Heisenberg

iTrader: (3)

So how are you going to regulate the flapper position?? boost conroller?

Xcentric

sorry, wrong thread

GregW

400hp Pro-rally cars use TS, if its good for them its good for me. It makes a big turbo act like a small turbo below 5k. Personally I think thats a good thing.

Whats with all the hate?

turbine

iTrader: (1)

i don't think you need to get to the melting point to damage the integrity of the metal. there will be a lot of pressure on that flap and there is a very large surface area to absorb heat with little means to dissipate the heat. and mind you it will always be in the exhaust stream where as the s4 twin scroll flapper sits out of the way when not in use
very nice fabing. it will be interesting to see the results.

dubulup

probably a solenoid...since he's using a stock actuator...the haltech will tell the solenoid when to open the flapper.

patiently awaiting results...

pistonsuk

Boost.

Yes. I might just tee off the line runing to my wg (I have an AVCR). Or I may build a manual one with a ball and spring to tune it separately. The first setup would be nice because I could change the twin scroll actuation with different desired boost pressures on the fly. However the wg opeing interval is unknown and might not be enough to completely open the twin scroll flap.

This will take some experimentation to get right. This is why: My guess is solenioding it to make it "pop" open just before desired boost is bad b/c it will make my boost pressure oscillate due to the turbine energy dropping off so fast. Due to this I have "guessed" a psi interval over which to open it. This value was choosen to be 5psi. That means if my desired boost level is 15psi, the actuator will open from 10-15psi. In actuallity I want the minimal interval length to maximize boost response but not one so short that it makes boost oscillate.

I will not disagree with this. The validity of this statment purely lies in the quantitative values of the word "integrity". What I mean is yes this is true, but does it still have enough integrity? I don't know, thats why I am trying it.



This is very true. I tested the flap at 1200F above the manifold temp and clearanced it for this "worst case" senario.

For reasons mentioned above I will probably not do this. Now that I think of it I could maximize the open speed and point of opening with a haltech controlled solenoid and manual boost controller. Hmmm..... have to figure this one out once I have the car.

I like the input, let's hear more.

Justin

Dom_C

Very nice work. Glad to see people fabricating stuff for them selves.

pistonsuk

I ceramic coated the flap with this CBX coating:

http://techlinecoatings.com/BulkEngine.htm

I hope it will help reduce the temperature variation between the flap and the manifold. The closer these are in temperature the less chance there will be of the flap expanding to the point that it binds.

GUITARJUNKIE28

pics are too big to fit on the screen.
can you resize them to 600-800 pixels? i think everyone will thank you.

pistonsuk

Well I just ordered a Non-BB GT4088 with a 1.34 A/R hotside. Hopefully in the next month or so I will have some boost vs. rpm graphs with and w/o the twin scroll actuated.

Justin

ScuttleRX

Very interesting reading so far in this thread, look forward to seeing what results you get and hope all goes well

Have an idea to contribute that may help to a certain degree with the heat issue, and may also have other benefits.

Have been looking at a lot of WI threads recently, some concerning injector placement, and as well as the usual pre-turbo, pre-IC, post IC, TB, etc, injecting into the exhaust manifold was mentioned. Thought it maybe might help with your design? Water spray would cool the EGTs and due to the expasion would probably increase the flow rate aswell, possibly helping what you'll already be achieving with the twin scroll design. All should aid the VE.

Thinking about experimenting with something similar myself, already planning on pre and post turbo injection points, but thinking about this aswell to effectively change the A/R. The theorys there (I think!) just haven't seen it done yet anyway, although im sure its been toyed with.

pistonsuk

Thanks for the comment. I currently have a DIY staged WI system plumbed in after my IC.

I have never heard of injecting into the exhaust manifold!? I cannot see any gain to this. Before the turbo? This seems completely wrong to me. Your turbo
is an energy extracter. Vaporizing water takes alot of energy. This energy would otherwise be extractrd by the turbo and made into useful work via the engine. I dont mean to attack, just curious as to what the idea is behind WI into the exhaust?

Justin

ScuttleRX

Yeah before the turbo (on the hot side), I never seen it done either, but I heard it discussed in theory a few times by some knowledgable enthusiasts (more knowledgeable than me!) and thought I would mention it

I thought for your application the main benefit would be the cooling action (just recalling what you said about possibly heat issues affecting the flap) as it would limit temps, like you say vapourising of the water will use a lot of heat energy.

I dont think it would take energy from the turbo though, if anything the expansion from water into gas would increase flow a touch? I think this was the benefit there were discussing more rather than cooling.

I shall have a hunt for the threads I got this info from, as you can tell im not fully conversed in what im preaching (!), its something I was planning to look at at a later date and your thread madde it pop back into my head.

If theres some theory backing it up it might be something I toy with, im off the road for the winter so have plenty of time to play, if it proves fruitless, i'll just plug the injector hole and be done with it

Can see your points in your reply, like I say i'll go hunt them threads and get back to you

ScuttleRX

http://ausrotary.dntinternet.com/for...ection+exhaust

Here ya go, not much on this one I think, think I recall a more detailed one somewhere, a.r info bottom end of first post

Dont think you have to register but its a good forum anyways if ya do

SPOautos

I didnt have time to read past the first page of that thread but it seems like you might be confused. When they say they are running WI preturbo, they are refering to the intake side not the turbine side....basically putting a nozzle between the filter and the turbo inlet. Then they mention how it lowers egt's because the heavy humidity thats now in the intake air makes for a cooler combustion because the water absorbs a lot of heat thru vaporization when its combusted....hence lower EGTs. Unless the thread wildly changes in teh next pages (which granted I didnt read) I know that on page one they arent refering to placing the nozzle pre turbo on the exhaust side to cool egt's. If thats what you were thinking, they just had you confused.

Stephen

ScuttleRX

Hi Stephen,

Its only a very small bit on the first page that refers to what I was talking about, its towards the bottom of the very first post. It crops up again later in the thread but theres no new information. Think it may have been on a WI forum I saw a more detailed thread about it.

Like you say majority of the rest of the thread relates to pre-turbo injection (what im really interested in )

Andy

ScuttleRX

Ooops, just noticed bit im talking about is in second post, i'll cut and paste to save confusion, is only a snippet anyways but explains what im talking about...

BLUE TII

iTrader: (9)

Injecting water into exhaust system before the turbine has been done on rotaries to improve spool.

I remember reading one forum members accounts of doing this a long time ago, but don't remember if it was here or Nopistons.

Summary- it works great, but easy to crack manifold w/ thermal shock, complex and water will run out as well. In my opinion you might as well use a real anti-lag system as the race cars use (even if they use intake manifold water injection) w/ air bypass and exhaust manifold fuel injection. You already have a tank of gas and air all around you. Of course this is hard on exhaust system parts as well.

ScuttleRX

Thanks for the info Blue TII, if you do stumble across them threads again would be good if you could post them up, something id like to read about even if I do decide against doing it.

Dont really think it would suit my application atm anyway as im sequential twins so spool up isnt much of an issue, good on a big single though I reckon.

So is a real anti lag a similar thing then just igniting air/fuel in the manifold rather than using water expansion?

ScuttleRX

Sorry im seem to be distracting from the original thread, shall I start a new thread or is it ok here for now?

pistonsuk

This topic seems to have alot of interest. Why dont you start a new thread, maybe with a fresh title some WI gurus will have some input.

Justin

ScuttleRX

How is this coming along matey, had chance to test it yet?

pistonsuk

You dont want to know. I got the car going last Thursday night and I blew an apex seal Sunday evening (this took out a rotor, new rotor housing, and a brand new GT40 turbine wheel). Yeah, 504miles with 300 of them "break in" miles.

Upon disassembly it looks like the flap broke away from the rod that was supposed to turn it. The engine blew under bad detonation (which hadnt been a problem until this point), I think it was caused by the flap sticking and causing increased back pressure and a boost spike (20psi from the peak hold setting).

The car ran really good before this. It got 15psi by 4200rpm on a GT4088 with 1.34A/R.

Well back to the drawing board. No more twin scroll for me.

Anyone want to buy a modified SSAC manifold?

Justin

ScuttleRX

Argh, sorry to hear that Justin. Looked really promising, are you going to be perservering or calling it quits on the twin scroll idea

tdazmansFD

iTrader: (1)

Ah man that sucks! Sorry to hear about that. It's unfortunate for you especially after puting in the hard work.
If anything, blame it on the SSAC Manifold!!

If you do decied to give it another go, maybe you should try it with the HKS cast Manny?