Hindsight's build thread

[Hindsight]

Thanks for all the well wishes guys. Good news and bad news. I only got two sessions in (warm up session and a solo session). The car felt REALLY great. I'll write more later but it's 100x better than it was last year. So much more stable. Still not happy with brakes... they stop the car well but pedal effort is high and they feel vague and a bit soft. ABS is nice though. My best time during the first actual session was 1:51 which is only 2 seconds off my previous best run from last year. That was me taking it easy and also getting stuck behind a couple people, so I'm certain I'll be dropping time from last year and hope to get into the lower 1:40 range.

Out of the blue, right as I pulled onto the track for my third session, the engine started cutting out and bogging. I see my AFR spike when that happens and I've got misfire codes for all four cylinders so I'm fairly certain it is a fuel issue. Unfortunately, there isn't much I can do at the track to troubleshoot that because to get at the fuel pump, fuel surge tank, wiring, fuses, relays, and fuel pressure gauge, I need to pull the floor pan, shoulder harnesses, seats, and firewall. Big job. I limped home, bogging all the way, and am now going out to the garage in hopes of figuring out the cause in time to have it fixed for the second day of racing tomorrow.

Sadly, I didn't get any video. My gopro battery must have gone bad because I charged it to full and now it won't turn on. I was going to get some video using my phone, but wanted to wait until the third session to do that.

Will update later.

[Hindsight]

Well the issue ended up being my traction control system. Embarrassing really. The system is not very well calibrated and I never turn it on; mostly because I don't have enough power yet to need it. But when it does come on, it cuts the injectors, sometimes even if there isn't any wheel spin. When an instructor got in to ride along with me so he could sign me off as a solo, he nudged the traction control knob and turned it on. I saw him nudge it but didn't think that the knob turned. As I dug into the car this afternoon, I saw the knob there and realized it was on. So, problem solved. It is too bad I had to lose my track day because of it but there is a second day tomorrow and if it doesn't rain, I'll be able to run in that. Fingers crossed for weather.


There were about a DOZEN GT3s there:

[Mitch Wright]

Always a great feeling when progress is made.

[Frank818]

There were about a DOZEN GT3s there:

How many RS?

[bbjones121]

Bummer, sorry to hear. At least it was not an issue at all, though frustrating

[Hindsight]

How many RS?

Frank, I'm not sure there were any RS there.

Back from day 2. Did four sessions today. I wasn't able to get any completely clean runs due to traffic, but on my best, I got a 1:45, which is a new personal best for me. My prev personal best was 1:49. Four seconds is a huge improvement, and I still have a ways to go on driving skill, so there is a lot more left in the car. If I can get these brakes sorted out and get some more seat time, maybe a few more suspension adjustments and start using my high boost map, I'm sure the car has 1:40 in it.

[Hindsight]

I forgot to mention: My fuel gauge stopped working after I installed the Hydramat inside the tank. I think it's because I either forgot to plug in the secondary fuel level sensor, or when I put everything back in the tank, I got the two fuel sensor floats tangled up on eachother or something else. So my gauge reads full all the time. During one fill-up at the race track over the weekend, I put 11 gallons in it which is more than I've ever put in the tank, and even though the tank was that low, I had zero issues with starvation in the corners. This means the surge tank and hydramat combination have fixed the issue. All for the bargain price of roughly $1,250 (counting the surge tank, pressure gauge, discriminator valve, AN hoses and fittings, second fuel pump, hydramat, relays and fuses) and a fair amount of work. But it's fixed.

[Bob_n_Cincy]

I forgot to mention: My fuel gauge stopped working after I installed the Hydramat inside the tank. I think it's because I either forgot to plug in the secondary fuel level sensor, or when I put everything back in the tank, I got the two fuel sensor floats tangled up on eachother or something else. So my gauge reads full all the time. During one fill-up at the race track over the weekend, I put 11 gallons in it which is more than I've ever put in the tank, and even though the tank was that low, I had zero issues with starvation in the corners. This means the surge tank and hydramat combination have fixed the issue. All for the bargain price of roughly $1,250 (counting the surge tank, pressure gauge, discriminator valve, AN hoses and fittings, second fuel pump, hydramat, relays and fuses) and a fair amount of work. But it's fixed.

Hindsight,
Good to hear you had a good track day.
Glad your fuel system is working. It reminds me of my dry sump system, almost 3k and lots of hours.
Bob

[Frank818]

Was your 4sec improvement due to driving skill or improved car? Or which one to what extent...

You went to a huge installation to fix your starvation, I damn hope the surge tank is not that mandatory for street driving, I don't have the space you had back there. 1300 is quite some money, but it fixed the issue and on the other hand in my case I "wasted" quite more than that to please my DMV, who will fix absolutely nothing and will cause other issues, so I'd go hands down with the super noisy surge tank.

[Hindsight]

Bob, thanks for the words of encouragement!

Frank, most of the 4 seconds was the car. I did spend a little more time researching the track online to improve my line, but the car was just much more stable and capable thanks to the suspension updates.

I've been following your struggles with the DMV and I am sure am sorry to hear it has been such a hassle for you. I think if you stick with it, it will be very rewarding in the long run, but I can understand how frustrating it must be.

[Frank818]

Now that you've driven and tracked the car more, are you still considering a custom high end suspension?

[Hindsight]

Hey Frank. Yes I am still considering it but I think there is a fairly low chance of me pulling the trigger any time real soon. $5k or so is a lot of cash that could buy a lot of other things. I have no doubt it would help me go faster, mostly by keeping a firmer grip on the pavement while hitting curbs and bumps on the track, but for right now, if I had an extra $5k laying around, there are probably other things I would put the money toward. More aero is quite high on the list, as is better brakes, and also more crash protection (considering a roll-cage). Also, more power.

Going to install the small master cylinder, new brake pads, and larger aftermarket adjustable front sway bar this weekend.

[Scargo]

Was asking John George what shocks he was using on his new Gen 3 coupe ST2 build and he said the FFR Koni reds. Right out of the gate his car seemed pretty well sorted and fast last week at VIR. So, wondering what you were running? Also, by what I gathered, you are having some understeer issues. How will the new sway bar help that?

[Hindsight]

Hey Glyn, I was running the FFR Koni reds (single adjustable). My only issue with those shocks is that shocks are not one-size-fits-all. They are supposed to be valved based on the spring rate and other factors. The rebound adjustability buys you a bit more "range" but you don't have compression adjustment so what you get is what you get. For right now, it's probably going to need to be good enough for me since I don't want to drop $5k for a perfect setup. Another note is that by my calculations, to hit an "ideal" suspension frequency of around 2.0hz, I'd need 275# front springs and 300# rear springs. That seems really soft, but that's what the numbers say. That setup would almost certainly require a front sway bar, and probably even a rear one as well which would require something custom/universal. I'm sticking with what I have for now, which gets me 2.5hz rear and 2.18hz front.

So, at first, I thought I was having understeer issues but as I continued pushing the car, it felt more like oversteer. The balance is pretty close right now though. The oversteer appears more at higher speeds. From my research, this is typical with mid and rear-engine cars (low speed understeer and high speed oversteer). Stock bar is 17mm. I have an adjustable 22mm Whiteline bar on order. I'm going to see if it fits the 818 (it's for a rear WRX so it SHOULD), and run it at the loosest setting and go from there. I can go back to the 17mm stock bar, or adjust the 22mm bar to be stiffer until I like the balance.

On the track, there is a turn at Road Atlanta that I'm taking at about 125-130mph. It's not much of a turn at all; just requires the smallest amount of steering input, but it happens at the crest of a small hill. The back feels loose there and like it wants to rotate. I might need to buy or fab a rear diffuser to see if that helps hold the car down a bit more, and if that doesn't work, I may need to try a rear wing and see if it is effective at all considering I have a windshield (I thought it wouldn't be but Jim Schenk told me it would still provide some down force). As-is, I am letting off the gas a bit before the hill crest to bleed some speed and then applying a little bit of throttle as I go over it to keep weight transferred to the rear. To go WOT the whole way I need more grip.

[Frank818]

Why is 2.0hz the ideal? Is it for everyone?

Your technique at the hill crest is very similar to Eau Rouge at Spa-Francorchamps. lollll OMG I would love so much driving my illegal 818 on that track!
At 125-130mph aero should give some effects. Enough we don't know, but it should do something.

[phil1734]

It sounds like you have a major aero imbalance. There are many GT cars with greenhouses that use rear wings to great effect so I wouldn't worry too much about the windshield thing.

[Hindsight]

Frank, there is a lot of opinion on suspension frequency, but the nice thing about it is that it CAN be used to directly compare the stiffness of one car vs another, unlike spring rates. Most people say that around 1.4 to 1.5 is a good "sporty" rate, less is good for comfort, and 1.6 to 2.0 is good for street/track, but considered a bit stiff. Above 2.0 is track only; and 2.5 to 3.0 and higher is mostly for track-only cars with a lot of aero. As for your car, you could always tow it to the track!!

Phil, it is definitely possible that I have an imbalance seeing as how I have a front splitter and no rear wing to balance it out. I need more track time to figure it out for sure. I will see what the thicker front bar does for me and if I still have imbalance, I will add a rear wing and try to get it as high as the windshield which should be pretty easy to do.

[DanielsDM]

Hindsight,
Sounds like you're having fun with the tuning of a new car. I'm looking forward to it, just have to finish the car first . There are so many adjustments that can affect the balance of the car, most changes affect the car in more than one way. Thus tuning is more art than science. If you haven't already I recommend getting a copy of Carrol Smith's Tune To Win, it was written almost 40 years ago, but the physics haven't changed. Also check out Buddy Fey's blog (buddyfey.blogspot.com). Buddy has worked as a race engineer since the early 90s and is a great guy, I've worked with him on getting Davidson Racing's cars converted to endurance racers (He did the setup I just designed and machined various parts).

-Daniel

[Hindsight]

Thanks for the input Daniel. I do have the "How to make your car handle" book, and like the ones you suggest, it is a bit dated but it's all still applicable today. I'll check out the book and blog you mentioned.

[Hindsight]

Installed the 7/8" master cylinder tonight. Put the master cylinder pushrod in the OEM hole on the brake pedal. I then put some Carbotech XP10 pads in. First test drive and bedding went well and the new setup feels better than my old. I need to put some more miles on it to really see what I think about it.

The 22mm sway bar showed up. 22mm looks a lot thicker than I thought it would! I am concerned it might be too thick for the light 818 but we shall see.

[RM1SepEx]

What were your old pads? My Hawk HPS need more initial bite for improved feel, I may change to something different.

[Mitch Wright]

Is your your 22mm bar solid or hollow? That will be a big change that you will feel right away.

[Hindsight]

Dan, at first I used Hawk HPS and they were AWFUL. I had to press the brake pedal super hard at parking lot speeds to get it to stop - it was a scary feeling. I upgraded to Ferrodo DS 2500 and it was an improvement, but still not fully happy with them, especially on the track because they seemed to fade quickly. These carbotechs have the added bonus of shooting out sparks at night, making me feel like an Indy car driver lol.

Mitch, it's solid. I agree, it will be a HUGE change, possibly too big. The problem is that no one makes an aftermarket rear bar for the WRX that is smaller than 22mm. So you have to go from 17mm stock to 22mm aftermarket. the aftermarket one is adjustable so I will start full loose and see what happens.

[ben1272]

Frank, there is a lot of opinion on suspension frequency, but the nice thing about it is that it CAN be used to directly compare the stiffness of one car vs another, unlike spring rates. Most people say that around 1.4 to 1.5 is a good "sporty" rate, less is good for comfort, and 1.6 to 2.0 is good for street/track, but considered a bit stiff. Above 2.0 is track only; and 2.5 to 3.0 and higher is mostly for track-only cars with a lot of aero. As for your car, you could always tow it to the track!!

Phil, it is definitely possible that I have an imbalance seeing as how I have a front splitter and no rear wing to balance it out. I need more track time to figure it out for sure. I will see what the thicker front bar does for me and if I still have imbalance, I will add a rear wing and try to get it as high as the windshield which should be pretty easy to do.

Doesnt Factory five only recommend front splitters when used with their corresponding rear wings? I assume they must have some data that tells them this, given their wind tunnel testing. Why not drop the spiltter and see if things improve, rather than building up a wing to try and solve? Seems like more work and it may not be your problem.

[Hindsight]

I put the Whiteline 22mm sway bar on today and sadly, it did not fit. The driver side fits ok but the passenger side contacts the coilover no matter what I do. I am using universal sway bar bushings with matching universal brackets (both for the OEM and the aftermarket bar). These are nice because they are slotted so you have some adjustment there, and can move the entire sway bar up or down an inch or so. In addition, you can lengthen or shorten the FFR-provided upright swaybar links via their threads, to bring the ends of the bar up or down to help with clearance. But no matter what I did, I couldn't get it to clear the coilovers.

My options are to go with softer rear springs, drill new holes further inward on the OEM sway bar to make it "adjustable" and get more force out of it (only room for one hole on each side, about 3/4" on-center from the old one which should help some but not sure how much), or get a universal style sway bar (along these lines: https://www.summitracing.com/ga/part...1-17/overview/). Once you move to the universal style, the sky is the limit in terms of sizes and adjustability.

At this point, since more work and money are involved, I'm putting the OEM bar back on and am going to find a parking lot where I can do some low-speed skid pad tests to triple check the balance of the car without influence of aero.

[Scargo]

The first thing that came to mind was modifying the bar to clear the coil. All the custom stuff I find looks to heavy for the front. Whiteline has this chart that may be helpful.
I would sure consider cutting and pasting and making something work. Welding is a bit of a problem but I believe it can be done with a perforated sleeve, and bars can be re-heat-treated. But I'm just speculating. I've not tried reworking a swaybar. I don't know if you can get away with spot re-hardening.

[RM1SepEx]

The 818 needs a straight tubular sway bar with adjustable effective arm lengths... I'm not sure if it can be done

[Mitch Wright]

I have made straight .750 4130 bars for my 818. Haven't installed and ran it yet but fit when I mocked it up.

I have also cut the ends off a bar and either weld a piece of tubing or flat stock to the end with a series of holes for your adjustment, works great.

[RM1SepEx]

Mitch, how much did you have to move one of the mounts up or down and which one did you move?

[Mitch Wright]

I mocked up the prototype using the FFR mount but moved the bar mounts up as high as I felt safe on the pads. Once I get moved in I will get it installed, I think I would go up which would give me more room around the spring. I have also pondered welding tabs on the upper ball joint mount and attach the bar links there. As soon as I can get to the proto type I will take a picture.
I have also played around with welding a small pedestal on the lower frame rail for the bar. Got lazy and didn't want to take the front end back apart to do the job so figured I would use the FFR mounts. I almost cut the mounts off during the build to save a little weight, now I am glad I didn't.

[Hindsight]

Been a while since my last update, but I haven't really done anything to the car. Just been enjoying it. My Roebling Road track day is coming up next weekend and I'm excited for that. Wish I would have had a new sway bar and some aero for it, but I will make-do with what I have now.

Road Atlanta has their "Mitty" event this weekend and Wayne said he was going so I stopped by to check it out and see Factory Five's new track-mule in person. There was also a lot of vintage, and Porsche racing which was awesome to watch. I brought my dog Fletcher, who wasted no time making friends with the guys at the Koni booth. I wonder if they'll give me a big discount now? lol.

The 818R that Wayne put together is super nice. Paint looks great in person. Pics don't do it justice. It had huge carbon fiber side scoops which are really cool and would work well for my plan to locate an oil cooler behind them. I might get a pair. There is a new wing on this 818R, but it is still from APR.

Here are some pics I took today. There were SO many cool cars at the event that I could have taken a thousand pics and not captured everything cool there.

[Hindsight]

[metros]

Thanks for sharing the pictures. Some great looking cars there!

I'm really happy that FFR decided to bring the 818 out this year. Looking forward to seeing what it can do.

[Hindsight]

Me too Metros! With Wayne handling everything from the mechanicals to the driving, the car should be very successful.

I think the skidpad challenge may be unfortunately rained out today. But there is the GRM challenge coming up at VIR in May and that's the big road racing event. That will be where the 818R can really shine.

[Hindsight]

The movie "Baby Driver" was filmed in Atlanta. A local Subaru repair shop procured and modified all the red WRX stunt cars used in the movie. The WRXAtlanta group held a photoshoot today with one of the main stunt cars used in the movie. This one was rear wheel drive and had a hydraulic rear parking brake added for the stunts.

Red White and Blue for the 4th of July!

[fastzrex]

The movie "Baby Driver" was filmed in Atlanta. A local Subaru repair shop procured and modified all the red WRX stunt cars used in the movie. The WRXAtlanta group held a photoshoot today with one of the main stunt cars used in the movie. This one was rear wheel drive and had a hydraulic rear parking brake added for the stunts.

Red White and Blue for the 4th of July!

Very cool!

[Hindsight]

I've ordered most of what I need to fabricate a new front sway bar. Using 3/4" 4130 tubing for the center section, some universal mounts, and will make the arms out of 1.25" x .25" steel. Haven't figured out what I will do for uprights just yet but am leaning toward swedge tubes with rod-ends. Will post pics of the process.

[Hindsight]

Starting to work on the sway bar......

[fastzrex]

Hindsight, thanks for showing your build up of sway bars. With so many other items to do myself, I appreciate all the work on this area as it will eventually help my build.

[Hindsight]

You are very welcome Mark. Since my car is done and I am now dialing everything in, my biggest hope is that I can help other builders who may not want to have to figure out things like ideal front sway bar size or how to get the brakes working and balanced properly.