Ae71 Suspension Mods

[rallydad]

Hello all. Just a couple of questions. Currently fiddling with AE71/4AGE/T50 combo. The conversion is done, and running well. Car is club car never to be registered and runs on dirt. My problem is understeer. I have changed front springs to 175lb as per rally forums and chatting to well known suspension mob in Melbourne and rears have one coil removed (for now with king springs on order) Car has slightly raised front ride height for that "nose up" rally attitude and with one coil removed slightly lowered rear (still noticeably softer than front). Shocks are in working order and I have standard front and rear sway bars. I have run as sweep for local rally sprint on rally tyres and had a small understeer problem (heading straight for a rather large drop woke me right up!)and competed last weekend in wet and slippery grass khanakross on road tyres and it plowed more dirt than a Massey Ferguson tractor in low speed slippery hairpins. Tyre pressure at khanacross was 32 front and 26 rear. I was advised by a couple of rally guys that I should increase my front track and add some camber to make up for the loss in negative camber due to the raise in ride height. So my first question is should I lengthen by cut and shut the XT130 LCA's (if so by how much) or spend yet more hard earned on adjustable items? To my mind adjustable items would be only beneficial if I had adjustable coilovers, camber plates etc and changed my ride height/setup for different events...? Next question: I have some XT130 struts that have the original "wet leg" factory inserts. These have 22mm shafts and are very strong. Has anyone used these for off road and if so any mods to the inserts required and/or what oil and how much did you use? Oh, and 3rd question: If I fit the XT130 struts is the axle at the same angle as the AE71 struts or will these yet again affect camber? I can weld and have good mechanical ability so can modify struts and bits as required. Any ideas? Sorry for no line breaks in this post, for some reason my "enter" button is not working. Cheers.

[snot35]

I can't say for sure, as I'm still experimenting with setup on mine, but 175 seems quite hard. Remember by stiffening/raising the front and lowering the back you're making it more difficult for weight to get forward onto the front tyres. Generally when setting up for a turn you're braking quite hard to put weight onto the tyres to make them work before turning in. My current setup is TE72 struts, stock height (currently too high I think, I also have slight positive camber). These springs are probably only 120lb though. I'm running stock rear springs too, should be 90-100lb. Stock front bar, no rear bar and a locked diff. I like the setup, I've never had noticeable under steer problems, but then the locked diff requires a bit more aggression. Road tyres on dirt are always going to be a bit hairy when it's wet. My first step would be to get some second hand rally treads if you can, they make all the difference in the world. They also like to be run without too much camber. AE71 and XT130 gear should not change camber.

 

Crank in as much caster as your arms can handle, that should help a lot. I need to trim the guards to get more into mine.

 

Personally I'd go for some gas struts. You can change the fluid in wet legs to firm them up, but given their age and springs and shims in there are probably pretty tired. Making them work harder will shorten their life quite quickly.

 

I reckon I'd save the money and skip adjustable LCA's for a while. Really good shocks are probably the best investment if you can swing it.

[corollaart]

Well i replyed on the other forum

 

But just to add i think that 175 lb would be close to the money.

 

The problem as i said with a lot of caster is that it will flog out the lca bush as it works at huge angle.(rose joint cure)

 

I don't think that there is any 0 money cure for it just do a bit at a time.

 

20 year old old filled shocks.

 

Locked diff?

 

road tyres.

[ke70dave]

In my very very limited experience with cars on dirt, everything i experienced suggested that tyre pressures made the biggest difference over everything.

 

Perhaps try dropping the front pressure and raising the rear a bit?

[rallydad]

Well i replyed on the other forum

 

But just to add i think that 175 lb would be close to the money.

 

The problem as i said with a lot of caster is that it will flog out the lca bush as it works at huge angle.(rose joint cure)

 

I don't think that there is any 0 money cure for it just do a bit at a time.

 

20 year old old filled shocks.

 

Locked diff?

 

road tyres.

 

Sorry should have been more specific, the car has monroe GT gas shocks all round currently (no budget for bil$teins or similar at the moment) XT130 struts are not yet fitted to the car it has strengthened AE struts, I was only looking for opiniions on the wet legs. I was put onto using them by a rally suspension bloke in Melbourne who plays with AE's and KE's and makes them very competitive. He said they can be made to work quite well but he wouldn't give me specific details on mods only I could freight them and have them sorted for a not so small fee. Fair enough he is a business but I just can't afford.

 

If i'm adding length to the LCA's perhaps I should angle the bush housing so the arm is more towards the front of the car to compensate for extra castor? Not a fan of rose joints, have seen plenty break on rough courses an they have no "give" like bushes do.

 

The diff is currently open soon to be welded and i do have experience with locked diffs and think that that once locked will only exacerbate the understeer.

 

I'm just struggling to understand how my old ke30 with stiff front, crap shocks, a little -ve camber and locked diff would have flogged my current car on the same tyres and tyre pressures. Maybe the leaf rear end had a heap more "give" which took the pressure off the front end.

 

Just to add i'm not looking to win events outright, just trying to dial in a little more balance and safety.

 

Cheers.

[rallydad]

I can't say for sure, as I'm still experimenting with setup on mine, but 175 seems quite hard. Remember by stiffening/raising the front and lowering the back you're making it more difficult for weight to get forward onto the front tyres. Generally when setting up for a turn you're braking quite hard to put weight onto the tyres to make them work before turning in. My current setup is TE72 struts, stock height (currently too high I think, I also have slight positive camber). These springs are probably only 120lb though. I'm running stock rear springs too, should be 90-100lb. Stock front bar, no rear bar and a locked diff. I like the setup, I've never had noticeable under steer problems, but then the locked diff requires a bit more aggression. Road tyres on dirt are always going to be a bit hairy when it's wet. My first step would be to get some second hand rally treads if you can, they make all the difference in the world. They also like to be run without too much camber. AE71 and XT130 gear should not change camber.

 

Crank in as much caster as your arms can handle, that should help a lot. I need to trim the guards to get more into mine.

 

Personally I'd go for some gas struts. You can change the fluid in wet legs to firm them up, but given their age and springs and shims in there are probably pretty tired. Making them work harder will shorten their life quite quickly.

 

I reckon I'd save the money and skip adjustable LCA's for a while. Really good shocks are probably the best investment if you can swing it.

 

Noted Snot,

 

I had rally tyres on for the rallysprint and the understeer was a lot less of a problem. this would make sense as the grip levels were a lot higher.

 

Raising front, lower rear also increases castor slightly?

 

Cheers

[corollaart]

Have a look around this site if this guy can't fix it no one can.

 

Lot of tar stuff and probably out of you budget and mine but you get a bit of under standing.

 

Mate of mine just bought a spare set for wrx gravel car at 2.5 a corner its good real good and Murray is the best around imo.

 

http://www.mcasuspension.com/infosheets/setup.pdf

[LittleRedSpirit]

You need rally tyres bud. Youll never do anything other than understeer followed by oversteer on street tyres in a turbo rwd car on grass.

 

Its really not worth setting your car up way different when all you need is more grip, a soft rear end and a little bit of camber.

 

Having the nose raised will tend towards understeer and lowering it too far can induce oversteer problems.

[snot35]

Well I'd say more grip is a function of setting a car up, but anyway.

 

Soft back, softening the front should also give back some grip as well. A little camber and as much castor as you can handle, done. It will be unhealthy for the bushes, as mentioned above.

[LittleRedSpirit]

Well my comments are more reading between the lines, in my limited experience its hard to make a car handle grass and tarmac well, and the way to get a more consistent set up between the two would be to have a more similar amount of grip available.

 

Changing from rally to street tyres for different grass events is a bit odd and makes it again hard to point your set up in any one direction.

 

Camber is great if you have the controlled body roll to plant the tyre flat down on the road while cornering. A soft rear end will enhance its grip by allowing it to squat and put more weight down, but also tend to lighten and push the front and doze the dirt as you have been doing. The raised front will also not help this.

 

Try a more uniform ride height between front and rear, try softer front springs, add a degree or 2 of negative camber to the mix, and use a consistent tyre that will allow you to build on your set up from event to event.

Edited June 25, 2013 by LittleRedSpirit

[rallydad]

Thanks all, and just to clarify, going from rally to road tyres may sound odd but it is decided by the organiser for each event. We don't have a choice of which tyre we are allowed to use it more depends on the location and surface we are running on. Lots of deep ruts and divots don't tend to impress land owners but rally tyres are ok on forest roads so I guess it is a case of trying to find a happy medium or just tip mega dollars into all the trick adjustable/unobtanium suspension bits...

 

Tarmac setup is not an issue here as I don't compete on it.

 

I'll have a play this weekend and report back.

 

Cheers

[snot35]

Ah, yes of course, I'd forgotten about that happening for smaller events. You're going to be stuck with compromises if that's the case, but if you're going to make it work reasonably well for both circumstances I'd be getting back to stock-ish ride height and be running reasonably soft springs. I don't think incredibly fancy suspension is going to help you.

 

One of the things I'd like to do further down the track is convert to 2.25" springs on the front struts (and maybe do some fabrication work so I can use the same style spring on the back) so that I have a decent range of springs available to me for tuning. Getting a decent range that will fit stock spring perches is difficult and usually the rates are designed for tarmac which is useless for dirt. Far too hard.

 

I'd consider going back to stock springs all 'round to be honest. Or if the XT130 is in a workable state try those. They will most likely have a harder spring than an AE71 which wouldn't be a bad thing, but it wouldn't be 175lb hard. You'd have to see what ride height you're left with though.

[rallydad]

OK so I had the grinder poised and ready to start hacking up the LCA's and had second thoughts.

The XT130 LCA's add 20mm track each side so do I really need more? Why not try the little things first before making wholesale changes to suspension.

So, I put the front end back in and would up the castor by 6 turns of the adjustment nut (as far as it would go) and wound the toe out a smidge. set the road tyres to 28 all round and went for a blat. (note the wheel alignment machine at this stage is my eye and tape measure)

Now while it was a short blat and on a sealed road, albeit with a little loose gravel and wet it did seem to improve the low speed turn in. Higher speeds still just require a flick of the wheel or a bit of a "skando" to get the car to break loose in the rear. Although with the neighbours giving me not so pleasant looks after my second strafing run I had to cut my session short.

The LCA bushes are now under load however a little fettling with the LCA's later will eliminate this allowing me to run standard bushes or nolathane without going to rose joints.

Next step is to have a look at the strut tops to see if they can be modified or remanufactured to further increase castor and more importantly to add negative camber. I have looked at a few aftermarket adjustable strut tops on line and they look a little flimsy (alloy and very small locking bolts) unless someone can point me in the direction of a cost effective set.

I'll keep experimenting and let you know.

Cheers

[altezzaclub]

We're running a dirt-cheap strut top camber/castor plate, I'll look it up later- Some red plastic thing with a thrust bearing.

 

Take the sway bars off and run without them, which is what I did to Steve in the Celcia. If you ever get fast enough to scare yourself with body roll at 140kph, let me know and I'll tell you the next mod...

 

Don't weld the spider gears to the top hat casing in the diff. Fill a tooth gap with weld, then fill the three corresponding ones so they all hit at once. You need some free turn in there to let the car turn in and stop understeer.

 

Springs I reckon should be as soft as possible but enough to stop coil-binding or bottoming out the shock. The Monroes are entirely wrong for gravel of course, they suck the car down into the dirt insterad of keeping the nose high. You can re-valve the stock wet struts yourself if you still have them. Make the holes on the 'compression' (going down) stiffer, and reduce the valving on the 'coming up'. Chat to TRDKE70 about his spring rates, but basically the fronts are just firm enough to land on and the rears are as soft as possible to get maximum squat. We're using 110lb/in rears and can't find anything softer at the wreckers.

 

Make sure you have long soft bump stops, you can buy some lovely progressive ones that ramp up in density towawds the end. Stock old ones are pretty hard, I found some Falcon fronts that I fitted to the rear of the Celica.

 

We have Sigma LCAs, gave us a max of about -4deg of camber I think, some of which we removed. Run zero or 2mm toe-in, although toe-out will make it turn in better. The trouble with toe-out is it makes the car nervous at speed and very darty. Run lots of castor. Stick to bushes if you can, I'm no rose-joint fan either.

 

Take a look through 'how not to build a rally car', that was an understeerng too-low dog when he started and now it floats over (almost) everything and turns in beautifully then slides controllably...

[altezzaclub]

These ones, the 'street' ones.- The urethane stands up to jumps and ditches OK, but the thrust bearing gets beaten to death. Sadly the urethane is molded around the bearing in the factory and you can't replace the bearing by itself, but they've done over a year's rallying and they weren't new when he got the car. $380 the pair, $110 odd each side for new thrust brgs with the urethane part.

 

http://www.k-mac.com...yota/toyota.htm

 

Don't be afraid to lathe the spring perch off the strut and reweld them on higher up. You want the shock to sit normally at about 80% of its extension, so when it lifts 20% more it tops out. That means it has 80% of its travel to go down when it absorbs the weight of the car coming down off a jump, rather than just 50%. If it tops out it doesn't matter, the weight of the strut plus disc & wheel just hangs off it OK.

 

I expect you'll build a low tarmac set of struts and a high gravel set separately and just swap them over for each event. They will have opposite valving, the tarmac has easy down hard up, & the gravel has hard down easy up.

 

We're running Kings Springs on the front, quite randomly, they were on there when he bought it. They're stock height KTFS14, but I don't know what rate they are.

Edited July 2, 2013 by altezzaclub