I'll like to know if there is any danger or drawback of welding the wastegate venting pipe into the DP? I can't stand the noise whenever the wastegate opens...... Thanks.

 

i dont know **** about rotaries! but on a turbo'd piston motor it is common to vent into the downpipe, most people have the most success when the vent it farther down on the downpipe and try to come in at a very smooth angle.. i'll try to find pics..

 

Indeed it is safe. This is what 99% of street set-ups do. It's rare to see street cars running open wastegates, especially rotaries since they are so loud. Then again... some guy are straight hardcore!

It's safe because there is no position change or much flex at all, since the downpipe is bolted solidly to the turbocharger.

 

alot of the HKS kits are made that way. It is safe, and quiet(in comparison). It also makes a waitegate legal in japan...

 

I had asked for pictures in an earlier thread, so you could search for that to see what others have done.

I'm in the same boat myself and am starting to lean a little away from going back into the downpipe. For one thing, there's very little room, so it's hard to get a good weld. Plus, some say you need a flex joint in there or it might crack. On top of all that, it will probably cost you some power if you vent back to the downpipe.

I'm kicking around the idea of trying to fit a small muffler on the wastegate now. Should be the best of both worlds if I can find the space.

So here it is half a year later and my wastegate's still open. Live with it a while and you just might get used to it.......

 

can you tell when the wastegate opens to vent the extra gases?

 

Welding it back to the DP will cause some backpressure to the gas in the DP. Don't do it unless you don't mind losing some a little ponies.

 

It will sound like runing the engine without an exhaust, I don't think you will be able to miss it...

 

If you come up with something.. please post it! I am curious to how it will sound, and how it fits.
-D

 

Be a man! Run it open like I do. I love the sound... it deafens people in other cars...

Brian

 

I don't care about the sound...but I am getting married and well, the lil lady isn't too big on the chainsaw/weedwacker/jetplane sound

 

APEX'i RX6 W/ TiAl wastegate 46mm

 

Looks good! Did you do your own welding?

 

Nice job 80-CU.IN.T! Do you have any boost control problem with it? Unfortunately I am using the Apexi wastegate with the same turbo kit. The problem with that is, it is already TOO close to the ground so there will be a sharp angle welding in to DP. I think that's why "TailHappy" is looking for other alternatives (let me know when you come with with something bro.)

Wargsam, you probably don't have the same kit so you can't feel my pain. This BB turbo reaches full boost around 4k, then the wastegate opens all the way up to the top. I hear the wastegate dumping even during normal driving!!!

If losing a little power is what it takes to get rid of this unpleasant sound, I would go for it. I will ask KDR if his shop can deal with the angle.

 

I am also debating about plumbing my wastegate dump tube into my downpipe. I like the sound at wide open throttle but sometimes when it's not at wide open throttle it kinda sounds like it's fluttering. The only thing I have read about this is to make sure and try to plumb it as far back into your downpipe as possible to reduce back pressure on your turbo. Here is a pic I found.

 

You do get a small amout of back pressure but it is very minimal as is the hp loss but it is there.

Here are some pics of what I am talking about on the HKS manifolds....

http://laujesse.tripod.com/sitebuild...tManiNGate.JPG

http://laujesse.tripod.com/sitebuild...DTurboKit2.jpg

 

To my knowledge GT 35/40 turbo kit was also designed with wastegate welded into DP. Some said I might get boost control problem if trying to do this mod.

I knew someone with T04E would felt the same way, small turbo get full boost too early (even though that's what the T88 guys trying to achieve.....)

 

COOP - I wish I could weld that well. I fabricated all the pieces and had my friend weld them. He is very good. Welds 5G - 3" SS pipe backwards using a mirror and passes X-ray. (The best welder I have ever seen)

Oy - I was using a Big Green wastegate spring ( 11 LBS. ). This gave me between 13 to 15 LBS. of boost leveling of at 14LBS at 6500 RPM with my plumbing setup. I will be changing to a small blue ( hopefully 10 - 11 LBS. ) so I can play with my mechanical boost control. ( High temp. air valve very cool - $22 )

jhammerrx7 - Plumb it as far back as possible. I would have put mine farther back but I ran out of material and I wanted to finish the fit up. ( I started the project at 12:00AM and finished at around 3:00AM. This included the fitment on the new wastegate.) Make sure to make a long Y connection where it connects to the downpipe so it will disturb the exhaust gasses as little as possible. ( Not 90 degrees if possible ) There have been posts of flexible connection available which I would have used to prevent cracking because of different expansion rates. I am 99% sure mine will not crack but the flexible fitting would have made fit up much easier.

laujesse2 - Yes there is back pressure. I was told by a reputable source that it can cause losses of up to 35 - 40 RWHP if done incorrectly. Personally I want to draw as little attention to myself as possible so being quite ( IS IMPORTANT ). I live in KALIFORNIA by choice and have been pulled over 6 times in around 1600 mile because I drive an import. ( 93 FD3S ) If I wasn't 41 and lookin like a Red Neck, I would have been ticketed. My car has been down for almost 2 months ( I'm broke and zero time to work on it.)

 

35-40hp is a pretty steep number, I know alot of people running the HKS kits with no boost control problems and the power loss isnt that high unless it is being done with a T51R or some messed up backwoods poorly concived kit... It also has a littlebit to do with the size of the midpipe and muffler.

 

If you're talking about routing the wastegate into the downpipe then there is a drawback. Koji and Eric at XS told me they've seen up to 20rwhp loss after routing the wastegate back into the downpipe because of increased backpressure. They said that you can get away with it somewhat, if you have a big flowing exhaust such as the apex'i GT but otherwise you'll lose power

 

After re-reading my post found a mistake - 1 typo - ( I was pulled over 6 times in 2600 miles.) I also talked with Koji at XS when I was there a couple months ago and he stated 27 RWHP loss caused by improper plumbing. I believe him because he is a hell of a lot more knowledgeable than I am when it comes to turbo charged engines. I also thought 35 - 40 was very high also. I won't throw out names because I don't like to bash people but the exhaust must have been a very FCKED if those numbers were correct. Supposedly it was dynoed before and after. I started to ask a lot of questions to many very sharp people because of what I was told about the plumbing for my intercooler and exhaust.

 

when i was down there in december, I asked XS to re-route my wastegate back into my dp. Koji told me I would lose power if they did it, so naturally I just changed my mind.

I don't know why people would want to re-route it anyways. The sound of an open wastegate sounds badass!

 

Badass - Until you get pulled over and your car confiscated. You can be finned up to $10,000 for altering the smog equipment also possibly 6 months to 1 year in jail.

 

Badass - Until you get pulled over and your car confiscated. You can be finned up to $10,000 for altering the smog equipment also possibly 6 months to 1 year in jail. ( Thats KALIFORNIA for ya ) Check the laws out for yourself if you don't believe me.

 

Even if you don't drive on the street. Circuit tracks have decible limits now. I doubt you would pass Laguna Seca @ 90 db. Track I'll be going in May has 85 db limit. (Waterford Hills) Though I've been assured it's behind a wall on the drivers side and I may have a chance. It will be very difficult to plumb my wastegate back into the downpipe.