Loss of power with different exhaust

[SilverStreak88]

Does anyone notice a power and torque loss when they change their exhaust out to something else? I lose quite a bit of torque it seems with an aftermarket exhaust as far as passing power. I've changed systems a few times now and I always end up back to stock.

Any ideas?

 

[Csanders1992]

All depends on what exhaust your putting on. A chambered muffler will keep torque down low but fall off with higher rpms. A straight through muffler will loose on the bottom end but pull harder at higher rpms. This is just what I have noticed.


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[HammerHead]

I messed with my exhaust and lost some low end and couldn't figure out why so I did literally hours of research and put all the articles in one place. It's hours of reading but you will understand how important your exhaust system is and that it can be designed to perform/tuned for your application. I lost low end but my 60-120MPH I gained big time. It can be designed to perform down low or up high, most stock system are in the middle somewhere. Me with the 6 speed after losing my low end I've decided to go with the high stall converter to get the low end back and keep the high end too. I decided to have my cake and eat it to


http://www.ramforum.com/f44/exhaust_systems_101_a-63137/

 

[MADDOG]

A lot of that low end loss is ******* in how big you go with your aftermarket exhaust. Bigger is not always better, especially when you end up going too big.

 

[SilverStreak88]

Well... I've literally had my exhaust set up about 7 or 8 different ways. i've run Flowmaster, Magnaflow, Borla, strait pipe, strait pipe with resonator, 10 series dumped, 10 series dueled out the back, super 40 dumped, super 40 out the back. Every system was the same - 3" in 3" out single both sides. The only one I every did down to a 2.5" was the 10 series, it was 3" in and 2.5" dual out.

I spoke with a gentleman at Inertia Motorsports about getting a cam put in and he was going to set me up with the Spartan Plus which was supposedly going to give me a big increase in grunt torque, but things kinda fell through when I didn't here back from him.

 

[HammerHead]

Well... I've literally had my exhaust set up about 7 or 8 different ways. i've run Flowmaster, Magnaflow, Borla, strait pipe, strait pipe with resonator, 10 series dumped, 10 series dueled out the back, super 40 dumped, super 40 out the back. Every system was the same - 3" in 3" out single both sides. The only one I every did down to a 2.5" was the 10 series, it was 3" in and 2.5" dual out.

I spoke with a gentleman at Inertia Motorsports about getting a cam put in and he was going to set me up with the Spartan Plus which was supposedly going to give me a big increase in grunt torque, but things kinda fell through when I didn't here back from him.

Drop a high stall torque converter in it and all your low end problems are Over.

 

[SilverStreak88]

Drop a high stall torque converter in it and all your low end problems are Over.

A different stall converter was in the works as I just had the trans rebuilt 1 month ago and had the guys put a shift kit in. I spoke with the guy in person who rebuilt my trans and he's got 2,000+ 545RFE's under his belt, but he asked me how I use my truck and and what I was looking to do. He said unless I start really jumping up in power I should stay at the factory stall with towing 4wheeling across my land.

Idk... I've kinda givin myself the nickname (never satisfied) because I tell myself I'm going to this, this and this and then I'm done, but it's grown into a sickness and it's never enough. I'm either throwing money into my truck or firearms and it's never enough for either of them. Just to the point now where I wanna stop dumping money in my truck on things that "might work" and put the on it that "will and do work".

 

[blackbetty14]

I did a 18" muffler swap (magnaflow clone) on the stock exhaust and I lost all the low end. I decided to go with a dynomax ultra flow SS catback, 23" muffler (stock is 26") but uses 2.5" from the muffler to the tips (OEM is 2.25") and it deletes the OEM resonators. I gained my low RPM tq back thanks to the more baffled larger muffler (but louder than stock while being 3" shorter) but got the loudess I was looking for thanks to the larger DIA Pipes and loss of resonators. Its a good compromise for the loudness I was willing to live with for a DD.

Exhausts need back pressure to work correctly, too much will cause bad scavenging but will promote more low end tq while limiting midrange/high RPM flow. So you have to tune it to the area (RPM) you will spend most of the time.

The best option for both worlds is a cutback of your choice/muffler swap or OEM to get desired tq band and then run a cutout before the muffler for when you decide to go Balls out high RPM. This will bypass the more restrictive full exhaust and give you the high RPM flow, a remote cutoff can be closed then and return back to full exhaust at your convenience even when still driving. its like having and eating your cake

I was under my truck the other day and noticed something very interesting. I found a heat band on the dynomax muffler ( a hot spot) toward the last 1/3 of the muffler. This usually represents the tuned exhausts "area" for things like Hpipes/Xpipes or resonator pipes. I just thought it was interesting to see and wanted to let you fine gentlemen know about.

 

[THETANK]

my MagnaFlow cat back seems to perform nicely with no low end tq loss

 

[Hemi8073]

If your wanting something that will work without a doubt that will be gears and stall converter. If you want it a step further headers and a custom can would really wake that thing up as well. Holler if you need any help as I can really help that QC fly if you would like

 

[Hemi_Express2013]

Here's the real deal. Your stock exhaust is tuned to your vvt system as well as intake runners. If you change the exhaust you are in fact changing how the charged intake air velocity works filling the cylinders. Meaning less vacuum when the exhaust valve is opened. Valve overlap, tuned exhaust, and intake manifold runners is key with the vvt system. It's a well engineered system.

Here's an excerpt from know your parts

Nowadays, computerized engine management systems have made variable valve timing a practical reality for most vehicles. But a historical discussion of the various engineering approaches to variable valve timing could fill an encyclopedia. Coupled with tuned intake and exhaust systems, variable valve timing can dramatically *increase low- and high-speed engine torque, *increase fuel economy and reduce exhaust emissions - See more at: http://www.knowyourparts.com/technical-articles/vvt-diagnostic-tips/#sthash.7ay9JhMX.dpuf

 

[adventurer]

I have tried almost every exhaust setup and finally i ended gutting the front parts of the cats and fitted 2 same size pipes as the factory pipes going out from each cat to rear 22 inch magnaflow muffler which i flipped to make it 2 inlets and exiting one outlet to be single at rear end and i kept the resonator because without it there was drone at 1800-2000 rpms though the sound was amazing and so deep without the resonator but the drone was killing , with this setup i didn't lose low or high end torque , the truck spins more even when floor it at speed of 30 miles which its not comfortable for me, even when i take off with my foot little heavy on paddle it spins like hell and all times the police stopping me because of spinning, so for my truck i found this as the best exhaust setup

 

[DoubleTap]

I think it's all in your guys head. Changing out a catback or changing the muffler is not going to gain or lose any measurable power or torque. Especially to the point that you would notice it. For you to be able to notice any gains or loss in power with any mod on your truck you would have to be losing or gaining 20-30rwhp/20+rwtq
Now if you are changing out the exhaust piping from the headers back to like 1.5"-2" or going huge from the headers back like 3.5"+ piping.
If you were talking about headers than that's a different story for losing low end and gaining top end power or the other way around. Which would be happening based on if you go long tube headers or shorty headers or tuned style shorty headers.

 

[SilverStreak88]

I think it's all in your guys head. Changing out a catback or changing the muffler is not going to gain or lose any measurable power or torque. Especially to the point that you would notice it. For you to be able to notice any gains or loss in power with any mod on your truck you would have to be losing or gaining 20-30rwhp/20+rwtq
Now if you are changing out the exhaust piping from the headers back to like 1.5"-2" or going huge from the headers back like 3.5"+ piping.
If you were talking about headers than that's a different story for losing low end and gaining top end power or the other way around. Which would be happening based on if you go long tube headers or shorty headers or tuned style shorty headers.

I have to disagree with you in being that I know for a fact that I lost torque when I changed the exhaust. I have to agree with Hemi_Express2013 that the factory system is tuned for my engine specifically and makes complete sense. I would much rather make power and torque and move it down the road then make lots of obnoxious noise and being almost sitting still. I have to be honest though, I don't really care for the rumble anymore and have gotten used to it being quiet. I can roll around incognito and not have to worry about standing out which when I did have an exhaust it "did" turn heads and got me tickets, but I'm not a social media attention getter and definitely like not getting tickets. I think for the times that I do want some rumble I'll just throw a cut-out in the mix then I can have the best of both worlds.

 

[jstacey8]

I had stright pipe and super 40 finally got it right with my 3 inch dyno max race bullet and the 3 in dual 2.5 out y pipe. Feels better then stock and much better the the stright pipe or super 40

 

[Ramrt1]

I felt the same way about chambered mufflers until I installed the flowmaster 50 series had muffler that's specifically designed for the hemi trucks, the other mufflers are universal. As far as not flowing well on the top end I don't agree, I have recorded my highest 1/4 mile top speed at 98.6 mph, that's better than the 14 and 18''inch magnaflows at 96.3 mph, borla xs pro at 95.1 mph, and maganflow 14'' and 18''inch true x pipe mufflers 93.3 mph. With the right custom tune and tuner they can add more fuel and less timing to give you the power at the top end, the low end torque is awesome with this muffler.

 

[Hemifatboy]

Most performance parts are a trade off , you can have low end torque or high rpm hp , this is how exhaust works and to a great degree cams as well , the only true ways to gain on the whole rpm band is higher compression or forced induction , factory tune should give good low rpm torque , which to most butt dynos feels the strongest

 

[Hemifatboy]

I should add a good custom tune to that , it will give more overall power especially at wot