2017 GTi PP at VIR

[GTIfan99]

After Daytona, car makes weird noise every time I turn the car off after driving for more that 5 minutes.

Any ideas? It's at the end of this clip. It makes this noise over and over every 30 to 60 seconds.

 

[DerHase]

After Daytona, car makes weird noise every time I turn the car off after driving for more that 5 minutes.

Any ideas? It's at the end of this clip. It makes this noise over and over every 30 to 60 seconds.

Reminds me a lot of when a secondary air injection pump fails, but that really should only be running on cold start.

Is the car running in the video? Hard to tell as you stated it’s after turning off?

 

[GTIfan99]

Reminds me a lot of when a secondary air injection pump fails, but that really should only be running on cold start.

Is the car running in the video? Hard to tell as you stated it’s after turning off?

No, it's off.

 

[DerHase]

No, it's off.

Very weird. I’d try using VCDS/OBD11 to actuate anything possible you suspect to duplicate the noise on command. Hard to discern where it’s coming from in the video, but I’d start with water pump and secondary air pump.

 

[GTIfan99]

Very weird. I’d try using VCDS/OBD11 to actuate anything possible you suspect to duplicate the noise on command. Hard to discern where it’s coming from in the video, but I’d start with water pump and secondary air pump.

Yeah, plan on pulling codes when I can, but I've been working 12 to 18 hours a day this week, so just haven't had the time. It's not my daily anymore, so should be ok for a few more days.

I have an autocross Sunday, so I want to get it resolved before then.

 

[MonkeyMD]

Had grinding noise on hard acceleration. Initially, it was faint. I thought maybe tire was slipping on wheel. Dumb, i know. Don't make anywhere near enough power for that and i wouldn't know what that would sound or feel like. Then it got progressively louder and car wouldn't accelerate hard, like a clutch slipping. I thought maybe axles, but really had no idea.

Took it to shop and my mechanic drove it and as soon as he felt it, he said lsd. He just knew right away. We'll know soon enough if he was right, although he has taken the tranny apart to get lsd out and tranny and axles all looked good.


For me it was when accelerating. Maybe a little more pronounced when accelerating and turning, but can't remember exactly.

Yes I'm replying to myself. Hate to clutter your thread but wanted to clarify, turns out my grinding nose was a motor mount that bolt backed out slowly and on hard acceleration, motor was moving too much. Just not sure which part was causing the noise.

I did switch out to Quaife anyway.
Since wavetrac was out, sent it to them to check it out an d I'll post it for sale soon. Just wanted a good bill of health first.

 

[Mini7]

Hey don’t sweat it. This is how we learn from one another.

I need to figure out my secondary air fault code.

 

[GTIfan99]

Yes I'm replying to myself. Hate to clutter your thread but wanted to clarify, turns out my grinding nose was a motor mount that bolt backed out slowly and on hard acceleration, motor was moving too much. Just not sure which part was causing the noise.

View attachment 249007

I did switch out to Quaife anyway.
Since wavetrac was out, sent it to them to check it out an d I'll post it for sale soon. Just wanted a good bill of health first.

I had a motor mount come loose on my new mk2 GTI 2l 16v. Tried to launch the engine through the hood.

 

[MonkeyMD]

I had a motor mount come loose on my new mk2 GTI 2l 16v. Tried to launch the engine through the hood.

I guess i was lucky then

 

[scrllock]

@GTIfan99 how much pressure are you running on the v730s?

 

[GTIfan99]

@GTIfan99 how much pressure are you running on the v730s?

Started at 39 hot due to recommendations from street fwd guys. That's too high if you have enough camber though. I'm at 35 hot now and still looks like I could go lower.

That's with 255 40 17.

RE71R's had a weird side wall flex below 38 psi in front, these don't seem to have the same issue.

 

[DerHase]

FYI I reached out to Jeff (mygolfmk7 guy) about testing intercooler cores for flow through to the radiator… which once some more get tested may be very relevant to those of us tracking:

http://mygolfmk7.com/2022/05/intercooler-external-airflow/

 

[Half fast]

I had a variable weekend at VIR. The first day, I had some major instability at the rear under braking. Everyone was complaining of low grip as the track had not rubbered in as there was no event prior to our DE.
The second day this disappeared but I had also backed up my brake zones. So ???? Not sure what was happening.

I need to check my alignment. Maybe my zero toe at the rear is too aggressive for the track???? The car felt fine around the corners. Just a handful under braking. Im also curious whether I have a rear caliper that is hanging up???
I’ve got 100k on my car now. They may be due a rebuild. I’ve been checking the rotor temps with an IR gun and the RHS is running 20-25F hotter than the LHS.

FWIW, I run 0 toe in the rear and haven’t had any issues. The rear does dance around a little under heavy braking, but every prepped GTI I’ve run has done that to some degree so maybe I’m just used to it. Before I fully disabled it, the stability control would try to kick in under heavy braking in a straight line. (I say try to because I’m not sure it really did anything since I already had my foot buried into the brake pedal. But the light would come on.)

 

[Mini7]

Last fall I ran 0.12 total toe in at the rear. I’ve had some instability into T1 at VIR. It’s a downhill brake zone and the approach tends to be slippery. Even with the ESC fully off I’d see the light flashing. More so this year with the zero toe. I’m comfortable with yaw and general instability. What I didn’t like is making a big steering correction under initial brake application. So much so that I started to make my approach to the brake zone almost mid track to give me room to get the car under control.

I appreciate your input. I believe zero toe is the way to go and that I have some other issue going on that I need to get to the bottom of. Just haven’t had the time to investigate the rear calipers yet. I would like to know why the ESC is still kicking in even though I have coded it out with OBD11. This happens more under heavy braking.

 

[Mini7]

FYI I reached out to Jeff (mygolfmk7 guy) about testing intercooler cores for flow through to the radiator… which once some more get tested may be very relevant to those of us tracking:

http://mygolfmk7.com/2022/05/intercooler-external-airflow/

My AMS IC has a more open core design than the bar and plate design of the IE IC I had originally purchased. It was also significantly lighter than the IE IC. Ive seen IAT temps within 10F of ambient on the highway with the AMS IC.

There is a definite impact on the cooling ability of the radiator due to restricted flow and the stack up of heat exchangers in front of the radiator core. One of the main reasons why I added hood vents.
My beat up AC condenser is definitely restricting air flow. Most of the fins have been impacted by rocks and are bent closed. I’d bet replacing that core would drop temps by 10F if not more.