So I just installed my RV6 HFPC's and j pipe on my 04 TL that already had XLR8 non resonated exhaust on it. The sound now when from great to AWESOME. The only drawback is a slight rasp, very slight as in it lasts for about half a second, in the 3500-4000 rpm range. The HFPC's are extra money for a main reason in making sure that the rasp doesn't occur, so I'm starting to think it is the RV6 j pipe. So what i need to know is what resonator gets rid of a small amount of rasp present while not affecting the amazing sound gains I got, or if all resonators do, what does it the VERY least.

 

It's not the j pipe, it's the exhaust. I had the resonated version from xlr8 and still had rasp. You need to add a big enough resonator in the exhaust.

 

I had the exhaust before the j pipe with no rasp

 

Yea but you said you added the j pipe AND the HFPCs right? I don't think people get rasp with just a j-pipe and exhaust, but once you do HFPCs or PCDs then you get rasp, and drone.

Either way doesn't really matter, because what you need to fix it is a resonator, which goes somewhere on the exhaust piping. Contact sockr1, he did it on his.

 

Yes I did, but HFPC's are known for not adding rasp right? Anyway i saw where rv6 j pipes have done this before, but you're right rasp is rasp and i need a reasonator. I saw where the magnaflow #10436 is good, but like i said i am looking for MINIMAL volume decrease, just rasp elimination. I will contact him, thank you

 

Mind doing a video of the exhaust just for the heck of it Lol?

Thinking of upgrading from stock to XLR8 non res myself since I also have the HFPC and jpipe

 

Well, PCDs def add rasp, so since HFPCs are only 200 cell cats and essentially in the same direction as eliminating your cats altogether compared to stock cats, yea they do increase rasp vs the OEM ones.

There's a video on YouTube of someone with a black type s with the xlr8 j pipe and exhaust along with PCDs IIRC. Hard to hear the rasp but it's there.

Yup that's why I said get in touch with sockr1, I think he used a resonator just large enough to reduce / eliminate the rasp / drone but not too big where it also reduced the awesome xlr8 sound any more than necessary.

 

OP we've already talked in PMs but i'll post some info here in case others look up this thread.

i replaced the super small xlr8 resonator with magnaflow resonator 10436 (4" round by 22" long) and this reduced any "rasp" (barely had any, if any) from the HFPCs and reduced the drone which is what i was mainly looking to do

if you want to keep most of the volume and try to get rid of the rasp, i would suggest the 10416 resonator which is 4" round and 14" long. you may look for something even smaller but make sure you have a 2.5" inlet/outlet.

basically you are adding volume to your exhaust piping, which changes the sound and the sound volume. i'm not saying this will be guaranteed to eliminate your rasp but i think it will work.

would also be good to have a before and after video!

here's some good threads to read and research:

https://acurazine.com/forums/perform...g-pcds-849750/

https://acurazine.com/forums/perform...posted-787693/

 

Here is the rasp at WOT:


and here is the rasp at normal acceleration, comes in at 3500-4000 rpms:

 

I just installed hfpc and I'm having the same issue. The video is identical to the noise I'm hearing

My current setup is stock cat back, RV6 Jpipe and HFPC. Should I go with the 10416 resonator?

 

^^ it should work. Post a video after if you do it so people can reference it.

 

Finally got around to installing the resonator(14") today. It eliminated any and all rasp I was experiencing. I'll try to post a video by the end of the weekend

 

nice!! glad it worked out. i've been questioning getting a smaller resonator like that size (right now i have the 22" long one) to get some growl back, so i'm interested to hear your video.

how's the drone inside your car?

 

The only exhaust mods I have are the j-pipe and the hfpc so there was never any drone to begin with. I'll have a good video by Sunday (hopefully)