Weight Transfer

[JLawrence]

I am absolutely having fits taming one of my old cars at the moment (Spitfire), and it is frustrating me to no end. I've completely killed the wheel spin, and made it a pretty neutral feeling car, that is, until I have to make a corner at any level of lateral g's. I can feel the weight transfer there, and it makes the rear end slide out much like the Yellowbird or the Caterham despite its 52/48 weight distribution. I am running very soft springs, dampers, and anti roll bars on it right now. Camber and toe are at a low(ish) level as well.

Could someone please explain how to settle down weight transfer for me? (And don't be afraid to get technical)

 

[CSLACR]

I am absolutely having fits taming one of my old cars at the moment (Spitfire), and it is frustrating me to no end. I've completely killed the wheel spin, and made it a pretty neutral feeling car, that is, until I have to make a corner at any level of lateral g's. I can feel the weight transfer there, and it makes the rear end slide out much like the Yellowbird or the Caterham despite its 52/48 weight distribution. I am running very soft springs, dampers, and anti roll bars on it right now. Camber and toe are at a low(ish) level as well.

Could someone please explain how to settle down weight transfer for me? (And don't be afraid to get technical)

Over-steer feels neutral until the back end comes out.
The easiest way to fix it is raise the rear ride height, or lower the front ride height.

 

[ACSR421]

I was having similar trouble tuning my Shelby gt350r online today when my PS3 died but I learned that it doesn't like the ride height set very low and I had to run the rear springs stiffer with low damper settings. I also raised the front springs to balance the car out but had to run them a little stiffer than I wanted too. This made a big difference for me but I never got to finish dialing it in. May be worth checking as I seemed to be headed in the right direction with the Shelby.

 

[JLawrence]

It is oversteer, yes, but oversteer brought on by uneven weight transfer. I currently am running the ride height at -8/4 which is about as big a gap as I feel there could be while still keeping some semblance of balance.

My problem lies in how my springs, dampers, and roll bars are set, though I feel I am making progress here with it, it still is not quite right. I am currently working from Highlandor's theory and it seems to be helping, but if I understood some of the physics here I think it'd be a lot easier. I've been running through my usual repertoire of techniques, ie- your standard raise the front, lower the rear, shenanigans, but for once that hasn't fixed it entirely. I may post a video here so I can show you what I am referring to as opposed to trying to explain it.

 

[oppositelock]

I am running very soft springs, dampers, and anti roll bars on it right now.

There's your problem. I curious for your reasoning for this if your goal is less weight transfer.

 

[CSLACR]

There's your problem. I curious for your reasoning for this if your goal is less weight transfer.

Yes, and from what I've seen sway bars have the strongest effect on weight transfer in GT5.
It's a light car, I wouldn't recommend real stiff suspension overall, this might be fixed with just swaybars.

If the OP posted an exact tune it would help though.

 

[JLawrence]

Here is my current, and most balance suspension set up thus far (220Hp, 815Kg, 460Pp)
Ballast: 71Kg @ -49 making the distribution 52/48, but it still slings out the rear like it is the opposite
RH: -8/4
SR: 6.9/7.1
D(E): 5/5
D(C): 5/4
ARB: 7/6
C: 1.7/1.1
T: -.05/-.04

Weight distribution / center of gravity towards rear / center of gravity towards front
Front sway bar / softer / stiffer
Rear sway bar / stiffer / softer
Front shock absorber / softer / stiffer
Rear shock absorber / stiffer / softer
Front wheel camber / increase negative camber / reduce negative camber
Rear wheel camber / reduce negative camber / increase negative camber
Front height / raise front end / lower front end
Rear height / lower rear end / raise rear end
Front toe in / decrease / increase
Rear toe in / decrease / increase

All of that aside from the ride height is how it applies in the real world, and how I try to tune in the game. I have some that seem a little off, but that is what it took to balance it out in terms of pushing and pulling in the corner (not considering the weight transfer)

 

[Sail IC]

I find springs/dampers/ARB to have faily little effect on balancing the car.

You run with a negative rear toe which will increase oversteer, so its set contradictory to your handling problem. Change it to positive starting lets say with 0.15 and see what's happening. I would even go as high as 0.30. If you then start to get too much untersteer I would as a first step start removing ballast or make the ridehight more even.

The other thing you can do is install an adjustable LSD. Then a whole new avenue opens to tune the car.

Your Ridehight looks good to cure oversteer and its quite substantial so I wouldn't go any further as you might get strong front tirewear over longer distances.

On a car difficult to handle, setting the suspension soft makes the cars handling a bit more dozzle giving you more time to react, so not such a bad idea. But you overall grip level will go down a bit if too soft.

 

[esoxhntr]

you havent told us where the oversteer occurs (or I missed it) is it turn in, mid-corner or exit?

some general things to try.. aforementioned rear + toe, more rear camber (as it relates to front) or less front, softer rear springs, softer rear swaybar. if the oversteer occurs on turn-in, stiffen the rear extension dampers and/or front compression, if on exit, soften front extension and or rear compression.

 

[Highlandor]

Here is my current, and most balance suspension set up thus far (220Hp, 815Kg, 460Pp)
Ballast: 71Kg @ -49 making the distribution 52/48, but it still slings out the rear like it is the opposite
RH: -8/4
SR: 6.9/7.1
D(E): 5/5
D(C): 5/4
ARB: 7/6
C: 1.7/1.1
T: -.05/-.04

Hi Lawrence..

I just crunched some numbers:

With 71kgs of ballast @ -49, confirmed as you wrote, this 'reverses' the weight distribution from 48fr - 52rr to 52fr - 48rr.

The springs, according to my theory would be starting at (then adjusted by % to suit track / driving style etc etc):

Fr = 8.8
Rr = 8.0

But you have yours:

Fr = 6.9 (alot less than 50% of 'travel')
Rr = 7.1 (same as fronts, less than 50%)

Dampers Fr & Rr = 50% (approximately)

Roll bars FR & Rr = nearly 100%

My initial thoughts are that this is going to cause in-balance in the handling in my opinion. I'm not sure why you'd need the ballast at the front to be honest. I can 'balance' cars that have 40-60 or 60-40 weight distribution or even worse than that, so 52-48 shouldn't be too bad to 'sort out'. Before I start making recommendations, as others said in this thread:

1) where is the oversteer happening???

Under braking
When you 'lift off' brakes and turn in
Under acceleration out of corner

2) You haven't quoted LSD, brake, tyres and whether this is offline or online, but after racing with you on Saturday I'm presuming the answers to the last two are online and racing hards.

Can you confirm your brake figures??

What's happening with your tyres, are your fronts and rears heating up the at the same time, or are either of them at operating temp and the other still cold?

Which tyres, if any, are going 'red' and where / when is this happening in terms of braking, turning in and accelerating out??

An LSD has a big affect on the car's handling, especially with this historic cars that seem to be in a world of their own when it comes to grip levels (compared to modern cars) online. It's dificult to recommend changes without knowing about the LSD and brakes, but from your setup post I'd say.

Front springs too soft (compared to rear) and roll bars to high to start off with, but almost impossible to diagnose accurately until all the missing info is quoted.

I'll be chilling in my lobby late night, pop in if you're not racing, we'll try and sort this out for you.

I find springs/dampers/ARB to have faily little effect on balancing the car.

I'm the opposite, I find these parts of setup's are very important for balance (sorry Johan!!).

I agree with what you say on ride height and toe in your post though 👍 but be careful, too much + rear toe can sometimes cause understeer at the front.

 

[zodicus]

what i did with my fireblade was i ran a pretty stiff spring because, It can corner very hard so while in a corner the load on the suspension will be very high even with its low weight. Then so that the car dosnt get upset on uneven roads i ran the roll bars low. With the dampers i figure there isnt a lot of weight there to controll so i ran them pretty low as well, slightly higher on rebound because of the high spring rate, i didnt want it to bounce. All this helpped the car a lot but it still felt real slippery. So i got real aggressive with the diff settings 30/60/30 if i remeber right,this helpped a ton! I love driving the car now (well i did before but...) The theroys behind what i did make sense to me, weather its the best set up idk but i can drive it and reasonably predict what its gonna do.

 

[JLawrence]

The other thing you can do is install an adjustable LSD. Then a whole new avenue opens to tune the car.

Your Ridehight looks good to cure oversteer and its quite substantial so I wouldn't go any further as you might get strong front tirewear over longer distances.

.

Alright, you guys are probably going to call me crazy for what I run on my differential, but on this car I like for it to be semi-locked, and it works (For me at least).
Initial Torque: 37
Acceleration Sensitivity: 18
Braking Sensitivity: 32

I just crunched some numbers:

With 71kgs of ballast @ -49, confirmed as you wrote, this 'reverses' the weight distribution from 48fr - 52rr to 52fr - 48rr.

The springs, according to my theory would be starting at (then adjusted by % to suit track / driving style etc etc):

Fr = 8.8
Rr = 8.0

But you have yours:

Fr = 6.9 (alot less than 50% of 'travel')
Rr = 7.1 (same as fronts, less than 50%)

Dampers Fr & Rr = 50% (approximately)

Roll bars FR & Rr = nearly 100%

I would just like to say that in my numbers crunching I completely failed to get that for a spring rate.

1) where is the oversteer happening???

Under braking
When you 'lift off' brakes and turn in
Under acceleration out of corner

2) You haven't quoted LSD, brake, tyres and whether this is offline or online, but after racing with you on Saturday I'm presuming the answers to the last two are online and racing hards.

Can you confirm your brake figures??

What's happening with your tyres, are your fronts and rears heating up the at the same time, or are either of them at operating temp and the other still cold?

Which tyres, if any, are going 'red' and where / when is this happening in terms of braking, turning in and accelerating out??

It loses traction mid, to late corner, generally after apexing, and more often on off camber corners.

It is online, for my vintage series, so it has to meet those specs.

Brakes are 3/5

The only tires that ever "light up" are the fronts due to it pushing if I over cook it into the corner. The rears don't do a thing until its already sliding around. It's not getting throttle oversteer

 

[Johnnypenso]

Raise the rear and/or lower the front to create a bigger ride height differential.

 

[Leonidae@MFT]

Rear end behavior is mostly a result of toe, diff and dampers. I can try fixing it for you, but there's a small price tag attached.

 

[JLawrence]

Man..I'm too poor to pay attention.

 

[Leonidae@MFT]

Heh, all you need to do is a review a car from our garage, then send the Troublesome Triumph to me to be hammered into obedience.

 

[JLawrence]

Haha, I think I can manage that, though I will send you an exact replica instead of the one I'm working on. Highlandor and I did some more work today and it is starting to get better.

 

[iamjajo]

I like the little Spitfire. I used to own a Triumph Sprite and lusted after the Spitfire many years ago.

Mine is tuned a little less than yours:
145HP
809kg
407PP

I just ran it around Tsukuba on 3 different types of tires

CS - 112.5
SH - 110.6
SS - 107.5

Nothing scientific, just two laps on each. I never felt any tendency to oversteer on any of the tires I tried. Here's my setup

Ride Height -11/-8
Springs 4.9/3.7
Ext 7/8
Comp 4/5
Bars 3/3

Camber 1.0/.7
Toe -.05 / .13

Diff 12/30/8
Trans 4.200@117mph

I used the Apex Guide (which some people call useless and pathetic) methodology to do the following, in this order:

Reduce corner entrance understeer
Reduce mid-corner understeer
Reduce corner exit understeer
Correct unwanted oversteer, as necessary

The soft comp front shock combined with the soft spring allows the car to shift weight forward when I brake for a corner.

The front ride height reduces understeer. Rear counters oversteer.
The firm Ext front shock keeps the front wheels planted
The firm Ext rear shock keeps the rear wheels planted
The soft rear spring helps reduce oversteer allowing rearward weight transfer during acceleration.
The medium firmness rear shock helps transfer weight forward.
The rollbars are just personal preference. I used them to reduce the car's tendency to wander and feel 'floaty'.

For the LSD, you can look at the car's HP and Torque output. It's got a little HP peak that can hit during corner exit. Couple that with the skinny rear tires, and I used these settings to reduce throttle-on oversteer issues.

I think you need to reduce your LSD settings to resolve your oversteer issue. I'd do that before making any other adjustments - if you like the way the car drives with the exception of that issue.

 

[JLawrence]

I love the Spitfire, its my favorite car, and I race a 1963 1147 Spit.

I tried it first with a more open diff, but it seemed to get more bite with a semi-locked setting, and no wheel spin what-so-ever. I actually like your setup a lot , and it is very much like the one I have been running on the car I have matched to my real life car (I think I may even keep that suspension on it). I think the difference here is because of the massive difference in the power to weight ratio.

Also, I forgot to mention before, but I am running on RH tires.

 

[CSLACR]

Initial Torque: 37
Acceleration Sensitivity: 18
Braking Sensitivity: 32

You like what you like, but you should know, higher numbers hasn't been proven to increase grip, from what I've seen, you can gain some rear grip by lowering both the initial and decel dramatically.

 

[JLawrence]

Proven or appear to?

 

[Highlandor]

Proven or appear to?

I use lower figures Lawrence...

I'd definately recommend you lower at least one of them anyway!!!

H

 

[CSLACR]

Proven or appear to?

I know some drivers think they do, but lap time evidence suggests strongly that lower is faster round a track.

 

[JLawrence]

I generally do too, but this one honestly just feels better lower for some reason. I'll try it again though.

 

[iamjajo]

I'll look at the effect of adding more HP and changing the LSD to your settings. If it's throttle-on oversteer, then there are some changes that can minimize the issue.

If it works, I'll post the changes to my setup.

PS. I also have a very good setup for the Jaguar E-type Coupe. It's a fun car to drive at 450PP. And, I have a higher powered one that won a couple of the supercar seasonal races (on racing soft tires).

 

[JLawrence]

I personally don't get any throttle oversteer, but I never hammer the gas out of a corner just out of habit, so keep that in mind.

I'd be interested to give it a go. 200MphFord has a pretty brilliant setup in the Vintage Tuning Garage, but it is all the way up at 509Pp, so a little slower set would be fun to try

 

[iamjajo]

I adjusted the Spitfire and re-tuned it.

220HP
809kg
463PP

I added a Stage 3 Turbo to get the HP up, and adjusted the power limiter for 220HP.

I also added chassis reinforcement to help combat the wallow.

I did not use any ballast.

Ride Height -9/-6
Springs 5.0/3.9
Ext 7/8
Comp 4/6
Bars 5/5

Camber 1.5/.5
Toe +.10/+.12

Diff 18/25/8
Trans 3.506@140mph

Yes. I raised the ride height for the more powerful car. Two reasons: I wanted more suspension travel, and the car had some issues with curbs (on Nurburgring).

The LSD settings. I tried using the numbers you provided, but had 2 issues. First, corner exit understeer. Second, the car was unstable under hard braking. I could have adjusted other things to compensate, but this was the easier route to get a good driving car that I could run with consistent lap times.

The stiffer anti-roll bars really helped fine tune the feel for me. When added to the chassis reinforcement, it made the car feel much more stable at speed.

The racing hard tires work really well when warmed up, which doesn't take long.

I think you'll like this one, but feel free to adjust for your own preferences.

I was in the 1:02s on Tsukuba and ran an 8:02 on the 'ring. Fast enough to win the British lightweight races (I think, but the server is down). I didn't get to try it online, but I don't think you'll have a problem. The car feels pretty good.

 

[JLawrence]

Honestly I couldn't even make a turn with out it just spinning like a top before I switched the ride height to -9/2. I'm not sure why, but all of the vintage cars I drive seem to require that sort of gap before they will even start to be reasonable

 

[Sail IC]

Honestly I couldn't even make a turn with out it just spinning like a top before I switched the ride height to -9/2. I'm not sure why, but all of the vintage cars I drive seem to require that sort of gap before they will even start to be reasonable

I still think just changing your rear toe from the negative number you have in your tune to a postitive number to lets say 0.15 is the best way to cure your oversteer problems. Rear toe is one of the most powerful tunes for balance. I like cars with some oversteer and usually have negative toe on my cars, but on cars with inherent oversteer like the GT500 NSX, I do use positive rear toe 0.10-0.20 depending of track.

 

[Leonidae@MFT]

Say, what controller are you using, JLawrence? Because DS3's lightning fast steering inputs can easily upset the car and cause the snappish behaviour you described. Since I have G27, my steering inputs can be more easily modulated than with a controller like DS3. I did have the Spit spin on me, but with few tweaks the rear end is far more controllable under all conditions without diminishing the agility of the car. Your setup had far too stiff spring rates for such a light car, amongst few other things. If you want/can, I'll race my revised version against yours online. Oh, and one other thing: this car desperately needs taller 5th gear.

P.S. This little bugger did a 4-wheel drift all the way through last tunnel of GVS.. Impressive with that little power!