To Dump or not to Dump, that is the question.
 

A little background.
I am thinking of getting a smaller T3 to put on the car. Right now I have a T3/4 that, I want to say is a 50 trim with a 60 Compressor and a .48 turbine. I need to measure the wheels to be sure, but they are huge compared to the T3 I that I am looking at now. Anyway the turbo itself is big, and since this was my 1st set up I learned my lesson regarding spool. The new T3 is the same 5 bolt pattern, and I was thinking of going with a Vband flange instead of the flange welded to the dp. Here is the question. If I redo the dp for vband, should I make the external wastegate open dump, or should I route the gases back into the dp? Any benefits to the open dump? Thoughts?

I've heard very mixed things on the open dump pipe. things like "It sounds wicked fucking sweet, dude" and "It sounds like total ass, like a really fat guy farting into a megaphone"

I would imagine it helps performance but I don't know how much.

Route the EWG back to to the exhaust system. Several reasons to do so.

1) Open dump tube is loud as fuck. If it's a street car, noway.
2) Open dump is a bit more dangerous. Best is to route it to underneath the car, which takes more work.
3) Open dump can cause some exhaust gases to be picked up by the intake, causing less oxygen in the mixture. While there are dyno proven results that show an open dump helping HP, there's also some where hooking the dump back to the exhaust or routing it further from the intake made more HP.
4) Still loud as fuck

Now, if you hook it back to the exhaust, it's quieter, and a bit safer, possibly more powerful, possibly less powerful, depending on how comparable dump tube was installed. Granted it will disrupt the flow in the exhaust some. How much, depends. But IMO it's not the end of the world. Best thing to do here is to have it separated as long as possible, and have it dump in at a angle close to parallel with the exhaust.

If it was a race car, I'd have a long dump tube that dumped under the car. If it was anything else, it would have a long tube that tied back into the exhaust smoothly. Mine ties back in after like 5", and it's practically 90* perpendicular to the exhaust. Not ideal at all. Works fine though, car hauls ass, so...

During regular driving running an open dump tube is no louder than any other setup.

As for the 1-4 that Pat listed, I disagree on all of them. But if you're like him and want your car to be as quiet as a Camry, then an open dump isn't for you either.

Look for videos, then decide. On my non-miata DD, I'm currently rerouting the external dump back into the downpipe. The turbo just sounds too good to me, and I really dislike the attention it demands.

Benefits to external dump are more power (how much depends) and better boost control, which is very possibly not a concern. Another benefit is simpler routing/design.

A couple things to note: Normal driving is the same, of course. As you approach full boost, the gate begins to open and the noise increases. It's loud. Will it be too loud? That depends on you and you only. And possibly your girlfriend. It will be louder than your exhaust and turbo. One time I opened it up to merge, the gate opened, and a nearby jogger nearly fained. Not a joke. If I was younger, or more of a dick, it would be funnier. For me, it's too much.

You can help quiet the dump tube by extending it. (Test this by pulling off the tube completely and listen at full boost.)

How loud the dump tube will be also depends on how much boost you are running on what turbo. Less boost = loud-ass external dump. More boost = quieter external dump. This is because more exhaust is routed through the turbo hotside to maintain more boost, thus less is expelled out the wastegate. Less exhaust, less noise.

Going to re-route it back into the downpipe? Try to do so a couple feet downstream in the exhaust. I've heard 18" tossed around. Will you lose power? Depends on the info above mainly, but you're really not loosing that much anyway you look at it, even with the exhaust reintroduced at a "bad angle." Are you running a cat? Reintroducing the exhaust into a turboback with a cat forces all the exhaust to travel through it, instead of a partial amount. This is also true with the turboback. Running 3" exhaust? Dumping will provide you slightly less benefit than if you are running a restrictive stock exhaust.

I've found that the external dump is really only great for one thing (not counting ricers), and that's Harleys. Harleys are loud to be loud, I don't like that. When they open it up full throttle in my window, I like to return the favor.

I agree with Jay, pat has some weird thing about his car being quiet as fuck..

Dump it

1) Its only loud when you are at full throttle.

2) If you dump it under the car it wont "mix" with the intake like pat said...

3) It will help power, and help boost control

4) It takes way less work

5) It sounds awesome!

I went open dump last year..I will never go back, the sound is off the hook..also picked up 25whp at 22psi

I have had one open, by the way its just awesome. I loved it.

But it does put much more heat and exhaust in the engine bay, if it is opened up and not rerouted.

lol not routing the gas under the car would be semi retarted.

And I've seen it done so many times.... Mainly the FWD honda crew. Love to bolt an EWG to a manifold and let it blow down on the radiator/block/right next to the air filter. Hence why I said what I said earlier.

And not my fault you guys haven't developed an appreciation for a quiet car yet. :fawk::fawk::fawk:



:giggle:

Get the best of both configurations; put a small muffler on the wg dump. Glass packs come in all sizes and shapes.

Psh there is a reason to have a separate DD. When I romp on my miata I want it to growl :skid::skid::skid:. Plus I never got how you dont like the intake sound lol!

I thought about it...but it sounded like ass imo.

Where did all of these noobs come from and why don't they have any location info under their names or car info in their signatures?

I like the open wg sound on other people's cars, but mine needs to be quiet.

Edit: FWIW, I guess you could tell pretty quick if your wg was leaking or creeping open early if it was open.

it would be like having a moped under the hood

I know what your saying pat about some people dumping all that shiz under the hood. I've got a friend who dumps it between the rad. and motor

Screamer pipes sound awesome when you come on boost, but at the same time it is probably way too loud for a road car, and yes I know its only when you come on full boost. I guess it all depends on what the local law enforcement are like, if I were to go out with a open screamer and give it some I would more than likely have a cop pulling me over within seconds. Around here all he would have to do is take one look and ask me if I brought a bottle of KY with me cos he is going to bend me over the boot and fuck my arsehole and that doesn't appeal to me much at all.

It will also tell you if you've developed any significant boost leaks.


Sounds about right. Are you running 3" exhaust/cat?

I have about 18" of pipe running from my external wastegate that dumps out under the car, no merge with the 3" exhaust.
It's startling when it cracks open the first time, now I'm ALMOST use to it.
I wouldn't say that it sounds "good" but it kinda gets lost in the induction and exhaust noise, which sound awesome (3" all the way from turbo flange to tail pipe). I purchased enough pipe to run the WG line all the way to the rear but by the time I was finished with the exhaust I didn't feel like welding anymore, for a little while anyway.

However, I seem to have settled on 18psi for my boost target, so I only hear from the wastegate when I'm indulging in the blatant disregard for all traffic laws (the heat will be more interested in my rate of travel than my noise level). Under "normal" driving conditions the WG is never heard from and very seldom during aggressive driving (that doesn't result in extra-limit excursions in a hurry).
I will say that IF I was to set my boost target such that the WG duty was increased anywhere near my normal driving range, I would muffle it in some way, either merge it with the exhaust or run it all the way out the back.

Good input guys. I looked at YT videos with DSM's with open dumps and so on. I need to hear it in person.

One more thing. I like quiet when cruising and driving around town under light loads. I don't need to be in boost all the time, but when I am in full boost, having the wrath come out isn't a bad thing. That is why I like my HKS SSQ BOV. Under full throttle and lift that thing screams "don't eff with me bitches". I love it.

Thanks for all the input. I am snagging that new turbo this weekend. I guess the outcome will depend on how motivated I get.

I like this too, but I'm having the dilemma of mine being a little too loud around town, but just right in full-fun-mode.