auricom

Just looking for some input from other users on this one…



I’m currently working on getting an S5 NA running with megasquirt. We are almost ready to get it idling.



Once we do a little more preliminary work, the goal is the use this engine as a test mule for an anti-lag-system.

The group I am working in have built 2 (3 depending on how you look at it) turbocharger jet engines.

We are planning on using our “expertise” in this field to build up a boost normalizer anti-lag device for the S5.



We have a Garrett GT47 with a twin scroll turbine housing. One of the scrolls will receive exhaust gas from the rotary. The other scroll will be fed by a combustor. All the thermodynamics seem to work on paper, but we have some more work to do on fuel (propane) delivery automation.

The goal is to put x psi of boost right up against the throttle body no matter what rpm the engine may be at. In this respect, you will have x psi of boost as soon as you hit the throttle, which as you can imagine will be great for auto crossing, among other things (provided it works). The x will probably be 10 psi or so while I am using the NA motor



Before I get flamed:

Yes I know I should be using a turbo rotary engine due to the lower compression ratio, but the rotary engine I got was free.

Yes I know the Garrett GT47 is oversized, but it’s the only turbo I have with a twin scroll (it was free too). I might be able to get a smaller one though, which will probably be a Holset Hx55 (which isn’t much smaller)



I plan on learning all I can with the NA S5, and if (when) it blows up I will purchase a proper rotary engine for forced induction. It also is not going to be an issue if the engine takes the turbo with it when it blows, I can get another turbo (free).



Anyone have any questions or comments on this concept?

wwshadowfoxww

so are u trying to make a kit u can sell or is it just a little side project for u

auricom

side project for now, but if it works well and others become interested i may consider making sales.

One320B

Why not just put those jet engines in the S5?



Be more entertaining to watch at least...

spaceman Spiff

sooo, to me it sounds like your using propane to spool up your turbo? which would need an extra tank in the car. i understand its just for fun but is it really any different than running a small shot of N2O in the end??

auricom

One320B:



We can only pull about 10 lbs of static thrust with these turbos running them at about 31000 rpm. The turbos are designed to go to around 95000 rpm, at which rpm we would make about %600 more thrust. We currently are running into the bottleneck with the fuel delivery system. We are working on switching from propane to diesel fuel injection (actually we might be using the S5 oil injectors as turbojet diesel fuel injectors, since we are running premix in the rotary, we don’t need them for it anymore) even if we get %600 more thrust, that still isn’t going to be very significant to move a car around. I think the system would be much better put to use as a turbocharger/turbine engine hybrid. Although, your right, that would be fun to watch.





Spaceman:



I honestly do not know a whole lot about N2O systems. I know what the end effect is, but not much else. With respect to having a bottle of compressed gas in the car, then yes it is similar to having N2O, and yes, it would probably be easier for us to just spray the engine, but I want to try this system out to understand its future viability. After all, if it were easy, everyone would be doing it, right? Anti-lag systems in WRC are approaching this sort of scheme it seems anyway. They used to just retart the hell out of their timing so that the gas blows up as it gets to the turbine. Now they are having “mini-combustors” in the exhaust system that introduce fresh air to additional fuel. I’m not sure of the details, it seems to be “trade secret” type stuff, so I can’t find schematics. As I understand it, in this system, the exhaust pressure before the turbine get VERY high, which helps to slow the rotating mass of the engine as well. This is all well and good when you are up-shifting, but in the system I am designing there shouldn’t ever be excessive exhaust manifold pressure, since in a twin scroll there is very little cross talk between the scrolls.

teknics

as for putting x amounts of psi at the throttle plates at all time, if the plates are closed and you're having boost, its gonna create a lot of pressure and basically cause something similar to compressor surge....id imagine, never really sat back and thought about it.



kevin.

auricom

We sat back and thought of that a lot. The pressure in front of the TB (before the plenum) will be at the same pressure as the combustor. There will be localized high pressure air flow in the combustor, the pipe leading to the TB will be relatively stagnant. I’m not saying that we can predict 100% of how everything will act in this system, but surging of the compressor will likely not be encountered. I’m a little more concerned about how the 13b will feel about having its peek boost as soon as it comes off idle. This would likely be an impossible feat if we were using the stock ECU, but being able to write all of our tables in MegaSquirt ought to make it manageable.