The case for Asymetrical Turbocharging

[spf_lexus]

Hey john, im fairly familiar with the underside of the LS and I know that underneath the rear seats (under the car) has a large gap on either side thats covered up by a splash guard. Im 90% sure a decent sized turbo would fit. of course, adding a charge pipe back to the throttle body might be a challenge to fit...

John, if your interested, give me your address and i'll ship you a free set of early UZ rods. I have a set sitting in front of me that I have no use for.

 

[JBrady]

Hey john, im fairly familiar with the underside of the LS and I know that underneath the rear seats (under the car) has a large gap on either side thats covered up by a splash guard. Im 90% sure a decent sized turbo would fit. of course, adding a charge pipe back to the throttle body might be a challenge to fit...

John, if your interested, give me your address and i'll ship you a free set of early UZ rods. I have a set sitting in front of me that I have no use for.

Sean, thank you for the offer. I am undecided on my plans for the car so I am holding off for the moment. Interesting thought about removing the heat shields for a low mount or even twins.

 

[spf_lexus]

No Prob John. Just let me know, they arn't going anywhere.

 

[Brad Bedell]

I'm currently running the Map ECU2 for tuning. Unfortunately, I have a ground loop that I can't find or a dirty power supply that's causing the stock ECU to generate noise on the IGT circuit.

Running additional injectors works well with the blower, but might be tricky for the fuel to make the plenum to runners with the OEM intake manifold.

IPT sells a rebuild kit and can set you up with a nice valve body. So far, my trans has been reliable. It's painfully simple to rebuild, you just have to be patient.

I'm also looking at turbos, not sure what I want to do. I don't really have room for Low mounted twins in the IS chassis but want something to handle 600hp range. I really like the compact Tial twin turbos on my Porsche. I may end up using my stockers on it, which will support ~480 wheel on the AWD setup. From there, there's a host of 'upgrades'.

 

[JBrady]

Brad,

Thank you for your imput.

For anyone that is unfamiliar with Brad and is craftsmanship you should visit his site:
www.bedellracing.com

He has done many projects and for Lextreme'rs interest his beautifully done Lexus IS Sportcross which he has completely rebuilt more than once and is "sporting" a 5.2 liter 2uzfe with a TRD supercharger, forged 9.5-1 pistons, H beam rods.

Brad, how much power is your rebuilt 5 speed transmission holding?

Extra injectors are a good way to fuel beyond the stock ECU.
One solution I always thought would work well is the Chevrolet/GM Vortec engine port injection layout that uses 2 large injectors into a distribution "log" and flexible thin fuel lines to each of the spring loaded "injectors" at each port. These port injectors are purely mechanical with no wiring and are small and thin allowing many location choices. Should work quite well for supplying additional fuel to the stock fuel system.

 

[Brad Bedell]

Honestly, I don't know on the power. I've never taken it to the dyno. But based on the TRD M90's anemia, most likely not more than 380-400hp. It's running 6psi boost and I don't have to take any timing out. In fact, I think I can add some timing, but with my IGT noise, I'm unable at the moment. I think 500-550 is achievable on this transmission. The key is in the valve body. Rods in the accumulators = blown sprag. The sprag simply can't take the shock.

Since I don't have a return fuel line, I 'crushed' my stock, in tank fuel pressure regulator a bit to raise the pre-load on the spring. It ended up with around 10psi more. (I forget the exact numbers) Stock ECU gets it close from there. The additional injectors are run on gasoline and seem to do a nice job. I may get around to adding a return line at some point, but for now this works well.

I have a couple of projects in the works for the car, but both require me to pull it off the road for a while. Until my wife's car gets out of hostage at the body shop, it's my daily driver. (she took the Porsche, go figure?)

I'd prefer an injector that I could control the phase of firing for fuel distribution over the mechanical. However, if implemented correctly,(as I know you will) the mechanical would be easy and work well.
-Brad

 

[JBrady]

Brad, while the low end torque of the supercharger is always nice it would seem that 400hp (engine? wheels?) is relatively mild for a 5.2 liter DOHC engine. Obviously something with more capacity than that M90 is needed. I see why turbos are the new plan. Either that or sell the TRD setup and replace with the new TVS 1900 or 2300...

Regarding additional fuel the GM Vortec MPI systems were originally (1992-1995) 2 central injectors batch firing feeding 6-8 poppet injectors. In 1996 GM went to very slim individual sequential injectors fueled with nylon hose from a central fuel and electrical connector well. Due to the compact nature either design would make a great additional injector option. Even with the poppets since it would run only under higher engine speeds.

Good articles here:

http://www.truckforum.org/forums/general-truck-forum/21456-vortec-article.html

http://www.fuelinjector.citymaker.com/Vortec_spider_fuel_injection_conversion.html

That second link sells complete new 8 cylinder sequential injector sets for $330.


GM has engineered a new Spider unit and it was used on 2002-2007 Vortec motors.

 

[Brad Bedell]

Looks simple enough and like a solid solution.

I'm eyeballing the bullet 2uz blower manifold with integrated a/w setup. If it's low enough to put a stock hood back on with an Autorotor MX422 (2.2l ) blower on it, 1850 seems like a fair price for me to avoid 30 hours of fabrication time. I've sent them email to see how tall the assembly is. If I can remove about 2" of overall height, I'm good to put a stock hood back on with the reinforcement bars cut out.