Skyline Nationals - Mallala Sprint - Sept 12

[Jap_star]

ah thats fantastic,

anyone know who was taking the photos from the kink in the parade lap?

[heslo's + 1]

or from the bunker at the start of the esses for that matter?

[nos man]

i remember my thought proces quite well:

"okay here we go, 50 meter board, wait, wait, wait BBBBRRRRAAAAAAKKKKEEEEE, turn in......

shit, too much

catch it... hey check out this cool slide.... ah wel its gone too far, keep the power on and do a big skidOOOOHHHHHH SSSHHHHHIIIIIIIITTTTTT!!!!!!!!"

then a little bit of wee came out

what lsd you got in the mx5? can't be the standard viscous?

[heslo's + 1]

no lsd mate, standard open wheeler.

i have got a cusco rs 1.5 way going in at the moment which should make some improvements

[nos man]

my viscous isn't locking as hard anymore! i'm just juggling between a new mechanical diff centre or going with the torsen

[heslo's + 1]

i went with a mechanical because for the price id much rather a brand new item. Second hand torsens still got for 8-900 bucks, where as i got my cusco for $1200. That and i want to keep taking mine to the track so i nice fresh meachanical lsd should make quite a big improvement....

"looks at josh"

[Blue]

Well the speedo is not connected, and I over estimated. just calculated my speed from my tach, only hit 180Km/h.

6500 rpm 235/45R17 (643mm dia) 4.36 diff in 4th 1.1

didn't mean to BS, but it was very hairy having the ass step right out on you at that speed any way

Interesting to compare setups, going by the calculator that was linked in this thread (Which must be in miles an hour not kilometers) I was doing roughly 185 through the kink and the car was dead stable at full noise in fourth (Where I could touch my conservative limiter before the hairpin) or in fifth gear. I have roughly 180-190 rwkw so I am happy enough with that for the first time I ever saw the track. The stability I reckon is the difference in our setups. my spring rates are about 8 / 5.6 and while it needed more roll stiffness, it had good traction out of most corners with an LSD that does not work (Budget) but it understeered a bit more than I liked in the slow stuff. on the plus side it just rode through the turn one bump like it was not there, flat in third gear at about 6000 RPM and it did not even change line. Biggest thing I would need to be at Mallala would be to be a lot more agressive under brakes, I was being pretty conservative on them to preserve the car, the pedal never even softened.

I should push the car a lot harder as I was only doing 25's or so on the laps I ran it up a bit, but I had a Hillclimb one week later back in Vic when I would only get home mid week so bending or breaking the car was just not on the screen for me at a day that I just wanted to have fun. I would have been out of the hillclimb if I broke ANYTHING on the car, as would the other bloke who usualy drives the car with me.

[semislickR32]

just to add my 2c to the speedo, my ecu reports 194-198km/h top speed on the kink, depending on how well I exit the southern hairpin and how late I brake.

Haven't yet cracked the 200, interesting that the R35 hits about the same, but given I'm doing 1:21's not 1:12's I'm guessing the R35 kisses 200 before the kink rather than at terminal velocity into the northern hairpin?

For sake of comparing apples and oranges, the car is a BNR32 with 285kw on A048 semis.

[Krishy]

how do you rate the A048's andrew???

[J - Rad]

just to add my 2c to the speedo, my ecu reports 194-198km/h top speed on the kink, depending on how well I exit the southern hairpin and how late I brake.

Haven't yet cracked the 200, interesting that the R35 hits about the same, but given I'm doing 1:21's not 1:12's I'm guessing the R35 kisses 200 before the kink rather than at terminal velocity into the northern hairpin?

For sake of comparing apples and oranges, the car is a BNR32 with 285kw on A048 semis.

How are you getting ECU speed read outs? PFC?

[Weezy]

Just quietly semislick... I love your 32 man .

[J - Rad]

Yeah oath. If I could get mine as clean as that I'm happy. +1 to the non- N1 slotted GT-R front bar!

[Martin Donnon]

Just as a point of interest. Our ECU logging at the Apex point of the Kink - not 100m before it - not 100m after it - will normally indicate around 228 - 232kmh. Actual GPS logged speed from the VBox is closer to 205 - 208km/h. A genuine 200km/h at the apex of the Kink needs three things - 1) A bloody powerful car to accelerate you to that true speed. 2) A very, very good chassis and normally slicks to take the side load generated (we generate around 1.4G lateral constant in the R35 at that point). 3) An even bigger set of balls as you need to clip the kerb on the outside of the track at that speed to make it all work

To put that in context our EVO X which just recorded 5th fastest outright 400m time at Tailem Bend sprints with an 11.9 second quarter pass touches an actual 185km/h on a flyer at the apex when on a 1:15.X lap. While huge amounts of Disney Dyno jiggerwatts help, the main thing that determines your speed at this point of the track is your exit from Turn 3, which must be flat from the apex onwards.

Also if you lift of the throttle - at all - for the Kink, you are doing it wrong. Its a bend that must be taken flat if you want a lap time....

As they say you need to drive 'Flat Out"

[Blue]

Just as a point of interest. Our ECU logging at the Apex point of the Kink - not 100m before it - not 100m after it - will normally indicate around 228 - 232kmh. Actual GPS logged speed from the VBox is closer to 205 - 208km/h. A genuine 200km/h at the apex of the Kink needs three things - 1) A bloody powerful car to accelerate you to that true speed. 2) A very, very good chassis and normally slicks to take the side load generated (we generate around 1.4G lateral constant in the R35 at that point). 3) An even bigger set of balls as you need to clip the kerb on the outside of the track at that speed to make it all work

To put that in context our EVO X which just recorded 5th fastest outright 400m time at Tailem Bend sprints with an 11.9 second quarter pass touches an actual 185km/h on a flyer at the apex when on a 1:15.X lap. While huge amounts of Disney Dyno jiggerwatts help, the main thing that determines your speed at this point of the track is your exit from Turn 3, which must be flat from the apex onwards.

Also if you lift of the throttle - at all - for the Kink, you are doing it wrong. Its a bend that must be taken flat if you want a lap time....

As they say you need to drive 'Flat Out"

What would account for the speed difference in what the ECU reports compared to GPS? Not wheelspin I would presume in a GTR even with big power?

I will have to have a look over my video footage again, I might have had only the first shift light stage on in the kink when I was running it flat in fourth, that is set at 6000 rpm with the second stage at 6500, if I was part way between the two that would be about 170KMH. Most laps to be nice on the car for the following weekend I slotted it into top gear before the kink and ran to the hairpin in that, would not have cost me much into the kink but it certainly cost me at the end of the straight.

[semislickR32]

how do you rate the A048's andrew???

pretty good but they're the only semis I've had on the GTR. I had RE55s on the S15 which I felt were much grippier, but the S15 is 200kg lighter and RWD so difficult to compare directly. If I had a choice I'd go RE55s next, but need to get a spare set of rims first as the RE55s aren't DOT approved. A048s are $100/corner cheaper though.

How are you getting ECU speed read outs? PFC?

I'm running a nistune and have the ecutalk LCD running off the consult port. For anyone running a nissan ecu I reckon it is a great little unit - max-value storage and over-limit alarming for most parameters like injector %, water temp, rpm, AFM Voltage etc. The guy who makes them is working on in-built data logging to the microSD card, currently you need to plug a laptop into the USB port for logging. For the price I think they are excellent trackday diagnostic tool, but there's a few things it doesn't have that would be good - boost, oil temp & oil pressure (not available from the Nissan ECU) and intake air temp (in the ECU for GTR but not used by ecutalk)

Max vals from one of the Skynats sessions:

Just as a point of interest. Our ECU logging at the Apex point of the Kink - not 100m before it - not 100m after it - will normally indicate around 228 - 232kmh.

Well that makes more sense! and man that is fast! Maybe rolling diameter might be some of the difference between GPS and ECU indicated speeds?

thanks for the comps guys I must say after switching from the S15 I am loving my GTR too!

[Martin Donnon]

What would account for the speed difference in what the ECU reports compared to GPS? Not wheelspin I would presume in a GTR even with big power?

Normally the basics of instrument inaccuracy (accounts for about 15km/h of it I reckon) plus the issues of tyre growth and distortion account for the error

Notably the 'Kink' is the place that makes or breaks your lap. You can make seconds up (or lose them) right there

[Krishy]

pretty good but they're the only semis I've had on the GTR. I had RE55s on the S15 which I felt were much grippier, but the S15 is 200kg lighter and RWD so difficult to compare directly. If I had a choice I'd go RE55s next, but need to get a spare set of rims first as the RE55s aren't DOT approved. A048s are $100/corner cheaper though.

thanks for that Andrew....i am prob going to be looking at a set sometime soon...the AO48's seem a lot cheaper then the RE55S...thats after i trial my set of KU36's

[Blue]

thanks for that Andrew....i am prob going to be looking at a set sometime soon...the AO48's seem a lot cheaper then the RE55S...thats after i trial my set of KU36's

Another tyre to have a look at would be the Toyo R888. That is what we have settled on for my coupe.

The Dunlop 01G was another we tried, I am sure they are a little faster overall than the Toyo, but it is more expensive, took longer to warm up and work, had less feel and was just not as nice in the rain as the Toyo. All things that worked against it for Hillclimbs on a typically damp and cold track! Even at Phillip Island the confidence you could have to just stick it in there on out laps at the 6 hour regularity was just not there compared to the Toyo. The Toyo started to feel good about halfway into the first corner.

[Krishy]

ummm so many choices out there....well the KU36's are on order so we shall go from there on....

[semislickR32]

Another tyre to have a look at would be the Toyo R888. That is what we have settled on for my coupe.

The Dunlop 01G was another we tried, I am sure they are a little faster overall than the Toyo, but it is more expensive, took longer to warm up and work, had less feel and was just not as nice in the rain as the Toyo. All things that worked against it for Hillclimbs on a typically damp and cold track! Even at Phillip Island the confidence you could have to just stick it in there on out laps at the 6 hour regularity was just not there compared to the Toyo. The Toyo started to feel good about halfway into the first corner.

Yeah what i have heard about the toyos is that they are softer, so good for light cars, out laps or short motorkhanas and hill climbs, but go off quickly after multiple laps in a heavy car (eg a GTR ). Ive got no direct experience in that though so could be totally wrong.

As a matter of interest how much does your car weigh?

Edited September 30, 2010 by semislickR32