Jump to content
SAU Community

3.9 seconds quicker at SMSP after large increase to Spring Rate - Vid in post.

25GTV
 Share

Recommended Posts

25GTV Experienced

25GTV

Posted
Posted (edited)

Hi guys, I spent days researching spring rates for skylines (particularly GTT R34s) the general info was that 8/6kg setups were too stiff for the road and many said even too stiff for track...  

My car felt way too soft on the track and still too much body roll after doing a larger front swaybar.

I went from 8/5kg to 14/8kg and the car felt amazing and no where near too stiff on track.  The car was also lowered 20mm when the springs were changed.

Result was a 1.547 around Gardner Circuit at SMSP which is still slow.  If you watch my vids, the car is very slidy which is fun but slow and rear grip is the next step.

 

https://youtu.be/PjyTZ4dOq0M

 

Basic info:

Front Tyres 235 Zestine 07R

Rear Tyres Chinese 265s

220rwkw 12 psi

Locked Diff

Drift knuckles (ex drift car)

Shockworks coilovers

Whiteline 24mm F swaybar

Ext front LCAs, basic adj rear arms.

Stock brakes

Bucket Seat, Half Cage and still has climate control.

 

 

Edited by 25GTV
Trying to embed yt vid.
  • Like 1
hattori hanzo Community Regular

hattori hanzo

Posted
Posted

went from 8/6 to MCA Red 13/10 (IIRC) and dropped a similar amount of time around barbagallo 

stops the weight transferring diagonally across and understeering  

set the ride height to the correct spec from mca website also makes a world of difference, it is a little higher than you would first suspect 

 

  • Like 3
Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted
18 minutes ago, 25GTV said:

168km/h on the gps into Turn 1.  Still not completely confident turning it in and I roll off the throttle after the finish line then coast turn 1.

wow that's pretty good!

I'm still a massive chicken shit and the fastest I've been was about 140km/h

  • Like 1
25GTV Experienced

25GTV

Posted
  • Author
Posted
31 minutes ago, Dose Pipe Sutututu said:

wow that's pretty good!

I'm still a massive chicken shit and the fastest I've been was about 140km/h

It's a bit scary...  Especially with a locked diff and zero aero.

  • Like 2
Duncan Grand Master

Duncan

Posted
Posted

Hi mate, glad you are enjoying your time at the track and looking to get your times down.

In my experience you will have more fun and way more lap time success changing things in the following order:

1. check wheel alignment

2. r spec tyres on spare set of rims

3. sway bars (stiffer springs are not the best way to reduce roll as they act in all compression conditions not just roll)

4. shocks and springs (lighter than you have)

5. mechanical diff

6. better pads and discs

7. replace sure all bushes, ball joints, rod ends etc 

8. more power

At the moment it is pretty clear from the video that it understeers mid corner (need more front end grip) and oversteers hugely under power on exit (needs more rear grip). Good tyres will make 200% difference to both of those and you won't really notice the effect of any change until you start with some grip.

Yes (comparably) stiff springs can be OK for track only use, as long as you stay off the ripple strips etc because they compromise the amount of time your tyres spend on the ground over bumps.

  • Like 3
25GTV Experienced

25GTV

Posted
  • Author
Posted

You're probably right Duncan, thanks for the info.  Unfortunately the car budget has very little funds available, so...  

I have in the garage a spare s15 Helcial diff that I believe I can swap the centre and run s15 shafts.

Also, I can add some camber and toe in the rear for free.

The front tyres will have to wait for additional funds...

Kinkstaah Grand Master

Kinkstaah

Posted
Posted

..... also get the rear swaybar. You would be stunned how much difference it makes with regards to turn in. I'm really surprised you didn't have one already from drift duties!

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted

Anti roll bars are very hot topic, I'm personally not a fan of the super stiff setup. From my personal experience, I prefer upping the spring rate (I'm planning to myself, especially for SMSP).

Since Matt's car already understeers, I would not be adding a front ARB, however introducing a rear should aid in it clocking better, however with a slight compromise as the car would snap oversteer much easier.

GTSBoy Grand Master

GTSBoy

Posted
Posted
7 minutes ago, Dose Pipe Sutututu said:

Since Matt's car already understeers, I would not be adding a front ARB

He has massive front spring rate AND a 24mm bar. It has a lot of roll stiffness in the front. It's really no wonder it wants to mid-corner understeer.

I suspect fixing the rear will come down more to getting rid of the welded diff and looking to the wheel alignment, and possibly bump steer geometry.

Plus tyres. The reason the V8 Supercars can get away with spooled diffs is the massively sticky slicks. Just watch how slidey they get on corner exit when the tyres go off.

Dose Pipe Sutututu Grand Master

Dose Pipe Sutututu

Posted
Posted
1 minute ago, GTSBoy said:

He has massive front spring rate AND a 24mm bar

Totally missed that part!

I would set it on the softest setting to aid front end grip, waits for everyone to flame me for saying that LOL

GTSBoy Grand Master

GTSBoy

Posted
Posted
1 minute ago, Dose Pipe Sutututu said:

I would set it on the softest setting to aid front end grip, waits for everyone to flame me for saying that LOL

If keeping the big springs, I would drop to a 22mm, or something. Maybe even a stocker.

Komdotkom Rising Star

Komdotkom

Posted
Posted

Wow, your mid corner grip is terrible.

Put some toe on the back, get some cheap track tyres like AR1's and ditch the locker. If the car is super low you might want to consider changing the sub frame bushes to solids or zero height units at the back and raising the rear, same ride height but your rear geo will be closer to standard giving you better camber and toe curves.

  • Like 1
Duncan Grand Master

Duncan

Posted
Posted

I urge you not to make any further setup changes until you put some proper tyres on it. There is no point trying to improve on a flawed foundation, you will likely find it handles totally differently (strengths/weaknesses) with new tyres.

  • Like 3
25GTV Experienced

25GTV

Posted
  • Author
Posted

The mid corner understeer is probably majority linked to the Drift Knuckle geomerty (extra lock knuckles).  In general they destroy everything whilst giving big lock.

I will say it is great fun to drive like this, predictable when the low grip limit is pushed.

  • Like 1
Kinkstaah Grand Master

Kinkstaah

Posted
Posted

I mean, I didn't drive your car and I am no expert track driver myself, but watching the video makes me think that car handles like an absolute uncontrollable bucket of shit.

I know you've drifted it, but if my 34 sedan started behaving like that it would have ended up on it's roof about five times trying to go around a corner with my hamfisted driving. That exit onto the main straight should absolutely not be a mission like that, in any car ever. It's not only rear grip being the issue there. This is an alarming set of tyres at the very least as mentioned.

  • Like 1
  • Haha 2

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Latest Posts

    • hoodedreeper
      Chris' R34 GTT Series 2

      By hoodedreeper · Posted

      Sorry for resurrecting an oldish thread Not much has happened in the past year since the last update. The car did another 1000 miles or so and failed the MOT for the first time in October (failed on tyres which had been advised for a couple of years) In October the car got put up for sale and was removed in November due to no interest, being so close to christmas it was to be expected. The roads were dry in February so I decided to tax it early and get the new tyres fitted.   Fast forward to April, I got someone in to give the car a good clean after sitting for the winter.                                 The car got re-advertised and today (Saturday 3rd May) the car sold. The new owner is planning a GTR conversion at some point and a respray in the same pearl white. It's bitter sweet, it's a shame to have the car sit there for half the year and then only do 1000 miles. The kids are growing too quick and space in the back is getting limited. It's been a great 6.5 years of ownership
    • MBS206
      Rb26/30 build

      By MBS206 · Posted

      And if you want more power, more reliably, and cheaper, go get the Aussie RB... The 4L Barra and put that in instead.
    • MBS206
      Nismo rear spats

      By MBS206 · Posted

      No cats will keep discolouring the rear bar. Sends white paint a weird yellow stain. Cut and polish normally gets it out, but you'll be doing that every fortnight I found.
    • Butters
      Rb26/30 build

      By Butters · Posted

      Both heads will be equally reliable or unreliable depending on what you do to them.  Stock the RB26 head will flow more. You have access to the stock intake ITB manifold on the RB26 cheaply which flows really well(1000hp+).   Arguably more aftermarket support for RB26, though in Aus we love our RB30 SOHC heads too.    The only downsides to the RB26 head is if you have a VL commodore and want to keep the SOHC look.  Where you may have an issue is drilling out the rb30 block for the bigger head studs but if you are building a big power motor you'd probably put bigger studs on the SOHC head too.  This is just about finding a good machine shop, sometimes easier said than done.  RB30 head worked can make big power just like a Rb26 head, so really it actually more comes down to what your preference is for your car.  People now even making billet versions of both.
    • GTSBoy
      Rb26/30 build

      By GTSBoy · Posted

      2630s work perfectly well. There is something to be said for just using the 30 head, as it saves all the pain of the conversion, still makes tons of power, still sounds cool, etc etc. 2630 will obviously make more power again, but the differences are not stupidly big. It really depends on whether you're racing for sheep stations or not. If it's dead serious, then it's a 26 head. If it's just for fun, it could go either way. But the 26 head and the effort to get it set up, etc etc, is part of the fun.
×
×
  • Create New...