dual vs. single exhaust

[Agent 409]

Right now i am currently shopping for exhaust for my truck..i was originally interested in the aero turbine but i decided that i want to get a loud exhaust system. I'm looking to buy the Bassani exhaust catback system because i've heard their real loud and i like the sound i've heard on keiphers videos..i like the look of single exit at the stock location with a slash cut tip better than the look of duals..but i'd go either way i think..i just don't want to lose any power whatsoever.

the bassani dual system has dual 3.5" tips side exits (like TRD)on it at the side exit and the bassani single exit (stock location) has a 4" tip on it..does any know if one would be louder than the other, or if there would be any power loss on either one??

[Agent WD-40]

The single is a 3" pipe and the duals use 2.5" pipe. They also appear to offer a dual inlet muffler with an x-pipe in the muffler and a single inlet muffler in both their single and dual exit setup. What are the advantages of either the x-pipe setup and the non x-pipe setup?

There is also the Bx system available that uses "composite" steel. It looks like they are a cheaper setup than the regular all aluminum Quiet Thunder series.

[flyin6]

Take a look at my exhaust outlets in my gallery. By routing the exhaust out the side in front of the rear tire, it become much more aggressive sounding.

[Sumo99]

Agent 409-
I noticed you are in So. Cal. Is the Bassani now legal in CA? I know they didn't meet CA emmission laws a few years back.

[Agent WD-40]

Originally Posted by Sumo99

Agent 409-
I noticed you are in So. Cal. Is the Bassani now legal in CA? I know they didn't meet CA emmission laws a few years back.

It looks like they have 2 types of systems available. The first type will fit all models (Access and Double cab) and is listed for years 2000-2004. It is a single inlet muffler with single or dual outlet (for single or dual pipes). I'm assuming this is just like the most of the other cat back systems (Borla, TRD) that attach at the flange after the factory pipes have merged into one. The DC and AC have the same exhaust system from that flange back. That is why the TRD system will work on the DC and AC. From 2000-2002 CA trucks had a 3rd catalytic converter right before the flange. So to be a cat back and not mess with emmisions they had to attach after this point. Bassani used to only sell a system that replaced that single pipe with the flange and 3rd cat with dual pipes that came straight back from each header. This eleminated the 3rd cat and thus wasn't CA legal. Because this single inlet Bassani system leaves that pipe in place and doesn't interfere with the 3rd cat it will work on CA trucks from 2000-2004, AC and DC.

The other system they list for only 2003-2004 Access Cab, short bed trucks. It is a dual inlet muffler with an x-pipe. I'm assuming this system comes with dual pipes that connect the each header to an inlet on the muffler with an x-pipe in between. This gets rid of the factory y-pipe and the pipe up to the flange. In 2003-2004 all Tundra's only have 2 cats, one on each header, none on the last stretch of pipe before the flange. There si only a resonator on that stretch of pipe with the flange. This is why Bassani can now offer their x-pipe system in CA. Hope that helps.

In this picture you can see a picture of the factory y-pipe, 3rd cat, flange, TRD resonator, and TRD muffler on my 2001 CA truck with the TRD exhaust.


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Agent 409, I believe in the past the systems people were posting gains with were the dual exit x-pipe systems. It seems like the consensus is that if you go duals you should go with an x-pipe. If your only going with the single exit then I'm not sure. If you got the x-pipe you would loose the factory y-pipe and resonator, but you would gain an x-pipe which is probably better than just that factory y-pipe. Perhaps v8toilet and Verndog could come comment on all of this. I believe Verndog gained 1 MPG and some power after adding a filter and his dual system with a crossover pipe.

I have no idea which one would sound louder or quieter than the other one though.

So your choices are:
1) Single inlet/single outlet system that has 3" pipe and attaches at the flange. 4" tip on this one.
2) Then there is the single inlet/dual outlet system that attaches at the same place that has 2.5" pipes. 3.5" tips.
3) Dual inlet/single outlet with an x-pipe and dual 2.5" (my guess) pipes that attach to each header and a 3" outlet pipe. 4" tip on this one.
4) Dual inlet/dual outlet with an x-pipe and 2.5" (again my guess) pipes that attach to each header and dual 2.5" pipes out the back. 3.5" tips.

[Verndog]

I added a true dual system, and used a H crossover with 2 1/4 pipe. The 2 1/4 pipe is thicker walled then 2.0 and will last a bit longer. After adding exhaust and TRD filter I picked up 1 MPG and some power above 2800...I felt no loss or difference below 2800. If you choose 2 1/2 pipe..you may experiance some loss on low end from others experiance.

I used H crossover and X crossover is (possibly) a tad better.

H crossover Pipe

This is the best mod I've done to date...wouldn't go back to single.

Cant post actual gains...all my dynos were after exhaust was done. Last 180 mile round trip I took...got 19.6 MPG 4.7L v8 4X4....not bad....good conditions I believe 20 MPG is propable.

Kevin

[Sumo99]

Originally Posted by Agent WD-40

Because this single inlet Bassani system leaves that pipe in place and doesn't interfere with the 3rd cat it will work on CA trucks from 2000-2004, AC and DC.

Good to know.

[v8Toilet]

If you want the most power with a great sound than don't spend a lot of money on a pre made system. Buy a muffler that you like and have it welded in place of the stock muffler reusing the stock pipe. Do this and you’ll gain low end torque (with a Spintech anyway). If you want a tip than buy one and have it welded on. I've learned from experience that if you increase the diameter of the exhaust tubing beyond the stock 2-3/8" pipe that you'll loose some low end torque. If you go with a cat back dual system than you'll loose even more. The problem is that most of the cat back exhaust systems out there are 2-1/2" in diameter or larger. That’s too big for a 285 cubic inch truck motor. I have no experience with true dual systems on the Tundra but will tell you that they are expensive to make and don't offer any advantage over a properly engineered single exhaust.

I’ve changed the y-pipe with an SSautochrome y and felt no difference in power. The only thing I got was a leaky rusting pipe. That Y-pipe is actually a good flowing piece and isn’t worth messing with.

Don’t be too worried about top end horsepower either. What your heavy truck needs is torque in the 2500-3500 range to make driving in everyday traffic enjoyable. The engines torque peak is @ 3400 rpm so this is the area you want to make the engine most efficient. See my dyno graphs. Here is a cut and paste from one of my previous posts.

The factory pipe is 2-3/8" OD. I measured it with my dial caliper. The exhaust gases travel through the exhaust in pulses causing the exhaust flow to slow down and speed up with the firing pulses of the engine. The smaller factory pipe keeps the exhaust gas velocity up at lower RPM so that those exhaust gases keep moving with the firing pulses of the engine. With the larger pipe diameter or dual pipes the exhaust gas pulses actually stop and go now inside the pipe at lower RPM making it harder for the engine to pump them out because energy is wasted getting the exhaust moving after it stops. This causes the engine to pump less air at lower RPM. The exhaust gases may also tumble causing flow robbing turbulence because they are moving too slowly or stopping and moving with the firing pulses of the engine.

The factory 2-3/8" single pipe is a perfectly engineered part on the Tundra. Don't increase it's size if you want the best compromise between low end torque and top end horsepower. For the best torque and horsepower I have found that replacing the stock muffler with a higher flower muffler and headers like the JBA or long tube headers work best.

If you install those headers with your duals you'll get that low end back but the single exhaust, high flow muffler with stock pipe, and headers will still make more power at lower RPM than the same setup with duals.

I disagree with them that the muffler alone decreases low end torque. If they do not have any leaks, bought a 2.5" inlet and outlet muffler, and reused all the stock piping including the rear tail pipe than they should have the same results that I got. I gained some low end torque with the addition of the Spintech muffler. My graphs didn't show it because I ran the truck in third gear but my 60-foot times at the track did and they improved. My dyno graphs start at about 3000 rpm. When you first install the muffler you might not notice anything until about 500+ miles because the computer will sense the change in air flow and richen the air fuel mixture at first and then lean it out as it relearns the new air flow characteristics of the engine. The same thing will happen with the addition of headers, and other breathing modifications.

I recommended the Magnaflow muffler because it is made of stainless steel and is cheaper than the Spintech. You can get the Spintech in stainless steel but it costs about $180 vs $99. The Aluminum coated muffler though is a stout piece and should last more than two years easy. The Spintech muffler is very well made! I don’t know for sure if the Magnaflow muffler will match the Spintech muffler for power; I can only assume they will be close based on dyno comparisons I have seen of them on other cars.

The Magnaflow muffler is a straight through glass packed style muffler much like the Borla and TRD muffler. All the glassed packed style mufflers have similar sound. The Spintech muffler is a chambered muffler but it is unique in that it has spiral shaped chambers (if you can call them that). Most chambered mufflers are more like a Flowmaster with triangular and baffled chambers to reflect the sound waves back at each other and cancel them out. The Glass style mufflers use sound absorbing insulation to absorb the sound waves. They both are affective at absorbing sound but glass packed mufflers usually have a more mellow deep sound to them and chambered style mufflers have more of a raspy crackly sound to them. Chambered style mufflers like the Spintech start out deep sounding and become more raspy and quiet as the engine rpm climbs. The sound of a chambered muffler will not change as long as the structural integrity remains but glass packed style mufflers loose there sound absorbing abilities as the miles pile on because the glass packing (sound insulation) breaks down and becomes less effective over time. Some people may comment that their TRD exhaust systems have gotten louder after 20+k miles.

Many people believe that if you loose back pressure than you loose low end torque. This misconception is complete BS. Pipe diameter has everything to do with Exhaust gas velocity and that is what effects how much torque you gain or loose with and exhaust.

[Dude Boy]

Many people believe that if you loose back pressure than you loose low end torque. This misconception is complete BS. Pipe diameter has everything to do with Exhaust gas velocity and that is what effects how much torque you gain or loose with and exhaust.

Maybe that's why my buddy's Tundra seems to have so much more power to spin the wheels than mine does. He has a completely stock system other than a piece of straight pipe welded in where the muffler used to be. It doesn't sound that bad either!

On the Bassani system (at least on mine), the muffler is stainless rather than aluminum and the x pipe is inside the muffler rather than external. They call it an "x" muffler. The pipe ahead of the dual inlet muffler is pretty close to 2-1/4" and it's 2-1/2" out the back. The stainless tips have baffles and fiberglass packing in them. I think I measured the pipe on the inside, so allowing 1/16" wall thickness, that would be about 2-3/8" on the outside as per V8's measurement.

[Agent 409]

for my exhaust choice..i'm not looking to really gain any power whatsoever..i just don't want to LOSE any power..torque especially..i am shopping based on sound only..price does not matter to me..i will pay to get a great exhaust..and i want a loud exhaust too..(loud, but not terribly loud like a glass pack).

i really like an exhaust system with a burble to the idle and acceleration..

[glenhaven]

I have a MagnaFlow tuned single exhaust AND I love it -- it added power in all ranges of RPM's = headers are to loud for me -- and a boost in performance and better gas milage - it has a healthy sound and that is all I wanted = my performance guy suggested it - he said if this was my truck this is what I would do -- Glen

[H2O_MAN]

Hey Glen,

Did you swap the muffler only?
If yes, what model/part# for the Magnaflow?

Thanks --

Originally Posted by glenhaven

I have a MagnaFlow tuned single exhaust AND I love it -- it added power in all ranges of RPM's = headers are to loud for me -- and a boost in performance and better gas milage - it has a healthy sound and that is all I wanted = my performance guy suggested it - he said if this was my truck this is what I would do -- Glen

[meself88]

So should I have lost power with my setup? SI/DO chambered style muffler with the stock 2 3/8 pipe going in and dual 2 1/4 pipe going out. the guy at the muffler place seemed to know what he was talking about. he said that the 2 1/4's would sound better. seeing as that they are LESS than the stock size shouldnt I be closer to having stock exhaust gas flow than say dual 2.5" or even dual 3" pipes which seem to be so common with pre-made setups? (note that I didn't measure the pipes going back from the muffler they just say 2.25 on them, not sure if that is OD or ID. If its 2.25 ID then it could be 2.375 OD which would be same as stock, in which case i theoretically would lose power(?)) And I have 3" oval tips, but I wouldn't think that would hurt anything since they are not long, just a few inches. also, 3400 rpm is still pretty high, so i'm not sure i would call that "low-end" torque myself. considering that the engine redlines at what, 5000 or a little over? I will agree with the descriptions of the glasspacks vs. chambered. my exhaust sounds deep v-8 throaty at lower rpm's and then when they get higher it sounds not raspy but just more like a powerful noise.