R32 Gtr Circuit Car Build Thread

[RS581]

Very nice Ollie, who did all the fabrication / cage etc: ??

[OLLIE_NZ]

Not really an update as such chaps but a small problem that has started to develop

My problem is a misifre which has become almost constant on our R32 GTR (track only car)

Any time under hard acceleration and high revs the car has quite a severe miss just a fraction of a second after we change gears and give it full throttle again

It only lasts for a fraction of a second too, just long enough to sort of throw your head back slightly then all is back to normal until the next gear change.

It happens regardless of whether the car is full of fuel or not.

I was at Hampton Downs track last Saturday and it happened after every gear change when I came out of the corners and gave it full throttle.

So without spending money on replacing Coils, plugs, ignitor pack etc is there a sensible place I can start lads?

Car is relatively standard with an Apexi Power FC, running just over 1 bar of boost.

Unfortunately I've flown back to Wellington and didn't have time to check the spark plugs etc. but thought someone might be able to point me to the most obvious area to check first when I next fly home for the weekend.

[Beer Baron]

well the little power FC miss is pretty common. you can try re-grounding the igniter, try improving the grounding points overall (can add a ground wire kit, it can help). obvious points are spark plugs and coils (check the plug gaps and heat range etc). but it can and does happen with power FCs that they get a little 'hiccup' every now and then. not usually as regular as you describe though. try the basic things first, next time you're at the track try and borrow a set of known good coil packs and see if that helps etc. just basically trial and error till you hit the problem.

[OLLIE_NZ]

Small update, no new pics sorry.

Had the plugs out, re-gapped them as they were quite out. We bought a set of cheaper NGK plugs to take to the track to see if they sort the misfire issue before we shell out for a new set of platinums.

Had a little spend up on some Ikeya bits also

- Roll centre adjust pillow arm kit

- Front upper link (non adjustable)

- Rear camber adjuster upper arm set

- Traction adjuster rod set

We're hoping to move up to some 18x10.5 or 11" rims and run Michelin 27-68-18 slicks (if we can get them to fit) or something similar in Dunlop as we plan on running some large brakes soon.

We've had the injectors out and them serviced

MARGIN OF ERROR +/- 2%

02.05.2011

NISSAN/JECS 1 2 3 4 5 6

WIDE OPEN FLOW TEST % 100% 99% 98% 99% 100% 100%

WIDE OPEN IN 1 MINUTE @ 300 KPA 500cc 495cc 490cc 495cc 500cc 500cc

PULSED FLOW TEST % 100% 99% 99% 100% 98% 99%

5.0 M/S PULSE WIDTH @ 7000 RPM 276cc 274cc 274cc 276cc 271cc 274cc

LEAK TEST pass pass pass pass pass pass

PATTERN TEST excellent excellent excellent excellent excellent excellent

[OLLIE_NZ]

Ended up spending a couple of hours on the lathe on Saturday making some aluminium spacers and bushes for the rear subframe.

Our factory Nissan bushes from the top of the subframe to the chassis measured 30.5mm at the rear and 28.5mm at the front with the subframe out of the car.

The subframe bush kit we bought reduced that down to only 9mm both front and rear of the subframe

We machined up two 4mm aluminium spacers to put in the rear of the subframe.

We're going to take Riskings advice (thanks mate) and make up a few 'C' shaped spacers for the rear of varying thickness's that we would be able to slip into the subframe without having to unbolt the whole lot.

4mm aluminium washer for the back of the subframe

Washers and spacers done

Rear about to be tightened up (showing how the spacer slots inside the subframe bush)

Rear

Front

Diff bolted back up with new Powerflex bushes

[Risking]

One thing to remember in the future.

Don't measure bush heights unladened.

When the weight of the car rests onto the top of the bush it compresses. They don't compress the same amount either front and rear of the subframe.

If you read the other thread the numbers I mentioned were ladened.

[savant]

Hi Risking,

Can you please PM how much your chromolly subframes are? We were discussing while putting it back together how it is probably easier to buy something from someone who knows what they are doing such as yourself, rather than us trying to figure out adjustable mounting points etc etc. We will probably pull the subframe out again in the next few months as we will be pulling the hub carriers off to finish rebushing them.

Cheers

[OLLIE_NZ]

This box arrived a few hours ago from Japan!

[Boss-zilla]

mmm yum

[sven]

mmm pretty bits, build has come along well mate looks really good...

[OLLIE_NZ]

Hey fellas,

I'm hoping you guys might be able to help with some ideal starting figures for camber, caster and toe-in?

The car is getting a wheel alignment on Friday and we're not really sure on a good base set-up for our car (circuit only)

Currently it has a Cusco sway bar in the front, stock sway bar in the rear.

HKS hipermax III coilovers

Running 17x9" rims with Dunlop 240/625R17 slicks

Ikeya stuff we've just fitted is:

Front upper links

Front lower arms (haven't fitted the roll centre adjusters yet) - adjustable

Rear upper arms - adjustable

Rear traction rod adjusters - adjustable

It also has the Driftworks total hicas eliminator kit

Solid subframe bushes with a 4mm spacer at the rear.

Cheers.

[Beer Baron]

well it's one of those things you really need to try and adjust as appropriate. tyre type makes a difference as does car set-up, track, power level etc.

I would start with:

front:

3-3.5 degrees neg camber

as much pos caster as you can comfortably have with the 3 degrees neg (around 6 to 8 degrees)

a bit of toe out, maybe .5mm each side (depends on how 'pointy' you like the car to feel)

rear:

1 degree neg camber

traction rods can be set to get the upright more upright

toe maybe 1mm toe in (again depends how pointy you want the car, toe will really change how the car steers)

see how you go from there. you might find you want even more camber at the front with slicks on.

also I reckon with the big cusco front bar and standard rear you ere going to battle some understeer. I'd go back to a stock front bar, or upgrade the rear to a cusco to match the front. even in standard form they have a bit too much front bar relative to the rear which makes them prone to understeer at the limit of grip. especially if you are going into corners a bit too hot.

[OLLIE_NZ]

^

Thanks for the help Beer Baron

Willie (savant) did some rough height measuring tonight and the ride height of the car is 330mm all round from the centre of the wheel to the top of the wheel arch, we're wondering if that is a good ride height or not?

Fitted all the new Ikeya gear

Taking it for a wheel alignment tomorrow to get the camber, caster and toe sorted.

Going to test it at an open day at Hampton Downs next Saturday (July 2nd) http://www.hamptondo...ircuit.htm#here

Stock Nissan arms vs new Ikeya stuff

Front upper arms are 15mm shorter than the stock ones

Got the cut off wheel busy and cut off the rear brake backing plates

Rear

Front

[Beer Baron]

330 is not bad. try raising the front a bit to 340mm. I think most circuit 32s seem to be happy around 340-345 rear and 350-355 front. you need the front a little higher than the rear. 2 reasons. for some reason attesa works much better and of course it's gives the car some squat and you need the front travel too.

I still think you need to do something about the swaybars. having a big upgraded front bar but standard rear is going to make the thing want to understeer a fair bit. I'd either go back to stock front bar for now, or upgrade the rear.

[djr81]

330 is not bad. try raising the front a bit to 340mm. I think most circuit 32s seem to be happy around 340-345 rear and 350-355 front. you need the front a little higher than the rear. 2 reasons. for some reason attesa works much better and of course it's gives the car some squat and you need the front travel too.

I still think you need to do something about the swaybars. having a big upgraded front bar but standard rear is going to make the thing want to understeer a fair bit. I'd either go back to stock front bar for now, or upgrade the rear.

Yeah go get a Cusco rear bar.

[sav man]

How come you got a ikea formula upper arm (non adjustable), instead of an adjustable upper arm for the front? Or did it all come in a kit?

[savant]

We went non adjustable after reading how rubbish most of the adjustable arms are for serious track use. The lower arms are adjustable at one end so we can fine tune camber with the lower arms and get a little bit more track at the same time. These arms being 15mm shorter run about 3 degrees static camber anyway, with the lower arms adjusted we are aiming for 3.5-4.

We are waiting for Cusco to get the rear bar in stock (in NZ), should be available in about a week.

Edited June 24, 2011 by savant

[OLLIE_NZ]

Did a bit of fiddling today with the ride height and made some adjustments to the hicas eliminator bar.

How the car sits (from centre of wheel to top of wheel arch, 340mm front and 330mm rear)

Should we jack the height up a bit more? It's easy enough to do as it's back up on axle stands

Front: is just a touch over 4 degrees (still needs the wheel alignment, only half done)

Rear

Can anyone help me with the front springs they read '25 250 59 118' and are Merwede (basically unsure what most of the numbers mean)

Rear springs , read 'Merwede Progressive 250 49 98' (again unsure what most of these mean)

Another question in the pursuit of weight saving, do we need the hi-cas computer? Does it have any effect on the Attessa system or any other functions at all? (obviously our entire hi-cas system has been removed)

Lastly, this little box that mounts behind the red arrow, what is this and do we need it

[sav man]

Yep rip the HICAS ecu out, it doesn't interact with any other ecu's, even better cut the loom of it out aswell. The other box is the timer for the rear demister, depends if you're running the demister or not.

[OLLIE_NZ]

^^

Thanks Ben, not running the rear demister so all that rubbish can go