedy stock replacement clutch
-T2 Torsen diff with 4.3FDG

Cooling
-custom aluminium radiator panel
-ASI 42mm aluminium radiator
-Toyota long life coolant
-Davies Craig transmission cooler for powersteering fluid

Interior
-Torque Box roll bar
-Sparco EVO bucket seat on PCI Engineering side mounts
-RPM race harness
-2kg fire extinguisher
-shift-i shift light

[mitch_f1]

SO it's been a little while. In the mean time I replaced both rear wheel bearings (wasn't the problem), and got the diff rebuilt, which fixed the noise I had...mostly. It's still there, which makes me think part of it was tyre noise, but whatever; I don't even have to think about the rear end now; it's all new!!!!

I went to a SOTS at Wakefield yesterday, which was my first proper trackday in like 6 months!!! Overall it was a good day; weather was perfect, but the slower lap traffic made it difficult to get successive clean laps in. At the lunch break I pulled the front pads to notice the diagonal wear on the outside pad that I am now so used to. I swapped that pad to the inside for the last 2 sessions, which was really weird initially as the pedal went straight to the floor, I assume because it didn't have the normal contact area from the inside pad??? I also had a few offs, with videos below. The last one was embarassing because it resulted in completely unavoidable damage at the end (I had a laugh when I saw the video; what else can you do!?!?)

Left the camera in the wrong mode here, so you can't see much. But rest assured, it was close, and bricks were shat


Probably should have just gone straight off in hindsight, but I swear I almost had it....


Urgh, so embarassing


Resulted in this:


Now to business. Guran had a look at my videos and lap data from my PB 1:14.5 lap and my most recent best of 1:15.3. He suggested I should be going into T4 full throttle and then touching the brakes for T5, and accelerating between 5 and 6 with just a lift for 6. It was also suggested to be apexing later for T9. I tried all of this. The first time I went full throttle through T4 resulted in the off track excursion seen above. Later I realised that I need to be right up on the ripple strip of T4 if I am going to full throttle it. I do still lift a little bit, because at that point I am on the rev limiter, and I think short shifting to 4th gear would slow me down as I would have to shift back down to 3rd at the top of the hill. I am still not accelerating between T5 and 6, mostly because I just don't have balls big enough to do that. Although I think if I did then I would be going too fast for the downhill T5. I tried apexing later into T9 which worked really well. Also, I tried pushing harder on the brakes...which suprisingly worked really well; I was only using maybe 70% of the pedal travel previously, but I tried going to 80-85% and I didn't really lock up (inside wheel sqeaked a bit occasionally).

Here is a video, with the lap times listed in the description of the video


So after yesterday I spent all morning pouring over my lap timer data to produce this spectacular graph:


The 1:15.3 lap (going to call it lap 1 from now on) is my best from my last trackday in January. The 1:14.7 lap (going to call it lap 2 from now on) is my best from yesterday. The 1:14.6 is my PB lap (although racechrono said 1:14.6, Dorian said 1:14.5 ;) ) which I included for comparisons sake (going to call it lap 3 from now on), as it was on my Dunlop D01J tyres, which I think had more grip, but also had a larger rolling diameter, which changed my shift points, put me in a differen rev range at the middle of the corner. This lap was also done with QFM A1RM pads. The 1:15.3 lap was also done with QFM pads, and yesterday was done with RSFS S500 pads.

You can see that I am braking 10m earlier when compared to lap 3, and carying about 10km/h less mid corner speed. Lap 1 and 2 have almost identical braking points, and only about 5kph at mid corner. What is really interesting to note is my lowest mid-corner speed at lap 3, which is 91.2kph, compared to 79.7 kph from yesterday (a difference of 11.5kph)!!!! You can also see that I am carying more lateral G-forces on lap 3. I have the most braking G-forces in lap 2.

T4 entry is higher on lap 2 because I wasn't lifting, which I normally would have done. Mid -corner T5 speed is down because of the touch of the brakes just before it. Between laps 1 and 3 there is negligible difference in speeds. Mid corner T6 is where it gets interesting; because I didn't have the usual understeer across the top of the hill I was able to carry a few kph more here, but this then set me up to be almost 5kph faster through T7 compared to lap 3. In terms of gravitational forces I am carrying more lateral G through T4 because i'm not lifting. Interestingly though I am carrying less lateral G forces on lap 3 at T6, which goes against my opinion that the Dunlops had more grip.

Fishook is a weird corner, which took a lot of time for me to work out. What I tried yesterday was cutting a straight line from T8 to the road at the turn in of T9, then turning in at the end of that road. This time I was turning in less, and aiming for just after the apex of the corner which worked well. Having the T2 LSD also really helped here, as I was no longer spinning the inside wheel; it was just power down. I did notice that if I hit the curbing too hard and the inside rear lost traction it would just spin up and I would lose speed and time in doing so. The top speeds reached at the braking point of T9 were very similar, but what was different was where I was braking; lap 2 I was braking 10m earlier than lap 1 or 3, and so was coasting for a bit and carrying almost 10kph less mid-corner speed. But, this meant that I was on the power sooner, and so was carrying more speed through T10, and on the back straight. For T9 it is also worthy to note that I wasn't braking nearly as hard as for T2, so that needs to be fixed. Another interestingly is that my lateral G in the middle of T9 is almost .1G more with the R888 than the D01J, and at T10 it was 0.5G more!!!!

Top speed on the back straight was almost similar for all laps (which is interesting because I am shifting into 4th in lap 1 and 2, which I wasn't in lap 3 because of the larger rolling diameter of the D01Js), as were braking points (between lap 2 and 3 at least). I was on the power earlier in lap 1, but then that also resulted in the lowest speed at the start finish line. Also as a result of the Dunlop rolling diameter, my shift into 3rd happened a lot earlier (40m earlier), and at a lower speed (I guess because it was earlier on the exit). I can't explain why I am shifting 20m earlier on lap 2 compared to lap 1. Again I seem to even have a bit more in the brakes for T2, as I am carrying a lot more braking G-forces coming into T11. the G-forces on lap 3 are quite low in comparison. It is also noted that I am carrying much less lateral G-forces through T11.

So, hopefully some of you read all that. If you want cliff notes, here they are:
-Need to brake harder
-Need to accelerate earlier in T2 and brake later
-Need to man up and accelerate through T4 and T6
-Coast less through T9 and brake harder

[mitch_f1]

The off in the 2nd video resulted in the tyres looking like this: