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I agree with BigDan. Use the oem damper, your crankshaft will thank you. In fact, a bit more rotational weight is an advantage you will notice in normal driving. More tractable at low speeds and takeoffs. The low rotating mass of a 4 cyl engine and low torque makes this more evident. I resisted the urge to go with a light flywheel for the same reason since I will use my car more for a gt than a track car.
Hahaha that sounds more accurate than the advertisementQuote:
idf
Quote Originally Posted by mcamera View Post
Does anybody else feel like this is optimistic? The crank pulley is the same diameter as the OEM pulley so it still has to produce the same amount of torque to turn the alternator on our cars (and maybe the AC for some people). You can make the pulley lighter but to say it reduces so much rotating mass (-4lbs) that it's equivalent to 100lbs off of the curb weight sounds like a stretch.
Attachment 190276
I have that pulley in red in my 818. It looks way faster.
I believe lightweight flywheels reduce enough rotating mass to make a noticeable difference. Those usually save ~12lbs and still have to turn everything between the engine and wheels. Same concept here with the crank pulley.
From reading many threads, there are claims that Subaru doesn't use their crank pulley as a harmonic damper. Including some emails from Subaru customer service saying it's just a pulley, not a damper. That being said, I agree any benefit is probably small enough to not be worth the risk or $150.
If it’s just a pulley, why does it incorporate the rubber isolator? It may not be a “harmonic balancer” but it is there to absorb secondary vibrations that are always present on a 4 cyl engine without a balance shaft.
Agreed, Lance. If it were just a pulley, there are cheaper ways to make them. Check out this very informative video of experts talking about the differences. MotoIQ is awesome, and they also have a video on performance alignments that may interest you for improving your autocross experience. Although they are quite aggressive settings in terms of tire wear for normal street driving.Quote:
Originally Posted by lance corsi
https://motoiq.com/watch-what-harmon...-you-need-one/
I never noticed the OEM pulley had a rubber isolator on it. I never took it off for anything in my build. I agree some extra weight and damping is better.
Wise decision Grasshopper!
Hello!
Autocross season has come to an end and I'm planning a few upgrades for this winter. If I'm not driving, I want to be building :). The biggest change will be switching from my cheap 460 treadwear Kumho tires to some sticky 200 treadwear tires which everybody runs in non-slick classes. I'm expecting this to make me a lot more competitive.
I'm also expecting this to start pushing the limits of my oil system. I know many of the track guys drop big $ on a dry sump but I'm looking more at an Accusump. For the price difference and limited time I spend at autocross, this is a better fit for me. I will pay for the electronic valve to make life easier, but does anybody have any good/bad experiences with this setup or any brands?
I can't confirm these numbers but I saw a thread online claiming the WRX motor can move up to 0.8L of oil per second (assuming max flow rate). So the 1L Accusump I'm looking at will probably only offer help for a few seconds (assuming pressure isn't a complete flatline at 0psi for 1.25 seconds).
But then I saw a claim by Killer B that their standard oil pan is good up to 1.6g's which is cheaper, simpler, and a better solution that doesn't wait for a bad condition to try and fix it like the accusump. Anybody have experience with this pan? It holds 40% more oil so will it hang out the bottom of the frame and be easy to damage? Pic of the claim below.
Attachment 192493
I can't remember why, but at the time I researched it, I concluded an Accusump was not in my future.
The OEM oil pressure sensor is very sensitive. It will trigger if oil pressure drops below about 10psi for even a momentary split second. The problem is, the oil pressure dash light will illuminate only for that split second. No one is staring at their gauges while going around a turn to see if the dash light lights. And an oil pressure gauge will not pick up a momentary drop in pressure in any meaningful way. I wired in an Amazon sourced: "Mini Timer Time Delay Relay .1 Sec to 400 days. 3V 12V 18V 5A. Power on or Off Delay, Cycling and More. Compatible with B00PD65UGA." I programed mine to flash the oil pressure light for 15 seconds if the oil pressure sensor triggers for even a split second. That way I'll be alerted to a momentary drop in pressure after it happens. I think this is a good setup on a track car. Maybe do that first and you'll discover you don't have any oil pressure issues. If you're not having fuel starvation issues in right turns with less than half a tank of gas, your oil pressure probably is fine (at least with FFR gas tank - not sure how the Boyd tank behaves).
A Killer B or some other robust oil pick up tube is a good idea as the OEM one has a reputation for breaking which will starve the engine of oil.
I have a Killer B pan (and pickup). It holds about 1 extra quart of oil. I put a 1/2" block between the motor mount and motor to raise the engine so the pan passes above the frame rails. Can't go any higher than that otherwise my turbo hits the bolt on engine compartment cross member. I also have an Arctangent oil control plate. No issues in long (8+ seconds) high G turns.
Thanks for the feedback Dave. I start my autocross events with a half tank of gas and at the last event I had fuel starvation on my last 2 runs. There were back to back left hand hairpins, and the engine cut power in the same spot twice. Coincidentally I got 8 runs that day instead of the usual 6, so I may have been getting close all year without knowing it! No problems since on the street. I have a Boyd tank and this is with my cheap 460 treadwear tires. Switching to grippier 200 TW tires will make this worse.
I have the Killer B oil pickup tube already so all I would need is the pan. Adding a spacer to the engine mount is a good idea. My ride height is 4.5" so I'm not super low which helps. I'm leaning towards the Killer B oil pan with windage tray. Even if it's not perfect it should be a big improvement over the stock pan.
I have 2 almost new accusumps. One 2 quart and the other is a 3 quart.Quote:
Originally Posted by mcamera
I make you a deal you can't pass on.
Bob
Both Killer-B and IAG make great oil pickup, windage tray and baffled oil pan solutions. I am running the Killer-B on mine. Can't say much about how well it works because it isn't running yet.
Sounds like you may have some fuel sloshing as well. I am not sure if you can open up the Boyd tank to add fuel foam to help reduce the sloshing. Otherwise maybe a surge tank is an option. I added Holley hydramat and foam to the FFR tank to prevent sloshing. I also have the IAG oil pickup and windage tray installed. I am close to my first track day shakedown to see how it all works.
I have a Holly Hydromat in my FFR tank, but no foam. It didn't save me from needing a surge tank.
I know the guys that made them don't make them anymore I don't think, but, it would be worthwhile to see if you can hunt down an arctangent oil control plate.
I went all out with a Radium surge tank and dry sump.
Ed
Thanks for the offer Bob, but I've decided to go with the KB oil pan and windage tray. Looking to keep it simple by swapping parts instead of adding, and preventing the problem instead of constantly supplementing one. That's my thought process at least. I appreciate it!
The Boyd tank (as of late 2020 when I bought mine) has some new baffles that prevented me from adding a hydramat. Diagram from an earlier post in pic below. I started my day with a half tank (5/10 gal) and it only starved on runs 7 and 8 (plus an hour of idling at that point). My blind guess is my tank starved around 4 gal? The easiest fix for me is to show up at autocross with more than a half tank of gas. I'll start with a 3/4 tank in the Spring (7.5 gal) and see if that gets me through my runs. If not, full tank it is!
Attachment 192572
Ah I missed that part about starting with only a half tank. Definitely fill it up before your first run!
With the holidays over and after a crazy amount of travel the last 6 weeks (Cleveland, Miami, Key West, Detroit, Toronto, Central KY, Vegas, Detroit) and catching Covid again... it's time to start chipping away at my winter projects!
https://youtu.be/JJkRnw-M9jI
I had the same rubbing on the control arm. It took 10mm of spacers for me with 255 tires. I put witness paint on the control arm rubbing spot to keep an on going check. On track, I'm still getting just a tiny bit of rubbing, but I can't see any indication of it on the tire. The rubbing was really bad before I put in fresh bushings.
Some simple Google research turned up that with our 12mx1.25 studs, we need a minimum of 9.5 turns on the lug nut. I assume that means full 360 degree turns (it looked like your count was the number of half or 180 degree turns). I was able to install longer studs on the rear hubs without removing the hubs from the car. It required cutting the anti-lock brakes sensor ring off. The front requires hub removal to switch out studs.
I bought my spacers from FastWRX and they say you can run the 5mm spacer on stock studs as long as you have at least 12mm of thread engagement. But I have aftermarket wheels so I double checked. I measured 12mm on the stud and that took 6 turns for my lug nut to reach. I put my wheel and 5mm spacer on and my lug nut took 7 turns to torque it down so I have enough engagement by their standards.
I'm upgrading my front lower control arms to the aluminum STi arms. My tire currently rubs the wheel well at full lock, even with my skinny 215/40 tire. This tire also looks bad on my 18x8 wheel because the rim sticks out further than the tire. The wheel also sits too far back in the wheel well and looks bad. Adding a wheel spacer isn't an option because it makes my interference even worse. Finally, I maxed out my alignment at 4deg caster and want more. When I updated my alignment from 3deg to 4deg I noticed an improvement in driving stability. I'm sure another 1-2deg will be even better.
Attachment 194606 Attachment 194607
Before and after the arm. You can see the wheel has moved from behind the centerline of the wheel well, to in front of the centerline. Probably moved 1/2"-3/4" overall. This gave me more clearance to the panel that the back of my tire was rubbing.
Attachment 194605 Attachment 194604 Attachment 194608
With this extra clearance I mocked up a 10mm wheel spacer to push the wheel out and increase clearance to that panel. I've ordered 10mm spacers and longer studs since this looks good. I'll check after those are installed and I'm hoping I can bump up to a 225 tire. Even if that brings back my tire rubbing at full lock, my bigger issues will be solved.
Attachment 194609
If you haven't bought the pan yet I would look at the new IAG Competition pan or their new street pan. The comp pan has many features that should work well, but may hang too low. I think the design is superior to the KB pan.
On the studs, you may want to make a project out of swapping all of them out for the ARP extended studs. My buddy just lost a wheel off his LGT track car when the oem studs snapped off at Area 53, it was costly. It's pretty easy to drive out the old studs and set the new ones if you have the right tools. I've never heard of an ARP stud failing, but seen multiple oem studs fail at the track, three times at AutoX events! (All makes, not just Subies). The extended studs give you lots of options for spacers too.
Edit, Whoops, missed that you had ordered the extended studs!
I already have the KB oil pickup so I'm going to stick with the KB oil pan to make sure everything is compatible. I added upgraded studs to my list for rear wheels though. Was going to leave those stock.
I'm looking at tires and my options are very limited. I'm only expecting there to be room to bump up my front tire to a 225/40/17. The only 200TW tire in that size is the CONTINENTAL EXTREMECONTACT FORCE. But they don't make a 255/35/18 to match. They only have a skinnier 245 or too big 275.
But several other brands make the 255 I need to fit my car perfectly. How do we feel about the fronts being Continentals and the rears being Falkens? Seems against etiquette but if they're the right sizes and same treadwear rating (I know this varies a little between brands), I don't see this causing any issues.
before my 818 we autocrossed a 2007 NA impreza. Heat and cool cycles of the brake rotors would cause center of the aluminum wheel to expand and contract. this would stretch the oem wheel studs until the lug nuts could not be removes without snapping them off. Probably one or 2 studs a weekend. in 2013 switched to the ARP Studs on all our subaru's. Problem solved.Quote:
Originally Posted by Sgt.Gator
Attachment 194644
I remember going through a lot of gyrations trying to switch from Hoosiers to something different. I found that the normal tire ratings/size did not always translate into exact dimensions for the tire. I found that some of the manufacturers provided actual dimensions, especially for diameter that proved invaluable.
I went to half a dozen autocrosses this year. About 70 cars at each event and I had no studs break, no lug nuts seize, and never saw anybody else have a failure. Am I not driving fast enough lol? I was on cheap 460TW summer tires so maybe I just wasn't able to create enough grip/heat to cause problems.
TireRack shares all of the dimensions for the tires I'm looking at. I need to check my tire clearance again with my new LCA's and my current 215's though. I realized when installing the passenger side LCA that the rear bushing mounts are not symmetrical. One side is 1/4" longer and will move the wheel forward a little more in the wheel well. I need to go back and flip the rear bushing on my driver side LCA.
I recently swapped my 2002 steel LCAs for 2006 alloy LCAs on my 2014 chassis. With the front pivot through bolts installed the rear "Z" bracket was 0.75 inward from the mount brackets on both sides.Quote:
Originally Posted by mcamera
I had to elongate the front bracket holes to eliminate side loading the isolators.
BTW the "Z" bracket installs with the smooth tab up and the stepped tab down. Not the same as Subaru orientation.
jim
I've got 32 track days with 215 front's, 255 rears. Last two sets, Falken RT660. Front grip has not been a problem. The only time I get understeer is in the rain or a (California) cold track on cold tires - occasionally only the first warm up lap of the day. I have no plans to go wider. Maybe it's different on a slower / tighter autocross track?
JR yeah I realized the smooth side up on the Z tab was the better way. Need to flip my driver side around since I did that one smooth side down. I also had to elongate the holes on the Z tab a little to help with the install.
Dave I agree with your notes. I don't have understeer with my 215's. They give me enough grip to make my rear tires the limiting factor. At this point I want wider front tires because they'll look better on my 8" wide wheels. Currently my rim sticks out further than my tire bead. The tire looks stretched and kind of dumb.
mcam,Quote:
Originally Posted by mcamera
Altering the Z bracket location (left or right) does displace the wheel/tire fore and aft.
jim
Something to consider with the 818 is it deletes the fore and aft top engine / transmission brace (I forget exactly what it's called).
It was impossible to see with a casual inspection, but I discovered my timing belt cover was all bashed up. I concluded that without that top brace and the soft OEM mounts, the engine was free to move forward and slam the timing belt cover against the coolant piping. Perhaps someone can repost the video of the engine movement at an autocross.
I used the stiffest Cusco through bolt engine and transmission mounts available. The next step is solid mounts. Vibration is absolutely not an issue and my timing covers are still intact. These cars need more than the OEM mounts just to make up for the top brace delete.
I think that most call it the dogbone. I went with the stiff Cusco mounts, and they are stiff. I had a belt adjuster pulley come loose and embedded the pulley into the timing belt cover. Yikes! Fortunately I heard the noisy belt when I was putting her back in the garage before it came all the way apart. My scavenge pump woulda quit and I would have been very sorry. Changing out the cover without pulling the engine wasn't easy.Quote:
Originally Posted by Dave 53
On another note about movement, my car had started pulling left under acceleration and darting right when I would lift for a shift. I've got nearly 3Kmiles on her. It was getting scary so I did another string alignment on it and it got a lot worse. I took it to an alignment shop and they got it straight but discovered that with it up in the air, you could shake the left rear wheel substantially. Pretty scary stuff. I got it home and found a lot of loose bolts. The jesus bolt through the lateral arms was the worst of them. I know I had all of them tight. I'm going to start checking all the suspension bolts every thousand miles. I do drive it hard on canyon roads. Lots of side loads.
Ed
Ed
Dave, that's why I went straight to the stiff rubber mounts when I built the car. I know all OEM mounts usually allow a lot of movement and I didn't know what would hit, but I suspected something could. The poly mounts will deform over time so I prefer solid/stiffer rubber mounts which I have more experience with. Glad to hear the vibration isn't bad for you, I've had several friends switch back from poly mounts on their street cars because the vibration was too much.
Ed, the thought of things shaking loose has crossed my mind but I haven't found anything yet in 2 years / 2k miles. I'm expecting to find something now that I autocross the car more often and I'm about to switch to stickier tires. It's going to be harder on everything.
I guess I should have expected stuff to loosen. I do a lot of second gear roads (so twisty that I just can't get into third) that are fairly bumpy. Gonna check all the suspension bolts every thousand miles until I gain some confidence that I could go 2 or 3K. It'd be good if I could trust it to the next oil change. ;-)
My first ride was a hardtail Triumph motorcycle that I bought in a basket. I had to tighten stuff on it every day and even then I kept losing stuff off it. I was dumb enough to mount my ignition coils on a cantilevered piece of sheet aluminum. One day I glanced down and they were hanging from the plug wires a quarter inch off the road. My first lesson in metal fatigue.
Ed
I thought we were in E Modified? That's what I've been running at least, but the PAX is killing me.
I've been on the fence about classing as XB. My car is technically a little under weight minimum, and XB classing specifically mentions having wipers and a heater, which I have neither. There also a bunch of wording for "finished" interior which I don't think my bare metal panels would pass...
Probably at a local level no one cares. Has anyone questioned your classing at the event you go to?
At my first event last year the workers recommended the XA class. I found out the minimum weight was 2930lbs, so I switched to XB the next time because the minimum weight was 2330lbs. Like you said I'm still underweight (2280lbs w/ driver) but much closer. If I fill my gas tank 100% I should be within 20lbs.
Attachment 198268
EM does list the 818 S/R, but not the C. And the minimum weight is only 1700lbs so I would be 600lbs over. Better for me to add 20lbs and stay in XB if that keeps me legal. Nobody has said anything because I'm not the fastest in XB. I'm not a threat yet lol.
Attachment 198264 Attachment 198266
Yeah same here. I'm not good enough to threaten anyone locally in XB. I think before next event I'm just going to ask in the FB group if anyone minds if I reclass. Just nice to have someone to race against (so far I've been the only EM car at any event I've gone to) and with EM PAX I'd never be even near competitive.
https://youtu.be/GT6TJGJmDyI
I finally made the jump to good track tires and I am not disappointed! I can't believe how much more grip these have.