I have ams down pipes and catted Cobb mid pipe and stock axle back. My car is not loud at all, doesn't smell much if any at all. I have 2017 so can always switch valve to make quieter. But never really need it.

 

If its possible, I'll try and keep the stock DPs in place. Hopefully someone has also done this with aftermarket turbos.

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Sure it can be done, however I do not think it would be long before you ingest the stock downpipe material. Hopefully your builder has told you it is not a good idea or atleast Ben has mentioned it.

Add a legit muffler in the midpipe and have a custom rear done with two more mufflers.

Below is a 1350+ awhp 3582 4.1 setup that was as quiet as a stock car out of boost, maybe quieter.

 

Sure it can be done, however I do not think it would not be long before you ingest the stock downpipe material. Hopefully your builder has told you it is not a good idea or atleast Ben has mentioned it.

Add a legit muffler in the midpipe and have a custom rear done with two more mufflers.

Below is a 1350+ awhp 3582 4.1 setup that was as quiet as a stock car out of boost, maybe quieter.

mate. Breaking down the DP internals was my biggest concern.

I'll have a chat with Ben.

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I have a Switzer P800 running with OEM catted downpipes on my 2017 gtr. Built and tuned by Switzer. It dynoed at 750 rwhp and capped a 600ft lbs of torque. I'm running a Switzer valved midpipe and oem titanium exhaust. Car runs clean. no smell or soot on the back bumper. I only run 93oct. Its sounds awesome when the midpipe valves open up on full boost.
My wife and toddler son are in the car with me many times. Running aftermarket downpipes was a no no for me I hate the drown, smell, soot and heat in the cabin associated with catless dowpipes.

Per Tym Switzer, the OEM catted dowpipes are engineered quite well and flow really well.

Ive been running this setup 2 years now with no issues so far.

 

That’s cool and pretty interesting. I’m actually surprised the stock down pipes hold up, Suppose it’s actually less heat than a stock FBO on 20/21 psi.

 

Yeah Switzer has this set up nicely sorted out. Im sure if I ran catless downpipes I get a little more hp 40 or so. but I was willing to sacrifice that for a clean smelling car and at most oem drown. Again I only want to run 93oct and I daily drive my GT-R.
Its the valved midpipe I bet that helps my GT-R run these numbers on OEM dps without issues.

 

Yes as a FBO I probably left 20hp +/- on a mustang dyno running catted DP. It was a long time ago.

You have the midpipe with BOV that basically acts as a dump tube when WOT correct ? Is that selectable by map or always on WOT ?

I like them quiet as well

 

This is exactly what I wanted to know.
I'll stick with the oem DPs.

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yes WOT . Sound very cool

 

Any vids?

 

Never seen this before

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Got some mil spec 100 cell cats for the midpipe. Hoping this will kill the smell and soot


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Got some mil spec 100 cell cats for the midpipe. Hoping this will kill the smell and soot

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I run a single 3.5" 100cpi cat after the merge on my midpipe and it only lost 10hp at 700hp@wheels vs dumping before the midpipe with a boost actuated valve.

You can run 200cpi cats on the midpipe since you will be running two of them with likely little effect on power, but will be more effective vs 100cpi cats. I made a custom midpipe for a friend using twin 200cpi cats and a single resonator.

BTW, you can get 100cpi stainless cats for $89 from Summit Racing, which is the same one I have been running for several years.
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