Exhaust Cutout

[ChefRacer]

Hey guys, I'm trying to plan out the mods for my car and I was wondering if anybody here has tried an exhaust cutout for their car. I figure that it could give me a total stock appearance and sound whenever the popo is around, but have plenty of power and be as loud as I want it to be the whenever else I want it to be. I saw an electronic one on jegs for $150 and thought that it would be nice to look stock, and save money on a cat back. What do you guys think?

[john]

No, as I would not like the noise.

[ChefRacer]

I actually just found somebody on the .com who just did this and he posted a video, it sounds awesome

[Dookie]

link?

[ChefRacer]

http://www.youtube.com/watch?v=JpDs7HSpbp4

[TSi+WRX]

One of the OGs on .com tested his cut-out, placed after the DP, on the dyno, as-compared to an aftermarket cat-back.

There was virtually no increase in performance to be had (i.e. that the dyno readings could have just as easily been chalked up to any variable), at the "Stage II" level.

It was speculated that you either had to be pushing even more flow, or that you'll really want to place the cut-out much more upstream of the exhaust flow, if you want it for anything other than sound.

[ChefRacer]

Well the guy on the .com forum dynoed his car with the cutout shut and then open , mind you his cutout is mounted at the bottom curve of his dp and he got 46 HP and 58 wtq more with it open

[ChefRacer]

Mind you he also had an upgraded turbo, and got an extra 2 psi of boost out of it with the exhaust open

[TSi+WRX]

^ Ah, perfect - then what I speculated above does hold. I think that's the difference, that this particular person's cut-out was both much more upstream as well as has a turbo which produced more exhaust flow.

Was this a comparison with a factory cat-back, or with an aftermarket? The long-ago OG .com made his comparison with an aftermarket system - given that the OG was still on the factory turbo, and the cut-out so far downstream (IIRC, his was placed somewhere in the "mid pipe" section), that could also explain the noted differences.

I forgot :redface: :embarrassed: that you're looking at an end-goal of 350-400 wHP (what's the numbers on the car that you cited that gained ~50 wHP/wTQ?)....in that case, a cut-out may well be worth the potential trouble (both with the law as well as in terms of maintaining the cutout itself). However, you'll want to consider that in order to maximize its potential, you'll either need to be able to map-switch on-the-fly or, alternatively, you'll have to restrict your right-foot-happy when the cut-out isn't open.

[ChefRacer]

This comparison was with a factory exhaust, and a tune which had been setup for his hks 2.5" catback. I realize that a setup like this would mean that I would be best off with the accesstuner, so I can have 2 diff maps setup and run optimally on either while being able to switch it up on the fly. Having a jekyl and Hyde car would be great for having a family tho, my wife is due any day now, and being able to have a family wagon that can kick add at the track is pretty Damn attractive to me.

[kagenmateer]

Sounds like poo IMHO.

[Jhony505]

Do I need to run different tune When I am installing exhaust cutout?

[ChefRacer]

I would say that the car should definitely be professionally tuned after the installation, I'm going to get an AP b4 I do it on my car so I can have a separate tune for having the cutout open and shut. I would assume that your boost levels and fuel trim would be all over the place without a proper tune for each separate setup. I'm still new to this scooby stuff, DSM Ecus were much more adaptive than these ones seem to be.

[TSi+WRX]

Originally Posted by Jhony505

Do I need to run different tune When I am installing exhaust cutout?

^ Like ChefRacer said, it wouldn't be a bad idea, particularly if you have other modifications already present. On an otherwise factory-stock vehicle, however, it's more than likely un-necessary.

Originally Posted by ChefRacer

This comparison was with a factory exhaust, and a tune which had been setup for his hks 2.5" catback. I realize that a setup like this would mean that I would be best off with the accesstuner, so I can have 2 diff maps setup and run optimally on either while being able to switch it up on the fly. Having a jekyl and Hyde car would be great for having a family tho, my wife is due any day now, and being able to have a family wagon that can kick add at the track is pretty Damn attractive to me.

^ Agreed.

Having a dual-nature car would be ideal for the weekend racer - the only downside being that the track/commuter vehicle is one and the same is potential race damage, but otherwise, it's truly the ideal.

I wonder if Open-Source now supports map-switching?

[ChefRacer]

The only problem with open source for map switching means that you have to have a laptop in the car all the time. Unless they have something for Android/Iphones now a days.

[TSi+WRX]

^ Ah, true, the interface is a concern. I had not thought much about that, since I'm an ECUTeK user, and rely on the laptop (Netbook) interface, anyway. .

[sean18337]

I have a catless 3" DP and a FMS Catback with a HTA86 Turbo, FMIC, 73mm KS TECH CAI, etc etc..
Car is not that loud but I would like it to be quieter....

I'm thinking of:

#1 - Stock catback with a Cut-out on the 3" DP
or
#2 - 3" FMS catback and and only putting the stock mufflers on the car...

With 350whp on a 5EAT one would think option #1 would yield the most HP or do you guys think at 350whp option #2 would not restrict flow as much as one would think?

[dutko2385]

I woud do the exhaust cutout because it will keep the stock appearance, yet have the "goods". Keeping the look of a stock car is best so people don't know what you have under the hood, etc..