Sent you another e-mail

 

Block of the holes where the WG is plumbed into the header now.

Then modify your Turbine housing and put the WG right of it ! Your manifold is beautiful, do not scrap it or modify the design you will not be able to fit any angle of pipes into the existing room you have they way you have designed the manifold.

I would just plumb the WG of the turbine housing, very easy to do and very effective, do it just above the flange and you get beatifull fom to the valve and it allows you to remote mount the valve too.

Think about it

 

12at- I'd love to make it flow out of the mains in more of a Y then hit the WG but I don't have the room with this manifold
Yes I'd like to see a pic of your setup. I don't have webspace either, I just upload them to the forum.

Directfreak- Yes a WG works off of pressure but in my case I think I don't have much exhaust manifold pressure to bleed off.
I don't see how routing the WG back in to teh DP will help my situation at all, if anything I would expect it to get worse because there would be back pressure on the outlet of the WG.
I don't understand why you think I will get more creep with a open WG vs one routed back into the DP.

Fatty- I have yet to see a heat issue under my hood due to radiant heat. I think it's because everything is so open in there. Even after driving the car home from work I can get out and lay my hand on the WG diaphragm housing. My fire wall does get a bit warm though, I can see how wraping my down pipe may help that.

Zero R- sent you a email.

Rice Racing- I don't think putting a single WG right on a divided turbine housing would be the best way to skin this cat would it?. Maybe if I made two tubes come off the turbine then have them join in the WG a few inches down the line?

 

You got it

cheap easy, simple mod and most effective while still retaining all that perfection you built into your manifold, infact much better than what you have now, because of what I mentioned to you ages back that having the WG intersect righ of the port is the WORST point to do such a thing cause it is interconnecting high pressure pulse to a low pressure side of the 180 deg phased rotor.

The further away you make this, idealy same point as the divided housing intersects the better.

You will see its your only solution, most elegant, TIG'ing the rear housing is fine and you can use 316 SS filler rod with great durability and finish. GO FOR IT !

 

I'll have to bolt the mani and turbo back on the car and have a look at this. I know I don't have the room to simply put the WG on the turbine housing. More then likely I would have to make a short runner(s) to place the WG away from the inner fender well.
I'll take a look at this option tomorrow after work.

 

ummm...
I really don't think moving the wastegate is gonna do diddley....
Setzep what size is your wastegate...?
As said, mine is a 40mm, I just can't see why yours doesn't work, and mine does, the only thing that is different is the turbo's and I think really thats where the answer lies.... The chance of me getting my runners into some mystical zone that works pure magic and you not, is pretty slime when the design is so similar....My boost is pretty much steady, the only thing that makes it fluctuate is my profec a, its kinda all over the place with the fuzzy logic control , but I can turn it off and get a rock steady 8 psi to 8500 rpm....max

 

Wow, Peter, haven't seen you post in a while. I'm a bit confused by your statememnt "WG intersect right off the port is the WORST point to do such a thing " Does this mean my WG placement for my second rotor is bad (see pics of previous page)... or is that more so for a collected WG system? (Don't mean to steal your thread Cam)

-Chris

 

^ Ahh, my wife was signed in again.

-Chris

 

Got it

 

If its a shared WG system, IE one WG of two exhaust port runners yes its BAD, the whole idea of longer tuned manifolds is to isolate the rotor thats cycle is sensitive to the high pressure discharge form the other rotor.

Having such an arangment as my fried setzep has is detrimental to the beautiful manifold design cause it allows the effects of "intereference to occur", this of course would not happen on a twin WG set up (one per runner), the only way to make it a non issue on a single WG system is to have the WG merge point similar to the merge point as its seen in the turbine housing, and it is also proven that the WG will work better near the restriction point offered by the turbine housing (best boost control).

For many cars plumbing the WG remotley of the turbine housing is an attractive option.

 

Peter idea is a good one. It's a great spot for a wastegate.

 

I find this thread very interesting since I am having some boost creep problems from my current setup. I also use a 46 mm Tial WG. My problem is very similar to setzep's problem. Once I hit 6000 rpms my boost creeps to 16 psi and I am using a .8 bar WG spring. I have seen flange units that bolt in between the manifold flange and the turbine housing where you can mount a WG directly to the flange. I have not seen this style flange in the "rx7 world" and I've always wondered why. I would hate to cut holes in my turbine housing and plumb the WG off of that if I didn't have to.

 

Max- 46mm tial. My turbine housing may be the problem but if I can adjust the manifold to accommodate I'd like to do that. I don't want to spend the money on another turbo when I like this one so much. I have more power than I can use at the moment.

carx7- no problem, we're all here for the same reason, to learn something about our cars.

Zero R- thanks again for the pic.

RiceRacing- Why you calling me fried, I look burnt to you??
I got to looking at my turbine and I'm not sure how I could tap from it. Being a mitsubishi turbine housing it looks strange and has different flow paths than the regular garrett housing. I'm not sure how I could cut into it and get equal flow from both sides.

Silver- Sounds like the same problem as mine. Could you post a picture of your manifold for us to look at/compare? Also what turbo do you have?

 

Setzep, I think it was bernoulli that found that in a dcut system, all pressures exert in all directions equally, when under pressure relative to the enviroment, I think thats moving your wastegate isn't really gonna accomplish much.. I think the truth is your turbine is jsut way to small...I don't know if tapping the turbine is the solution.. you seem to be having the same problem Blue TI was having, he tapped the housing in a massive way but at the end of the day the truth is sometimes you can only cram so much through a small a/r turbine and wheel... Its hack fix if you are a turbo afficianodo(sp?), but yours is truly a case for clipping the exhaust wheel....Max

 

I think it may be different in a manifold that doesn't have static gas in it. With dynamic flow pressures in the manifold will be different in different areas.
I'm still a little skeptical about the turbine being too small. I bought it from Brian at bnr supercars and the reason he was selling it off his FC was he thought it was too big for a street car. He did have it on a undivided HKS cast though... hmm

 

I'm using a 60-1 with a divided turbine (1.0 AR). Here is the manifold..

manfold1 manifold2

 

Maybe both you guys should try a different wastegate, I noticed both of you are using the 46 mm, I use the 40 , if anyone should have that problem, it would be me, if it was the manifold design, which because mine work, I would say the problem is not manifold related, I mean look at the **** flow pattern of the HKS manifold,s the gas has to turn completely backwards on those things, same with the Feed, and panspeed manifolds, yet they sell tons of those things...
Setzep, judging by the problems with the BNR stuff, I would rethink anything they told you...
Its fun to get all scientific hypothesizing about flow in a tube, but it all comes down to trubo sizing more or less in the end... Blue TII pretty much went as far as one can go with blowing a huge whole in a stock turbine housing trying to fix his creep problem, in the end the turbine is simply to small for the amount of energy and volume coming out of an uncorked 13b with no intake restrictions, richer fuel mixtures , and porting...Alot of people use that turbo in Japan, but they also have the afm, the stock airbox, and cat converter in places as well...Max

 

That is a seriously phallic manifold, silver7. Who designed it.. Peter North?

 

wow, can I buy one of of you?

 

Since people keep talking about having a double wastegate setup...


Who has a double setup that works? Id like to see pictures on how you managed to plumb the extra wastegate and have both merge into the downpipe. Must be a work of art!

Anyone have picutures of a twin wastegate setup?

 

I had the manifold built to resemble the HKS SS manifold. Here are a couple of pics of the HKS manifold.

HKS1

HKS2

I am considering building a similar design this winter and changing the design of the WG runners.

 

Silver- What is the ID of the main runners on your manifold?

Max- When you said 2" was that OD or ID? I think my smallish 1.68" ID runners aren't helping matters much either.
There have been problems with the BNR stuff? What kinds?
Alot of people use the AFM and cat or the stock turbo or the TD07? You lost me on that one.

 

My stuff is tubing so its OD.....
The Bnr clip job of the turbine really kills the spool of the turbo, search out Rpecks posts and have a read ...
Looking at the Td07 and stuff used by guys in Japan, they all tend to use smaller turbines then us, for spool puposes, becuase alot of them are using add on or piggyback computers, and thus still have AFM's and alot of the guys still have stock airboxes and emmissions equipmetn, thus, their engines are not moving the air say a ported 13b without an AFM/cat is, its just like the stock s4 turbo, start pulling away the intake restriction, and all of a sudden the wasteagate starts to become inadequate and the boost creeps, simply because of the turbine flow rate in conjuction with wastegate size versus the volume of air and fuel burnt. Now I think your turbo is useable, but you are gonna end up with 2 60mm wastegates in order to control turbine speed, no matter what manifold you run, or how you weld them on...
I think you could fix this, by clipping the turbo, I generally think Corky bell is a but of an overrated hack, but both him and Hugh Macinnis both agree that clipping the turbine helps to control turbine speed , and thus stop overboosting, but in truth is a patch for a poorly selected turbine ....
No one has offered up a reasonable explanation of why mine works and yours doesn't taking into an account the similarity of construction, there has been alot of black magic gobbledy gook about flow paths and subsonic reversion pulse with flux capacitors etc etc, the truth is the turbine flow rate of my turbo is probably about a 1/3 greater than yours, and thats why mine doesn't overboost... It can't be anything else, I even use a smaller wastegate and still don't have the problem... If I bridge my motor I would probably start to see some creep, I minor changes like throttle body porting, a street port, and some intake tract changes , all cumulated to about a 2000 rpm drop in spool speed from when I first started running this turbo.. A little bit of air makes a big change, mostly because of the when fuel is added to that little bit of air, then burnt the resulting exhaust gas volume increase exponentially...Max

 

alright, i just skimmed through this thread, and picked up some points that caught my eye.

Setzep, you mentioned your 13b was ported rigth? is it possible that you chose the wrong turbo for your application? and that at high rpm you are below the surge limit point of the turbo and the turbo is behaving outside of any efficient zone?

this is ofcourse just an idea, i could be entirely wrong.

 

Max- I'll take my turbine housing off and measure the wheel, I thought the TD07 wheel was larger than a P-trim garrett? If this turbine housing is hurting me I think it's because the "dual a/r" it has. You can see how the rear part of the snail is smaller than the front part. On all the T-78 turbos I've seen they are more closely matched.

Cheers- I never said my engine is ported. It's a stock port 13B-RE, right down to the stock exhaust sleeves.