Here is the short version since I don't really feel like typing an essay right now.
On my personal car I now have an aggressive street port upgraded injectors no boost cut on the stock ecu and a whole lot of other mods that were originally intended for a 500 RW build. But last week I had some free time on my hands and an old Re Amemiya S4 turbo manifold ( sweet piece of work too BTW) . Then I say to myself hmm, I wonder how much power I can squeeze out of a modified s4 turbo. And thus it began. So now i have a stock hotside with a 60 trim compressor modified internal wastegate and a cut out back plate ( the whole back is now effectively a bell-mouth down pipe. ). for the turbo to prevent boost creep. The goal 400 to the wheels at 20PSI . The risks are high but the rewards will be sweet. Worse case is the experiments fails and I just bolt up a GT42 . Anyone have any thoughts to share.

 

You have seen the BNR Stage 4 right? I don't know whether it was with an S4 or S5, as the website doesn't say, but they hit a maximum of ~403 RWHP. And that was with a factory style wastegate, it sounds like yours should flow more.

Good luck and keep us updated.

 

"60 trim" doesn't really give us a lot to go on as far as the compressor is concerned...

 

My comment is, if you take the time to get the car running right with this turbo and all the supporting hardware for the 500R build-

you will be disappointed if you ever do go on to a larger turbo!

 

it's a T04E .60 trim compressor and the stock hot-side. Originally I was going to upgrade to the ball bearing P-trim hot-side I've got sitting on my pool table, but figured this would be fun Stock liek boost with much more flow. Can't beat that with a stick. errr um apex seal..... Anyway, here go some pics. And before the naysayers start nay saying. Lets remember this whole idea came to me after a few beers and it's only been in development for a few days.

 

it'll be neat to see what it does. i think BLUETII has been up around that power level

 

there's nothing new about hybrid turbos even T04E, been around since these cars were new.

just keep in mind with the stock hotside you will compromise turbo spool speed for power moreso than in larger framed turbos as the aspect ration between hot and cold sides becomes more out of keel. porting will help to some extent.

 

yea I wasn't expecting to do something awe inspiring or record breaking. Just had some parts laying around and enough drinks to get the creative juices flowing. That's the downside to Formula One weekends. I start watching qualifying and then bam. some awesome idea strikes out of the blue, and suddenly I'm ordering parts ... Damn I need a wife to reign me in . Preferably one that works on rotaries.

But seriously this is more about retaining the internal wastegate sans boost creep than anything. so hopefully I can sort out this bellmouth down pipe idea. everything else is secondary.

 

maybe i can convince mine to wash parts.

yeah right.... lol

 

From my research it seems that the to4e is a bit large for the stock turbine. Not sure if that just hurts spool or whether it actually limits power potential though. Would be nice if you could slip a p-trim wheel in there.

Lol, I got my friend's fiance' to clean the undercarriage when I replaced the diff, even painted the gas tank heat shield ! But my girl.....not bloody likely

 

it's not just the aspect that hurts spool but longevity also. as you have a small wheel on one side and a large one on the other, minor imbalances will cause severe vibrations.

 

The back up plan ^_^!! dual ball bearing P-trim turbine.

 

have a boring tool to machine out the turbine housing? better yet, ditch the hybrid at that point and add all the functionality of a standalone turbo with v-bands and much better exhaust flow.

 

<-- wants to see pics of the manifold

 

That bellmouth is going to be a exhaust makers nightmare. Good idea for a s4 though has the backplate is not big enough to support a seperate pipe for a screamer or divided wastegate runner like what can be done to the s5 turbos and second pics of manifold

 

I wonder what would happen if you did pre-turbo water injection.

 

This is the manifold post modification. Before it was more diagonal. But with the To4E compressor it simply wouldn't fit. In hind sight drunk welding is not the best idea . Anyway there are no leaks so I can live with it. The flange is now almost completely vertical which strangely enough dropped the turbo enough that ts almost a straight shot into the trans tunnel. so its not going to be so much a down pipe and a straight pipe with a slight bend to the left ( something like 20 degrees).

 

you can. well ok YOU can't, but there is an O trim/stock hotside in the k2rd bins, and Ian's got a P trim in his.

it takes a special tool to machine the turbine housing, but turbo shops have them....

 

If the internal wastegate cannot handle the flow and you get creep the good news is if you do a pipe off of the manifold behind the motor mount for an external gate it will get good flow from both runners.

Stick with this!

I wanna see your turbo response. I will look for the posts by the member who did this same set up years ago (S4 compressor upgrade hybrid/tubular manifold/big exhaust) and had INSANE low end power and 350+ RWP from what I remember.

 

the goal is 400 + with good low end response to 6K or so.

 

with the bellmouth downpipe and some porting to the stock wastegate, boost creep will not be a problem

 

For the record the original idea for this came from a conversation with Jamin ( ^ that guy right there) at J-Tech turbo's . So if you need some parts or something awesome turbos built at a reasonable price shoot him a PM. He builds knows his stuff. Not to mention he's a great all around guy.

Boost creep! Bah, who cares about boost creep just add more fuel and tune for some ludicrous amount of boost.