The turbos are from Nissan Skyline VG30DET.  They are imported from Japan via Thailand.  The turbos have about 25k miles on it.  The turbos are carefully exam for shaft play and spin.  The VG30DET turbos are made by Garrett for Nissan.  These turbos are the usual upgrade of choice for the Skyline RB25DET.  The T3s are ceramic bearing with both oil and water cooled capability.  However, these turbos will max out at around 640 bhp.  For this system and the location of the turbos, the turbos are 100% air cooled. Therefore, water cooled is not necessary.  These turbos spool up very quick.  I get 8 psi at around 3100 rpm, which is excellent for street use.  Not too low and not too high.  Due to the original application was not intended to my car, I have to make some custom flanges in order to fit them under the car.  Upgrade turbos head unit (T3) are available to 900 rwhp.  Low mount turbos will not allow you to lowered your ride.

OIL:   

    The oil system is unique to low mount turbos.  Due the location and height, oil return is unlike traditional method.  The oil is obtained from the engine oil pressure gauge by using a T adapter along with a restrictor orifice bypass to control the oil flow to the turbos.  The turbos are drain to a 8-AN stainless steel braided line, immediately the oil is be pick up by a Tilton self primed differential oil pump.  After the hot oil being drawn out of the turbos, it quickly pump the oil back to the oil pan.  The rate of the inlet and outlet must be precisely accurate, otherwise your turbo will smoke or run dry.  All the line being used are capable to withstand high temperature and pressure.  All the connections are use Army/Navy (AN) standard fittings.  With high temperature area, steel fittings are used.  Low temperature area, aluminum fittings use for weight saving reasons. 

The hardest part of this low turbo mount system is the oil.  Too much oil or oil pressures going to the turbos will cause the turbo to smoke.  Not enough oil, the turbo seals will break.  Either way is not good news.  Therefore, precise tuning of the oil flow is very important.  After I destroyed 3 good condition turbos I finally realize that the proper oil flow is very important.  The oil being pump out of the turbos must be faster than the oil coming into the turbos, but not by much.  This oil system utilized oil from the crank pressure.  As the engine rev at higher rpm, so does the oil pressure.  The increase of oil pressure will have higher oil flow.  Currently, the system is tune to around 3000 rpm.  For optimal oil cooler and lubrication, a small oil sump will be very useful.

I have a custom oil sump made with 1" thick at one and 2" at the other end with two 8-AN inlet and one 8-AN outlet.  The oil sump is mounted between the two turbos and the Tilton oil pump pulls the oil out from the sump to the oil pan.  The oil sump is made specifically for low mount turbo/turbos.  The sump solved all my oil problem.  I also have a small opening on top of the oil sump for ventilation.

AIR INLET:   

    The air inlet from the turbos are unique in its own rights.  The inlet air is travel under the car and jointing two 2" mandrel bend tubes into one 3" tube.  The 3" mandrel tube then lope up between the radiator and the engine.  During this path, some intercooling is obtain.  However, an intercooler can be place under the car.  The compressor inlet of fresh air is place under the car.  It uses two 2.5" opening K&N high performance, low resistance air filter.  However, due to the low mount of these air filters, it is highly recommended to having a custom tube made up into the suspension area.  Recently, I have a local muffler shop made me two custom turbo inlet extension.  These extensions are great with heavy rain.  However, with those 2.25" extension tubes, I noticed a slight restriction on the intake side.  During summer time, I will remove the extension tubes to achieve better flow.

INTAKE:     

    The intake uses a combinations of products.  For example, Turbonetics short radius aluminum cast elbow is being used.  Due to the tight space in the V8 engine bay, tight radius elbow is a favorable choice.  The intake is connected with high quality silicon hoses by Hosetechniques along with heavy duty T-Bolt clamps.  All pipes have flare ends for strong connection.  A Blow Off Valve (BOV) is being used.  I choose Greddy Type S because is very quite.  Due to the location and the routing of the intake pipe, the fan cover need to be slightly modify.  Running my turbo LS400 without a fan cover will cause excessive heat.  You can modify the OEM fan safety cover or get an aftermarket electric fan.  16" electric fan is highly recommended.

INTERCOOLING:   

    Traditionally, a front or side mount air to air intercooler would be used.  Due the limitation of the Lexus LS400.  A small front mount intercooler was impossible.  Therefore, I used a Methanol/Water injection system was used.  The system was purchased via www.snowperformance.net. The methanol and water work as a median to cool the charged air through a boost sensitive activation.  Currently, its set to be activated at 7 psi.  For stage I, I am running 8 psi.  Since I purchased this kit from above link, I have modified this kit heavily for safety sake.  I replaced all cheap Home Depot plastic line to Stainless Steel Braided Lines and I also replaced those Push-In connectors to aluminum -AN fittings.  I also completely replace the cheap plastic bottle with Jaz Fuel Cell.  All connection are via metal/aluminum fittings. 

I will increase boost to 9-11 psi in the near future with further fuel system upgrade.  Secondly, due to the location of the turbos, water cooling is not necessary.  Since my turbos are air cooled, I have no change in my engine temperature.  The engine temperature is the same even with twin turbo.  Due to the cool running turbos, turbo timer for cooling turbos down after ignition shutdown is not require.  However, an air to air intercooler can be place under the car or some where by the fender.  After few days of assessment, I realized the horizontal and front mount would be very labor some and practical. 

First, horizontal mount would have a ground clearance problem and front mount will be labor some due to the OEM AC fans and few other mounts.  I have been reading about side mount turbos.  The top two candidates of OEM intercooler would be Saab Turbo Intercooler or Eclipse 1st generation intercooler.

As for update on intercooling.  I purchased a 3" x 6" x 31" intercooler which be mounted under the bumper.

IGNITION:   

    The ignition and timing retardation will be control by MSD DIS 4.  This unit is capable increasing ignition at the same it also control timing.  Besides MSD DIS-4, Unichip can also control timing too.  Currently, I am running complete stock ignition.

FUEL:   

    Upgrade in-take fuel is a must if more power is desired.  A High Pressure Walbro 255 L/H in-fuel pump is being used along with Aeromotive adjustable fuel pressure regulator (AFPR).  If higher horse power is needed, 440 cc top feed injectors are highly recommended.  Currently my stock fuel pressure is set to 39 psi.  For Stage I (8 psi) stock fuel system is sufficient with a rising fuel pressure regulator to support up to 325 rwhp.  For great horse power, larger injectors will be require.  400 rwhp would require 440cc and 500 rwhp would require 550cc.  With larger injectors like 550cc a stand alone is highly recommended to control the large injectors during idle.  I have been looking at an Australian product call Wolf 3D Version 4.  This stand alone computer is very affordable comparing to the rest of the stand alone computer on the market today.  The Wolf 3D is about $700 U.S. Dollars.  Any sponsor out there?  I need one.

CONTROL:   

    Currently, An Apexi Super AFC is being used as a piggy back computer along with OEM ECU.  An Unichip is also a highly favorable choice.  After playing around with my system, I finally realized with 8 psi, a piggyback is not necessary.  A basic adjustable rising fuel pressure regulator will do the job.  Piggyback computer is necessary when bigger injectors are installed.  Between 8-15 psi piggy back would work.  More than 15 psi, a stand alone computer is high recommended or a combination of piggyback with rising fuel pressure regulator.  Here is my recommendation:

<8 psi - Rising Fuel Pressure Regulator with stock fuel system

8-15 psi - 440 cc with piggyback computer

>15 psi - Stand alone computer or a combination of RFPR and piggyback computer

However, I would recommended a stand alone computer for higher boost.  The worst thing about boost engine is ill tuned.

PERFORMANCE:

    Currently, car is dynoed at 324.5 rwhp and 324.7 rwtq at 8 psi without intercooler.  I am sure that I can push it to 350 rwhp with more tuning and an intercooler.  The stock 90 LS400 was dynoed at 172 rwhp.  That is about 152 rwhp increase.  That is about 20 rwhp per pound of boost.  The car pulls very hard after 3000 rpm to redline.  The dyno result on 01-30-03 was using stock fuel system.  Please see dyno result http://www.lextreme.com/Dyno.htm  I can not wait to see Stage II with estimated 500 rwhp.  I would like to take this sleeper to the track and find out what this beast can do in 0-60, 1/4 mile and so on.  I would not be surprise to see low to mid 13 seconds with proper traction and driving skills.  Currently, my spare engine is being build by a 36 years of experience engine builder.  He was one of the original engine builder for the legendary Carol Shelby in the 60's.  The new engine is getting custom JE Dish pistons with over bored .020" along with O-ring head and groove block and ARP head studs and few other boost friendly goodies.

COPY RIGHTS:

There is no copy rights to this system.  If you have some mechanical knowledge and skills, please feel free to copy my kit.  You are welcome to ask any questions regarding this kit.  Secondly, I have received many emails regarding in the production of this kit.  As I have responded to all emails, I will only produce this kit if there is a large order.  Large order means 10-15 pre-paid kits at a time.

INSTALLATION:

If the kit ever see the light of production, this kit will be truly Bolts-On with few minor modifications to the exhaust and oil system. I estimated the complete kit will take around 5-8 hours to complete.  It will be direct copy of my kit.