Camera's 818C

[Bicyclops]

I was feeling my rear suspension bottoming and there was evidence of rubbing in the wheel liners. I went to Eibach 425lb springs in the rear. While I was at it, I added thrust bearings under all four. It makes it so much easier to adjust ride height.

Ed

[Bicyclops]

Lance,

Do you have a part number on the QA-1 shocks. I was looking but didn't really come up with one.

Ed

[mcamera]

Yeah I'm still using the FFR coil overs and can tell they're basic. Thanks for the suggestion. I don't know much about shocks so I'm doing some research. External adjustments look like a great feature. I've learned how important setup is for racing this year so easy adjustments will be helpful to dial things in. The pricing doesn't look that bad, and they have options. I appreciate it!

[lance corsi]

I’ll look at mine to see if they have a part number. Mine are dual adjustable and the springs I ordered to go with them are the same value as the Koni springs, although you may want a higher rate.

[mcamera]

1 upgrade I know I'll be doing this winter is installing STi Group N bushings on the rear links/arms. I don't think my 17yr old stock bushings are up to the task. Should be a big improvement without the harshness and squeaking of poly mounts or upgrading to links with spherical bearings. Not to mention 1/4 the cost.

IMG_4148.jpg IMG_4149.jpg

[mcamera]

After my final autocross run of the year, I rolled into the grid with smoke pouring out of my car and somebody running at me with a fire extinguisher. Luckily we quickly found that the nipple on top of my coolant bottle had broken and sprayed my engine bay with coolant. No fire. It was cold outside (got down to 40 that night) and my tires were sliding and hopping aggressively every run until something broke.

IMG_4488.jpg

I was also significantly slower than the other guys in my class this race. I think the RT660's are really sensitive to cold temps. The MR2 I beat last time, crushed me and I know he runs RE71's. Even a FWD GTI with all season 300's matched my best time. I was pushing it but also might have been rusty from not racing for 2 months. Video to come.

I'm going to upgrade to the aluminum Mishimoto bottle
https://www.fastwrx.com/products/mis...nt=25315809808

[Dave 53]

After my final autocross run of the year, I rolled into the grid with smoke pouring out of my car and somebody running at me with a fire extinguisher. Luckily we quickly found that the nipple on top of my coolant bottle had broken and sprayed my engine bay with coolant. No fire. It was cold outside (got down to 40 that night) and my tires were sliding and hopping aggressively every run until something broke.

IMG_4488.jpg

I was also significantly slower than the other guys in my class this race. I think the RT660's are really sensitive to cold temps. The MR2 I beat last time, crushed me and I know he runs RE71's. Even a FWD GTI with all season 300's matched my best time. I was pushing it but also might have been rusty from not racing for 2 months. Video to come.

I'm going to upgrade to the aluminum Mishimoto bottle
https://www.fastwrx.com/products/mis...nt=25315809808

Maybe more than temp, the RT 660 might be sensitive to psi. I recall you ran the RT660's at really high psi. What psi were you targeting? I liked the RT660 performance, but after one of them completely chunked apart after one day and hearing similar stories, I switched to V730's and did a PB at Thunderhill last weekend. But when I was on the RT660's, I was looking for 28 psi hot.

[mcamera]

I started the season at 40psi but the last few races I've been running 30psi (cold and hot). I tried 28psi on my last 2 runs to see if my times improved but they didn't. Ran 39.7 on all 3 of my last runs. One of those runs was even with a 230lb passenger. The car just felt slippery compared to the hot summer races I've done all year. My temp probe showed the tires never got above 90F yesterday.

The car also hops more with the lower pressures. My times have proven there's more grip with 30psi vs 40psi but I think the extra grip is pushing other things past their limit and causing the hopping. My springs are maxing out and bouncing off the bump stops and I'm guessing my 20 year old rubber bushings are flexing a lot. All are getting upgraded this winter.

I was hoping to run the RT660's for 1 more season but if they can't keep up in the spring, I'd be willing to give the V730's a shot.

[mcamera]

Found a little info to support my theory that the RT660's are more sensitive to cold than other 200's.

TireRack says their optimal temp is 120-130F. My tires never got above 90F.
Slide1.JPG

Grassroots showed the RE71's running a full second faster when stone cold vs the RT660's best time of their test.
Slide2.JPG

[mcamera]

[mcamera]

Winter upgrades have started. Here's the plan to get in the top 10 for autocross this year (18/100 last year).

- New dual adjustable QA1 dampers

- Stiffer rear springs to reduce body roll / stop tires from rubbing the fender (275# to 500#). I used a dynamics calculator to find the optimal spring rate and 500# should be appropriate.

- Upgrade rear suspension bushings to stiffer STI Group N rally bushings

- Longer rear wheel studs and larger wheel spacers to eliminate tire rub on the trail arm (5mm to 10mm). I checked my suspension travel without the spring on the car and my tire should still clear my fender lip. Especially with stiffer springs. Makes my rear track 10mm wider as a bonus.

- Add 50lbs to the rear passenger corner. Needed for class min weight and allows me to rebalance the car for a better setup.
- I'll be able to reduce my bite from 40lbs to 0lbs for even weight on the rear drive wheels
- It'll shift 1% more of my weight to the rear end for added traction (42% front / 58% rear).
- My Left/Right balance will improve 1% (50.5% L / 49.5% R)
- I'll be able to level the car more since the passenger side currently sits 0.75" higher for cross balance. Will look better, lower the car slightly, and should improve my roll center.

I've finished swapping the Group N bushing in on the passenger side arms. I have 1 more bushing to press in on the driver side arms and then I can reassemble. The trail arms are a pain. 1 bushing has a metal sleeve that I had to cut out, but luckily my bushing tool was strong enough to press the new one in. The other trail bushing is in the knuckle and there's very little room to work with (I'm doing this without taking the knuckle off the car). On top of that, the Group N bushing is so much stiffer and oversized by ~4mm that it's a really tight squeeze to get it back in the knuckle. I had to preload the bushing into a sleeve ~2mm smaller, and then press it into the knuckle from there for the last ~2mm of compression.

IMG_4916.jpg Bushing Tool.jpg IMG_4818.jpg IMG_4904.jpg IMG_4918.jpg

[mcamera]

[mcamera]

After a little more research, several sources are saying to not place ballast weight far from the car's center of gravity to balance corner weights. So my idea to add 50lbs close to my passenger rear wheel doesn't sound like a good idea even though it would make the numbers look good on the scales. The analogy I've seen is having 500lbs on one side of a teeter totter. You can put 500lbs on the other side to balance it, but each side will be difficult to move and harder to stop once it is moving. There's a lot of momentum so the car will not transfer weight quickly during turns.

I can still put my weight low in the car to lower the center of gravity but I'm not sure how to get more weight on the passenger rear wheel without jacking that corner up 1" higher than the driver side (already 0.75" higher) or putting weight near it. Maybe put the weight near my center of gravity but slightly to the passenger side as a compromise? Back to the teeter totter analogy, I think adding a counterweight to the light side but near the fulcrum would help things move more easily in both directions. Without creating a 2nd slow reacting side. Does that make sense to anybody else?

Also ordered my dual adjustable QA1 dampers. They'll be here in 3 weeks!

[J R Jones]

Add weight? How about reposition weight? Like move the battery.
I have not seen your corner weights. You can add weight to the RR by jacking up the LF. Of course you do not want to create a miss-match LF to RF.
You could unload the RF and LR. Or a mix of those suggestions.
The circumstance you are trying to correct is with driver weight in the car?
Unless you are loosing traction why strive to increase rear weight bias?
jim

[Dave 53]

It is possible to corner weight the car and keep the ride heights equal. It just takes time playing with it - at least when I did mine. Numerous iterations, I had perfect 50/50 and the heights were off. But, I eventually got 50.0/50.0 and corner ride heights within 1/8". I had half a tank of gas and 200 pounds of bricks in my driver's seat when I did it.

When I was racing go karts, we had to come in at a minimum weight and the skinny racers bolted on lead. When we worked on the karts, we'd lift them up onto a stand. The etiquette is you would just ask someone that was walking by to help lift the kart onto the stand. Everyone would avoid skinny Rob because he had 60 pounds of lead on his seat.

I had a 1999 BMW M Raodster. BMW proudly advertised it's 50/50 weight distribution. Those cars have 40 pounds of lead in the rear bumper.

[FFRWRX]

It is possible to corner weight the car and keep the ride heights equal. It just takes time playing with it

I don't know much about corner weighting a car, but how is this possible? If you start with the corners equal height and the corner weights are off, how can you adjust things, have the corner weights correct, but end up where you started with the heights correct?

[mcamera]

Here are a few pics with my corner weights and the problems I'm trying to improve by adding weight.

Slide4.JPG Slide5.JPG Slide6.JPG

Great suggestions to get me thinking. The battery is in a great center position for left-right balance, but you're right moving it more to the rear of the vehicle could help. I think the only place I could easily mount it is on the driver side of the engine bay to stay away from the exhaust. Which would make my balance even more left side heavy. I'm not sure what other items I could relocate to the passenger side. Almost everything on the car is symmetrical. I debated my coolant overflow bottle but that would also put it near the exhaust.

IMG_3684.jpg IMG_5004.jpg

My LF is already heavier than my RF. Jacking up the LF will add weight more quickly to the LF than the RR. This could work for a few pounds though since my LF has the lowest ride height. It'll make my front wheels more uneven, but at the moment my front wheels are not my bottleneck for grip so it might be a decent trade off.

I don't want to unload the RF or LR. RF is already lighter than the LF. The LR is already near a 4" ride height which is my minimum for a street car.

Weights are with me in the driver seat.

I often spin 1 rear tire coming out of slow turns and in general my rear end loses grip before my front end. So I'm trying to improve rear grip by putting even loads on both tires and shifting weight to the rear bias. I'm at 57% rear bias, and I've read up to 60% is good for a mid engine car as it helps press the tires into the ground for more grip.


Dave,
I used ride height gauges during my corner balancing to help choose which corners could go lower or higher. I did my best to keep things in check, but by the end the only way I could reach 50% cross weight was by raising the passenger side of the car 0.75" higher than the driver side. I'm using a 10gal Boyd fuel tank that's symmetrical and adds even weight on the driver side and passenger side. If you're using the FF tank which is 18gal and larger on the passenger side, you may have some extra weight on the passenger side which helped you achieve balance easier? If the passenger side of the tank is 12gal vs 6gal on the driver side, that's an extra 6 gal (48lbs) on the passenger side, and it runs all the way out to the side frame (further from the center of gravity = more leverage). Just one idea...

I hope by the end of the karting season skinny Rob packed on some muscle from lifting that kart so much lol.

BMW marketing made sure they hit 50/50 no matter what it took!

[J R Jones]

Thoughts on anti-roll bars. When you measure/balance weights, disconnect a link on each bar and adjust for no preload when you reattach the links.
If you have a rear bar, disconnect it (for oversteer).
The (Subaru rear) front ARB is pretty light. Hard to correct on the 818, shorter arms is an option. I adapted a heavier bar and location. I will not run a rear bar to start.
jim
I still can not load photos here. Not even small jpegs.

[Dave 53]

Not saying I'm an expert. Just sharing what I did based on the various methods of research I've done and being stubborn.

My priority #1 was 50/50 cross weight.
#2 Level 4" ride height.

It took 30 minutes to get 50.0/50.0 cross weight. Then 6 hours to get 50.0/50.0 cross weight and level 4". I can't articulate exactly how I did it. Mostly, if I needed an adjustment, there are two ways to make it - lower something or raise something and I just kept strategically picking what to do. I recall at times lowering or raising all 4 corners together to establish a new baseline and starting all over again. Maybe try swapping springs left to right?

I haven't put any effort into adjusting left to right or front to rear weight. Nothing to work with other than battery placement - mine is up front.

It's interesting to see your weights compared to mine. I think my 6 speed is 85 pounds heavier than a 5 speed! I've also got a fairly heavy passenger seat.

The FFR gas tank is larger on passenger side by a couple of gallons. It's about 14 gallons full. I wish it was 18 gallons! Actually, I wish it was 16 gallons. I can get 3 20 minutes track sessions on a tank of gas at every track except Thunderhill East. It's the only track I get into 6th gear and can't quite get 3 sessions on a tank. I need to add 2 gallons before that 3rd session. Running out of gas on the track is a HUGE party foul!

cross weight.jpg

[mcamera]

I only have a front roll bar and I disconnected it during corner balancing. Then adjusted it for zero preload when I reattached it. Thanks for checking though as that can easily be forgotten. I can reduce oversteer by increasing my front tire pressures too, but I'm trying to add grip to the rear instead of reduce grip at the front if possible. It's not a lot of oversteer I'm playing with. I would like more rear grip for my launch and coming out of slow corners though.

Sounds like we had a similar method to corner balancing. Took me half a day too. I started off at a 4.5" ride height and would review my weights and heights with every adjustment. Carefully picking which corners to raise or lower so I didn't go below 4" at any corner. I got to 50/50 cross weights but my driver side is near 4" and the passenger rear damper was maxed out for height adjustability at 4.75".

I agree with FFRWRX. You have to make a change to get a change right? My weights at an even 4.5" ride height were TERRIBLE. My cross was 57%, my rear tires were 200lbs different, my fronts were 130lbs different. I linked my video to the spot where I talk about it. I had to shift a lot of weight to get a 50% cross.

IMG_1580 (1).jpg

https://youtu.be/w_brzs9bPIY?si=8LCzduvK9V0cz_X9&t=180

I believe what you're saying I'm just not sure why we're seeing such different results. My driver side is also near a 4" ride height so I don't think your lower ride height is reducing the effects of anything by that much. I'm only 165lbs too, you mentioned you used 200lbs in the driver seat during balancing. You should have more driver side weight to overcome (31lbs based on your scale pic).

[J R Jones]

A detail to consider is the influence or rubber/urethane bushings in (rotational) tension or compression which results in adding or reducing spring rate.
My rear suspension is/was all rod ends that do not bind.
Installing 2006 STI alloy front LCA was an education. The chassis mount holes were not close to fitting and had to be reworked in order to slide the fasteners in without binding.
I tightened the fasteners with the suspension drooping, I expect at ride height the joint isolation adds to the spring rate.
jim

[Dave 53]

The goal of corner weighting is to get the front to rear weight bias of each side equal regardless of the absolute weight of each side. We both did that. Maybe a difference in ride height is mostly just aesthetic.

You're 69 pounds heavier on the left to my 68 pounds. If our in-seat weights (200 v. 165) were closer to each other, I'd say all is well with the world. How am I 35 pounds heavier than you, but my left cars is 1 pounds lighter? I have a light driver's seat and a heavy passenger seat, but by only a handful of pounds. And as you pointed out, more gas on the right which would explain some of it, but not enough to make up for my extra body weight. Curious....

Front to rear, you're 43.0/57.0 to my 40.8/59.2. My greater rear weight bias is easily explained by my much heavier 6 speed (I'm assuming you have a 5 speed).

If you need to add 50 pounds for your racing class, put it between your passenger seat and the door. Then re-corner weight the car with the ballast in place. You will have the best weight balanced car at the events!

[mcamera]

Jim I also did the aluminum front control arms last winter and I rebalanced after I installed them. It only moved my cross weight by a few pounds. I made sure to tighten those bushings at ride height. I'll make sure to do all my balancing before I fully tighten my rear suspension this winter since I'm replacing springs, dampers, and bushings on the rear. Maybe that will help keep the rear bushings from adding force.

Dave, yes I have a 5 speed. Both my seats are racing seats, but not bare bones like a Kirkey seat. About half the weight of the OEM Subaru seats. Our weight comparison is strange. I wonder if the scales not being level could throw things off this much. I've corner weighted my car twice and both times were consistent when I put them on the scales.

Putting the weight by my passenger door circles back to my original question/concern. Longacre and Speedway Motors both say to not put ballast far from the center of gravity. They say it will look great on the scale, but make it harder for your car to transfer weight since it's so far away from the center of gravity (the point the car rotates its weight around). But I don't think putting ballast at my center of gravity will improve my left/right or front/rear weight distribution. I should be able to put it below my center of gravity which will lower my center of gravity though. That's all I can think of doing to make the weight useful.

Also I think Google was spying on us. YouTube started suggesting a bunch of corner weight videos. I watched one from DS3shooter that explained when you raise 1 corner to increase weight, you should also lower the opposite corner to maintain your ride height. And vice versa. I did not follow this method. I linked to the video at the point where he explains it.

https://youtu.be/yssSSfubGE8?si=pF1zii_KWSQ6-gcq&t=276

[Dave 53]

Assuming a track with left and right turns, if my car is 69 pounds heavy on the left and I get 50 pounds to play with, I'm putting it all the way to the right! The goal of ballast placement is to MOVE the center of mass. The ballast isn't acting about the center of mass- it's MOVING the center of mass.

I recall the crazy forum debates we had about that weight in the BMW M Roadster rear bumper.

[RPGs818SNA]

Academic question: Adding weight far from the center of mass moves the center of mass some toward that added weight, but placement has no effect on the force needed for acceleration in a straight line. However, adding weight away from the center of mass increases the moment of inertia or rotational inertia. Depending on placement, it makes the car harder to turn (or stop turning), harder to roll, or harder to raise or lower the front during acceleration or braking. Is this effect noticeable in a racing environment?

Curious,
RPG

[J R Jones]

Academic question: Adding weight far from the center of mass moves the center of mass some toward that added weight, but placement has no effect on the force needed for acceleration in a straight line. However, adding weight away from the center of mass increases the moment of inertia or rotational inertia. Depending on placement, it makes the car harder to turn (or stop turning), harder to roll, or harder to raise or lower the front during acceleration or braking. Is this effect noticeable in a racing environment?

Curious,
RPG

A sructured lab test would employ the scientific method to get your answer. A drag race would get you an answer.
A road racing course, (to a lesser extent an autocross) would result in a nebulous answer. What you gain in one dynamic you may loose to the opposite dynamic.
In our last roadracing endeavor we set the car up for each track. More and/or more significant right turns were prioritzied over left turns, or vice versa.
A track with significant straight would be set up for less drag and top speed. Aero and chassis were adjusted appropriately. Data recording helped evaluate each segment of the track. Lap time is less precise as it averages change.
We were using our strengths and the environment to our advantage.
jim

[driveslikejehu]

The results on my R are similar to yours. In fact, your first posts about it were very instructive. Where I ended up, with all ride heights within a .25" plane.
cbal.png
I think once you get this close, its diminishing returns relative to what I'm going to experience on the track. But that's just where I'm at, which is no expert. I've driven many track days, but not in an adjustable car.
And like you I have plenty of front bite and loose rear under power. So I'm adding a wing over the winter, mostly for fun.
The knowledge required to truly "dial it in" is harder to come by than spending money on parts, lol.

If I had to add weight, I think I'd bolt it on outside the passenger seat, to balance the driver placement. I'm pretty sure the moment of inertia doesn't know if you have a big weight in the driver's seat, or smaller weight outboard.

Thanks for sharing your development. It's useful/enjoyable to see someone else actively doing it.

[Dave 53]

Academic question: Adding weight far from the center of mass moves the center of mass some toward that added weight, but placement has no effect on the force needed for acceleration in a straight line. However, adding weight away from the center of mass increases the moment of inertia or rotational inertia. Depending on placement, it makes the car harder to turn (or stop turning), harder to roll, or harder to raise or lower the front during acceleration or braking. Is this effect noticeable in a racing environment?

Curious,
RPG

Google says a 6 speed transmission is about 65 pounds heavier than a 5 speed. I also got heavier Driveshaft Shop axles. After switching to the 6 speed and new axles, I didn't notice any significant change in handling. But, there are factors to consider other than just the addition of 65 pounds to the rear of the car. A 200 pound passenger... I can absolutely feel that!

[mcamera]

Dave, your comments resonated with me. Ballast is used to move the center of gravity, but the ballast weight also reacts around that center of gravity. Both are true. However, I think you've pointed me down the more important path. If I mount 50lbs of ballast by the passenger door, sure it isn't ideal for the forces acting on that 50lbs, but it moves the center of gravity to a better position for the other 2,280lbs in my car. That sounds like a good tradeoff to me. I've also driven with 180# passengers in my car and it didn't trash my handling or times. So I think it can handle 50lbs of well placed ballast. I'm going to avoid putting the weight near a corner though like I originally planned, and put it near the passenger door. That's at least good for the center of gravity axis that runs across the car.

Slide5.JPG

driveslikejehu, I'm glad you found some of my info useful! Your car does have really similar corner weights to mine but with more consistent ride heights. I agree there are some diminishing returns but keeping your tires in their optimal working range is so important. If I can get the rear tires loaded evenly for launching / exiting corners, and the front tires loaded evenly for consistent turning, it's going to pay off. Making one tire work harder than the other will limit my potential grip. Just trying to make every change for the better! I'll have to check out your wing when you're done.

[mcamera]

As I'm installing my new dampers and springs, I'm realizing how poorly sized the FFR dampers and springs were. The old Koni's only have 2.5" of total travel and at ride height I was not in the middle of this range. There's very little extension possible before the dampers reach max length.

Screenshot 2025-01-22 092410.jpg

They're especially bad at the rear. I thought the suspension would bind close to where the damper was fully extended, but that's not the case. The damper could only extend about 1" before maxing out and limiting suspension travel. My car never got on 3 wheels during racing, but it hopped across long sweepers and during heavy leaning. I think my inside tire was touching the ground but had almost not weight on it, so it would skip across the asphalt instead of being pressed down far enough to grip well. My stiffer 500lb springs will help reduce that roll but 1" of damper extension is still not enough. This is an unexpected bottleneck that I'm glad I found and I think it will be a huge improvement for my rear grip.

My new QA1 dampers (part number DD501) are a similar size but have 5.25" of total travel. Twice the Koni's. I also had the benefit of measuring my suspension at ride height on my old Koni's, so I could choose a new damper that would be in the middle of it's range at ride height. So equal compression and extension. These are going to do such a better job of keeping the tires pressed into the pavement across a wider range of suspension travel. I'm glad I didn't take the cheap route and just put stiffer springs on the old Koni's.

The extra travel and stiffer spring does mean the spring comes unseated at high extension as shown in this pic. So I got 4" helper springs and adapters to keep the spring engaged across the new wider range on the rears. The front suspension doesn't extend as far and from my measurements should keep the spring engaged across it's range. I'll need to confirm that once I get everything set at ride height and corner balanced but it looks like helper springs aren't needed on the front.

Screenshot 2025-01-22 092617.jpg Screenshot 2025-01-23 113042.jpg Screenshot 2025-01-23 113212.jpg

Thought I'd share some of my progress. I'm finding all of this really interesting and seeing more benefits than I originally expected for upgrading the dampers.

[Dave 53]

I'm looking forward to your impressions of the new shocks.

Spring rates will also affect where in the ride height adjustment you end up. When I switched to the heavier 6 speed transmission, the extra weight lowered the car. I maxed out the ride height adjustment on the rear shocks trying to raise it back up. The solution was stiffer springs. It seems springs that are too stiff might have the opposite effect - inability to lower the car.

If you have an open diff, I would diagnose your spinning of the inside tire as 98% open diff, 2% some other factor. I solved the problem with a Quaife QDH3Y LSD. I think it's the best option for a street / track car. Not 100% sure, but I think all WRX 5 speeds came with an open diff. STi came with a LSD.

[mcamera]

Correct, my stiffer rear springs should move the spring perch down 1" to maintain my current ride height. This will keep me in the middle of the damper's range at ride height. It just requires a helper spring for large extensions of the damper where my main spring fully decompresses and would leave the spring seat.

I didn't have clearance to go from an 8" spring to a longer 10" spring to help with this, since the 10" spring would move the spring perch down another 2". It would interfere with my hub and I wouldn't be able to lower my car at all since the spring would be at the bottom of the height adjustment.

You're also right that it'll reduce how much you can lower the car. From my measurements I should still have no problem going down to a 4" ride height which is the lowest I'd want for a car I drive on the street. I'll be aiming for a 4.5" ride height.

If somehow these changes did force me to move away from the center of the damper travel though, I'd rather shift 1" of travel on a damper that can move 5.25" (QA1) than shift 1" on a damper than can only move 2.5" (Koni). A lot more options for tuning.

I have an open diff with my 5 speed and I agree. I'll look at an LSD whenever I need to change my clutch. I have no clue how old mine is. Thought I should fix the soft rear suspension that's bouncing off of bump stops and making my tires rub on other parts first. Using ballast to get even weights on my rear tires was one way I thought I could improve my rear power distribution without going to an LSD yet. Trying to make the most of what I have.

[mcamera]