818R chassis build questions

[mrvwcastner]

Please help me clarify. What are the best donor components for a no compromise chassis build? I'm not talking one off CNC or custom fabbed just the best year part for each element of the chassis looked at separately without worries of it coming from one single donor. Please include in the thought that upgrades like poly bushings, stainless lines heim joints etc.. I want to source everything to build a roller so that I can replace all maintenance items as well as clean polish powdercoat prior to kit arriving. I don't want to go as far as spherical bearings or anything that would mean it COULDN'T be street driven but I don't want any compromise down the road thinking I should have......

I will most likely not order my frame powdercoated from FF so that I can make minor mods like tow hooks etc.prior to completion & that leaves me open to rework slight details that limit what rack fits best or moving brace in cockpit area things of that nature.

Sean Castner

[Rasmus]

What are the best donor components for a no compromise chassis build?
Only you can answer this question. The problem is the word "Best". Best for what? Durability? Weightsavings? Price? Availability?

OEM only or is aftermarket allowed? Because the aftermarket

http://www.advancespeedshop.com/images/DME-S005.jpg
has some really nice stuff. (Rear trailing arms pictured)

No compromise 818R build to me means Heim Joints or Delrin Bushings everywhere and lightweight.

[mrvwcastner]

Aftermarket is fine. Tuneability for track use with keeping in mind some drivability on the street. I'm new to subaru market. Only reason for me to choose 818R is performance. I would love to know best OEM as well as some proven choices for aftermarket mainly focusing on longevity, tuneability and weight while still being able to drive on streets. Thanks in advance please educate me.

[Rasmus]

For you I'd look into MSI's front billet aluminium uprights.

http://www.mooresport.com/images/grandes/67-2011-11-04-upright-1.jpg (http://www.mooresport.com/produit.php?prod_id=67)
The cast iron OEM unit are H-E-A-V-Y. These are super light. Has lots of adjusability and accept the OEM bolt in bearings. Nice.

While there check out
http://www.mooresport.com/images/grandes/69-2011-12-01-front-lateral-3.jpg (http://www.mooresport.com/produit.php?prod_id=69)
their front a-arms too. Nice pieces and lighter than the OEM aluminum arms.

[PhyrraM]

.......and accept the OEM bolt in bearings. ....

None of the supported donor cars have bolt in bearings. Are these for an '05-'07 STI?

[Rasmus]

Excellent question.

http://www.mooresport.com/images/grandes/67-2011-11-04-upright-6.jpg
I know MSI lists them for Impreza 2001 - 2004 (press in type) and Impreza 2005 - 2011 (bolt in type). But if you're buying these just choose the bearing style you want (bolt in) then roll over to the dealership and get the appropriate bearing.

[Mechie3]

Make sure the strut connection is the right thickness.

[PhyrraM]

Ah-ha, the "2001-2004 press in bearing" should really be listed as "all 1999-2007 Impreza excluding 2005-2007 STI)" - Those are the ones for an 818.

I, personally, would not use something like that on the street unless I had seen that MSI has done a ton of strength, durability and HEAT testing. Aluminum and steel react to the process of pressing in a bearing differently and need to be engineered as such. Beleive it or not, race cars and parts can use a "lower spec" (for lack of a better term) because they recieve MUCH more attention and maintnence. Some race car parts are only designed for a few hundered miles with a service every 50.

Parts destined for the street don't even get looked at for 100K+.

I'm not saying these (or anything similiar) won't work, I'm just saying that you need to do the research when replacing any cast iron or forged steel part with something aluminum.

They look beautiful though and I do hope they can be used on the street, as I see the increased percentage of unsprung weight (because of the declined body weight and apparantly increased wheel/tires) as the biggest challange to the ultimate handling of the 818.

[mrvwcastner]

Thank you this is exactly what I had in mind. I really don't want to pick iffy aftermarket parts since I'm new to subby (I need others experience here) ods are this will put me into the 25k range finished but I expected that & might as well spend it up front. My goal is to build "my perfect chassis" move seat to center position run a descent NA motor learn to drive this car then reassess motor options. Most likely I will do basic ISIS wiring or get help from one of my co-workers who built harnesses for military drones, but I want to do it correct the first time no compromises yet spend money wisely.

[Mechie3]

Msi makes very good but very expensive parts.

[mrvwcastner]

Okay, lets talk best OEM mixed bag of parts ie-what year parts make up best options for best chassis performance lightest weight strength response tune ability. I think I can justify some aftermarket, but most likely not entirely aftermarket, and some people may want all Subaru components.

[Mechie3]

Hubs: Any Year
Brakes: 06/07 WRX
Front control arm: 06 WRX or 04-07 STI
Steering rack: 05(?)-07WRX or 04-07 STI
Lateral links: 05-07WRX or 04-07STI (STI aluminum/aluminum and are $$ and not worth it, cheaper to get two sets of teh front aluminum links off of an 05-07 WRX)

[PhyrraM]

I think you should put a "why" for each item.

I, personally, don't see the brakes or the aluminum arms on such a light car. The two pots are both more powerful and lighter. Thermal capacity is much reduced in importance on such a light car, ultimate braking is, and always has been, a function of the tires.

The aluminum control arms are not measurably lighter then the steel arms. They are more ridged and stronger, and again, the lighter weight may mitigate much of the 'advantage'. I see an advantage in the steel arms that if you hit a curb the arms may bend before the chassis pick-up points are ripped out, with the aluminum, your certainly also repairing the chassis.

IMHO, it's easy to do one of two things...1. Get caught up in the Bling. (which is OK if that's a goal) and 2. Assume all WRX upgrades are also upgrades on a much lighter vehicle.

[HelluvaEngineer]

Hubs: Any Year
Brakes: 06/07 WRX
Front control arm: 06 WRX or 04-07 STI
Steering rack: 05(?)-07WRX or 04-07 STI
Lateral links: 05-07WRX or 04-07STI (STI aluminum/aluminum and are $$ and not worth it, cheaper to get two sets of teh front aluminum links off of an 05-07 WRX)

I think the 2005 - 2009 LGT brakes are better.

[Etos]

Bushings: Turnin Concepts Old new Refresh bushing kit. Comes with every single suspension bushing the car uses. They are graphite bushings. 100x better then the factory rubber.

Engine and Trans mount: This is touchy as the harder you go the more vibrations. Group N tranny mounts don't add much NVH but the engine mounts start to. You can ofcourse go much stiffer then GroupN like solid mounts or urethane mounts.

Brakes: For a car this light pretty much any brake caliper will brake well. A 4pot is going to feel better and have more control with the brake peddle so consider STi brembos.

Steering Rack: Q-Rack will take your subaru rack and modify it to turn much quicker. It's expensive though at about 3k.

MSI parts are all very very nice parts. There's no question to their quality nor their price lol. If money was no object I'd get the uprights with Alcon brakes and ceramic wheel bearings. Also their front control arm rear bushing housing is not expensive at all and should be considered if you get the TIC old new refresh bushing kit.

Also do not get MSI front control arm. Remember that the front strut assembly needs a good portion of that to bolt to. I highly doubt MSI will work with the 818.

You never mentioned your engine needs. You can shoot for the sky at 700hp or have a very highly efficient 300hp that makes power everywhere. All I know is Maxwell Power Services in WA is the place to get any engine work done. That and 3MI, both are easily the best there is hands down. MPS has a sweeeeet engine which is a destroked 2.5 to 2.34 that can rev to 9.5k. It's a serious engine and it's actually what I'm getting but I went with darton sleeves and 102.X pistons to bring displacement back to 2.5 for my STi. 2.34L is far more then enough to provide enough torque for a 1800 pound car.

Also look into Full Race and their stock location EFR turbos/headers/up pipe. Pretty insane stuff.

[mrvwcastner]

I think the 2005 - 2009 LGT brakes are better.

why do you like these brakes more? I personally think unsprung weight would be right next to tune ability and would be hard pushed to think we need to worry about premature failure on anything short of a design flaw since so many WRX owners have proven reliability on much heavier cars on & off road. I personally think I will choose as much quality aftermarket as possible, but $5000 on front hubs not going to happen. I don't want to dismiss good OEM options either.

[Mechie3]

LGT have the same size rear rotor as the red WRX brakes use and a slightly larger front rotor.

Here is my logic:

02-05 WRX brakes do not have a rear vented rotor (and won't work with one). The red 4 pot/2pot comes with vented front/rear.
4pot/2pot setups can change the pads without removing the brakes, just pull the spring and pins and slide the brakes out the rear
4pot/2pot arguably look better.
Better pedal feel than a sliding caliper setup.
Most of the rally teams out there choose the 4pot setup over other brakes
4pots fit with some 16" wheels (offset is usually the issue), LGT brakes don't fit with 16's (the newer LGT brakes)

Aluminum control arm:
Looks better
Won't rust (Subaru has a recall out for these rusting and snapping in half)
With the way FFR is mounting the front spring on the control arm, I'd rather have the solid aluminum piece, not bolt into a box section
If you hit a curb with either you're likely to brake or bend the frame (unless it's rusty and they snap)

Rear Control Arm:
Looks better
Won't rust
Larger OD and better moment of inertia.

Steering rack:
The one with the aluminum body had a faster rack (at least 06/07 did) and it has bolts that mount through the body instead of two clamps to mount it.

In general, they were items that don't cost that much more and have a mild performance advantage and look nicer. If you're already spending $15k on a toy, another few hundred isn't that much more. The brakes will be the most expensive item on that list, but the lateral links aren't that much. I found someone selling them for $19 ea. A lot of people put them on ebay for $80 for a set. Just be patient and a good deal comes by.

[RM1SepEx]

I bought adjustable steel rear links, here is my ebay listing for the rear aluminum links transverse links $25 ea, two ship for the same as one!

http://www.ebay.com/item/170928133153?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649

The 06-07 WRX rack is identical to the 05 rack/same ratio I have my destroyed original 05 rack and I took apart my 06 wrx rack... exactly the same pinion and rack gears, interchangable... no faster ratio unless you get an STI rack I'm afraid. I agree the 05 plus mounting looks much more secure as the mounting tabs on one end of the rack are cast into the housing vs clamping around the rack with a rubber bushing.

The aluminum arms are about 2 lbs lighter each and are indeed stronger. They also look to be better suited to the Factory 5 shock mount adaptation.

At 2000 lbs (driver only) the stock brakes will be more than adequate for anything other than track use. The booster will make the brakes very touchy, too much assist, I also expect that an adjustable proportioning valve will be required due to the vastly different weight bias of the 818

[Mechie3]

I meant different ratio from the 02-04. My 02 feels like driving a school bus after being used to the 06.

[Mechie3]

I pressed the OEM bushings out of some aluminum links yesterday and took my TIC bushings out of my steel arms and swapped them into the aluminum. The bare steel arm weighs 1lb 12oz. The bare aluminum arm weighs 1 lb. Total of 1.5lbs saved. You could always cut the swaybar endlink bracket off a steel one and save some weight. I've heard of the steel arms bending, but haven't heard of aluminum ones bending unless you hit a curb hard.

[PhyrraM]

.... I've heard of the steel arms bending, but haven't heard of aluminum ones bending unless you hit a curb hard.

That's my point. The aluminum arms could be considered a detriment on a tube frame car like the 818. The aluminum arms were developed for Group N rally racing, where stock parts are mandated. They were designed to be stronger than the steel arms for that purpose.

On a street car, it's rare for the steel arms to bend a subframe because they themselves bend first. The same accident with aluminum arms will bend the subframe. Group N rally cars are allowed to reinforce the suspension pickup points, so that's why they were developed the way they were.

By all means, if you've got the aluminum arms use them. Same if you prefer the looks of them for when your under the car. I just don't want folks thinking they HAVE to upgrade. Subaru folks tend to express opinions as facts - it's a Nasioc trait that I'd like to see curtailed here.

[Mechie3]

No, you don't have to upgrade. Didn't mean to imply that.

To be clear, I'm talking about the rear arms, not the front arms that also have steel and aluminum variants. I'm just listing ways to have a "no compromise build" as listed in the first post.

FWIW, I completely rebuilt my Fmod last winter and machined lots of new parts. Some people gave me a hard time when I would scallop a part or drill holes in a bracket as it wasn't meaningful. In the end, I dropped 26lbs and greatly reduced rotating mass. I was .5seconds behind a former national champ in a car that everyone said was no longer competitive. I'm of the "every little bit counts" camp. Granted, time and money put a limit to it, but low hanging fruit is always nice.

I'm not sure how well the frame would hold up to impact with steel or aluminum arms (front or rear) honestly. Best case, don't hit curbs ;)

[longislandwrx]

Holy moly those uprights are $5000.

[Rasmus]

Holy moly those uprights are $5000.

*evil grin*

Don't forget the $3600 in upgrades to set it right:

Carbon fiber / carbon kevlar hybrid brake duct. Up to 365mm diameter disc. Sold PER SIDE +395
Ceramic Bearing upgrade. Price per bearing +795
Uniball (pin type) ball joint (per side) +195
Heim-Joint rod ends + adapter (per side) +295
Alignment washer kit (8 pcs extra) +195

Only $8600. You don't want your Ohlins controlling anything else. What are we farmers?!

[longislandwrx]

<--- raids daughters college fund.

[FFRSpec72]

Seems like extreme list of add on parts here, may look nice but are they really needed? We run the challenge series on mostly stock mustang parts none of these fancy control arms, brakes, etc and the car is competitive. My goal is to build it pretty much stock as I know that something will go wrong and I want to keep costs low as this is just a track car.

[mrvwcastner]

I have been talking with MSI about a complete kit for 818R chassis. They were interested in putting a complete kit less brakes together & suggested 06-07 wrx brakes with the option to use factory spindles. The reason I want to think about going this route is tune ability. I think I need to sort what brakes to use & what wheels/tires will be best (3 sets 1 for street, 1 for dry track days, & 1 for rainy track days). Hard to justify 10G having not seen finished 818 yet much less driven it. I really hate my normal habbitts of building & rebuilding every time I decide something is better than what I have now. On the other hand I may be setting myself up for 30K all said & done might be better to just build 2 kits & 15k each. Just kidding, but....?

[HelluvaEngineer]

why do you like these brakes more? I personally think unsprung weight would be right next to tune ability and would be hard pushed to think we need to worry about premature failure on anything short of a design flaw since so many WRX owners have proven reliability on much heavier cars on & off road. I personally think I will choose as much quality aftermarket as possible, but $5000 on front hubs not going to happen. I don't want to dismiss good OEM options either.


Sorry, I was not ignoring you. I need to get on here every day when I post. I thought the rears on the WRX were not vented and the Legacy GT has vented rears. Plus the front rotors are a little bigger. I thought I saw some threads about WRX owners upgrading to LGT brakes. So I think you can use the WRX and still upgrade. New rotors from Centrix were about $50 each when I replaced them on my LGT


edit: Thanks Mechie3 for the details.

[metalmaker12]

The oem spindles will be plenty, your really not gaining much by spending all that on Msi stuff, if you want a 15k car to turn into a 50-60k project and you got the funds than have at it. I will bet my 818 that the most successful street and race 818's will use 85 percent oem components