too much weight reduction?

[nineteen_twelve]

hey guys, i have one question to ask. is too much weight reduction (as in stage 3) can have adverse effects in handling? i am planning to tune a R34 skyline into a racing machine and i want to apply weight reduction to it. i have previously done that to an R33 skyline and its handling was very twitchy. i applied stage 3 weight reduction and it went to full blast. however, as i tested it in the nurburgring, its performance withered away. it got three wheel spins at the long straight just before the start/finish line. it also has the tendency to oversteer at tight corners, just like in the last turn in apricot hill. can you advice me what stage of weight reduction can i apply to my skyline? thanks.

 

[Flerbizky]

Reducing weight will without a doubt make a change for less stability.

Am I correct when guessing you're messing around with 800+ Bhp ?....

 

[nineteen_twelve]

currently i am having it to around 540hp stage 3 turbo. i have'nt done any weight reductions yet

 

[Scaff]

Less weight is always better, with some cars in GT4 even WR3 does not get them down to a realistic race weight. The older Primera 2.0e is a good example, even with WR3 you can't get the weight down to weight of a real BTCC Primera touring car.

What you do have to remember is that as you reduce the weight of a car, you will also need to consider spring and damper settings, as these will need to be checked and possiable reduced as well.

A spring rate of 10 may be soft for a car that weights 2,000 kilos, but it will be very, very stiff on a car that weighs 1,000 kilos; so as a cars weight reduces then you need to adjust the spring rate to suit.

The same logic also applies to damper values as well.

I would suggest downloading and printing off the first of my GT4 tuning guides (click on th elink in my sig to open up the thread and download links), as this subject is covered in greater detail in the guide, as well as a lot more on tuning.

Regards

Scaff

 

[VQuick]

You can't take away enough weight on an R34. Just fix your suspension settings like Scaff said.

 

[nineteen_twelve]

i bought the original suspension set from HKS and the stage 2 weight reduction. it performs well as i adjust the suspension settings. control is normal, though the car 'shivers' as it run at high speeds. does this mean instability or just an effect?

i also have it applied on my viper GTS and corvette ZO6. it works fine, though it drifts off the line while cornering at tight spots

 

[Scaff]

i bought the original suspension set from HKS and the stage 2 weight reduction. it performs well as i adjust the suspension settings. control is normal, though the car 'shivers' as it run at high speeds. does this mean instability or just an effect?

i also have it applied on my viper GTS and corvette ZO6. it works fine, though it drifts off the line while cornering at tight spots

Could be a number of things, what are the exact settings you are using?

I take it that this is for the Nurburgring and what is the exact model of car?

Regards

Scaff

 

[nineteen_twelve]

here's the specs

model: nissan skyline GT-R V-spec II
power: 822hp

suspension: original from HKS

suspension settings

spring rate: front: 8.0 rear 10.0

ride height: 115mm (both)

shock absorbers: 8 (both)

camber angle: 2.0 (front) 1.0 (rear)

toe angle: 0 (both)

tires: medium racing

weight reduction: stage 2

lap time: 7.08.234

here is it...

 

[Leonidae]

aren't those stock suspension settings?

 

[Scaff]

aren't those stock suspension settings?

They certainly apear to be, and with an 800bhp Skyline at the 'ring you certainly need to have a tweak to get the most out of the car.

First place I would personally start is the Dampers, the default values are normally far to firm for the 'ring, and are also not going to help you get the power down.

Reducing the damper values would be my starting point, but if I get a chance I will run the car tonight and see what I can come up with, could you post up a complete list of the mods carried out to the car.

I must also confess I would go for Racing suspension at the 'ring as the ability to set bound and rebound seperatly is valuable given the bumps, crests and compresions that the track has.

Regards

Scaff

 

[stiggs]

i have the settings for my v-spec II floating round somewere it as 911 bhp
probably could be tweaked a little more for the ring, i managed a 6:29 though it wasn't a clean run left the track twice, they may help you as soon as i have found them i'll post them in here for you 👍

doh forgot to mention it as stage 3 weight reduction on it

 

[stiggs]

here's the specs

model: nissan skyline GT-R V-spec II nur
power: 911hp

suspension: racing

suspension settings

spring rate: front: 8.9 rear 10.7

ride height: 102 / 104

shock bound: 5 / 4

shock rebound: 6 / 6

camber angle: 3.0 / 1.8

toe angle: 0 / -1

tires: medium racing

weight reduction: stage 3

and everything else pretty much racing exept stage 5 turbo from tunning village HSK i think

Downforce: 30 / 33

Asm over: 0

Asm under: 0

Tcs: 0 - 3 no higher than 3 as this will lower your top end speed, personaly i go with 0

lap time: 6.33 ish.

Now i did have both vcd and fully custom'd LSD on her originally and found that she too would leave the line in tight turns and display the wobbling at high speeds so i set the gears to 16 auto then slid the final drive to 3.235
which seems to work fine on the ring but didnt fix the problem so i red through some of the forums on here to see if i could find any posts about cars with simular problems and did manage to find a few posts though i cant recall the links how ever, to fix the wobbling ditch your fully custom LSD and VCD use 1.5 way instead and that should sort it out

👍

 

[Scaff]

Now i did have both vcd and fully custom'd LSD on her originally and found that she too would leave the line in tight turns and display the wobbling at high speeds so i set the gears to 16 auto then slid the final drive to 3.235
which seems to work fine on the ring but didnt fix the problem so i red through some of the forums on here to see if i could find any posts about cars with simular problems and did manage to find a few posts though i cant recall the links how ever, to fix the wobbling ditch your fully custom LSD and VCD use 1.5 way instead and that should sort it out

👍

It is a known issue with the LSD and VCD and has been covered here a few times before, its also covered in the second of my tuning guides.

Basically put, certain cars which as standard are fitted with 'trick' diffs by the manufacturer (and the R33 and R34 Skylines are excellent examples) perform better if you don't fit any form of LSD and/or VCD. The standard diff is already more than good enough.

Regards

Scaff

 

[nineteen_twelve]

yes they are stock suspension settings. i have not modified them during the last test run. is the lsd have to be tuned also?

 

[stiggs]

yes they are stock suspension settings. i have not modified them during the last test run. is the lsd have to be tuned also?

i and scaff have both said your better off leaving the vcd and lcd as they are when you first buy the car but its up to you really

 

[nineteen_twelve]

i have disabled the lsd and i got better handling on the track. i have also adjusted the suspension settings tuned to track conditions. it performs nicely than it was before. thanks guys!

 

[Scaff]

i have disabled the lsd and i got better handling on the track. i have also adjusted the suspension settings tuned to track conditions. it performs nicely than it was before. thanks guys!

No problem at all - just glad to help.

👍

Scaff

 

[stiggs]

glad to hear you managed to sort out your car:tup:

 

[Rick G]

I have had problems getting cars to go around nurinburg circuit. Then I found if I reduce the spring settings to about 10.4 in front and10.8 in the rear that most of my cars perform better. Plus on two laps around this circuit you have to have hard tires in the rear. I use medium racing tires in front and hard racing tires in rear.