Ok, here goes: I have a Yank TP4400. Current exhaust is Macs, ORP, 3" Flowmaster in stock location, stock tips. Old exhaust setup was Macs, ORP, 4" Mufflex with single out Flowmaster. Last exhaust sounded AWESOME, but had an awful growl when the trans locked up, and AWFUL GROWL when the trans went into OD. I thought that a quiter exhaust would hide it some, but, well, ummm, no. Does any exhaust not magnify this? My car sounds great through first, second, and third gears, but sounds like a dying hippopotamus when it locks-up or goes into OD. Sounds like I can't drive, like something is wrong with the car. Anybody found a solution to this? I would LOVE to go back to a Mufflex system. Would a bullet help stop this? It just sounds like the motor is lugging too much. (Shouldn't be wth 4.11s <img src="images/icons/grin.gif" border="0"> ) Thanks, Shawn

 

Ah yes.. sounds like the infamous "fart drone" associated with MAC's ORP. Bullet mufflers in the y-pipe will help out with this.

Also, DamianLS1 on this board says that the Hooker 3" catback totally cured it. But I doubt you want to step down from the 4" exhaust you currently have.

Try out the bullet mufflers, they are only about $35 each from Jeg's plus the cost of welding them in.

 

Hey, Dan. Remember me from Commerce? I have the red Z28 with the "sport appearance package". Anyways, will long tubes help any with this? I will be swapping the Macs for longtubes in the next week or two, maybe this would help? Thanks, Shawn

 

Hey Shawn, I remember you from Commerce. When did you move to Chicago? Long tubes should help with this, I'm sure. And if those MACs are looking for a good home, let me know. <img src="images/icons/smile.gif" border="0">

Dan

 

Yelllllllooooooo.......

Shawn, I feel your pain!!! I drove around with Mac's, ORP, and the Loudmouth exhaust. Now I don't think you could fathom how TERRIBLE that rasp was. I was seriously embarrassed to drive my car.

I installed a Hooker catback, thanks to Dan's advice, about 2 months after having the headers. I can assure you it sounds like musical viagra. There is ZERO rasp that you speak of, and while cruising down the highway at high speeds I could barely tell I had no cats.

If you ever decide to go that route, I doubt you would lose much, if anything. Dan's car made 16 rwhp just slapping on this exhaust. You don't even see that much from a wide open Loudmouth <img src="images/icons/shocked.gif" border="0">

Good luck and email me if you have any other questions.


Josh

 

Hey, can I pipe in a question here since this seems related to something I am considering?

I have the Hooker catback, and have been trying to decide if I need to get another catback once I get the 422 in (which will be in a few weeks). Does the Hooker flow well enough to work on the larger displacement engine with either Mac (with stock cats) or FLP headers? I had been thinking about going with the LM, but you guys seem to indicate that this combination would lead to bad fart-drone. Any comments??

 

Personally, at that power level, I would consider a Mufflex 4" with the Spintech muffler. <img src="images/icons/smile.gif" border="0"> But that's just me. The Hooker is a chambered muffler so it might restrict you at that power level.

As far as I know, the fart-drone is only present when using MAC ORP's. FLP's may have it as well, but when cats are used, it goes away.

While I like the sound of ORP cars, I need to keep my sanity so I'll be running cats when I do my headers (most likely MACs with Random Tech bullet cats).

Dan

 

Yeah with 4.10's you cruise right in the middle of the RASP zone... 2500-3000 rpms.

Bullets will help cut out the resonance.