Whatever became of the airflow at 6K RPM?

 

That is to do with my wastegate siamese setup . The siamese was acting as the wastegate restriction at 10psi which allowed the wastegate to be fully open . This meant there was low pressure post siamese which allowed the Bridgeport to flow more air through the chamber . I was hoping this would translate into more whp .... but it didn't.
I concluded from this that the extra air was just flowing straight through into the exhaust and not filling the combustion chamber with fresh air as i had hoped.

Once I wound on boost , this effect disappeared as the wastegate took over control .

 

Turbine backpressure on front scroll with 1.01 twin scroll housing . Tested at slightly lower boost but same whp and airflow rates.It seems the BP engine has a slight advantage but this could also be due to other minor tweaks i did .



.......old engine 16psi..vs..new BP engine 15psi

3000.................4....................4
4000.................10..................10
5000.................14..................13
6000.................18..................16
7000.................23..................21
8000.................26..................24

 

Still good data and appreciate the lengths you went to for this! What minor tweaks dost thou speak of?

 

Thanks Slash
Machined the compressor housing for better back clearance on the compressor , couldn't do anything with the parallel section clearance unfortunately.Should make the compressor more efficient plus looks like it's given me better spool by 200 odd rpm.
Also did a mod to the siamese sleeve which made it more restrictive but lessened the chance of any reversion of exhaust gases from one rotor to the other.
And ......modified the engine mount so i could get the intake hose through without squashing it .

 

You are a true soldier to the boost cause!

 

Just tested the rear scroll ..... Very happy with what I'm seeing here as it is indicating that the front scroll is venting some pressure through the balance tube to the wastegate at 8000rpm vs previous engine which was flowing air in the opposite direction .
This is significant IMO, because there now is very little chance of reversion from one rotor to the other at peak rpm as it indicates a lower pressure area between siamese sleeve and wastegate.

Turbine backpressure difference between scrolls with 1.01 twin scroll housing .
at 15psi...........front scroll......rear scroll

3000.................4...................4
4000.................10.................10
5000.................13.................12
6000.................16.................15
7000.................21.................20
8000.................24.................24.5

 

Possibly will be getting on the dyno on Saturday morning .
Not expecting more power (dyno is a conservative one as well) but am hopeful that the improvements made will allow the engine to run way more safely at the 400 plus power level.

Hitting 450-460g/s which is near the max. of the current maf setup
Near the max. turbo output (62lbs/min)
Injectors are close to max.
Turbo exit pipe is way maxxed

Everything is maxxxxxxxxxxxxxxxxxxxxxxxxxed.

 

450rwhp ftw! Good luck man!

 

Pac Performance were running 19psi on E85 on their Project 500 car. 4 port auto, stock internals + dowels, 2000cc injectors....just sayin'.

 

I don't recall, did they ever dyno that?

 

Prolly flooded and couldnt start it

 

And what happened ?

 

Not much detail that I could find. It survived the dyno, making 427whp. Your setup would make a lot more whp at that boost level of course, since you've spent so much time making it very efficient.

I saw that Pac Performance recently advertised drive in turbo installations on the rx8 Oz FB page. Low mount (per the above setup) and top mount options appeared to be available. Couldn't find any details on their website though.

 

it's Sat. in NZ right?

 

Well .................. made exactly the same power as last time on that dyno ..... just shy of 400 .

 

well well well
good numbers but I'm disappointed. My theory was just disproved.

 

You need a different dyno

 

I might just do that ...lol

I have to say the current setup hasn't been any sort of breakthrough though . Bridgeport has had zero positive effect .
If my theory that the benefits you get in an rew engine are from fuel going straight through the engine and igniting in the manifold , then the wastegate setup i have was never going to take advantage of that effect anyway.

 

All you need to do is allow a measured amount of air into the manifold pre-turbo. Just skip flowing it through the engine.

A tiny port from the UIM to the Exhaust manifold with a needle valve inline would work.

 

Wouldn't it need to have fuel in it to do anything ?

 

You wouldn't need to add any more fuel into it unless you're running lean or at stoich (which you might be, I don't know anything about E85). My thinking is that it will at the very least lead to a more complete combustion and put abit more energy into the turbo. It's the same concept one of the of the secondary air system functions, which is allowing more complete combustion on startup.

From what I got out of your idea on why the PP is more effective this would do the same thing without introducing and relying on overlap to supply the oxygen to the exhaust.

 

With the PP , my thinking is that the fuel and air passes straight through the engine , getting preheated on the way, and into the manifold . That gives you air+fuel in the manifold .
I think with your suggestion for the renesis there would have to be unburnt fuel from combustion . I don't think our engines are that inefficient ...........

 

But if it's running at all rich wouldn't it be impossible for all of the fuel to be burnt? Or does it just turn into soot?

 

I don't think you would get the same effect .... just not a high enough concentration of leftover fuel to make a decent fire .