Exploring The Space in the Money Pit

5327 Views 68 Replies 7 Participants Last post by Karlot, 2 mo ago

jharris48

Discussion Starter · Jun 20, 2021

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awenthol

· #61 · 2 mo ago

jharris48 said:
I wanted the STi parts for the spherical bearings while maintaining OEM weight. Most the aftermarket lower adjustable control arms with spherical bearings are heavier than the OEM arm.

The Racer X upper control arms are nice for adjustability because the toe change due to camber changes is much smaller than when you adjust camber via the lower control arm. The only down side is you have to remove the upper arm from the hub to adjust the camber. Once you get the hang of it, the process is quick. I’m very happy with the purchases, but admit you can save some money with just a good set of lower adjustable arms and get similar results.

Careful with some of these parts. I have noticed very few of these companies do actual development and just "throw something together" that looks motorsport.....yet geometries are effed and completely throws off alignment/compression alignment. I have zero experience with the parts you're running but my impression was always that that company was one of those types.

Interesting brake ducts but why no backing plates on the hub/rotor and hose running to it?

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jharris48

Discussion Starter · #62 · 2 mo ago

awenthol said:
Careful with some of these parts. I have noticed very few of these companies do actual development and just "throw something together" that looks motorsport.....yet geometries are effed and completely throws off alignment/compression alignment. I have zero experience with the parts you're running but my impression was always that that company was one of those types.

Interesting brake ducts but why no backing plates on the hub/rotor and hose running to it?

I don’t need backing plates at this point. If not done right, backing plates can be problematic plus it’s that much more hosing to keep pinned up and clear. If I exceed the current limits of the set up I may transition to them in the future, but my brakes are keeping up with the RooDucts as currently configured. Read about some of the OEM applications of brake ducting via air channeled into the wheel well without backing plates such as Porsche applications for more info.

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Karlot

· #63 · 2 mo ago

How do you like the tires? You seem to? They good in wet too?
I’m debating a set because of the price. I’m nowhere near good enough (yet) to need to get something nicer. Just want something grippy with a decently stiff sidewall that is 200tw for summers. And fairly grippy lol.

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jharris48

Discussion Starter · #64 · 2 mo ago

Karlot said:
How do you like the tires? You seem to? They good in wet too?
I’m debating a set because of the price. I’m nowhere near good enough (yet) to need to get something nicer. Just want something grippy with a decently stiff sidewall that is 200tw for summers. And fairly grippy lol.

I do really like the Kumos. They give up a little speed compared to the Falkens or Yokohama 200 tread wear contenders, but the Kumos wear like iron for a 200 TW tire. They are also really consistent on track where the others hit their peak around lap 2 or 3 and then tapper off a bit. However for performance in the wet, the Kumos aren’t the best they do have two channels to evacuate water once the shallow tread blocks wear down, but there are better 200 TW for the rain. I haven’t driven them in any heavy rain, so I’d largely just defer to something like tire rack reviews for wet performance. Looking at the tread pattern though, they definitely optimized for dry conditions.

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Karlot

· #65 · 2 mo ago (Edited)

jharris48 said:
I do really like the Kumos. They give up a little speed compared to the Falkens or Yokohama 200 tread wear contenders, but the Kumos wear like iron for a 200 TW tire. They are also really consistent on track where the others hit their peak around lap 2 or 3 and then tapper off a bit. However for performance in the wet, the Kumos aren’t the best they do have two channels to evacuate water once the shallow tread blocks wear down, but there are better 200 TW for the rain. I haven’t driven them in any heavy rain, so I’d largely just defer to something like tire rack reviews for wet performance. Looking at the tread pattern though, they definitely optimized for dry conditions.

true. i'm up in the air between these or the falken 615k's. it's going to 100% depend on the size i run, if i go 255/35, it'll be the kumho's, if i go to a 265/35, the falken's may be the choice. they seem to be pretty comparable. and honestly i rarely drive in the rain, but if i schedule a track day and it's raining, well...i'm in the rain lol. so if it's even remotely decent i'd be ok. i'm also fairly new to tracking the car, and have only ever done autocrosses, so having something that is consistent is nice, and I have a newborn daughter, so having something that lasts is also nice lol. they will see both street and track driving. probably more street. but still.

how wide do they run?

also, just curious, how's road noise?

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jharris48

Discussion Starter · #66 · 2 mo ago

Karlot said:
true. i'm up in the air between these or the falken 615k's. it's going to 100% depend on the size i run, if i go 255/35, it'll be the kumho's, if i go to a 265/35, the falken's may be the choice. they seem to be pretty comparable. and honestly i rarely drive in the rain, but if i schedule a track day and it's raining, well...i'm in the rain lol. so if it's even remotely decent i'd be ok. i'm also fairly new to tracking the car, and have only ever done autocrosses, so having something that is consistent is nice, and I have a newborn daughter, so having something that lasts is also nice lol. they will see both street and track driving. probably more street. but still.

how wide do they run?

also, just curious, how's road noise?

Road noise is so subjective it’s hard to give you a good answer. They are noisy to me but not to an extent that it bothers me. Not sure what you mean about how wide they run? If you are talking sizing, I don’t know. I’d just search or check the manufacture website. And of note when I referenced the Falkens in my previous post, I was talking about the 660s not the 615s. The 660s are the fast one 615s are more like the Kumos, decent grip, not cutting edge, but last a long time. The 615s have been around a long time and over to someone who’s run them for a better review. Grassroots Motorsports has a great buyers guide that compares all the 200 TW tires along with 100s and slicks.

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Karlot

· #67 · 2 mo ago

jharris48 said:
Road noise is so subjective it’s hard to give you a good answer. They are noisy to me but not to an extent that it bothers me. Not sure what you mean about how wide they run? If you are talking sizing, I don’t know. I’d just search or check the manufacture website. And of note when I referenced the Falkens in my previous post, I was talking about the 660s not the 615s. The 660s are the fast one 615s are more like the Kumos, decent grip, not cutting edge, but last a long time. The 615s have been around a long time and over to someone who’s run them for a better review. Grassroots Motorsports has a great buyers guide that compares all the 200 TW tires along with 100s and slicks.

fair enough. i currently have advan ad08r tires, and man are they loud lol. they did start cupping so that's possibly contributing to the noise. and my car is loud in general. i get that it's hard to truly give an answer.

also, i figured you meant the 660s. lol. since i'm likely going to buy wheels now anyway, i just planned on getting a cheaper, but still quality tire. because i'll still have to buy new winter tires for my oem wheels this year, and i just had a kid, bought a house..etc. lol. so i figured the lower priced 200tw would work, especially since i'm not super competitive yet, and need more seat time. so i figured the 615 or the kumos would be good for my needs. and yes, i was curious if they ran normal/wide lol. i know the dunlop star specs run wider in terms of section width, but wasnt sure about kumos. and i cant decide if i should run a 255 which i know will fit with some work, or if i should step up to a 265 and hope i can make it fit on the gd lol. the class i want to race in doesnt limit tire width, so i can run either.

i'll try to find that article. sorry to hijack the thread lol. thank you for the info.

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jharris48

Discussion Starter · #68 · 2 mo ago

Went Back to the track!

Swapped in a new MAF to eliminate it as a cause of the issues I had last time and did a bunch of street driving with data logging to try to understand if I have a problem or if it was just past time to swap my plugs from last time. Ultimately I could not get any knock to duplicate during pulls on the street. Given the nature of the forged internals, hard shifts on track, the aggressiveness of track driving, and the fact my DAM never decreased from 1 it seemed that the knock I was seeing on track was likely false knock.

I also brought 91 ACN with me to the track to rule out the 91VP Racing gas as a contributing factor. The thinking was the 91 ACN contains about 10% ethanol compared to the VP racing fuels that don't have any ethanol. Though the difference is minor, I wanted to rule out the possibility that the fuel could be throwing off the fuel ratios on my tune.

Additionally I cleaned the air filter before going to the track to just rule out all possibilities. So, I guess good news first.

The car did not break down at all this time 😂 and I set a new personal best of 2:03.22 around Button Willow 13CW! The temperature was about 10 degrees warmer than last time, around mid to high 60s throughout the day. The oil and coolant temps stayed under control no matter how many hard laps I took in the session. The only time the coolant creeped above 225 was when I ended up behind some traffic that was still running fast enough that I could push the car hard, but the airflow across the heat exchangers was just not as good due to the traffic.

Wheel Tire Vehicle Car Automotive lighting

The bad news is something isn't quite right and I don't think the knock is all false knock. During four of the five sessions that day, the DAM didn't move despite some feedback knock. However on the fifth and last session of the day, I pulled off track and saw the DAM had fallen to 0.526 and long term fuel trims were around 5% off. The car isn't showing any drivability issues and it made it home fine without any knock.

Reviewing the data logs there isn't anything obviously wrong. The boost stays within 1psi of target, intake temps look normal (although they are measured from the MAF I believe on the OEM MAF system), coolant temp is under control, AFR is on target, etc. Some of the knock occurs right at shift changes, which seem to be false knock. There are other times that the knock appears under WOT in the 4k range which is not good.

Ultimately I have to investigate more before any more track time. However, I'm just glad to have had a sold day, get faster, and identify a problem before it caused any damage. With a little time and maybe a pile of cash anything can be fixed! 🤣😂🤣

Oh, and just a cool point, after one full day of hard track driving the COBB titanium exhaust turned blue from the cat all the way to the tips! 🔥🔥🔥