Author Topic: $150 cat back Dynomax super turbo exhaust.  (Read 4780 times)

benz-tech

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$150 cat back Dynomax super turbo exhaust.
« on: April 13, 2015, 10:43:24 PM »
Being the bang for the buck (read: cheapo) guy I am, I was searching for a less expensive way to replace my stock and mostly blown exhaust. I wanted to buy some 2.25 mandrel bends, a basic resonator and an Super Turbo. It started adding up quickly. Then I stumbled upon a Dynomax exhaust system for a Chevy Blazer or something that looks to have plenty of mandrel-bent piping and a offset/center muffler and even a decent tip. All for $125 at Summit. Add an $18 dollar weld-in resonator and I'm on my way to a new $150 exhaust system. It obviously won't just bolt in but I just so happen to have a welder, cutter and expander avail as well,  otherwise this would be a no go. I thought I'd share this. The p/n is WLK-17471 for the exh system with the 20" dynomax muffler. 

Edit: the new system is in! After the initial wam-up which is buzzy it sounds mellow and only slightly louder than my stock blown muffler. Mostly it just sounds good. Healthy without being too loud. A lot like the Lotus Exige that I see ripping down the street where I work.
Fitting it was an exercise in imagination. Trying to visualize something from nothing was tough until the first pipe got tacked on and the it just flowed from there. I still need to adjust the muffler fitment but the plumbing is done otherwise.
Power power everywhere. So I figured I'd loose low end with a larger pipe diameter but was pleasantly surprised. SOTP dyno feels like nearly 10 ft lbs of torque between 2-3k rpm. Top end up a little less than that. Maybe 5 hp. Now this is with late M42 cams I popped in this engine which were clearly 'torquier' than '91 cams. I'll save that for a different write-up if Delta confirms my suspicions.
« Last Edit: May 10, 2015, 11:19:52 AM by benz-tech »
Pi is apparently the multiplier for your engine swap budget as well.

bflan2001

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #1 on: April 14, 2015, 03:08:27 PM »
Very interested to know if this works out for you, good luck and let us know!

Gunner_1886

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #2 on: April 14, 2015, 06:18:29 PM »
Definitely would like to see some videos when everything is sorted!

benz-tech

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #3 on: April 19, 2015, 12:24:14 AM »
Parts are ordered!  I tend to disagree with everyone saying the stock piping is fine and just the stock muffler/resonator is/are restrictive. The pipe size gets significantly smaller after my 2.25" cat so I'd guess its around 2" or possibly even less. The following page agrees with me:

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/#easy

I'm not sure how accurate that is or even if it can be fudged a bit. I hope to be getting close to the 185 bhp mark with my new engine. So this makes 2.25" ideal for my application. Also,
I will do a 2nd gear pull vid with maybe a afm voltage comparison before and after to put my money( all $137 of it, shipped) where my mouth is.
I just hope it isn't too loud. I like the stealth mode...and I'm over 40.
Pi is apparently the multiplier for your engine swap budget as well.

benz-tech

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #4 on: May 10, 2015, 11:22:33 AM »
It's in! Pics to come. I edited the first post with more info. And if you're handy with a welder, I highly recommend this. The 20" turbo muffler actually sounds good with a resonator.
Pi is apparently the multiplier for your engine swap budget as well.

benz-tech

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #5 on: May 13, 2015, 01:05:36 AM »
I used one of the existing straps to hold the muffler up and cut off the center hangar and welded it to the new pipe.
« Last Edit: May 13, 2015, 01:13:08 AM by benz-tech »
Pi is apparently the multiplier for your engine swap budget as well.

benz-tech

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #6 on: May 13, 2015, 01:10:09 AM »
The bends are all smooth and de-burred for optimum flow but I think it will look a lot better after I tuck it up a bit. Sound quality is amazing. I figured it would be buzzy but the more it breaks in the better it gets. It's also much more drive able. Both features I didn't think I'd get from building my own exhaust.
« Last Edit: May 13, 2015, 01:17:04 AM by benz-tech »
Pi is apparently the multiplier for your engine swap budget as well.

colin86325

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #7 on: May 13, 2015, 07:27:58 AM »
That's a very clever find, thanks for sharing!

Tgoode318

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #8 on: May 13, 2015, 09:59:34 AM »
Nice job benz-tech. Screw all those expensive pre made exhaust set ups, it seems like the 318 has the worst selection of exhaust i have ever seen for a performance car. The set ups  i have seen are all extremely over priced and don't give much in terms of power especially for the money they are asking!
-'94/05 M42 Convertible
-2001 330CI M Package
-2016 M4 Competition

benz-tech

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Re: $150 cat back Dynomax super turbo exhaust.
« Reply #9 on: May 13, 2015, 07:07:21 PM »
Nice job benz-tech. Screw all those expensive pre made exhaust set ups, it seems like the 318 has the worst selection of exhaust i have ever seen for a performance car. The set ups  i have seen are all extremely over priced and don't give much in terms of power especially for the money they are asking!
Thank you. Yeah I wasn't keen on $600 for a few HP at best. Surprisingly, though, the power delivery and sound quality ended being far better than what I expected. Anyone in Sacramento area is welcome to come for a ride along.
Pi is apparently the multiplier for your engine swap budget as well.