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 Post subject: Re: Yowie's SH turbo
PostPosted: Mon Aug 14, 2017 11:57 am 
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Vehicle: MY08 XT (SH)

Posts: 725
Location: Brisbane
dwee. wrote:
In terms of understeer, the caster bushes will help you turn in better and the front sway bar apparently would help you with understeer too (depending what size you have already; I'm yet to test out my front sway bar on track). I don't know much about the pineapple slices but I would think they would help too.


The car is in the shop at Fulcrum today for the work (but not a front swaybar replacement over OEM yet).

For context, i already have a 22mm rear swaybar.

Front swaybar replacement is worth considering, however i'm keen to test the results of "more castor" first.

I haven't figured out whether it's as simple as "thicker front swaybar = more understeer again" or if I would be improving the overall grip/stability and the bias towards under or oversteer is more of an incidental footnote.

The other thing is that i'm happy enough with a bias towards understeer if the overall package/balance handles well in various conditions. It's a bit myopic/dangerous to aim for oversteer as the end goal. However, at the moment the front end is far too loose in "not pushing THAT hard" conditions, so the understeer can be wound in a bit to see how we go.

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 Post subject: Re: Yowie's SH turbo
PostPosted: Wed Aug 16, 2017 7:58 pm 
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Vehicle: MY08 XT (SH)

Posts: 725
Location: Brisbane
Boring stuff out of the way first.

Fulcrum Suspension rebuilt the upper ball joints on my rear control arms. They were $120 each with a 5-year warranty. That stacks up well against $635 each for replacement OEM upper rear control arms.

Image

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 Post subject: Re: Yowie's SH turbo
PostPosted: Wed Aug 16, 2017 8:02 pm 
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Vehicle: MY08 XT (SH)

Posts: 725
Location: Brisbane
Fulcrum also installed upper and lower subframe voidfillers ("slices of tinned pineapple") while the rear was off to fix the ball joints:-

Image

The intention is to tighten up the rear end.

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 Post subject: Re: Yowie's SH turbo
PostPosted: Wed Aug 16, 2017 9:13 pm 
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Vehicle: MY12 XT Premium Auto White

Posts: 219
Location: Brisbane
[quote="Yowie"]Boring stuff out of the way first.

Fulcrum Suspension rebuilt the upper ball joints on my rear control arms. They were $120 each with a 5-year warranty. That stacks up well against $635 each for replacement OEM upper rear control arms.

Hi Yowie,
Mate are the prices your quoting Supply and Installation totals?
Their rebuilt the upper ball joints seem like good value if that price includes Installation.
Cheers Al
PS what's the SH drive like now?


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 Post subject: Re: Yowie's SH turbo
PostPosted: Wed Aug 16, 2017 9:46 pm 
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Vehicle: MY08 XT (SH)

Posts: 725
Location: Brisbane
Al

There is a non-itemised labour component on the bill for $255, so I suspect the ball joint replacement is just parts.

----

Now for the most anticipated thing since King Kong vs Godzilla, the Superpro replacement front lower control arms:-

Image

Image
Rear bush - an offset bush (for caster) within an arm with geometry to add caster.

Image


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Inner bushing.

Image
The start point for my rough measurement.

Image
Rough measurement end point. I don't have the OEM equivalent measurement handy (although I can check the next time I'm under my wife's stock SH - not a euphemism).

I suspect the Superpro arm will be a bit longer than standard along this axis to add caster.

The construction is solid cast aluminium (as opposed to pressed & welded steel sheeting with a hollow interior of the OEM arm).

Superpro claim their product is lighted than OEM, but I couldn't detect much weight difference holding one example of each.

On the invoice, the arms are described as "Subaru WRX 14-on Alloy arm kit". Desmond Hallam at Fulcrum Yeerongpilly says he changed some of the fittings to make it fit the SH Forester. I get the impression it was different fittings into the rear bushing area. More specifically, Des says he's developing this product offering and can fit SH foresters or supply sufficient parts to non-Brisbane Forester owners.

My earlier post about "similar cost to just bushings once labour is taken into account" reflected a misunderstanding. Fulcrum ended up doing me a good deal, however the total for arms (as opposed to just bushes) was more than my earlier post indicated.

Comments on handling differences to follow.

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Last edited by Yowie on Wed Aug 16, 2017 10:18 pm, edited 1 time in total.

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 Post subject: Re: Yowie's SH turbo
PostPosted: Wed Aug 16, 2017 10:16 pm 
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Vehicle: MY08 XT (SH)

Posts: 725
Location: Brisbane
Before Monday's work the suspension/wheels/height was standard, subject to the following notes:-

- WHITELINE Adj Rear Swaybar 22mm (middle setting)
- 2009-model OEM rear struts (thicker springs than 2008)
- Pedders front swaybar bushes (on OEM front swaybar)
- "Cheapo" tyres - Achilles ATR Sport
- recently worn/loose rear upper control arm ball joints

After Monday's work the following has changed:-

- reconditioned rear upper control arm ball joints
- Superpro rear subframe top & bottom void-fillers
- Superpro alloy front lower control arm with offset rear bush for more caster.
- front static camber changed from -0.37 degrees (Left) and -0.51 degrees (Right) to -0.82 degrees (Left) and -0.86 degrees (Right)
- toe changed from 0.9mm (L) and 0.3mm (R) to 0.5mm (L&R)
- other numbers and details on the wheel alignment report I wont bore you with.

The additional caster from the front lower control arms is likely to be the most significant element. The textbook says that more caster adds more dynamic camber with few down-sides.

Before Monday's work the handling was described as "Turn-in understeer, an oversteer moment, then all understeer when pushing harder past a fairly low limit". It wasn't confidence-inspiring to drive fast in anything except a straight line.

After Monday's work the handling can be described as follows. This is based on suburban roads plus the Mt Glorious/Mt Nebo run in dry conditions:-

- sharp turn-in
- whole vehicle turns better/faster through the corner. I'm not sure if that is "oversteer" as the rear comes around faster or if it's just well-balanced now.
- still quite forgiving (in the dry at least). Eg stays composed if I back off the throttle or apply brakes half way through a corner. At one point I detected the rear starting to come out and was able to correct it - not a nasty surprise into screeching oversteer.
- much higher speed limit on corners, not reached in testing so far. As a rough guide, double the "yellow sign recommended" speed is consistently achievable without fuss now.

Apart from the cost of parts & work, the "down-sides" of the new setup are:-

- more NVH. You feel every painted section on the road now. This might be more of a symptom of the polly bushes than the caster, but who knows.

- heavier steering (although with power steering it's not an issue). Besides, a sports car is supposed to have heavier steering with more feedback from the road.

Overall it's very much worth it in my opinion.

Best of all, I get to keep the standard ride height and have a much better handling car.

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 Post subject: Re: Yowie's SH turbo
PostPosted: Thu Aug 17, 2017 12:37 am 
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I Say: There's no 'i' in Team, but there is in Winner!
Vehicle: MY10 XT

Posts: 1458
Location: Mealbun Orstraya
Nice detailed write up :thumbs:
So there are the pineapple slices, beetroot slices and now the blue slices..


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 Post subject: Yowie's SH turbo
PostPosted: Thu Aug 17, 2017 9:50 am 
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Vehicle: MY11 S-Edition - SWP

Posts: 690
Location: Sydney
Good to hear about the changes you made - some nice new purple bits and some new shiny bits :) and that these have improved the handling. You may find your tyres are now a limitation. Enjoy the new ride :)

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 Post subject: Re: Yowie's SH turbo
PostPosted: Sun Aug 20, 2017 2:52 pm 
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Vehicle: MY10 XT -

Posts: 252
Location: Brisbane
Nice mate, I just caught up on the reading on the latest. Certainly got some work done there, was very interesting. Must be very happy with it all and how it handles and feels now.


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 Post subject: Re: Yowie's SH turbo
PostPosted: Sun Aug 20, 2017 3:24 pm 
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Vehicle: MY08 XT (SH)

Posts: 725
Location: Brisbane
Thanks for all the comments.

I agree that tyres are probably the next frontier of improved handling, although i'll give the Achilles ATR Sports a lot of credit for what they can do as part of this package. It probably wasn't a bad thing to set up the handling on "cheap tyres" because quality tyres might have hidden some of the balance symptoms a lot better.

Yeah, i'm very happy about how it handles & feels now. The novelty is still yet to wear off, however the change in handling is as remarkable as a major change to the power (eg new turbo/tune or switching to E85) in terms of the overall package. That probably speaks for how poorly it handled before.

Oddly enough, i got to test some of the car's limits (and, more accurately, my skill limits) at the Skid Control rally day on Saturday (19 Aug).

Apart from my steep learning curve going fast on a dirt track, the Stability Control kept intervening to prevent the car from sliding too much. This was the case even with "traction control switched off" (that button near the mirror controls). Given that you're supposed to slide a bit and then power-out of the corner with AWD, that Stability Control intervention was counter-productive.

Subsequent research indicates i should probably pull out the ABS fuse for a future dirt event in order to disable the whole Stability Contol system, presumably in calmer circumstances than this:- https://www.youtube.com/watch?v=u18mbeb_mcA

That aside, it was very interesting to see/feel how the Stability Control kicks in - momentarily braking individual wheels to stop a slide and get the car more-or-less pointed straight again. It's probably a life-saver on a wet road if, as blokes, we can put away the "i'm as good as a racing driver and can react better than Stability Control" talk for a minute :mrgreen:

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