Today at a test and tune/ warmup for Topeka my 01 ITR developed a noise under heavy braking.

Background:
Installed new shocks 1 month ago
Ran 2 events and 1st half of today's test and tune without any problems.
The test and tune has been wet all day, so there has been plenty of ABS engagement.

Symptoms:

1. Under 8/10ths - 10/10ths a hard clanging noise happens. Usually one or two thuds then it stops.
2. The car behaves normal. Brakes are fine and nothing weird is going on with the handling.
3. You can feel the thud in the floor with your feet, both driver and passenger.
4. No noises under accleration or turn in.
5. Possibly some slight noise when transferring the weight from front to back after hard braking.
6. Nothing obviously loose in the suspension or brakes.

Any Ideas?

Thanks

Shawn

 

Can you feel it in the steering wheel or shifter?

 

Definetly not in the wheel. Not sure about the shifter.

I am going to put it up on a rack today and remove/lube and/or re-torque all suspension bolts today.

Hope it is nothing serious. Suposed to leave for Topeka in 2 days.

 

Check the engine mounts

 

i had something like this happen on my car. have you had the front swaybar mounts off recently?? it turned out that on my car i had installed one of the d-brackets backwards, shifting the swaybar forward enough that as it rotated under compression the bar hit the cross-member, bound for a second then "popped" free. it gave a heavy thud under braking/acceleration and depending on what i was doing with the car at the time, it would do it once or twice. and you could definitely feel it through the floor. good luck! see ya in kansas!

nate

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shamun &raquo;</TD></TR><TR><TD CLASS="quote">Today at a test and tune/ warmup for Topeka my 01 ITR developed a noise under heavy braking.

Background:
Installed new shocks 1 month ago
Ran 2 events and 1st half of today's test and tune without any problems.
The test and tune has been wet all day, so there has been plenty of ABS engagement.

Symptoms:

1. Under 8/10ths - 10/10ths a hard clanging noise happens. Usually one or two thuds then it stops.
2. The car behaves normal. Brakes are fine and nothing weird is going on with the handling.
3. You can feel the thud in the floor with your feet, both driver and passenger.
4. No noises under accleration or turn in.
5. Possibly some slight noise when transferring the weight from front to back after hard braking.
6. Nothing obviously loose in the suspension or brakes.

Any Ideas?

Thanks

Shawn</TD></TR></TABLE>


This sounds extremely similar to what I experienced when I too ran in the rain at an autocross last winter.

Towards the end of the run which was a reasonably high speed 3rd gear into a chicago box towards the finish line the suspension would compress to take the corner and then release and I would apply the throttle towards the finish line.

Just as I applied the throttle as the suspension was releasing I heard this horrible BANGING sound, almost like I droppped some part of the transmission or one of the suspension arms or an axle or other extreme damage.

We drove the car to check the sound after the run and it still made the horrible sound. We jacked it up (rodney, myself and el pollo diablo) and checked the whole front end. Nothing! Not one thing wrong or misplaced or leaking. Very odd.

Then Matt (el pollo) mentioned that his R would get a similar banging sound when driving in the wet. He attributed it to water in or on the anti swaybar bushing or bushings.

I was careful and drove it home and after the trip checked it thoroughly again. Couldn't find any issues.

I ordered new swaybar bushings and installed them and applied graphite lube just to be sure but, noticed the origional stock bushings were just fine.

I ran the car to & at Beaverun for 2 days then home with no issues. Then ran 2 more Autocrosses and Noticed No rubbing or vibrating at all, even under severe braking.

So in the end I really couldn't find anything wrong other than MAYBE the bushing became bound up or water seeped in and made it skip or pop or whatever that horrible sound feeling I had was.

I don't have a definitive answer for you, just thought I'd share my experience especally since 2 other drivers in this forum were with me that day and heard/ felt it as well. Matt (El Pollo) was the only other person I could find that had any experience similar to mine.

Don't know if I helped any. But, your expereince sounds extremely similar to mine. BTW I have a completely stock suspension no mods to it whatsoever and only 35K on the ODO, drive it almost exclusively at autocrosses and tracks. Never heard anything before that day and never ehard anything since.


Anton

 

Thanks for the responses.

Had the car on the rack today. Checked torque on everything and it was fine. Tried to replicate the noise on street tires (both wet and dry roads), and nothing.

Hopefully just some mystery that has run its course.

 

I'm experiencing the same type of problem now too.
Under 9/10's 10/10's braking, sometimes I hear a pop. Almost sounds like its coming from the floor. I have the Azenis on right now. I've never been able to duplicate with the Sumitomo tires because they do not grip very well under hard braking.