External wastegate on O2 housing

[Clipse90Turbo]

I just wanted some helpful info from you guys. I've been running a mitsu style turbo (14b and s16g) since I've owned my car. I'm now upgrading and going with a 57 trim t3/t4 hybrid turbo. I'm trying to get my manifold and O2 set-up correct. I have a guy I might be buying a manifold flanged for a t3 and an O2 housing with dump tube. Now I've seen this before at Victory performance and DNP and so forth, but his wastegate flange is coming off the flange of the O2 housing. Is this better than having it on the manifold? I know it depends on the manifold, but I guess what I'm asking is if I get this will it work and be beneficial. I know some modifying will be done to the downpipe.

Someone I was talking to mentioned that the wastegate is suppost to be before the turbo and that's what was confusing him in if it would work or be worthwhile. I'm new to this kind of set-up and would like some helpful advice to educate me further!

Thanks for the space and info

 

[eclipsegsx1736]

Off the manifold is usually the preferred method, but I bought my turbo wtih a Tial 38mm off a Victory o2 housing that recirculates back before the downpipe, and it holds whatever boost I set it to redline, with no creep or spike.

 

[Boost Demon]

I run an external waste gate off of my O2 housing on my TDO6H-20g (see pictures below it's rerouted back into itself) and controlling boost has never been easier. Basically you need a place for the exhaust stream to go besides back at the turbine, so this is the way to go if you ever run into problems like I did with a big turbo and boost control issues on an internally gated turbo. Here are a few things I had to do to run this setup:
1. Remove the wastegate (It will no longer be needed, sell it on E-bay)
2. Remove the WG flapper and the moveable arm piece that extends out of the exhaust housing (connects the flapper to the rod section of the wastegate in the exhaust housing side of the turbo, I used a hammer and chisle to break things apart )
3.*edited*Use one of the old internal WG bolt holes as a boost source by installing an npt fitting (I did not initiallyknow this until I did a boost leak test and found that one of the holes goes deep into the turbo compressor housing)**edit 4 Aug 06*
4. Have the hole that the moveable wastegate flapper arm use to stick out of, welded shut
5. Hog out the hole where the WG flapper use to be and tidy up any porting that may be needed on the exhaust housing side (make more of a shelf for the exhaust stream to hit the old flapper door area).
6. Prepare to loose your drivers side fan or go with a slimmer one. Mock things up and assemble.

If you wanted to go with a manifold mounted ext. wastegate then you would do step one and three from above and then have the the wastegate flapper welded shut. I would highly suggest running this external setup For turbos like the Evo III 16g and up, this will make controlling boost so much more easier.
Here's an idea of what it cost for me to run my ext O2 setup:
1. 40mm HKS ext. wastegate (used)- $115 shipped
2. 122Performance custom made O2 sensor housing-$295shipped to me and $10 to initially have the WG sent to them.
3. Slim driver's side fan from Summit Racing-$60
Total (for me personnally): $480
Hope that helped sorry for the novel

 

[Clipse90Turbo]

I enjoyed the "novel." I really appreciate it when people take the time to help educate others. That made a lot of sense. I'm running a t3 though and mine doesn't have a flapper on it. A question I was wondering about is this. The hole on the turbine side is small and if I understood right your saying I would have to open it up so it could fglow with a 38mm wastegate? Also, I wouldn't be re-routing my wastegate like yours since I have the dump tube. Right?!! Is that bad with boost creep, or doesn't make a difference. I just want to make sure I understand all of this completely. I'll try to attach a pic of the set-up I'm trying to get. LEt me know if it looks good.

 

[Clipse90Turbo]

didn't realize how big the image was...let me know what u think

 

[awdrst]

That should work fine. Just make sure you port the wastegate hole alot. I've used the same setup on a tt stealth with t3/t4's. If i can find some pics of it i'll post them up.

 

[Clipse90Turbo]

Right on. I'd appreciate those pics if you find them. Thanks again for the reply!!

 

[Clipse90Turbo]

Also was wondering what size bar spring I should go for with the wastegate.

 

[Boost Demon]

Wow, bling bling going in the right place, I didn't realize the picture I had was that big either. You are correct, you have a dump tube that will be attatched to one side of the ext. WG while the other opening from the WG will be connected to that flange on your O2 sensor housing. Some people use tubular O2 housings w/ the dump tubes on internally gated turbos as a way of fighting off boost creep/spike, but I don't know personally how well that works other than the dump tube is loud . I don't know what way is better, O2/manifold mounted, but I'm just happy boost creep issues are a thing of the past. I run a MBC on my setup and only use the boost source from the side of the WG w/ the top open (I was a little skeptical at first, but it hasn't done me wrong yet ).

 

[awdrst]

Also was wondering what size bar spring I should go for with the wastegate.

It all depends on what the lowest boost you want to run. You can always toss on a boost controller to up the boost later on.

 

[Clipse90Turbo]

I would like to say thanks for all of your help from the people who replied. I completely understand and have learned something new! That's the one thing I love about cars is that you can always learn something different. I decided to buy that set-up and I'm purchasing a Tial 38mm Wastegate with a 1.1 bar spring. I already have a MBC so I'll be having fun with my new stroker engine hopefully in a couple weeks. I'll post pics of the new set-up and of the new paint too. Hopefully this will come out sick as hell. Take it easy!




That's just wrong!

 

[Boost Demon]

Upon further review....
Edited content in my first post w/ the picture to better describe what should be done when swapping to ext. WG off of the O2 housing .

 

[leet]

We have a pixel limit for a reason.

Since I'm drunk and almost 23, I won't warn you for it. Don't do it again.

 

[brute]

I'm drunk and almost 23

 

[Clipse90Turbo]

Huh? I'm 23 too and yeah.....So what where you talking about???

 

[DGajre777]

Post number 4 had a huge pic, he removed it.

 

[Clipse90Turbo]

Right on. I forgot about that pic! I'll make sure my pics aren't outside the limits again. Later