Divorced Wastegate Downpipe?
 

Hey guys, so I know this is going to be considered a "Ricer Mod", but has anyone done a divorced downpipe with the wastage tube dumped on k04? In other words an Internal Waste Gate dump tube on K04. I haven't seen any offered for sale and figured I would have to have it made. Any idea what would be the easiest way to do this?

So...you want to spend a lot of labor and money for zero performance gains?

I know its really stupid but yes. I saw another thread on it but it just fell apart. If i had it make it would just be the time of replacing the downpipe myself and buying a flange plus piping. But i was curious if any company offered one already or if anyone had pointers from them doing it.

Why would you want to do this?

Oh gawd. I would delete this thread before the wolves see it.

You are talking several hundred dollars and hours of labor that could..no fuck that SHOULD.....be invested else where.

Find a different way to get your post count up guy.

Corksport's dp uses a divorced wastegate but it feeds back into the dp. What's the point of an external dump for an iwg? noise? Get that ewg sound w/o an actual ewg?

I'm just confused what the is the end game

I mean its not like I'm going from a good downpipe to this which i wouldnt. Ive been looking into downpipes because its the only thing keeping me from being fully bolted. And figured if Im going to spend the money on a downpipes why not just make one with a dump on it. Sure theres no point besides possibly better flow but I would see performance gains out of a new down pipe anyways regardless of if its divorced or not right? i could careless if the "wolves" got to this thread and tried to tear me apart. Doesnt make a difference to me, just a person trying new things.

and I thought about using the CorkSport downpipes and just cutting the dump and welding a piece of metal to cover the hole. My best friend is a welder so no big deal labor wise.

What are your current mods?

tr8 fmic, fuel pump internals, htp 3.5" intake, hks bov, straight piped, 1 step colders, purple drank tuned

Go VIP and get a used cork sport. Just hack it up. If you are on the stock catback this could free up some topend.

dude, what you're saying makes no fucking sense.


you want to do it just for the hell of it?
you think a divorced wastegate is going to make the DP flow better?

make up your mind. which is it? there's no point or you think you'll get improved flow?


http://s2.quickmeme.com/img/fa/fa6c3...f2a42005c0.jpg

Its a popular Evox mod, ETS makes one. The thought process being, i think, that you basically free up some efficiency in the wastegate by letting it VTA, and removing that extra exhaust from the normal exhaust stream lets the turbo breathe a little easier. It works very well for them.

That being said, the EvoX turbo is damn near the size of a GT3071, twin scroll, and otherwise just moves a shitload more air than the factory K04.

Issue number two is space. The mazda does not have much for this type of modification, and it will be entirely more effort than it is worth.

Lastly, the way the turbine housing is shaped (small) it will be very difficult to completely isolate the wastegate from the turbine wheel.


Your best bet would be to just get an external wastegate CP-e manifold for the same money and just have a proper EWG and decent HP bump to go with it.

If you did this and increased the the length of the 'dump tube' portion it will be more difficult for the bypass gasses to exit that longer pipe. Could lead to potential boost control/boost creep issues since you're still limited to tiny IWG. This is not usually a problem with EWG because the diameter is much larger. It may work out fine like it does on the Evo X, but it's another potential downside.

Yes I know the evo guys do it which is why I thought of it. Ill look into finding a stock corksport or a good deal on a manifold. I know its wouldn't benefit nearly as much as it does on evo x because of the much bigger turbo reason. Thank you to those that didn't give me shit and just asked legit questions. And yes I am going VIP on here. Just havn't had to time to donate money.

Best bet is to get a manifold with a ewg. If you modify a Corksport down pipe you will have a constant exhaust leak out the dump tube since the WG flapper is not isolated from the rest of the exhaust housing.

THE TURBINE HOUSING ISN'T DIVIDED THEREFORE A DIVORCED DOWNPIPE WON'T DO ANYTHING.

Don't listen to these naysayers. While there is likely no benefit to you doing this there are also few benefits. The corksport dp has a tab that attempts to separate the two pipes it does not seal perfectly Therefore you will have some noise from the dump all the time. This was determined by another user who did this exact mod. I think that if your exhaust is restrictive at all that this could help you on the top end. Just make sure that you don't put any restrictive bends on the dump pipe.

The rest of you need to check yourselves if I'm the only helpful one in a thread.

The flange on the downpipe is divided.

If you give a man a fish, you'll feed him for a day. But if you teach a man to fish, you'll feed him for life. ..

Or, another analogy is from working in a kitchen. If you're under a good chef, he won't usually give you an answer to a question. He'll just ask, "well, what do you think? " and once you've worked through the questions yourself, you'll have the answers you need. And you'll learn that you had most of the answers the whole time.

If he is on a k04 his restriction is not his exhaust, but his turbo.

As far as that tab on the flange, it'll do an ok job but again there are no benefits/gains to be had.

If his wastgate duty cycle is at 100% then there is no gain. I did state that he would have a leak. However if he just wants to do something different and make some noise it won't actually cause any harm.

WGDC directly reflects compressor efficiency? I think not.

The bottom line is that this is a k04. This k04 is not hung up by the IWG. It is compressor limited.

If anything modifying the Corksport manifold would cause you to loose power because there will be a pressure difference between the to atmosphere dump and the exhaust. Your going to create a lot of turbulence in the exhaust housing, which will more than likely slow down your exhaust gas and make the turbo work harder to move the air. This is all an assumption but so is this entire thread so wtf.

That's a good point as well that I forgot about. If that tab isn't sealed perfectly you're effectively going to have an exhaust leak all the time-- especially noticeable at idle. I agree with you on all points.

I did this on the Miata w/ GT2560 IWG. I ended up having boost creep issues due to a long dump tube. I even had my turbine housing ported to promote exhaust flow through the wastegate... did not help all that much. In the end it was not worth the hassle or effort for me, and I honestly would expect about the same for the OP in this application on stock turbo K04, but go for it if the OP feels like giving it a shot, I won't knock him for trying.

Sorry if I came off as a dick (kinda). Ultimately I was just trying to save you time/money/effort. If I had a buddy that was a welder I would probably experiment with random weird shit too.

Good luck if you do attempt this, and make sure to post a video afterwards.

The main reason why us evo guys did it was because of fp turbos. I was running an fp red (basically a 35r wheel inside the stock evo9 turbo) and running vta drastically improved boost spike/creep. I thought about what youre wanting do as well, but we dont have "o2" housings like dsm's do so it would be very difficuly. My vote is for a cpe manifold w/ a tial 44mm wg. Use it with the cobb iwg bracket, then when youre ready to go BT, youve got a bad ass manifold for an atp.

:bong:

I can't believe it took this long for that to get caught.

*downsides.

Hey bro, I was thinking about what you were wanting to do, and I think Imay have a solution. I assume you want the ewg for the sound. If thats the case, buy a boost actuated exhaust cutout. Its like an electronic cutout, but it uses a wastegate actuator to open the cutout during hight boost levels. It sounds just like an ewg, just have a muffler shop fit it in where the second cat would be and whalaaahh!

Edit: I guess @aaronc7 isnt the only "helpful" one afterall!

Besides, my idea is way more awsome. And you wont have to listen to a leaky wg at all times.

Didn't even know these existed!! Any idea where I can find one? Or if they make a direct bolt in for speed3.

3" Boost Activated Exhaust Cutout DSM Honda Mustang Camaro Ecoboost | eBay


Theyre all over ebay. They came out long before electronic cutouts. They were designed to the when you went to the drag strip you could get maximum spool time without having to remove your cat back. Theyre cheap too. The best place to put them would be where your second cat would be. If you have a test pipe already, just have them cut the pipe and weld it in there. If not, have them fabricate a "test pipe" or buy a cheap ebay down pipe like an m2 and splice it in there. Theres lot of clearance in that area. It will literally sound sound almost, if not totally, identical to an external wastegate. I will warn you, installing a downpipe without a lift is pain (totally worth it tho), so either buying a cheap ebay test pipe and cutting it or having an exhaust shop make it will be much easier.

I don't think it'll sound exactly like a EWG. The EWG has a flutter once it's regulating boost.

It would sound closer to an EWG on spring pressure which just sounds like a bad exhaust leak.