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 Post subject: Re: QLD Raceway sprints
PostPosted: Tue Sep 02, 2008 1:57 pm 
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Location: Brisbane
datto-510 wrote:
datsblue wrote:
I'm pretty keen see how these alterations effect your turn 1 & 2 Jeff!
yeah i reckon i have lost 2 seconds a lap in cornering since removing the negative camber in the rear, turbo PB is only 0.5 seconds quicker than the n/a pb. hopefully a stiffer rear end will bring it back. If not I will have to get the grinder out :twisted:
So why was the negative camber in the rear removed? Was it because there was too much camber change going on? If so I'd be looking at modifying the sweep angle of the semi trailing arms to reduce that.

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 Post subject: Re: QLD Raceway sprints
PostPosted: Tue Sep 02, 2008 2:01 pm 
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Location: brisvegas
26ODET wrote:
So why was the negative camber in the rear removed? Was it because there was too much camber change going on? If so I'd be looking at modifying the sweep angle of the semi trailing arms to reduce that.
neg camber removed from the rear as Ken (accurate suspension) suggested that I remove it to get better drive out of the corners. This was when the car was still N/A.


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 Post subject: Re: QLD Raceway sprints
PostPosted: Tue Sep 02, 2008 2:07 pm 
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Location: Bris
Hey Harry,

Carrolls book is full of honesty: Corner Entry Understeer = Driver braking too hard, too late!

That pocket cause and effect guide is gold!

My thought is to try a slightly higher spring rate, as I am not experiencing any of the
- harsh or choppy ride,
- unprovoked sliding, or
- lack of ability to put my small amount of power to the ground - excessive wheelspin

Also, sometimes, it's not the car, but the driver who causes the problems.


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 Post subject: Re: QLD Raceway sprints
PostPosted: Tue Sep 02, 2008 3:06 pm 
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Location: Brisbane
datto-510 wrote:
26ODET wrote:
So why was the negative camber in the rear removed? Was it because there was too much camber change going on? If so I'd be looking at modifying the sweep angle of the semi trailing arms to reduce that.
neg camber removed from the rear as Ken (accurate suspension) suggested that I remove it to get better drive out of the corners. This was when the car was still N/A.
I've got a lot of time for Ken but he must have a thing about rear negative camber. Mine was set up with 1.5 degrees but its not enough, as indicated by tyre wear, although the car seems to be jacking up a bit at the rear for some reason.

The more power you have the harder the car is to setup and drive of course, so thats another thing.

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 Post subject: Re: QLD Raceway sprints
PostPosted: Tue Sep 02, 2008 4:58 pm 
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Location: Brisbane
datto-510 wrote:
Yeah too stiff has been the concern about winding it right up, but until I try it I wont know what works and what doesnt.
very true!

datsblue, I haven't seen his full book, just have the cause and effect guide. very good reference particularly when trying new things - like this shock setting. let's you know what signs to look out for to let you know you've gone too far and wind it back a bit.


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 Post subject: Re: QLD Raceway sprints
PostPosted: Mon Sep 08, 2008 9:30 am 
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well my experimentation was a partial success.
definitely too much rebound as we suspected, but qr was the safest place to test it out.
wouldnt want the arse skipping around at mt cotton or lakeside.

anyway managed a new PB of 61.9 and the car definitely felt grippier with the stiffer rear end.
most of my times were low 62's and it has been a struggle to run that low since i changed the rear end.

I am going to drop another 10mm out of the rear ride height, cant take anymore height out without getting the grinder out, unfortunately. Will test the rebound settings in the middle at Mt cotton this weekend, and lakeside.

the car developed a rear end knock in the passenger ride with no noticeable driveline problems.
put it up on stands and everything looks good underneath so i dont know if its in the diff or just because i had the extra weight in the car, but didnt do it for the first few laps. seems to drive OK on the road so FIIK.
might have to open up the diff for a look, but would rather not if i can help it. anybody got a spare r180 ?

last 2 runs are probably the most interesting to watch.
run 4 - Datsun Attack (untimed) http://www.youtube.com/watch?v=D4fs3P-j ... re=related
passenger race.....oops ride http://www.youtube.com/watch?v=WLdiDbHA8Zo
safety car in the passenger ride :oops:

the Z in run 4 was on slicks with a 240 cross flow in it. :o


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 Post subject: Re: QLD Raceway sprints
PostPosted: Mon Sep 08, 2008 2:45 pm 
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Location: BrisVegas
Not much improvement in time, but I had a ball in session 2 following Jeff and that very surprising ute. We were about 0.5 secs apart overall in lap times and running nose to tail the whole way. Sadly I didn't hit the record button on the camera :doh: We'll have to organise to do every run like that swapping chase cars so we get some exciting vids.

Here's the pretty boring vid of the last run which ended up being my slowest despite having a clear track I was getting tired - http://www.youtube.com/watch?v=dUsjbbYJEqs

That poor SLR5000 got rounded up every sesssion by yours truly, but he looked like he was having fun kicking it sideways.

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 Post subject: Re: QLD Raceway sprints
PostPosted: Mon Sep 08, 2008 5:19 pm 
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Hey Jeff & Rog,

Looks like you both had some fun. It's all about improving, and congrats on your 61.9 Jeff. I would like to have been there.

Were there many starters?


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 Post subject: Re: QLD Raceway sprints
PostPosted: Mon Sep 08, 2008 7:50 pm 
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Location: brisvegas
5 or 6 groups i think.

I have checked out the rear end and I have concluded that the banging was the left rear tyre scrubbing on the inside of the guard due to having a passenger in the car.

have put smaller spacers in and shifted rebound to middle position ready for sunday.
still reckon stiffer springs need to be on the shopping list.

yeah that torana got overtaken by me as well, pretty much setup for the street I think.
tuff looking thing though, I wouldnt mind owning one !

poor old 300z thingo banged the wall at turn 2 first session out.

[ img ]
[ img ]

who said cars dont bleed (head gasket)
[ img ]


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 Post subject: Re: QLD Raceway sprints
PostPosted: Mon Sep 08, 2008 10:02 pm 
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Posts: 120
Location: BrisVegas
Ouch. I missed seeing exactly what hit the wall. Looks like there might be some 300ZX parts up for sale soon.

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Gazelle MotorSport
RPJS12 Gazelle - Big Block CA20DET
S12 RXG Silvia - Green Machine SR20DET
[ img ] [ img ] [ img ]


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 Post subject: Re: QLD Raceway sprints
PostPosted: Mon Sep 08, 2008 10:24 pm 
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Posts: 1901
Location: Coffs Harbour, NSW
a few suspension pieces and she'll be fine!! to drive straight again anyway

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 Post subject: Re: QLD Raceway sprints
PostPosted: Wed Sep 17, 2008 1:46 pm 
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Location: Brisbane
This coming weekend's SAS for me and old mate, may try driving there on the RE55's rather than changing from road tyres. So, any other Datto boys coming?

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 Post subject: Re: QLD Raceway sprints
PostPosted: Wed Sep 17, 2008 4:54 pm 
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Location: BrisVegas
Latest points are up. Road 6 is now the class to be in as Jeff's time would've been podium material in Road 4 & 8 classes.

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Gazelle MotorSport
RPJS12 Gazelle - Big Block CA20DET
S12 RXG Silvia - Green Machine SR20DET
[ img ] [ img ] [ img ]


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 Post subject: Re: QLD Raceway sprints
PostPosted: Thu Sep 18, 2008 10:36 am 
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Location: Bris
strange as it is, race < 2L is the class to be in for the wednesday afternoon sprints. Unfortunately, I identified this 2 meets ago and didn't opt to change it! buggger.


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 Post subject: Re: QLD Raceway sprints
PostPosted: Sat Sep 20, 2008 9:52 pm 
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Location: Brisbane
Hot day, plenty of runs, no smashed cars, we got garages, what more could you want. Pic of mine looking like its going fast :giggle:


Attachments:
[ attachment ]
QR 20 Sep 08 sprints.jpg [ 26.09 KiB | Viewed 2675 times ]

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