Turbo guys...which axleback?

[KrisR]

I have a 2005 GT with an On3 kit making a little over 550rwhp and 560ft-lbs at ~16psi on pump gas (low-comp forged motor, stock h/c/i/tb). I still have the stock GT axleback on it, and I'm guessing that at this power level it's a restriction, if not for peak power then for spoolup time. What exhaust are you turbo guys running? Anyone actually done a before/after dyno test of an axleback swap on a turbo car? I don't want anything too loud and droney.

 

[pacettr]

Any straight thru design. Stay away from chambered.

 

[retfr8flyr]

I don't think a chambered design hurts as much with our setup as with a mid muffler system but a straight through will work best. I have Zoomers on mine and they sound very good with zero drone. It all depends on how loud you want it. Stingers or Magnapack's will sound good but are fairly loud and have a drone problem.


Earl

 

[JeremyH]

Any straight thru design. Stay away from chambered.

+1. You want a blow-thru style muffler.

I just picked up a 3" magnaflow magnapack exhuast, so I will be selling my current axlebacks, they are bullet-style blow thru mufflers with 4" rolled ss tips. Ran 650rwhp through them. Give ya good deal on them if you are interested.

 

[KrisR]

+1. You want a blow-thru style muffler.

I just picked up a 3" magnaflow magnapack exhuast, so I will be selling my current axlebacks, they are bullet-style blow thru mufflers with 4" rolled ss tips. Ran 650rwhp through them. Give ya good deal on them if you are interested.

What kind/brand are your old ones? Got any pics/vids? How much $$? Send me a PM if you want. Thanks.

 

[chad05gt]

i like chambered for street w/ elec. cutouts for racing

 

[JoshK]

OP, how did the car sound with the turbo kit going through the stock axleback. I am going to be buying this turbo kit soon and am wondering which axleback to purchase also.

ON another note, how much power did you make with the on3 kit before you were forged and did you blow it up?

 

[JeremyH]

What kind/brand are your old ones? Got any pics/vids? How much $$? Send me a PM if you want. Thanks.

I will russel up some vids/pics and send you a pm.

OP, how did the car sound with the turbo kit going through the stock axleback. I am going to be buying this turbo kit soon and am wondering which axleback to purchase also.

ON another note, how much power did you make with the on3 kit before you were forged and did you blow it up?

He was built from the get go. There are stock block members here making 450-480 at 8-9psi with the on3 kit.

 

[stang67gt]

i like chambered for street w/ elec. cutouts for racing

+1

I like stock mufflers for a stealthy look.

 

[Redfire]

I have a 2005 GT with an On3 kit making a little over 550rwhp and 560ft-lbs at ~16psi on pump gas (low-comp forged motor, stock h/c/i/tb). I still have the stock GT axleback on it, and I'm guessing that at this power level it's a restriction, if not for peak power then for spoolup time. What exhaust are you turbo guys running? Anyone actually done a before/after dyno test of an axleback swap on a turbo car? I don't want anything too loud and droney.

The stock mufflers are not a big restriction. A few years back I did a comparison with and without the stock mufflers and the difference was about 6rwhp loss with the mufflers installed. I don't have the graph but the loss was at peak hp. I do not have cats but the stock ones sound good with a turbo IMO.

 

[JeremyH]

The stock mufflers are not a big restriction. A few years back I did a comparison with and without the stock mufflers and the difference was about 6rwhp loss with the mufflers installed. I don't have the graph but the loss was at peak hp. I do not have cats but the stock ones sound good with a turbo IMO.

The power gains aren't the big point here, we are talking less back pressue/efficiency. The turbo will breath/run better is the main advantage. A little power gain is just a side effect. One eye willy did some back pressure measurements on this matter.

 

[KrisR]

The stock mufflers are not a big restriction. A few years back I did a comparison with and without the stock mufflers and the difference was about 6rwhp loss with the mufflers installed. I don't have the graph but the loss was at peak hp. I do not have cats but the stock ones sound good with a turbo IMO.

You did this comparison when the car was near stock, or with the turbo setup you have now or...? Just curious. If I'm not going to gain much, I'll leave the stock mufflers on it. I like quiet cars.

 

[2006torquefreak]

I run borla singers. I love the sound. Not to loud and quite when idle or cruising. Screams at WOT. With a single turbo it won't be to loud anyway.

 

[JeremyH]

You did this comparison when the car was near stock, or with the turbo setup you have now or...? Just curious. If I'm not going to gain much, I'll leave the stock mufflers on it. I like quiet cars.

The car is still quiet with blow-thru muffs and a turbo.

I run borla singers. I love the sound. Not to loud and quite when idle or cruising. Screams at WOT. With a single turbo it won't be to loud anyway.

Yup yup, Sounds just like how mine are.

 

[Greg Hazlett]

Are you an automatic or manual? I had horrible drone with the Stingers on my automatic around 45 mph...so bad that I sold them and went with the KR's.

 

[JeremyH]

Are you an automatic or manual? I had horrible drone with the Stingers on my automatic around 45 mph...so bad that I sold them and went with the KR's.

Whole new ballgame for him greg, he's got the trubo kit now.

 

[Greg Hazlett]

I know...understand turbo is not the same as a s/c but he said he wanted to avoid drone...I hoped the s/c would get rid of the drone for me and it did not...I can't see it mattering whether he had a turbo or a s/c with regard to drone.

 

[KrisR]

I know...understand turbo is not the same as a s/c but he said he wanted to avoid drone...I hoped the s/c would get rid of the drone for me and it did not...I can't see it mattering whether he had a turbo or a s/c with regard to drone.

Completely different, as all of the exhaust goes through the turbo housing (instead of straight out through the exhaust pipes) and the car has a Y-pipe instead of an H or X pipe. Supercharger has no way to quiet exhaust down, actually its louder when you're under boost due to more cylinder pressure.

 

[Greg Hazlett]

I still don't see how that would affect drone since they are still going out the mufflers...

 

[KrisR]

OP, how did the car sound with the turbo kit going through the stock axleback. I am going to be buying this turbo kit soon and am wondering which axleback to purchase also.

ON another note, how much power did you make with the on3 kit before you were forged and did you blow it up?

It sounds good through the stock axleback. A little deeper and louder than when the car was stock but quieter than it was with longtubes and an offroad X-pipe. Its stealthy but you can hear it.

I already had the forged motor from my old blower setup (broke a piston on the original engine a couple years ago). I have seen power numbers in the mid-400s and around 480 ft-lbs with 8-10lbs of boost on stock engines.