So i have a o2 housing dump on my car. Wastegate dump that is, and stock exhaust from there back. My question is, How much of a benefit would I even see from getting a full exhaust as well? Would it be worth the extra money? Or should I just stick with the o2 dump alone, and keep the stock exhaust for silent driving under part-throttle?
If you care about performance, then a full exhaust will yield significant gains. Remember a forced induction system is pushing air. If you have a bottleneck (your exhaust) then you slow the amount of air being processed. The minute you free that up your system will be more efficient.
If you are more concerned with keeping the noise level of you car down, then I would remove the dump tube. That’s where a lot of your noise is coming from.
Well, I could care less about sound level while WOT, which the dump is painfully loud at WOT. My main question is, with the wastegate gasses being dumped and not being put back into the exhaust system, is there really a need for an aftermarket exhaust? Especially since I’m small turbo, and not a lot of CFMs either?
Yes, because not all of your exhaust is exiting through the dump tube. You need the exhaust.
As for the dump tube, it doesn’t matter whether you are WOT or partial throttle, it is LOUD. No matter how you play with the throttle. If noise is an issue, remove it or route your wastegate dump back into the exhaust, or add a muffler to the dump tube to deaden the noise. If noise is not an issue, then carry on with what you have.
i would say that it would still be a good idea to get a performance exhaust, even though your open dump you still probably have to much backpressure in the system
upgrade past what u need, and if you want to keep the cruising sound level down, there ARE mufflers out there that allow for high flow / low noise level
BigAir… remember last year when we did some pulls on the 990. I have the white Plymouth Laser. All i had done at the time was full 3" exhaust and MBC @ 15psi and I put like 8 cars on you. Exhuast does wonders for DSMs. Do it.
Do what I did, which was one of my favorite mods this year. Off my new turbosunleashed 3" swingvalve housing, I have a custom made 3" downpipe that I welded up. It has very few turns, and it’s about 30" long or so? I wrapped the downpipe in wrap and painted it with wrap paint to help keep the velocity up and keep it nice looking.
On the end of the downpipe, is “cut out” TEE/splitter. On one is my QTEC 3" electronic cut out. When open, my exhaust is effectivly all 3" wrapped pipe and less then 3 feet long. It exits right in front of my firewall into the exhaust tunnel. When closed, it goes thru the other side, and is converted to my stock 2 1/4" exhaust, and then into a 2" catback aftermarket crush bent POS pipe a previous owner put on and then into my walker super turbo muffler.
There is a CONSIDERABLE difference between dump open and closed, in both sound and power. My car can be very queit with a it closed, and then open in a few seconds at the flip of a switch.
I may consider running 3" all the way back but it will be a hell of a project and I’ll have to convert it to two 2 1/4" pipes in more then one spot just to fit it… I’ll keep the cut out. It rules.
How about pics? These are the ones of my new downpipe and cut out setup. Any questions feel free to ask etc.
I have been thinking of doing the E-Cutout for a while. my main concern is clearance underneath the car. I don’t know of any DSM guys running the cut-out and I’m not sure if there are any issues with fitment. I was thinking pre-cat cutout, and reduced back into stock exhaust.
If any DSM guys can chime in if anyone knows about the fitment of E-cutouts.
Looks nice Protonus. I’ve seen a manufactured cutout for the Scooby crowd, and that particular manufacturer (name escapes me) also makes one for the DSM. I just can’t remember the URL. :shrug:
dumping the wastegate to atmosphere doesnt really do much for you. You are just bleeding off exhaust better when under low boost. Under full throttle and boost, when you want the most power, the wastegate is mostly closed anyway. Your exhaust system is whats important at that point.
make a cut out with a spare throttle body, a piece of steel plate and a door lock solonoid … prob solved !
You have been talking about an exhaust since you have owned the car…I told you it needed one bad when you brought the car to be test drove.,…just do it already, it will yield significant gains at all points on the power band and will put less stress on your engine as it can then now breathe properly. 674-2772 we are only a phone call away 
Make your car breathe TODAY 
this is the wrong way to go, cut outs are only a bandaid, not a cure…you dont put neosporin on herpes
im heading over to bigairs house now with my sawzall
you guys at hybrid are gonna cut me in for 10% of all sales i create for ya … right ?
just get the exhaust already, you need it!!
Huh? Am I the only one taking issue with this? Perhaps you just don’t know how it works…
Venting your wastegate to atmosphere is venting it when you need it MOST. It’s venting it under full throttle and full boost, OPPOSITE of what you said. Your wastegate only opens when you hit the boost pressure set by your boost controller, not the other way around. it’s normally closed. That’s why when you dump your wastegate, it’s only loud once the wastegate opens, which is why it’s a cool mod. It’s also much louder then just a cut out on the exhaust, because the air goes around the turbo not thru it, and therefore has a higher velocity and none of the “muffling effects” of the turbine wheel to quiet it down.
I dont’ have a dumped wastegate btw, yet. My turbo uses a swingvalve still and I love my new 3" swingvalve housing… don’t really need an external for any reason yet.
Thank you, I was about to say that protonuts