Does anyone know how the Fuji compares to the RSR Ex-mag. I ask because they look somewhat similar and the RSR exhaust made up to 10whp LESS than other exhausts tested in a recent article in TM.

 

It is being installed as we speak. I did some road dyno runs w/ the old exhaust before I dropped it off. At lunch today, I will have some more dyno runs w/ the Fuji. I am thinking a 20whp loss.

 

Was your old exhaust (the UR) straight thru 3" no resonators?

 

Yep, 3", no resonators, w/ a Magnaflow muffler.

 

...and what Jay didn't go into was that even on an otherwise stock application (at Evo power levels), a full 3" turboback WILL generally gain power down low... not lose it. When you see a "loss" on people's dynos, what you are seeing is a tuning deficiency induced by the new volumetric efficiency. What people "feel" as a low end loss on a tuned car is generally in fact just a disproportionate gain on the top end. You get that "rush" of power making you believe there is now "less" on the bottom.

Now what remains to be seen is how this system will effect jj 008's state of tune, or system as a whole. Will it "kill" his power? I doubt it. Will he lose some power? Tunes being equal, I'd all but guarantee it however small it may or may not be.

 

+1 ... I've actually already read most of that before from different sources ... and it is true that the bigger the turbo or mass/volume of exhaust you are moving the more in-efficient a narrower catback with resonators will be. For my application, I'm willing to give up a few ponies for the lack of noise.

 

this is actually not the reason at all... even after you read the long post by jay at garret (i see you're whippin' it out zeus!) the results are in the details.

the reason why you don't run a 5" pipe is not because of the gas losing temperature. while hot gases move faster they also move more turbulently, if you had colder gases they'd move striaghter and with less losses. that said, temperature is not the MAIN concern altho it is nice to keep the temps high until the downpipe.

what is the main concern is the a rapid expansion in air, if you have rapid expansions and contractions in the duct sizing you will encounter minor head losses from the gases doing work either expanding or the gases doing work on the gases in front of them to compress into a contracted diameter duct. the expansions are thermodynamically irreversible processes and hence must have work done to them to reverse them.

with that out of the way you want a pipe that is as uniform as possible and if it has growth in diameter the growth should be smooth. this is what jay is talking about when he says hyperbolic turbine exit. you want the gases to expand in a laminar flow fashion, it's a bit tricky to visualize.

the catch is that you only need so much laminar flow before it doesn't matter anymore and you can just eject into the atmosphere safely... actually this would best be done with a hyperbolic exit too probably, but would look incredibly funny.

you can do this experiement, with a lawnmower engine, take the exhaust pipe and run "open header" you will dyno it and find a certain horsepower. then take a really long exhaust pipe put it on and dyno it you will find a decrease in horsepower. now start gradually chopping off pieces of the exhuast pipe until you get the maximum horsepower... now this will be a finite length! some pipe is better than no pipe, becuase it keeps the flow straight so that you dont' get turbulent losses at the head.

 

Let me chime in here since I have this RS-R Exmag on my IX along with HFC & 70mm downpipe. Fujitsbo and RS-R were my two choices and I went w/ RS-R Exmag due to following reasons: 1) 80mm piping w/o reasonators (But, it does taper down to 70mm at the flange that meets the cat) 2) Stock appearance 3) Relatively quiet tone, it gets deep at WOT, yet it is very quiet (stock) at idle.
Lastly, the price, a lot cheaper than Fujitsbo.

I went with this exhaust, fully knowing that I would leave few hp on the table, compared to going w/ other exhausts. However, I must tell you that I've been very happy with Exmag in terms of its fitment, quality and power improvement.
I would recommend this exhaust to anyone who looks for an exhaust that is somewhat stock-appearance, relatively quiet with decent performance gains.

 

trinydex,

It was quicker to whip it out (cut and paste) than to type out my own sumation... I only have net time out of the garage today at lunch and during phone calls...


jj_008,

Get some installed road dynos yet?

 

Not yet. I will have some in about 2-3 hours.

The damn vendors lied to me again. I asked if the tip would clear the bumper and it doesn't . It almost 1/2-1" inside the bumper.

 

Thats a good review and Im glad your happy with it. Interesting the ExMag is cheaper, I didnt know that.

 

Might I add to what ROK EVO said, I have had the opportunity to compare a stock catback EVO, my stock EVO with a Fujitsubo RM01A catback and my friends stock EVO with an RS-R Ex-mag catback. The RS-R, like the Fujitsubo, does taper down to the stock piping diameter and while it doesn't have the 2 resonators it is also louder than the Fujitsubo RM01A. Ofcourse nothing beats the stock interms of noise levels but where's the fun in that ...

I would love to see an EVO owner with a trumpet shaped pipe attached to his oulet (hot) side of the turbo for maximum power ... band camp anyone?

 

MY RNR is 3in the whole way back to the muffler but at the HKS part it gets down to 2.75

 

Interesting stuff.

Is the Fujitsibo Legalis quieter than the RMXXX?

I had a Helix 3" with my Helix DP and RT HFC, and it was just too damn loud. I always drove around with the silencer, and knew it was slower, but it didn't "feel" that much slower.

At my custom dynoflash at Pruven, I made 50 (FIFTY!) more hp with the silencer removed (258 whp vs 306 whp). I left with 331 WHP and 338 WTQ. I have since sold the Helix and I'm running the stock cat-back. I would guess that I'm down about 20 HP compared to the Helix.

I'm happy with the noise levels, but if I can get back 10-15 HP and have almost the same level of quiet, at least at idle and part throttle, I would do it. It seems like everyone mentions the Fujitsibo, so I'm leaning that way... Alternately, I'll just leave the stock cat-back or try one of the dump valve.

Oh well, looking forward to the dyno results.

take care,

FB

 

Everything you said is exactly the reasons I went with the Ex-mag.
My HKS Hi-power got bent in a skirmish with a guardrail. I plan on using it as an "organ donor" to eliminate the neck-down at the cat.

Don't mean to hijack the thread, but for reference, here is a couple pics of the Exmag and the stock system layed side by side.