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Yet another dynomax super turbo question

TGtrac05

Well-Known Member
Joined
June 14, 2012
Messages
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City, State
Texas
Year, Model & Trim Level
2005 Sport Trac XLT
Ok, I'm ordering the dynomax super turbo right now, have read all the exhaust threads and everything, but there is one thing that is still confusing. I've read that the stock exhaust is 2.25 in/out, and I've read confusing things about getting either the 2.25 in/out or the 2.5 in/out. What I'm looking to do at least in the beginning is just simply replace the stock muffler with the dynomax, keeping the resonator and everything else, until I decide to get rid of it. So to me it would make sense to go with the 2.25 one, but every single website says only the 2.5 one will fit the sport tracs. So is it not a problem for shops to make the 2.5 inch muffler fit, or are they going to say I got the wrong size? Just want to make sure before I buy this thing. Thanks in advance

EDIT: basically a decision between the 17731 and the 17733
 



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All they will do is bolt on for 2.25" in/out, the 2.5" will need a reducer/expander. The stock muffler is huge in length compared to aftermarket so extensions will likely be needed too. All easily done by the local muffler shop
 






Get the 2.25" min/out muffler, you'll probably need a piece of 2.25" exhaust pipe between 12"-24" depending on length of the aftermarket muffler.
 






I find that with a stock engine and the little power it is making, 2.25" exhaust system throughout for this truck is large enough and work more efficient than 2.5".
 






I would go with the 2.5" in/out, and try to make the rest of the exhaust AFTER the muffler also 2.5" But, even if you can't I would still do the muffler in 2.5"

Why? The muffler is a restriction to flow. So, a muffler with 2.25" diameter tubing will not flow as much as the 2.25 pipe going into it, or out. Oversizing the muffler a little helps to compensate for the restrictive nature of the all the bends/twists,etc.. inside the muffler.

On my '80 Chevy K20, with a mildly built 350ci, I ran true dual 2.5" pipes, with a pair of 3" Dynomax Super Turbo's. It worked well, sounded good, and made more power then anyone would have expected. It was quiet when you were easy on the gas, and then got the right kind of loud when you really put it to work. As I recall, it sounded similar to a late-model Hemi, when under load and full throttle.
 






I doubt you'll find much difference with either and it won't make a lick of difference to your muffler guy. I left the resonator initially but later removed it. I'd say go ahead and remove it. If you're anything like me, curiosity will eventually put you under the truck with a sawzall one boring afternoon and you'll cut it out anyway and then have to go back to have a tailpipe added again.
 






Alright, thanks for the help guys. That's been the big debate for me offtrac, I just didn't want to get rid of it right away before seeing how the sound is with the resonator. I've seen your sound clips with it on but don't think I've found clips of anyone's with it taken off. Oh well I'll think about that for a while, main thing is I try to keep my truck really simple and clean so I didn't want it to be overwhelming if I had it removed.
 






I would go with the 2.5" in/out, and try to make the rest of the exhaust AFTER the muffler also 2.5" But, even if you can't I would still do the muffler in 2.5"

Why? The muffler is a restriction to flow. So, a muffler with 2.25" diameter tubing will not flow as much as the 2.25 pipe going into it, or out. Oversizing the muffler a little helps to compensate for the restrictive nature of the all the bends/twists,etc.. inside the muffler.

On my '80 Chevy K20, with a mildly built 350ci, I ran true dual 2.5" pipes, with a pair of 3" Dynomax Super Turbo's. It worked well, sounded good, and made more power then anyone would have expected. It was quiet when you were easy on the gas, and then got the right kind of loud when you really put it to work. As I recall, it sounded similar to a late-model Hemi, when under load and full throttle.

Our Explorer is a special kind of breed. It feels like the engine is tuned to run with small diameter exhaust with all the restriction it has from the factory. I experimented with my 4.0 SOHC and it gives me more "pull" at a dead stop with 2.25" muffler and piping.
 






It's hardly a noticeable difference honestly. I'll try to get a clip of it as it is now. When are you taking it to the shop?
 






I also used the 2.5" SuperTurbo #17733 because every fitment guide I found had it listed rather than the 2.25" #17731 . The biggest restriction with the stock exhaust system is the ST's huge muffler. After installation the tone was deeper, but not much louder than stock at any RPM. The resonator is designed to reduce drone and rasp, but I decided to ditch it for added loudness. IMO, without the resonator it had a deeper tone with slight loudness increase I would guess around 5db at 2000 RPM highway cruising speed, with no increase in drone. The exhaust shop reused the elbow that exited out the side to run it straight back under the bumper. I supplied and paid $50 for the muffler, and $20 for a Vibrant #1575 T304 stainless tip. The labor including any needed 2.5" pipe and clamps was $130 out the door. I didn't see the rusty seams closely until I took these pics and I'll give them a good wire brushing followed with high temp spray paint where needed.

Front.jpg
Rear.jpg

ElbowampTip.jpg
DSC02970.jpg
 






I probably won't be installing it until sometime late December, or early January when I get back to college station after the winter break because I think the shops here will be cheaper than where I'm from. If I get rid of the resonator I won't run it all the way back with a tip because I like having the exhaust pipe not showing like I have it now. I guess I would just have them put a turn down right after the muffler? Right now I have it cut after the resonator before it exits under the bumper. I went ahead and got the 17731 though
 






I intalled a Flowmaster 40 series over the Super Turbo. However, I got the 2.25" in/out to mate up with the stock exhaust. I also had the shop cut out the resonator and throw in a connector pipe that runs from the muffler back to the axle to connect up with the existing pipe rearward of the resonator. I understand what you mean about having the exhaust hidden. I personally hid it so it doesn't get crushed on trails. About a year and a half ago when I did my body lift, I cut the stock pipe where it turns downward just after the rear axle. I had the bed off at the time and made it extremely easy to get in there with a sawzall. By cutting it back there it will keep the noise and drone (not much with the super turbo, but something I have to think about with the louder FM) down in the cabin. Basically that will make your truck sound good outside and keep the noise down in the cabin. I wouldn't dump the exhaust right after the muffler just because that would put it right under the middle of the cab.
 






Yeah that's what I'm thinking. I did the same thing after the body lift because it looked bad hanging down there so low. You're right it would't be the best to dump it under the cab so I guess I'll run it back further
 






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