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Location:
Terrigal
Registered:
May 2002
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eliminating body roll - ra28
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Mon, 27 May 2002 01:15
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Hello, I ran the RA28 around Wakefield last week. Went quite well and was happy..
Main problems I could see was no brakes after a few laps.
This can easily be solved with brake upgrade..
Other prob was a fair amount of body roll around hard corners.
Currently the setup is :
Pedders sports ryder shocks all round
1" lowered king springs all round
whiteline adjustable front sway bar
I think most the roll was coming from the rear, i could see from some pictures that were taken of the car the rear wheel on the outside of the corner is right up in the arch.
What ways is best to rid of car of so much bodyroll and get it sitting flatter?
BTW total weight of the car after 3t-gte engine conversion is 1100kg. - Not sure if this is relivant.
Thanks
Joel
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Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 02:30
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get a roll cage !!
looks madddddddd 2 
Mr Enforcer Engineering
Chipping Norton
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Location:
Wollongong
Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 06:52
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Huge sway bars did wonders to the sloppy handling of my old Camry. I got some K-Mac bars fitted... 26mm front and 24mm rear.
I couldn't get the car to roll again after installing those babies... I could take corners virtually flat (and much faster of course!)
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Location:
Terrigal
Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 06:57
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Sounds good. I will have to look into getting a rear sway bar.
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Location:
Newcastle
Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 08:31
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What times did you run?
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Location:
melbourne
Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 11:04
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run 24mm for front bar i would not worry about back bar as it will make car oversteer ,buy some good shocks like bilstein or konis front springs 250 lbs rear 110 to 145 and your car will go around corners ,also you said you had a adjustable bar what size i have a 20mm set 2 holes back from full bar this stops me lifting the front wheel off the track in corners ,i have been told my front wheel get to 150mm off the ground with full bar .
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Location:
melbourne
Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 11:06
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also for a simple brake up grade use RT132 brakes off a corona liftback will bolt straight in and will do the job for track work for a while
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Location:
Tasmania
Registered:
May 2002
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Re: eliminating body roll - ra28
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Mon, 27 May 2002 13:59
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I would go stiffer than standard springs all round, not sure of exact specs (front are stiffer than the back). And maybe 26mm anti-roll bar up front. 15-19mm anti-roll bar at the back. Good shocks all round.
Go for vented disks off a RA60, will bolt on. And get the RA60 matching calibers, but you may need a conversion plate made to bolt on the calibers. With a disk upgrade, forget anything that is not vented.
Then either lengthen the control arms or get adjustable tops for a bit of neg camber, and increase the caster a bit (alot). This will reduce understeer.
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Location:
Terrigal
Registered:
May 2002
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Re: eliminating body roll - ra28
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Tue, 28 May 2002 04:44
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Best time was around 1.30 .. Thought this was ok for my first go on a track.
Thanks for all the info being supplied. Looks like i'll be changing a few things..
Are the pedders shocks ok, or these should go?
Also is it possible to find out what rate my springs are so I can determine if they need replacing or not?
Does anyone have some ideas about adjusting the whiteline sway bars? I think the bar has 4 holes and the bit that bolts to the control arm has 3 holes.
Thanks again.
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Location:
Eastern Sydney
Registered:
May 2002
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Re: eliminating body roll - ra28
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Tue, 28 May 2002 08:36
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how to eliminate roll? you can't eliminate it toally,and not get bump-steer,but you can reduce it.
sway bars are the best bet. the whiteline units work quite well,I have their fixed bars in my car,and have fitted quite a few adjustable units to friend's silvias.
for the RA28,you can also use their roll centre adjusters,which I'd recommend if you've lowered the car. these reduce bump steer,and take a LOT of roll out of the chassis in the sprinter.
seeing as the 28 is quite similar,you could expect similar results.
if you haven't fitted better shocks and springs yet,I'd recommend that next after the sways.
Justin...
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Location:
Tasmania
Registered:
May 2002
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Re: eliminating body roll - ra28
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Wed, 29 May 2002 03:37
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Roll centre adjuster blocks do not effect bump steer. They effect roll center. If you lower the car 2", you can use a 2" block under the strut to maintain factory roll center height. Weather the factory roll center height is at a good position or not I do not know. It is hard to get the bump steer out of these cars without modifying the steering knuckles. Although stiffer springs and bars means less suspension travel, which means less noticable bump steer.
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Location:
Eastern Sydney
Registered:
May 2002
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Re: eliminating body roll - ra28
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Wed, 29 May 2002 09:18
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Jonny,
let me make what I said clearer.
if you lower an early toyota,you will increase the bumpsteer-as the steering links straighten out. if you then add roll centre adjusting blocks,the arms return to the factory position,which brings bump steer back to the level you originally had.
this is what I meant by "they reduce bump steer" -in a lowered car,they will. in a std height car,yeah,I doubt they would help.
please note that the sentence directly before 'they will help reduce bump steer" was "in a lowered car..."
Justin...
| Jonny2TG wrote on Wed, 29 May 2002 1:37 PM |
Roll centre adjuster blocks do not effect bump steer. They effect roll center. It is hard to get the bump steer out of these cars without modifying the steering knuckles. Although stiffer springs and bars means less suspension travel, which means less noticable bump steer.
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Location:
Tasmania
Registered:
May 2002
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Re: eliminating body roll - ra28
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Wed, 29 May 2002 15:16
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I understand what you are saying, but I disagree. If you have bump steer, I don't think changing the height or the roll centre will change things, you still have bump steer. I don't think lowering will increase bump steer. If you have bump steer you need to change the way the steering arms/ control arms/ steering knuckles relate to each other. Adding roll centre blocks does not effect this at all, but only changes the roll center, nothing else. There is no easy way to get rid of bump steer on a standard car if that is what you have. Roll center height can easily be adjusted though.
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Location:
Terrigal
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 00:54
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Sorry for the dumb question but what exactly is roll center?
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Location:
Sydney
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 07:08
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joel just curious.. 1100kg.. what was in the car..
stereo stuff? fuel wise etc...
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Location:
Terrigal
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 07:13
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It was actually 1120 with almost full tank of fuel and stereo gear.
I have actually removed the stereo gear now and saved close to 30kg!
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Location:
Eastern Sydney
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 07:28
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| TurboRA28 wrote on Thu, 30 May 2002 10:54 AM |
Sorry for the dumb question but what exactly is roll center?
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Roll centre is the theoretical point in the chassis where the weight pivots from when you apply a side load (i.e. turn into a corner).
the closer you can get your roll centre to the centre of gravity,
the less tendency the car will have to rolling,as you shorten this pivot's length.
roll centre adjusters are necessary with some live axle cars (e.g older toyotas)when they are lowered. this is because the rear roll centre is most commonly the centre of the diff housing,which doesn't alter when you lower the car. unfortunately,the front RC does move,and you end up with a low front RC,and a high rear RC,which isn't the best-the car will tend to roll over itself-pivot from the rear axle before the front.
roll centre adjusters bolted to the base of macpherson struts lift the front roll centre,fixing it's relationship with the rear,as well as bringing the RC and the CoG closer together.
the result is greater overall stability,and less body roll,but without the downsides that very large swaybars give for the same roll reduction.
the only downsides are a small increase in tramlining,and a shift in camber to positive by about half a degree.
Justin...
[Updated on: Thu, 30 May 2002 07:31]
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Location:
Melbourne
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 07:38
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Nothing stops roll like Bilsteins and Konis. I have Bilsteins in my rally car and konis in my road car, neither rolls at all, and they both have stock bars. Custom springs tho. about 140 front and 120 rear.
Where do you get these adjusters from?
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Location:
Terrigal
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 07:57
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Do the roll center adjusters raise the height of the car if they are being placed under the strut?
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Location:
Eastern Sydney
Registered:
May 2002
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Re: eliminating body roll - ra28
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Thu, 30 May 2002 13:05
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| TurboRA28 wrote on Thu, 30 May 2002 5:57 PM |
Do the roll center adjusters raise the height of the car if they are being placed under the strut?
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no,they don't,as they are fitted BELOW the stub axle. the lower arms sit in a lower position than they normally would with an RCA block fitted. ride height is unchanged.
Justin...
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Location:
Sydney
Registered:
June 2004
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Re: eliminating body roll - ra28
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Tue, 08 February 2005 19:22
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guys i know this is an old thread but i would like more info on RCAs...
firstly how can i measure the RC in a car (namely the TA22)? the car im rebuilding has been lowered 2" all round and therefore the front RC is off and i want to know by how much i have to raise it
also in the last post of this thread it states that the ride height doesnt change. how is this so? i dont understand? if you have lowered the car 2" and then have added a block to make the RC stock again then is the height going to change?
thanks
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Location:
Sydney
Registered:
May 2004
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Re: eliminating body roll - ra28
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Tue, 08 February 2005 20:50
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more importantly how much do they cost? 
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Location:
Terrigal
Registered:
May 2002
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Location:
Terrigal
Registered:
May 2002
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Location:
Madrid - Spain
Registered:
August 2002
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 00:53
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I did a write up on roll centre measurements I did of my 28, both with and without RCA's fitted.
http://members.optushome.com.au/gold28/RCA.htm
There is a couple of references in this page to some really good books. If you can't figure out how I put the diagrams together, then I recommend you obtain one of these books. If you are interested in car suspension, they are well worth the investment.
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Location:
Hobart, Tas
Registered:
May 2002
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 03:06
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| Quote: |
If you've lowered the car 2 inches, then probably best to fit a 2 inch RCA. That'll get it back to standard at least. How are the control arms now, is the inside pivot lower than the outside? Or horizontal?
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I have a diagram at home explaining RCAs I drew for someone - I'll post it tonight. But basically:
Say that, stock, your lower control arms are horizontal. When you lower the car by fitting lower springs, the distance between the lower spring perch and strut top os shorter. The control arms are now angled upwards - affecting steering geometry, and lowering the roll centre.
If you add appropriately sized RCA blocks UNDER the bottom of the strut, and ON TOP of where the lower control arm is attached, the lower control arms are now horizontal again, but the car is still lowered. Make sense?
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Location:
Sydney
Registered:
June 2004
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Location:
Melbourne
Registered:
December 2004
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 06:34
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what about strut bracing? my ra28 had pedders comfort gas shocks and sports rider springs, lowered about an inch, big front sway bar but no rear bar.
this made a big difference over stock but i look at my mr2 stock setup and it has strut bracing front and back, and sway bars front and back and it corners really flat!
i have had it on a skid pan under heavy tight turning conditions and photos of it from the outside show how amazingly flat it stays
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Location:
Sydney
Registered:
May 2004
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 06:53
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| BlackMR2 wrote on Wed, 09 February 2005 17:34 |
my mr2 stock setup and it has strut bracing front and back, and sway bars front and back and it corners really flat!
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I think the weight distribution would be on your side with an mr2!
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Location:
Castle Hill, Sydney
Registered:
February 2004
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 08:30
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wow i didnt check the date of this thread, i thought 1.30's sounded a little slow for you joel!!
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Location:
Hobart, Tas
Registered:
May 2002
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 12:03
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Everyone understand now? 
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Location:
Sydney
Registered:
June 2004
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Re: eliminating body roll - ra28
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Wed, 09 February 2005 12:04
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definately understand now... love the photoshop pics 
now who can make me some to fit MX73 struts???
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