Ok,
This week, i got the bug, and bought the Pacesetter LT's (coated) ORY-pipe, o2 sims, front harness extensions (felt like an *** when i opened the pacesetter box, and seen that there is wiring to extend your stock harnesses, but anyway...), SLP Lid, K&N, SLP MAF sensor. Installed everything (had to take it to the exhaust shop after b/c the pacesetter ORY pipe, is the exact same diameter as my factory dual/dual intermediate pipe, so they had to put an adapter in to make it work), and took it for a spin. The performance is unbelievable, the car feels completely different then it did last week. My question is this, does anyone else with LT's and an ORY pipe have like a weird noise? I will try and explain it, If i take off from a dead stop, and give it like 1/2 throttle, or more, there is noise (almost sounds like an exhaust leak), but only at the begining of the rpm range (1500-2600 or so) then it goes away with higher rpm's. Now if i take off, and really grandpa it (meaning letting it rev throughout the rpm range, but letting it climb very slowly) i hear no noise at all. I have checked every possible exhaust connection, and i am positive there are no leaks. A buddy of mine who had an LS1 a while back, said he thought he heard something about a certain collector noise??? Something about exhaust gases inside the collectors making a weird tone at certain RPM's. Anybody know if this holds water or not? Cant wait to get to the track with my new mods, IDK if i can hit a 12 w/o drag radials, but i am sure going to try. Thanks in advance.

 

i wouldn't worry about it....my exhaust setup makes a ton of weird, barely perceptible noises...if it's not a distinct ticking noise, i wouldnt worry about a leak. more than likely you're just getting used to the new noises emanating from your LS1.

 

YES!! I had my Pacesetters installed a few months ago and have the same noise. It sounds like a whistling, almost like a turbo or something. I've learned to accept it, since I put it on a lift and didn't notice any leaks.

 

yeah same here

I noticed that sound since the Pacesetters, when say in 2nd at 1500 rpms I hit the gas and when there is a heavy load on the engine. Its only when the load on the engine is high though, because when the rpms start rising fast (2000 rpms) its no longer 'hearable'

Its just the sound that LTs make...dont worry about it

The stock manifolds were thicker, which is a good sound insulator. Since the headers arent that thick, I guess you can hear the sound more easily.

-Chris

BTW I also ordered the 02 extensions and when I got the Pacesetters & opened the box...saw the wiring kit they provide to extend them yourself
I used the extensions I bought anyways....I still have the kit they sent me...maybe one day I will use it on something else....(Hey my '91 Z needs some headers.....

 

have you looked into the check valves on the AIR tubes? heard they make some strange noises...not sure what kind...

congrats on the mods...that's a hell of a round of modifications all at once!!!

 

Mine doesnt have air tubes......

You have to ride in the car to understand...its not a bad sound.....it just sounds like air rushing.....

I dont know exactly what causes the sound but I am certain it has something to do with the fact that headers are relatively thin compared to the stock manifolds. And the fact that they are long tube headers I am sure adds to it as well. I dont remember hearing of this with mids or shorties.

BTW Have you guys had to retorque your header bolts?

Mine have been fine ever since I installed them....I checked them after 200 miles, 1000 miles and 3000 miles....still to spec. I used the bolts supplied by Pacesetter. Non-locking at that! ( oh yeah i almost forgot...[knocks on wood]) Hopefully they dont loosen up.

The reason I ask is because on my '79 Trans Am I always had to retighten them around every other oil change. Same thing on my '84 Monte Carlo. Neither of my 3rd gens have headers so those I dont have to deal with it on them.
If they all had headers I would have my hands full lol That is if they all needed tightening periodically.

 

You got it stone, that is the EXACT noise i am talking about, well i feel much better now, lol. I had to retorque my header bolts on my 95Z almost weekly. So far so good on the pacesetters on the SS, but i plan on checking them every couple hundred miles until i am positive they aren't moving. I noticed you have the LT's ORY, and flowmaster. Are you running the American Thunder Cat Back? If so, how do you like the sound of it, raspy at all w/o cats? I was thinking of doing that in the next few weeks, but idk, it sounds pretty mean through the stock dual dual, but not quite meaty enough. How about you 1bad, do you have cats? How does the borla sound, which plate do you use, if any, any rasp? Thanks for all the input guys, i feel much better now, peace.

 

I used the factory MLS gaskets and Stage 8 locking bolts. No leaks yet.
I think that on our old V8 cars that the composite gaskets were the cause of the constant bolt tightening and the header leaks.

 

yeah I used the GM gaskets...they work great so far...

Black00SS: I have a dual chamber, single muffler setup...the two 3" pipes go from the header collectors and merge into one 3" pipe, then go into the muffler, which then has dual 3" tips coming out.

I do get a little rasp when I go WOT to redline and then left off the gas abruptly...but other than that, its perfect. I may add a bullet but that will be in the far future as its not really that much of a concern since its very minimal rasp. The sound of a single mufflered manual LS1 sounds awesome under WOT, and ESPECIALLY when decelerating in gear. The rumble is awesome.

The muffler is the Flowmaster transverse muffler....80 series I think....I cant remember. Its specifically for F-Bodies though.

I just wonder how much power the cool Flowmaster sound is costing me. I was hoping to make up for some of the loss by removing the cats and going 3".

I like the true dual sound, but I wanted something different....I like how this setup sounds extremely mellow under part throttle, and also how it gets loud when Im going *****-to-the-walls. I like the sound of my car to match the speed its going...this setup is perfect. Too many times I see people fly by sounding like they are racing in the the NASCAR series or something, but they are only cruising.

 

I have the same problem and I have had Pacesetter on for over a year. I need to change my gaskets.. The only problem, It does it after I drive a while and then goes away

 

Ok, i know which Flowmaster muffler you are talking about. I thought you might have the single chamber 40 series on there, thats what i was thinking about getting ( i bet it would be raspy and louder then i could stand though). I used the gaskets provided with the Pacesetter LT's, no problems yet (knock on wood...twice, its only been a week). I went to GM, and they only had 1 freakin gasket in stock, and said it would be 2 days before they could have another so i said **** on it, and used what i had. Thanks a million for all the help, and stuff.

 

It could also be that your car is probably running lean as a **** now and it's time for a dyno tune before you pop your head gaskets. Also, a tiny dab of medium or light strength thread lock will keep your bolts in place, and you'll still be able to get them off should you need to.

 

Did you plug the hole in the offroad pipe where they had an O2 bung? Mine made a whistling sound before I plugged that hole. I can't figure out why in the world they put an O2 bung on an offroad pipe.