My Turbo Project:

The Goal: 300rwhp @16PSI

The Donor Car:

I spied this:

Still waiting for "Administrative Approval" from my wife!!!

The Turbo:

1.  Turbo maps have lead me to this on the compressor side:

2. Reading the map:

• For 10psi of boost, the efficiency range is 73% to 77% with 78% for nearly half the band 3250 rpm to 6500rpm
• For 16psi of boost, the efficiency range is 75% to 76% with 78% for nearly half the band  3250 rpm to 6500rpm
• For 16psi of boost, the efficiency range is 75% to 74% with 78% for nearly on third of this band  3250 rpm to 6500rpm

Since most people report full boost at 3000 rpm, the 3250rpm estimate is in the ball park and the map clearly shows plenty of "elbow room" between 3000rpm and the surge limit.

3. Here is what others using similar compressors have reported:
   
   T3/T04E; stock .63 exhaust housing and wheel; 57 trim wheel on the compressor side w/ stage one wheels. I don't get full boost till bout 4000 rpm (20psi) and then my car pulls hard past 6500rpm.
   
   You should have gone to the stage 3 or better the stage 5 exhaust turbine wheel with the bigger compressor. The slip ratio is all out of whack with the stock turbine wheel.
   The turbo you described should be able to spool to 20psi @ 3000 rpm's
   I was running a stock exhaust turbine housing with a stage 5 turbine wheel, and a TO4E 60 trim compressor. The turbo was in full boost @ 3K
   
   I'm running 60-1 in T04B housing and Stage III and I get boost just fine before around 3000rpm also.
   
   First off lose the BOV on stock ECM car and do check for a leak at the waste gate door other than that your fuel curve may be a problem. If you don't have a correct A/F ration the car wont make power. You should pin that boost gauge with any T3 turbine wheel. Good luck.
   
   The "e" has a larger compressor housing....the "b" (as a rule) spools faster.....the "e" (as a rule) moves more air, more efficiently, or that's the way I think it is ..I have a "b" but had it machined to have a 57trim compressor....stage III turbine.....love it for a streetcar...
   
   http://www.spdexhaust.com/  SPD sells the flanges for a T3 and they are .5" thick. I used that specific turbo you listed and it worked rather well. Spacer is needed as the TO4E housing is larger than stock and will hit the exhaust manifold. Try to retain some sort of heat shield between the compressor housing and exhaust manifold.
   
   I got a the exact turbo your describing. A Turbonetics T3/T04E BB turbo, but its on my Eclipse though. Its a good turbo lots of top end. One my engine it gets full spool at 3k but since the L28 has lots of torque it should have better spool up. If you have a lot of money you could get the BB one but to me it looks like a waste of money I don't really see the difference. And yes this turbo will spool at 20 PSI no problem, crap I spiked to 20 one night and man it felt good haha. The turbo is supposedly good for up to 400+ HP!
   
   ....depends on what you want to get out of it (hp) and what kinda driving you want to do....drag racing,road racing,street.....its prbly gonna be a T3/T04E (if you want to wear your rear tires out) hehehe....but there are a whole bunch of different kinds of T3/T04E's (they are made different ways)......the pitch of the blades,watercooled (or not),the bearings in 'em,and kinda wastegate they use...there are $300 ones and there are $3000 ones....
   ...your stock turbo is a T3(/T3) meaning both sections are a T3....the T3/T04E has the same wheel on one side (the T3/xx) this is the side that the exhaust blows through ....the other (xx/T04E) side blows air into your i.c./intake... this side is a lot bigger than the original (so it blows more air @ the same rpm).....which is good....but it takes it a little longer (not much) to spin up because its larger and pushing more air.....(thats where the lag is)
   ....youre prbly gonna need a T04E because you have a huge (too big i think) intercooler (if its like the ones i've seen)...but thats cool......
   ....the i.c. and turbo will get you to where you can run high boost......but you cant use but around 12psi of it because the stock fuel system will only provide enough for around 12 psi (w/the i.c.)......
   ....if you want to run more than that (and i bet you do)...its starts getting ex$pen$ive.....a rising rate fuel pressure regulator will get you a little more gas in there (not much)...but you may get enough fuel to run 15psi?(not sure).....but after that you gotta get bigger injector$....and youre ecu wont really run 'em right so you have to get an after market fuel controller (that really should have a bunch of "s" to change to "$")......and it'd be good to have a better fuel pump 'cause the stock one is gonna be "gettin' it".......w/the bigger injectors...
   ...the first thing i'd do (after i researched it real well) is find a shop thats willing to work on something like that....a bunch of 'em wont touch it....
   .......s
   
   I was reading down below about your setup and just wanted to give some inputs. Make sure you port the $hit out of the exhaust manifold and especially where ports 1-4 feed into the turbo through the single opening. If you stick your finger into that area, you will feel that you can remove about 3/4" of material from that hole and do some serious porting in the area where the turbo is connected. Also, you should seriously consider using a bigger TB to generate the 500bhp. I would think atleast 65 for your cause. Also, I was sort of unclear about the specs on your turbo charger. Which compressor housing do you use. Is it the T04E housing or just the T3 housing with a T04E wheel? Also, what were you saying about the turbine side of that turbo? Just trying to help.
   
   the T04E is the king in overall efficiency and has a low surge line for good low boost characteristics
   
   The reason I say not to pay much concern to the thermal efficiency of the
   turbo is because you are running an intercooler. The variations in thermal
   effeciency from the 46 to the 57 are probably very small. The intercooler has
   its own efficiency. I think regardless of whether you ran the 57 or the 46,
   your intake charge temperature would be relatively the same once it passes
   through the intercooler. I use to run the starion intercooler and could easily
   run 14-15 psi mid day in the houston summers. Talk about freakin hot. With the
   46mm I was able to run 17 psi of boost and that was a limit because of pinging
   above that boost pressure. I could have backed off the timing a degree or two
   and uped the boost to 18 or 19. When I went to the 57 mm, I was able to
   consistently run 18-19 psi on 93 octane pump gas. Now for the exhaust, the
   downpipe I have runs down to where it becomes parallel with the ground. I use
   to run the 3" down pipe into a straight 2.5" exhaust with no muffler. The car
   sounded mean. The restriction from going 3" to 2.5" creates some hp robbing
   backpressure. I would recommend going straight 3" into a straight through
   3"-3.5" muffler, borla or sebring. The sounds should be tame, but this will
   give you awesome boost response and more hp under full boost. Also, what kind
   of setup do you currently have, block, internals, head, etc.
   
   I know you aren't arguing, I am the king of asking questions. I use to run the
   46mm wheel before I upgraded. I started with a t3/to4b then went to a straight
   t3 with a monster compressor, then to a t3/t04e with 46mm, then t3/t04e with
   tc-3 turbine wheel and 46mm, and finally the turbo I have today. The bigger
   turbo will give you a much denser charge which is why you will produce more hp
   at a given boost level. The reason for the upgrades was in search of a good
   combination of boost response and power for a streetable car. The turbo I had
   gave me just that. My new turbo is a quest for all out power with not so much
   emphasis on boost response. Now as far as thermal effeciency above 6K, the
   stock turbo cam peaks at 4800 and I rarely had to take my engine over 6K. The
   exhaust manifold was port matched to the turbo and visa versa, Also a shim was
   made to space the turbo further off the manifold because the T04E compressor
   housing is quite a bit bigger than the T04B. I also have the seals that are
   placed on either side of the shim. Very easy to do. Also, the TC-3 wheel uses
   a housing with a slightly thicker flange. The flange holes were drilled in a
   press slightly larger and the studs in the exhaust manifold were replaced with
   longer and thicker ones. Everything is a straight bolt up affair.
   
   The EGT probe MUST be in front of the turbo to get an accurate reading.
   
   The turbo we are using is a pretty extreme application that in theory should work well. It is basically a Garret TO4, T3 hybrid with a few twists. The compressor is a TO4E rather than the common TO4B that most people run. The TO4E is remarkably efficient, being able to maintain close to 78% efficiency from 10 to 20 psi of boost pressure.
   
   On a side note, the TO4E originally came from a big diesel truck motor and is a mid eighties design. The common TO4B was designed in the late 60’s. Thus the T04E has the benefit of being designed after at least ten years of fluid dynamic research which shows in its better performance.
   
   On the exhaust side is a T-3 turbine, but it is the biggest T-3 turbine available, known as the stage III by Turbonetics. It is used on their all out Buick Grand National turbo It was originally OEM for a Navistar Diesel engine! This is a pretty free flowing turbine selected in our case mostly to eliminate backpressure.
   
   The lower shaft speed of the TO4E results in a more gentile handling of the air and thus less charge heating.
   
   
   
   T04E/T3 in a 200sx

The External Waste Gate:

Picked up Audi external waste gate locally for $50 . 

Audi External Wastegate

It is interesting as it has two pressure connections. I learned that the side connection is for controlling boost and the top connection is for applying a counter pressure to keep the WG shut until needed.

Typical External Waste Gate

Audi Waste Gate Controls

The upper cap on the Waste Gate (WG) has a small connection. The large hose from the intake manifold to the lower chamber in the waste gate opens WG  to control the boost level.

The Waste Gate Solenoid inlets are connected to the intake manifold and to the turbo intake boot. This solenoid mixes the pressurized air from the intake manifold  and applies this pressurized air to the top of the WG diaphragm to assist holding the WG closed. The pressurized air applied to the top of the WG diaphragm assists holding the WG closed along with the WG spring tension. Go to the ECU System Component section for details on checking the operation of the waste gate control system.

 

Waste Gate Spring Details:

A stiffer Waste Gate spring prevents the waste gate valve from opening too quickly before the turbo can produce boost. This delayed Waste Gate "cracking" improves transient throttle response and allows the boost to increase at a quicker rate.

The wastegate contains a diaphram and a spring to allow control of boost. The spring is a static/failsafe boost control mechanism, while the upper portion of the diaphram allows "tweaks" by the computer. The wastegate spring "balances" against pressurized air exiting from the turbo. This is the only boost control non-computer controlled cars have. The computer monitors boost on the downstream side of throttle. If the computer thinks the boost is too low, it switches a valve (frequency valve in Audi lingo) to allow boost pressure to be applied on top of the wastegate diaphram. This has the effect of making the wastegate spring appear stronger. If the boost gets too high, the computer switches the frequency valve to vacuum and lowers the pressure on top of the wastegate diaphram. This has the effect of making the wastegate spring appear weaker. Where do you get vacuum when a turbo engine is running at full boost? Only one place; the air intake to the turbo (just like a vacuum cleaner). It's important to note that there is pre-throttle boost, and post throttle boost. Application of the correct "boost" at the proper place is essential to safe operation. 

 

Thus, in order to increase boost, you need a computer that will allow higher boost levels. This can either be achieved by fooling the computer into thinking that the boost is lower than it is, or by altering the computer's boost map. Note that running with higher boost will increase engine wear, and oil/fuel consumption.

Waste Gate Spring and Diaphragm supplier:

http://www.audifans.com/archives/1994/12/msg00244.html

http://www.sjmautotechnik.com/10vwaste.html#wgcnt

http://www.sjmautotechnik.com/wginst.html.

http://www.sjmautotechnik.com/prod.html#wgdia

The Blow Off Valve:

The stock pre-95 BOV (aka 1g BOV).Eagle Talon BOV is economical and is good to 17 PSI. A simple mod can push that to 30psi
Modifying a Talon BOV

The Mitsubishi BOV that was used on all Mitsubishi Eclipse, Eagle Talon, and Plymouth Laser cars equipped with a 2.0L Turbo engine is a very high quality BOV.  It is all aluminum and has a VERY stiff spring.  It will not forced open until over 23psi!  In 1995, the BOV was changed and is of poor quality so be sure to get a pre-1995 (1st generation DSM) BOV.  They are about $95 from the dealer, or around $50-$75 from the DSM Parts Trader.  This BOV has a 1" inlet and outlet, but only has one hose connection because it is designed to be mounted to a manifold.  It can be retrofitted for hoses, thanks to Gus Mahon.  See Garry Donovan's web page in it.  His web page also has other BOV info and shows some pictures of other, aftermarket BOVs.  The Mitsubishi BOV also has a faster response time than the stock or Bosch BOVs.  This is because of the stiff spring in conjunction with the diaphram vent.  The vent is a small tube that feeds the back of the diaphram with boost from the outside of the valve.  So when you are in boost, the pressure is pushing on the valve and on the back of the diaphram to try and open the valve, but the stiff spring holds it shut.  When the throttle is closed, vacuum appears on the front of the diaphram and the combination of the vacuum on the front of the diaphram, the pressure on the back of the diaphram, and the pressure on the valve causes it to open quickly.  Once the valve is open, the pressure from the turbo is released along with the pressure on the back of the diaphram.  Now, only the vacuum on the front of the diaphram is holding it open.  Once the throttle is opened, the vacuum disappears and the BOV slams shut because of the stiff spring.

Also keep in mind the blow-off point of the BOV you are using.  The stock Chrysler BOV will blow off (be forced open) at about 15psi.  The Bosch BOV will blow off at about 9psi, while the Mitsubishi BOV won't blow off until about 23psi.  If you are running boost levels that are higher than the blow-off point of your BOV, then you will be leaking boost through the BOV.

0 Boost Compression Info from Tony D

Author: Tony D (---.dsl.kscymo.swbell.net)
Date:   Mar 10, 10:52pm

I have run a N42 with 8.5:1 for 17 years now..put well over 50K on it with boost pressures in the 15 to 17 PSI range.

JDM engine bought out of a Nissan Cedric with 40,000 km on it. N42 block and head and 8.5:1 compression. NO problems there.

The stock unit used 7.4 to compensate for no intercooler, bad gas available in the USA, and 200,000+ mile durability.

I know of several 200K+ Stock Turbo motors going strong with NO internal breakages. In fact the latest got a new turbo at 208,000 miles (the first one!) and the owner had the head gasket changed just to "check it all out" and be sure.

Nothing was found bad at all! Gasket was fine, crosshatching still in the bore. Do you plan on driving the car 200K+ miles? If not, even if you figure doubling the boost to 12 to 14# cuts the life to 100K miles, that's STILL an acceptable engine lifetime in my book! Especially for the performance offered.

"Conservative" does not begin to describe the way Nissan built these engine. "Like a Tank" might be more apt!