Bisimoto Pulse Chamber first and last impressions

[trond]

Today I decided to try the Bisimoto Pulsechamber I purchased after one too many late one night last June, to decide what to do with it. It has been sitting as a garage as an ornament while I have been pondering what to do with it after it failed to install, interfering with both the bumper valence and also with the lower quarter panel. It is a sk 'prototype' item, and I have been told later by the vendor that I should not have expected it to fit....

So finally today I removed rear bumper valence and lower quarter panel and bolted it on. To reduce noise levels, and to add some backpressure I fitted the catalytic converter. I had to grind off the protruding flange from the cat but thats what angle grinders are for.

After 10 miles of driving I had enough of the hellish noise. I always drive with windows open but not possible with this thing. Cruising with low load around 3000 rpm it is almost bearable but step on it and every head within half a mile turns. This is without the 'sound arrestor' which I assume would help

Powerwise I would say if anything the car felt down on torque in the midrange, possibly because of lack of backpressure.

Tomorrow I have an appointment with a TIG welder to cut and re-angle and then I will make an attempt to sell it. Can't wait to install the SSIs and new Dansk Sport muffler

[72911]

Yes, Franziskaner Weissbier and a credit card can be dangerous!

[Joe Bob]

Some motors prefer back pressure....

[Jp-oh]

When I am feeling particularly antisocial (sadly more often that I'd like) and run my homegrown muffler delete I am certain the car feels down on the torques.

[Trakrat]

Originally Posted by trond

After 10 miles of driving I had enough of the hellish noise.

LOL!! So was it just LOUD?? Or did it actually sound really really bad?

[HWG09]

I'm installing one of these this weekend although it is the spec version with sound arrestor that I can remove for track days.

Will have a full review soon.

[trond]

Antisocially loud. Almost like driving without a muffler. Which is what this thing is, just a very short very open large diameter stub after the cat. I like very much the typical tinny rasping aircooled flat6 porsche sound typically heard with banana mufflers. This is on the opposite end of the scale. Definitely not for everyone.

And then the loss of performance. It is supposed to make the car quicker, but my feeling (undocumented) is you will get no extra performance at all in returns for being an obnoxious antisocial jerk. My impression is a very noticable loss of midrange torque. I only let it scream past 6000 a couple of times and the noise was approaching a commercial jet on take-off and. I limped home as quiet as I could before the police and army could get to the crime scene.

Will not use it again

[VW_NUTT]

So just to clarify, You start your first thread about the muffler not fitting correctly, then you hijack another thread to trash Bisi some more. I guess that's not enough and you start another thread to throw Bisi under the bus again. We are not seeing both sides of this story unfortunately. Bisi stated he would make it right. Are you the kind of guy to call the number on the side of a service truck and demand the driver be fired because you didn't like what he did in traffic? Its not $1000000.00. Why be a dick about it? My pulse chamber fits perfect. I find it a bit too loud for driving out the street Sunday morning at 7:00 am for breakfast with the wife. I ordered the sound arrestor. Ill try that, and if I don't like it I will pull it off and stick it on my fireplace like a piece of art.

[VW_NUTT]

[kaidohaus]

trond,

I've had my Bisimoto Pulse Chamber for roughly a year (you can check my original post if you like, it's here somewhere) that documented the process and results.

First, the volume. Yes, it's on the louder side as is, and the decibel level may not be for everyone. I installed the sound arrestor (which Bisi does make available) and the volume goes WAY down with no loss in performance. Have you inquired about it? Before you dismiss this exhaust due to volume level, install the sound arrestor and enjoy your radio with the windows down.

Second, performance. We all love our butt dynos but they are no match to a proper dyno session. I've had my 3.2 dyno'd twice at Bisi's shop and we saw an increase in HP and torque on both sessions. Have you checked the article about Bisi's pulse chamber on European Car? That is my car in the article. You can see the sound arrestor installed as well.

Exhausting Porsche Power - Bisimoto Pulse Wave

And third, I have never met someone who wholeheartedly stands behind his product and will take the time to explain the science behind the gains, like Bisi. He and his team are a class act, and I have nothing but praise for their product and services.

[tdw28210]

Move on.

[RarlyL8]

An accurate comparison would be against a premuffler with muffler bypass tailpipe. When you eliminate the large banana muffler and cat on a Carrera and just run a premuffler you gain 12hp and ramp up the sound level.

[Ydobbs]

I've had Bisi's muffler w/sound arrestor installed (only took about 20 minutes and fit perfectly) for about 3 weeks now and I could not be more pleased. I think my 3.2 sounds perfect and I do feel a power/torque gain for sure. Most importantly - I can't help but smile every time I get above 4000 RPM. Consider me a satisfied customer.

[911SauCy]

Originally Posted by RarlyL8

An accurate comparison would be against a premuffler with muffler bypass tailpipe. When you eliminate the large banana muffler and cat on a Carrera and just run a premuffler you gain 12hp and ramp up the sound level.

I have THIS but the parts are Fabspeed...Cat-bypass and muffler delete.

The car sounds phenomenal...and if you're not some whiney purist, the volume is spectacular as well

[911SauCy]

Originally Posted by Ydobbs

I've had Bisi's muffler w/sound arrestor installed (only took about 20 minutes and fit perfectly) for about 3 weeks now and I could not be more pleased. I think my 3.2 sounds perfect and I do feel a power/torque gain for sure. Most importantly - I can't help but smile every time I get above 4000 RPM. Consider me a satisfied customer.

Of course.

It's clear that Bisi is an emphatically detail oriented fabricator/engineer. The part is dyno tuned and documented.

[HWG09]

I put my pulse chamber exhaust on yesterday and it's amazing. I can't express all the smiles it brings when I drive the car now.

To the original poster, yes the exhaust w/out the sound arrestor is VERY LOUD. Not sure I would want to be driving it like that all the time but for the track or some spirited driving it would be great.

Before you get rid of it get the optional sound arrestor. Huge difference. Still sounds great but not quite wake your neighbors loud.

I'm putting together a video of the install and fly bys shortly.

[HWG09]

Here is a video I put together of the install as well as different shots of the car with stock exhaust, no sound arrestor and with the sound arrestor.

https://www.youtube.com/watch?v=NuzIn000xi8&lc=z13gzv3y4syujpu2a23cj5th4s3gjt55t04

Every exhaust will sound different but for the money and the performance I love my pulse chamber.

Also if anyone is interested I started a 911 podcast and one of my first episodes is with Bisi from Bisimoto. We talk about the Pulse Chamber quite a bit.

Check it out here.

https://flatsixpodcast.com/2017/04/22/episode-3-with-bisimoto/

[tobluforu]

Originally Posted by HWG09

Here is a video I put together of the install as well as different shots of the car with stock exhaust, no sound arrestor and with the sound arrestor.

https://www.youtube.com/watch?v=NuzIn000xi8&lc=z13gzv3y4syujpu2a23cj5th4s3gjt55t04

Every exhaust will sound different but for the money and the performance I love my pulse chamber.

Also if anyone is interested I started a 911 podcast and one of my first episodes is with Bisi from Bisimoto. We talk about the Pulse Chamber quite a bit.

Check it out here.

https://flatsixpodcast.com/2017/04/22/episode-3-with-bisimoto/

Geez, how many Porsches do you have at that house?

[VW_NUTT]

Well I received my sound arrestor Friday in the mail. Drilled the hole for the bolt. I took the wife out for breakfast this morning. She approves , and thinks it sounds great! I didn't want to have to have a wrench on hand to remove the nut so I welded the nut in permanent. just need an allen wrench to remove. I think I might weld some kind of tab on it to assist in pulling it out because its a tight fit. This works perfect now so I can drive past the neighbour who thought my Dansk was too loud and be obnoxious till I get past his house then stick in the arrestor. Thank You Bisi!!!

[HWG09]

Originally Posted by tobluforu

Geez, how many Porsches do you have at that house?

Ha, I wish they were all mine.

Just some buddies of mine here in Omaha.

We make quite the scene in my neighborhood when we're all together.