cvince

KWV2s still available?

Today i received a used muffler from japanese Legacy Tuned By STI (PN ST4430021001). Unfortunately to install them I wait for the end of Covid lockdown in my city.

 

Do these bolt right on? Or do you need to make modifications to the Y pipe?

Need one of these (scroll to the bottom), but they're discontinued. Will pay top dollar!

(see attachment)

https://www.btssm.com/?page=hardware

Butt hurt cause I didnt get accepted for Boxerfest. Oh well

 

Sent from my LG-LS998 using Tapatalk

Are those Enkei M52s? I was wondering how the car looks with those! HAWT!

I wouldn't rule out wheel bearings just yet.

How many years/miles and original or what brand?

Probably got them replaced around 2012-2013, car is at 91,000mi. Had left/right replaced probably around 60 and 70 respectively. Right one was under recall.

Parking brake shoes, either not hooked up correctly, worn out or not properly adjusted. How high can you raise the parking brake handle? Does the noise change if you try to raise that handle in motion (SLOWLY WHILE HOLDING THE RELEASE BUTTON DOWN) ?

Thanks! I actually did this experiment. The noise doesn't seem to change with parking brake. It also has a dead spot of maybe 5 degrees. I need to raise it around 10 degrees (or 2-3 inches) before parking brakes are applied sufficiently.

How would this explain the engine load dependency though?

I have a strange noise that's best described as wheel bearing noise, but I have doubts it's the wheel bearings because it doesn't vary with suspension load (though it does with engine load). It's loudest at exactly 60mph, and makes the same pitch as the engine at 5th gear (but it happens in all gears).

When it first comes on, it's pretty quiet, but gets louder over time. Here are a few symptoms (some that contradict each other)

1) When hot, brakes make the same noise (or make the existing noise louder --I dont know which it is) when applied.

2) When the noise just starts, it's entirely ENGINE load dependent (but not suspension load --when I upset the balance of the car, the noise does not change). No load, no/low noise.

3) When traveling at >60mph for an extended period, the noise begins to persist even though there's no engine load. I can shift to neutral, and the noise continues.

4) Rear brakes seem quite hot (I don't dare touch them) after an extended highway drive. Getting an IR thermometer soon to see if I can get an actual temp.

The strange thing is, everything points towards rotors, but I had both rears machined, and it didn't eliminate the noise. However, if it's rotors, that doesn't explain the engine-load affecting the noise.

My next best guess would be driveshaft or CV shaft. I got a shitty junkyard CV shaft as a replacement because I wanted OEM, and couldn't find it anywhere. Finally found a dealership who stocks them and will pay an arm and a leg for them if this is the real culprit.

Anyone here experience something similar or have thoughts?

I'm running a south bend stage 2 endurance on my 05 gt and a Act HDSS on my 08 spec b, never had a issue with chatter or anything like that.

Did you notice a large decrease in damping on the low end with either of them (<1500rpm)? Or are they roughly the same?

First thing I noticed when I put the WRX/Exedy in was decel chatter (faint, but still noticeable enough to be annoying to me). Engine also transmits a lot more vibration than stock (you probably need to drive one with the stock DMFW to tell the difference though)

People love to go with a better exedy clutch and fly. With your power level you will be fine with a better exedy and light fly. I always prefer a stage 2 and light fly wheels. I am going with spec clutch and fly. get rid of that dual mass fly man. this is all if your pockets are nice if not a stock will be fine at that power as long as you can drive good.

I'm currently with an Exedy (not sure what model) and 06 WRX fly and to me it's a little harsh and makes the car sound boomy. I liked the smooth stock feel and sound and not crazy about racing the clutch or anything. I treat the car as more of a cruiser and dont need perfect rev-matching.

I did a huge amount of forum searching and haven't really found an answer to my problem.

I know most folks (including my old mechanic) recommend a switch to SMFWs. I had my DMFW and clutch changed to an Exedy/06 WRX setup about 5-6 years ago. I immediately noticed a stark increase in NVH at lower RPMs (and the decel chatter), as well as a more metallic sound at low-load around 3000/4000RPMs, and it has bothered me since.

It's time for me to do another clutch job, I'd like to either switch back to the DMFW or a quieter option.

Just wondering if any of you have any thoughts on:

1) whether there is a quieter SMFW setup (ex: does 6 spring vs 4 spring make a difference?)

2) what options I have for a more reliable DMFW setup (or if OEM is the only way to go).

3) Car is now at Stage 2 and will be going for a conservative VF52 tune (maybe 260whp, stock fueling). Will the stock DMFW setup handle this?

4) Other options for preserving OEM smoothness/quietness

I need to say this though: I am NOT a pro tuner by any means!

So the LWG map helped smoothen it out a smidge. Here are some graphs.... but it definitely still feels like the hesitation is still there.

Without LWG

With LWG

It's certainly not a normal feeling by any measure.

Also attached are the logs. If this is different from what the folks experience on this thread, maybe there's a better thread I can post this in in order to get more opinions.

datalog47.csv

datalog48.csv

I need to say this though: I am NOT a pro tuner by any means!

So the LWG map helped smoothen it out a smidge. Here are some graphs.... but it definitely still feels like the hesitation is still there.

It's certainly not a normal feeling by any measure.

yeah. maybe log the turbo dynamic variables too, so you can see when they kick in and stuff. Then, try to find a correlation with the sawtooth pattern you feel, by plotting timeseries of the various variables. It may or may not be related.

 

I know in my case it was (and still is to a certain extent). For instance, when I changed turbo and readjusted the wastegate duty cycles, I put too much duty cycle around the rpm range where the turbo was beginning to spool (in the hope of reaching target boost quickly). But then, it always resulted in overboosting at the beginning of the curve. And as I previously said, turbo dynamics kicked in (by modifying wastegate duty cycles) and try to reduce boost as the rpm increased. Resulted in that sawtooth pattern.

 

After fine tuning the wastegate duty cycle, actual boost started to get very close to target boost and that jerky feeling slowly went away.

 

 

We should note that this is different than what most people describe in this thread. I believe they refer to an rpm/throttle plate opening/load ranges where one is still under vacuum and closed loop.

I don't actually have access to AccessPortTuner. Do you think a low-wastegate map could be used to test this?

It might be related to this:

 

 

 

Although, looking at your logs, you are not overboosting by much I think. But still, the turbo dynamic stuff will kick in if actual is not equal to target. If that is really the cause, one solution is to modify your wastegate duty cycle in your tune.

Thanks for having a look! The funny thing is that TD boost Error is showing positive values (slight underboost?) in all the logs, all within acceptable ranges (about 0.5 psi). I'll do another log that includes Target boost later today to see if this is it. One at 50% throttle, and the other at WOT. Would that give a good picture?

It certainly FEELS like the sort of "sawtooth" pattern that you described though.

Car is a 2005 Legacy GT 5MT, 142000km. Non-Limited. Recently upgraded to Stage 2.

TYPE OF STUTTER/STUMBLE

Steady throttle/Increasing throttle/Both:

Steady throttle has no stumble

Increasing throttle has very noticeable flutter/stumble at close to WOT and higher RPMs (4000+)

MODS

Intake: Stock

Exhaust: Cobb Catless UP, Cobb High-flow Catted DP

Fuel: Canadian Chevron 94 (currently mixed in with quarter tank of 91)

Turbo: Stock

Engine Management: Cobb AP

Tuner and revision of tune(if you don't mind): Cobb OTS AP Stage 2, 91 ACN map

MAINTENANCE

Sensors changed: Original O2 Sensor

Plugs changed: About 30000-40000km ago

Coil Packs changed: Cyl 3 coilpack just changed

Recently got fuel system cleaning/oil change from Midas prior to stage 2 (bad idea?)

OTHER SYMPTOMS

Check Engine Light: None

Etc:

- Cyl 3 Coilpack was bad, causing misfire code and major stutter at slight throttle at all RPMs. This was just recently changed, and the problem was fixed (this was before going Stage 2).

- Pulling with near WOT uphill shows slight knock (-2) with the ACN tune, and up to -6 with normal 91 tune, and you can smell some burning.

RESULTS

What has and hasn't worked for you: Nothing has worked so far.. car has about 300km on the current tune and Stg 2 upgrades. Car pulls great and feels smooth for daily driving. Problem only exists when I drive at near 100% throttle doing 3rd gear pulls.

If something worked, how long has it been working for:N/A

Wondering if you guys have any ideas. I've attached some logs and based on my research they seem fine, but I'm no expert at reading logs. My mechanic told me to log AFR so will do that tonight, but AF Learning doesnt show anything weird.

datalog45.csv

datalog44.csv

datalog43.csv

datalog38.csv