Jim Green's 90q 20vt - 636whp 07k

[nismo]

Jimmy, have you thought about using a TB with a throttle plate that is a few mm too small? This would make the worst case scenario that it wouldn't touch, and failure would still leave some flow. I had thought about doing something similar and using a vacuum actuator with a bleeder (or something similar) to adjust the response. My thought was to use vacuum to hold it closed (with a stop), and a spring to pull it WOT with loss of vacuum.

I'm not sure whether I have to have emissions testing here, but having something like that hidden in an empty kitty would be nice!

Eric

[audifreakjim]

Yeah, that was my original design because I was afraid the single 2.5" pipe would hurt my spool, but it doesn't and the car is happy until about 20 psi of boost or 5500 Rpms, then it need more flow. So having this open at 7-8 psi will be ok, and I can add a pressure regulator to the lower chamber to ease the opening pressure.

[audifreakjim]

I am only one nut and a zip tie away from an open exhaust.

Aren't we all, aren't we all...

Ha! So true! More thoughts on using a TB.. Leaky exhausts drive me bat-shit-crazy so this valve has to seal well. Part of what makes these work is a step in the housing that the butterfly can rest on when closed. This valve seals up pretty well, and since it's some distance from the motor, you don't get any ticking from it.

[pkw]

Hey jim, did you do anything special to derive that 7-8psi crossover point? That is what my actuator on mine is set to but I was thinking for spool and flow it should be a bit lower. I would like to hear that all is 100 percent great at that level because that is a nice level for quietly and effectively scooting around town.

[audifreakjim]

7-8 psi is what the WG is rated for, I figured it was good enough to start. Also remember I have the quick spool valve on my car that is closed until 15 psi or so. I think this is why I am not seeing a reduction in spool. In the past I have definitely noticed when I was trying different mufflers, if they choked down to 2.5" anywhere, I could immediately tell. The QSV changes everything, a single 2.5" exhaust seems to be ideal when half of the exhaust housing is closed off. I would almost venture to say spool time has dropped slightly with the new exhaust!

SOME day I will get on an dyno and vet all of this out, but I keep changing things and have a list of stuff to get done before the car hits the dyno. Port water injection and possibly pre-compressor water injection are on the list

[audifreakjim]

Here is a horrible pic (hides my horrible welds ) of the exhaust before I went back under the car.

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[Wheeljack]

...possibly pre-compressor water injection...

Oh buddy! Wet compression FTW. Can't wait to see your results...

[audifreakjim]

Yeah, Chris! I am thinking the smallest nozzle possible is a safe bet and with good placement I should avoid large drops forming. 600whp on pump gas? Maybe!

[Hank]

Have you decided how you are mounting the injectors yet pre turbo?

[Marc]

Have you decided how you are mounting the injectors yet pre turbo?

I really want to see someone try this. sounds "interesting", but still scares the shit out of me.

[PRY4SNO]

Jim,

My brother is experimenting with pre-turbo w/m injection right now on his mk4 GLI. He's having some success too, hitting 30psi in 4th gear on a stock K03S with Uni stage 2 and some TT225 hardware but otherwise all stock. EGT temps mid800s! Since he's been testing Doug of Frankenturbo has partnered with him for data sharing and is himself working turbine w/m injection into his FrankenFamily.

If you'd like some more info, PM me and I can send you his contact info and he can bring you up to speed on the details! Otherwise, disregard, haha

http://forums.vwvortex.com/showthread.p ... h...-hmm...

[audifreakjim]

LMAO, hello my project. There are a bunch of different options for mounting the nozzle, I think i will make a bracket that looks similar to this.
http://www.howertonengineering.net/prod ... older.html


I hate having stuff like this in front of a pricey turbo like this, but since I know a guy who can rebuild these, and put's these hair brained ideas in my head I am willing to try it. I need a better logging solution, and I also want to get a camera of sorts on the nozzle to make sure water droplets are not forming anywhere. I think the anti-surge housing is going to cause some issues with water dumping back into the intake. Thinking one of these guys mounted in a sacrificial intake boot.
http://www.newegg.com/Product/Product.a ... 0006-00032

[All_Euro]

Nice link to the camera Jim!

I was speaking with USRT about pre-turbo injection, a while back, and they recommend spraying perpendicular to air-flow... as close to the inlet as reasonably possible. An auto-x racer I know of has been using this method with success as well.

[Hank]

Anybody serious about water injection pre-turbo should read this thread and perhaps do a little homework on the idea gas law ad some basic turbine theory.

http://www.aquamist.co.uk/vbulletin/showthread.php?t=251

[alxdgr8]

Here's how the Cosworth Indy cars did it. They could run the car on gas with meth injector or run straight meth so it's almost like pre-turbo fuel injection.

http://www.lolachampcar.com/Cosworth%20XD.htm
http://www.lolachampcar.com/pci_ring_fueling.htm

It is a 2.65 liter V-8 burning methanol and producing in excess of 750 horsepower at 12,000 RPM and 45" of boost.they were run to 13,200 RPM in their day,
The XB uses sixteen primary Bosch Motorsport injectors, two per cylinder http://www.lolachampcar.com/images/X...B%20Intake.jpg , and four side feed Bosch injectors arranged in a ring, called the PCI, at the turbo compressor inlet. Fuel rail pressure is 8 Bar or approximately 120 psi! Atomization at this pressure is a sight to behold.The compressor inlet injectors serve to cool the incoming mixture as it is compressed. Fuel is supplied by a mechanical fuel pump located in the fuel cell

The system works remarkably well. When I first started looking at engine data, I really thought the inlet air temperature sensor was broken. It just sat on 68 DegF which just could not be so given that there was a turbocharger and ambient temperatures were up around 90 DegF. I then expanded the data session to look at all the data from the session including firing up in the hot pits. As you can see below, inlet air temperatures start off at about 130 DegF then rapidly fall when the PCI ring fires. With heat soak, I've seen these temperatures up in the 190s and yet they fall like a rock when you stand on the gas. Neat trick Cosworth!

[Mcstiff]

sexy

[chaloux]

Dear Lord, so cool. So no intercooler eh... scary but someone's gotta do it! Go for it Jim, I may follow...

[All_Euro]

Haven't had a chance to read through the full article yet but - the intercooler heating up the charged air? I'm spraying into my turbo and the temp gauge that's mounted immediately after the turbo still shoots up to and past 100*C pretty quickly (KO3). I'd say my wimpy stock IC is still doing it's job

I've heard of guys getting rid of their IC's to avoid the pressure drop… kind of need a fail-safe in case there's an issue with the meth pump or something though. I've been pretty tempted to try removing the IC but still

[Hank]

ALL_Euro, so you are injecting pre turbo into the compressor or in the housing after the compressor?

[All_Euro]

ALL_Euro, so you are injecting pre turbo into the compressor or in the housing after the compressor?

Currently I'm injecting directly into the compressor housing. When I have time I'll tap into the TIP immediately before the compressor wheel as well… then experiment with both nozzles on / one or the other off, etc.

EDIT: a couple pics might help…

[Hank]

Yeah, injecting pre-turbo is where hte huge gains in turbine efficiency will manifest themselves. IE, if you are running 27psi now, you could shift the map enough to the left to now be running 31psi by operating close to an isothermal condition. By reducing the boost back to 27psi, you are removing a lot of heat out of hte system by not over spinning the turbine go get your target of 27psi.

Pre-turbo injection also requires a fraction of the water/meth that post turbo injection requires to get lower IAT. I think in my next revision, I am going to pre turbo inject water/meth in small doses and then water inject at the throttle body as well. I'd like to see if I can get away with no intercooler at all by means of injection.

[85oceanic]

I'd like to see if I can get away with no intercooler at all by means of injection.

That would be awesome!

[Hank]

Yeah, less weight in front of the axle!

[All_Euro]

Agreed: I ran pre-turbo for about a year before deciding to experiment with in-turbo... the pre-turbo gains were immediately noticeable. Butt-dyno verified

Spraying into the turbine housing still addresses the heat issue at the source - but what I don't know at this point is whether the injection (as I currently have it) is relieving any of the pressure right at the compressor wheel... or if it's just after the incoming air is compressed and spun into the comp housing - have to pull the turbo and check for discoloration of the wheel.

Good read as well... http://www.max-boost.co.uk/max-boost/re ... ESSION.pdf

[Mcstiff]

Yeah, less weight in front of the axle!

AWIC