I have a 1997 Z/28 LT1 Camaro doing the exact same thing as this guys car.......................



I have a 2002 35th Anniversary Camaro SS.

About 2 months ago, Several friends helped me install a set of MAC mid-length headers and Off-road Y-pipe. I then headed to a local muffler shop to have the intermetiate pipe and ORY welded together.

With this install came a loud resonance between 2100 and 2500 rpm. One of my friends has a 1999 Z28 and he said his does the same thing. His comments were that "The MAC mid-lengths do that on the LS1 f-body cars".

My questions are: Is that the case, all LS1 f-bodies get this resonance? Is there something that was possibly done wrong in the install that would possibly cause the resonance? Is there something I can do to correct it? Has anyone else experienced this same thing?

I love the way the car sounds, I just either have to stand on the gas to get past the 2500 range or accelerate slower so the car shifts prior to 2100. That's just not what this car was built to do though.


Has anyone else had this problem, if so how did you fix it???????

 

:ugh:

First off, do you have the 93-95 style, or the 96-97?

The 93-95 style aren't junk, they are arguably the best mid length header for the LT1.


The resonance you are hearing, if im understanding you correctly, has to do with your free flowing exhaust, and muffler design.

The only solution i can possibly suggest is to either put your converter back on, or if you dont want to do that, put a resonator or bullet style muffler in place.

 

I have a 96 with hooker longtubes and magnaflow muffler. I just got rid of my cats and now it has the resonance between 2500-3000 rpms. It is annoying. Sounds great at all rpm ranges except the 2500-3000.

 

Would a resonator or bullet style muffler cut the flow????Will I loose horse power????What will it do to the sound?????

I do have the 96-97 style....

 

sry to be negative but get some different headers :/

 

Make absolutely sure the exhaust pipes are not touching the unibody or suspension or braces. If the pipe is touching anything you get what you are describing. Do you have a pipe support brace at the catalytic converter.

I have a very small resonance at 2K and its due to not having the support brace at the cat.

 

I've got JH long tubes, !Cats, and a hooker cat back. My car has the same type resonance in about the same RPM range. It does sound like poopy for a few hundered RPM but before and after the RPM range it sounds great.

 

There is no similarity between the LT1 headers and the LS1 headers, so any comparison to a 2002 SS is sort of irrelevant, given the different firing order, different exhaust port layout and different primary layouts.

 

I have a '97 with MAC midlength headers. Love them.

You have MAC shorties. Not the mids. I can't speak for the MAC shorties, but my MAC mids do not have the problem you are describing at all.

I doubt that it is a function of the headers. Like mentioned earlier. Look every where in the entire exhaust to check for places that it could be touching the car. My 3" pipe that goes over the axle started to touch my sheet metal once, and the car got very loud inside. Once fixed, it sounded great again. Check everywhere.

My setup: '94-'95 MAC mids into the Off Road Y-pipe into a bullet muffler into the Hooker catback.

To me, it either sounds like the exhaust touching somewhere, or your catback or straight pipe could be causing it.

Dan

 

Thanx for all the replies......Will a resonator or bullet style muffler help???

 

No, but a cat will, you will give up some performance. I absolutly LOVE the sound you all are complaining about!!!! Different strokes for different folks?
Steve

 

i have put a bullet style muffler on some cars to delete resonance and it worked, however i think a high flo cat would be a better option. I have mac mid's with a high flo cat and borla catback and I love it. the headers alone(okay, maybe i also learned to drive better ) got me 8.6mph better in the 1/4 mile

 

I have both a high flow cat, and a bullet muffler that I can interchange in my exhaust. They unbolt easily so I can swap them. The only difference that I saw when going from a high flow cat to the bullet muffler is that the bullet muffler is deeper and a little louder. Plus the bullet muffler flows better.

My bet is that it's your catback/muffler. What catback do you have?

Dan