kenji211

Does anybody have any quantitative data on horsepower gains and weight differences between a true dual exhaust and a single exhaust with dual mufflers?

What I'm really asking is....is it worth it to spend more on a true dual exhaust system (JoeZ or ARK) versus a Tanabe with an aftermarket mid-pipe?

-Kenji

badx33

iTrader: (53)

kenji211

I appreciate the weight information. It gives me a starting point to compare to other exhausts.

DickH

We don't really have a lot of solid information on what gives what gains with these cars, you probably aren't going to get the boys answers you want. That said, I can tell you that you will want 2.5" exhaust. Redspencer and myself both switched to 2.5" exhaust and have noticed an increase in power. I have a proper dual exhaust and his goes to single. I'm not sure what if any gains a dual exhaust would have over a single but I know I am happy be with the sound of my dual exhaust. I would recommend looking into how different exhaust components sound and talk to an exhaust shop about making you a custom exhaust. I was surprised how cheap this option was for me. I think I dropped off something like 300-400 in parts them paid 400 for them to build my exhaust out of stainless.
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2013FSport

iTrader: (2)

D i c k, did you get those small primary tube headers on there yet?

We need flyby at cruise and perhaps under load! Hint hint!

bakalag

I went from Tanabe axle back to X-Pipe to dual Flowmaster 40s mufflers and felt more power after 80mph and also mid range. 4th gear actually accelerates the car more noticeably now...I still have all cats and no header upgrade. Sounds super amazing too.

redspencer

iTrader: (1)

You'll have to do some digging with the search function but I do remember the CL forums having some very old threads (probably in the 08-10 era) when the JoeZ true dual exhaust was made available for the IS250/IS350 which included the benefits of a dual exhaust that was explained by JoeZ himself as well as associated dynos for the catback exhaust (for both the road legal and off-road versions). I recall the off-road catless version being approx. 3-5 rwhp higher than the road legal catback version but I don't recall if those threads had any data to support any horsepower gains from a true dual to a single piped exhaust.

Some recent data that significantly favors the dual exhaust setup over the single pipe version is when forced induction is introduced. Supercharged IS350s with a true dual exhaust setup are making at least 20rwhp more than a non dual exhaust setup.

2013FSport

iTrader: (2)

Looks like a clean fit. No droning?
Who made the crossover pipe and what size did you run? 2.25"?

bakalag

I think it's 2.25", not sure what kind of crossover pipe, it droned beyond bad I had resonators put in after a week, pulls was fine but cruising drone was death. I wish I had recorded an acceleration run on, people were telling me they thought a GTR was approaching, and it back popped really nice...


Added Helmholtz style resonators and it reduced drone by 70-80% now it's only a bit louder than my Tanabe cruising and 90% loud compared to setup # 1 WOT outside. Drone inside a tad bit less than Tanabe. I tried resonators going through the mid but it reduced drone by 20% or so and outside noise by 50-60% and felt minor loss of top end. I'm pretty happy with the final set up though.

below is a clip of a pull, the iphone mic picked up a tinny sound that isn't as noticeable in person.

I'm debating on redo-ing it to 2.5 if that's better. I didn't know prior and just let the shop do what they thought was best, but I found a better shop and might just do HFC and PPE headers with the same mufflers.

2013FSport

iTrader: (2)

B, thanks for sharing.

I wish I had $$$ to burn as I don't know if it's the firing order of our Weeee Six or a simple change in setup over time?
My old V8's never droned but the block angle "V" is different as are the crank journal spacing thus the event timing into the exhaust is very different but back in the day the muffler was between the axles and as long as the section between the headers and muffler was a bit larger than the muffler to bumper the velocity was good, sound was good and no droning. In this configuration the muffler acted as a resonator and muffler so if you bought good stuff, there were no problems.

Anyone ever tried that on V6? i.e. place the muffler back next to the drive shaft?

DangerDad

i want this!