AE92 Race Spring rates

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AE92 Race Spring rates

Postby Linesy » Thu Nov 08, 2018 11:51 am

I am setting up an AE92 for Circuit Racing.
It is currently fitted with a Whiteline rear Sway bar (16mm??), BC Reds with 8KG/mm front springs and 4KG/mm rears.
Poly bushes in the front arms and RCA's.

The car has had one track outing in very mixed conditions making good analysis difficult.

I'm keen to learn where most people land with Spring rates etc and what their real world experience has been.
I'm experiencing Understeer in most corners, so suspect a rear rate increase is on the cards.

Any experiences out there?

Thanks
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Re: AE92 Race Spring rates

Postby Bling » Sat Nov 17, 2018 4:07 pm

No experience with that platform, but ae86 coilover kits (likely aimed at drift...) are 8kg front 6kg rear. I'm going to be 6kg front 3.5kg rear in my AE70, but that isn't a track car.

Do you have adjustable dampening?

I'd do a bit of googling too as there are many forums where spring rate is discussed, as well as sway bar sizes etc. No links as i've only been researching my AE70 platform, but have learned a lot though reading threads on car setups. 8kg and 4kg does seem a bit unbalanced.
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Re: AE92 Race Spring rates

Postby GDII » Tue Nov 20, 2018 11:41 am

I can't give you specific answers for this car but more a general overview of spring rates and swaybars.

Your car is more front weight biased and being FWD the front tyres do all the work. Stiffer front springs will be needed due to more weight in the front however with the rears and you experiencing understeer they are too soft compared to the front. This is a typical trait of spring rates front to rear. A stiffer front spring will make the car more neutral or understeer. Stiffer rears will make it oversteer more. Same goes for the swaybars. If you add a stiffer rear bar on FWD cars or 4WD cars they tend to turn in better. Obviously too much stiffness in the rear will make it too twitchy and hard to drive especially under braking and quick direction changes.

8kg front and 6kg rear is a typical setup for these cars however it is not a hard and fast rule as driving style come into how a car will drive. Or driver preference on how the car is to handle. One person might really like a particular setup while another may not.

Sometimes people will go really stiff with springs and remove the swaybars all together. Sometimes this requires a certain driving style to get the car to turn in.

In the case of the SW20 quite often people will remove the rear swaybar as they are quite a rear biased car so if you drive it correctly the car will turn as you want it. I've disconnected my rear bar but found the handling really odd with too much body roll in the rear but I'm not running super stiff springs in the rear. 3kg front and 5.5kg rear TRD.
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Previous 1990 EE90 Corolla
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Re: AE92 Race Spring rates

Postby 1I1 » Fri Nov 23, 2018 11:14 am

Would say you could do with some stiffer rear springs if you're just doing circuit. 6-8kg range in the rear with that size bar.



I started off in my AE111 with 6kg front and 4kg rear (BC Gold coilovers, stock 25mm front sway bar and a BZR 18mm rear sway bar). Tyres have been either Nitto NT01 or Toyo R888. Cars still used heaps on the road so tried not getting carried away with too stiffer spring rates.
Moved to 8kg front and 6.2kg rear - found that the car much better corner entry and mid corner. Though had to be careful as the front end could push a little if you were too eager on throttle.
Next I put the old 6kg back in the front and left the 6.2kg in the rear. Result was that front end push was gone, could get on throttle at or slightly before apex.
Current setup is now Fortune Auto 500s and 7kg front/rear. Only had limited racing in the dry at Manfeild though but seems better again.


With FWD you need to try and keep the weight on the front wheels - go too soft in the back and it'll pull weight off that inside front wheel
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Re: AE92 Race Spring rates

Postby Linesy » Fri Nov 23, 2018 10:33 pm

Thanks Guys,

Bloody good to get peoples real world experiences on these things.
I knew that the rears were too soft, the car takes far to long to lift the inside rear (too much droop).

I've ordered some 6.5kg rears as a starter, Will test next weekend at our local club meeting.
I'll also be throwing some slicks on so should be interesting.

The car is a bit of a mongrel, tube front, SR powered with the E58 box.
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