Has anybody ever used one of these on their subaru? http://www.dmhperformance.com/ I want to keep my car with COBB stage 2 tuning, but the loudness of the exhaust is REALLY freakin' getting to me. It got to the point that I put the stock exhaust back on and went back to stage 1. It's a shame really. Here is what I want to do and I need some opinions. I'll have this puppy welded in at the end of my 3" downpipe. I'll have my stock catback from there. I will hook this up to the pressure switch on my auto intercooler spray system. Just driving around town, this will stay closed and there is probably not enough exhaust flow rate to develope significant back pressure anyway. When I floor it, this will automatically open when the boost hits whatever level I have the trigger switch set at and the tuning will be happy. I think I could have the best of both worlds. Anybody agree? As a side benefit, that would really add a level of sleeperness that wasn't there before.
What aftermarket Exhaust were you using. Did they have a Silencer that fits in the tip? If not, is it a 3" Diameter? You may be able to use a Silencer from a different Exhaust. I know Milo has a Silencer for his Exhaust that he never uses, maybe he can lend it to you to see if it fits. I don't know of anyone that has ever tried a cutout, but there is lots of talk on Nasioc about them. May want to post this question there, after using the Search button obviously, or prepare to get flamed.
I don't like NASIOC. I tried to search there a little while back and just got annoyed by reading some threads. I trust our local knowledge a lot more...espcially the local tuners. I have a 3" helix dp with cat and a 3" perrin twin tip catback. Perrin does make silencers, but they say it can cause a drop of up to 20 HP. That will cause too much back pressure to still run with stage 2 all the time. By the way, did I mention that I am really lazy and I would rather not fuss with silencers and switching maps.
Just did a quick search on Naisoc and the DMH Cutout seems to get a better response then the Quicktime Cutout. Also, supposedly Dave at DHM is very helpful. Definitely worth a shot, and then you can post up your review for us.
Ive got a cut out on my wrx. however mine is just before the muffler and i dont have the electric plate... though i do plan on getting one, i researched it on nasioc a while ago. i found this company http://www.mccordcg.com/mpp/mpp.htm Seems to be cheaper(around $117) than the qtp, but doesent come with the cut out. I bought my cut-out from Summit Racing down in Mcdonough. I paid 25 bucks for the pipe and 40 bucks to have it welded in(at Sharpsburg Muffler) Hopes this helps:wiggle:
I've been searching on NASIOC and every person I read about that has the cutout and cobb stage 2 does not seem to know what they are talking about. Pretty much every single one seems to think that the tuning is happy with a stock catback and the valve open or closed. Well, I'm pretty sure that isn't true and I sure won't be taking that chance. I may have to just take the plunge.
If you like the dual tip exhaust, but still want to go down to a 2.5" (same as stock) with a cutout. I have a Stromung 2.5" Dual Tip Catback that is throaty when you step on it, but a nice deep rumble when just chugging around town. Would you be interested in trading your Perrin exhaust for that? This way you don't have to worry about messing up your stock exhaust when doing the cutout, so you have that exhaust intact for when you want to sell. I've been interested in getting something a little more throaty as well as a 3", with the dual tip muffler to look as close to stock as possible. Good luck with the cut out idea, & let me know if you're interested. Thanks! Craig
Thanks, but no. If I decide to move forward with this, I plan on selling my perrin exhaust to fund the cutout project.
I've seen them run a few times. Pretty funny to be able to go from quiet to loud... There shouldn't be a problem tuning for either. I would say tune for the open and just make sure you open it any time you are playing hard... I do NOT think I would suggest making it boost-referenced, it would be opening and closing all the time, each shift, etc. Just mount the switch where it's easily accessable (sp?) SS
Yeah..I really don't think there would be a tuning problem with a stock catback and just tooling around town. I don't drive hard..gas prices suck...so I would have opportunity to open it when I want to GO. As I said before though, I am really lazy, so it would be nice to have a way for it to open automatically when I floor it. I should hook up my delta dash and see what kind of boost levels I hit by just driving around town.
Yeah..that is a very easy option, but I've read conflicting reviews about how quite those really are. I also saw a file on NASIOC that had a list of exhaust systems and the dB measured for the Borla hush was way higher than stock. Without first hand observation, I won't go down that road. Does anybody with an STI and a "quiet" 3" exhaust want to go for a drive?
You would have to get another type of controller for it then because the switch that comes with these is a "hold it one way until it finishes opening, and hold it the other way to close it" type switch. I was thinking the same thing when I got mine. The problem with using the existing switch is that it would have to send a signal to the cutout to close, and the signal would have to be halted after its closed, otherwise the cutout motor will continue to "close" it. Same thing with the throttle switch for opening it. The motor will continue to try to open it further if you are at full throttle for more than a second or so, also straining the opening motor. I have mine wired up with the switch right next to my parking brake and the downpipe in place, but haven't actually welded in the cutout portion yet - which is soon. I'll let everyone know how it goes when I get it done, but it might be awhile.
Would you not just be able to splice the control wiring up similar to the way the meth pumps and IC sprayers only turn on past a certain boost? It sounds like a really good idea to have great exhaust flow at WOT but quiet when you're not hitting full boost. I know Ford Racing had an exhaust they made for late model Mustangs that had little trap doors in the mufflers that turn them into straight pipes when the exhaust flow was sufficiently fast; this sounds like a good electronic alternative since nobody makes an exhaust like that for our cars.
So I drove around town for a while with my buddy watching the boost on my delta dash. With my normal driving style, I rarely hit 10 psi and usually topped out at 8 psi or less. I think it would be really easy to ditch the electrical motor and hook up a wastegate actuator instead. No need for a control circuit, gradually opens as boost builds, no delay as the motor spin to open the valve. Instant boost controlled exhaust dump valve. I've almost completely talked myself into doing this. I also read on NASIOC about a guy who put this valve IN the exhaust line rather than branch it off. Instead of a solid butterfly plate, he drilled a bunch of holes in it. He basically made an electronically controlled silencer that goes before the muffler instead of at the exhaust tip. He claimed a 10 dB drop. Any opinions on that?