3000GT VR4 performance builds or staged upgrades for your sportscar.
Whether for fun on the street, track, or drag racing, there are some things that make planning it out a little easier. This section goes through those things and more.

3000GT Photos
(showing modifications)
Performance Build




for the 3000GT VR-4




Okay so here is page 5 of a listing of "staged upgrades" or modification stages as some might say. These modifications are a lot more money and time. They will also change the car substantially. There's always a trade off for reliability and high horsepower and high performance. Most will also cause you to not meet EPA reg's or pass inspection (depending on your state of course).

Taking this step requires a lot more planning than the previous pages. This page has upgrades that pretty much require to work together with other upgrades or additional systems to be installed.

Power Producing Upgrades / Stages
These provide additional power on their own as opposed to just increasing efficiency.
Many of these require supporting modifications.

Larger Injectors


Now that you've pretty much squeezed the most out of the bolts ons and efficiency mods, if you want more power you've got to burn more fuel. Fuel produces the power. So you want to put more of it into your engine. You don't want to go too small for your expected goals but you also don't want to toss in huge injectors if that is not matching up with your turbos or your performance plans and goals. But this must be decided because the car will have to be tuned for them. Usually this is done on a dyno which is the most accurate and professional way to do it.

There are several brands out there and varying prices. Personally I recommend Injector Dynamics brand. They are more expensive than the others but they tune up quicker and nicer than any other injector around. They are also high impedance so you will want to remove your injector resistor pack under your hood too. Or you can go with a set of RC or other brand too. It's up to you but in my opinion the Injector Dynamic brand gives the best results and are nice and stable (and the battery offset tables are dead on which can't be said for the others).

Anyway, match up the size (550cc, 650cc, 750cc, 1000cc, etc) to your plan / goal.

Be wary of used injectors unless you trust the seller. Even then you might want to send them in to get cleaned and checked before using them if they are not brand new.

The problem is - to control it properly You cannot just put more gasoline into the engine and call it a day.

Your stock ECU is expecting 360cc injectors. That is what it bases all of it's calculations on. And there are many (remember the air calculation from the intake MAF v BOV?, things like that). So when you put in larger injectors you must add something to control them properly. See below.

Engine Management System

The EMS (ECU) is a very critical component of your car and your performance build.

In fact everything can be riding on it. There are details here to read and understand to make sure you make an INFORMED DECISION.




You have an ECU (Engine Control Unit) in your car now. It is a LOCKED system. Meaning you cannot 'tune' or adjust it. So how do you get it to work with larger injectors?

Two answers - A) piggybacking, or B) replace it.

A) Piggyback units like an aftermarket fuel controller (Apexi, etc) or The Greddy eManage, go in between your ECU and your injectors. They then translate the signals and "fool" your ECU into thinking the injectors are stock. That's it in a nutshell.

This is the lesser expensive way (initially) but not that much once you add up the added wiring and tuning time to get it dialed in. The other drawback in my opinion is that these devices always drift or are needing tweaking ALL the time. I've yet to see a high HP performance car with a piggyback in it that the owner wasn't fussing with all the time. To me that's a big PITA. But some have luck with them. They also couple it with a MAF translator too. By the time you are done figure on at least $800-$1500 (approximate). For those that it works for, great, for most others I recommend against them if possible to budget a standalone:

B) Replace it with what's called a Standalone or EMS (Engine Management System). The one most people use in our cars is by AEM. But there are also other brands like Motec and Haltech.

The standalone replaces the entire ECU. It is open meaning that everything (and I mean EVERYTHING) is now adjustable / tunable! So you tune for the larger injectors directly. As well as your timing map, fan controls, knock sensing, O2 feedback, the works. You basically now have control over just about every aspect of your engine. It will control nitrous, transmission operations, boost (no need for a boost controller - you save 600-700 bucks right there!) and a huge list of other things.

The AEM serial gauges also plug right in and save you from multiple gauges (each one can monitor multiple parameters at once).

Your professional tuner at the AWD dyno will also be able to tune the car faster and better. AND it will stay dead on unlike the tweaking piggybacks.

So in the end it is actually LESS money to go standalone
due to savings on boost controller (saving you almost $700 right there if going for a top EBC!), gauge abilities, tuning costs, and also many other things that would take too long to go into here.

The standalone is the better way to take care of tuning your bigger injectors and getting the HP you want out of your engine safely and consistently. It is what I recommend. The EMS box and sensors will cost you approximately $2,000-$2300 (AEM brand that is). The AEM is the most used brand name for the 3000GT. Just about all professional tuners are familiar with the AEM software and setup.

Considering it controls the entire engine and many other things too - doing it right the first time makes sense. Your VR4 depends on the ECU/EMS for so much that to go cheap just doesn't make sense to me. It is a critical component in the performance build. If you want an even nicer setup checkout the MoTec system. Again, a bit more money but very nice and superb engine management and control.

There is now a third option so here are some notes about the recent "chrome" or reflashing of the factory ECU that has come up - The factory 3000GT ECU was never intended to be "open source" by the mfg to the public nor be programmable by the end user. This is a fact. So it is NOT like many other car ECUs that are open and intended to be reflashed. Many mfg's have "open source" and the layout is intended for access and was engineered with that in mind. This is why it is referred to as a "hack" because it had to be hacked into versus being open source like other cars and models. This is an important disctinction to compare apples to apples. There is nothing wrong with hacking or creating other options per-se but just realize the differences (know what you are dealing with). Some compare these with other brands or cars and it is not the same thing as with open source ECUs at all.

It is pretty much just a hobbyist type scenario IMO and also allows for a few individuals hoping to make a little money off those wanting a stand alone but not wanting to spend the money. Unless you are into tinkering and have nothing better to do I suggest steering clear of it. If you like to tinker and play with things like this then by all means go for it. Just know IN ADVANCE that you are limiting yourself if doing a SERIOUS or HIGH HP build (and since you are at a stage 5 I assume you are).

One other important aspect to consider is how many problems there are with the Mitsubishi ECUs already. They are prone to capacitor issues, board failures and other problems. Everyone knows this. Especially the 91-93. Many times these problems render the car un-drivable. So is this really the Engine Management System you want in your high HP or expensive build? You are going to spend how much to get here and on these modificiations only to worry about spending some money on a decent system to run it all? That makes no sense IMO.

There's no professional support for such methods either (because it is not being done by a real company) and you cannot obtain technical support except maybe from some guy on a forum or running his own side deal out of his garage. Nor will many professional uners usually bother with such non-standard programs or software. Some might, but majority won't except maybe the specialty 3S places.

EPA and emission testing concerns - most people that reach this stage aren't worried about this. But if you are then realize that just leaving in the old ECU and then hacking it does violate the clean-air-act and you are modifying the emissions by doing this. So it isn't going to guarantee you will not be in violation of the EPA regulations/laws. With the standalones you do lose your OBD port ability but no one I know that modifies to this level bothers with those. If these issues are important to you then you must look at this issue in more depth. Just don't believe that by having your OEM ECU in there and it being modified that you will be compliant. Especially in CA where they pay closer attention to this type of thing. It's just one more misrepresentation on this issue.

A modified OEM ECU has no where near the abilities of a true standalone like the AEM or MoTec. Not even close. A true standalone does hundreds of other settings, controlling, and monitoring (telemetry, gauge controls and outputs, transmission and shifting control, nitrous control, staging, launch control, boost control and racing controls, dozens of switches with parameters to do whatever you want (at xxx rpm do this and do that unless over/under/at xx mph, traction controls, tons of ignition options, custom and water injection controls, etc. etc). My recommendation - if you need a standalone system then do it properly and buy the AEM or equal standalone EMS system. You'd be glad you did. It is just too important to your entire engine and performance to risk with some homespun hack job or hobby-style reprogramming.

Lastly it goes back to the beginning of this writeup and listening to forum parrots and nutswingers that just read about others and follow. The majority of those making online statements about engine EMS systems have never themselves even tuned a car or used a standalone system of any kind. It's called rationalization. For those that do - no offense meant but if I am going to be honest in this guide then these things need to be said to prevent others from spending money or planning before they see the entire playing field and stop listening to parrots on car forums. Everyone has their opinion and I am sure there are some that disagree. That's fine. .

This is not intended to take away from the guy(s) that reverse engineered (hacked) the code inside the ECU. Whether for fun, something to do, or whatever. For people that like to do that stuff it's great and it has it's place. But there are other people trying to make out that they are something they aren't so they can make a quick dollar off the unknowing and claiming they are an alternative or are equal to a true stand alone. They are not. NOT EVEN CLOSE. That is the point of this section.

As I said, these are fine if it is something you want to play around with and know what you are getting into. Key statement there: KNOW what you are GETTING INTO. But for a serious build, done right, no shortcuts, and not limiting your options and growth (in power and options) then it is not a good selection IMO and you'll end up ditching it later which is a waste of time at the very least. IOW - do it right the first time.

NOTE: The term AEM is used to represent "standalone" interchangeably becuase it is the most used standalone EMS out there right now for this car. If you want to go a step up then I suggest MoTec. But either AEM or MoTec are miles ahead of piggybacks of the chrome or reflash stuff.

Fuel Pressure Regulator

Once you start needing to deliver higher volumes of fuel with the larger injectors you will need an aftermarket FPR. The most popular is made by AEM. The really big systems go to the Aeromotive brand. The stock FPR will get overrun and not be able to properly control your fuel pressure. You also need to get the fuel rail adapter and there is an optional gauge to screw in at the rail too (which is handy for setting the regulator)
Fuel Rails and Larger Lines

The stock fuel rails can handle a pretty good amount of fuel. There is a fuel rail loop that is popular due to the belief that the stock one (that joins the front rail to the back rail) is restrictive. I don't know when that would truly present itself but they aren't much money so it is not a bad idea. I don't know any numbers that anyone has produced that actually show this to be the case though.

The aftermarket fuel rails do look a lot nicer though!

As for larger fuel lines. All but the biggest builds go to new fuel lines and fittings and filters. Pretty much 1000 HP and higher are the ones that need to do this. The stock lines can easily handle a 750hp range build.

Radiator / Fans


Once you start making more horsepower you also create more heat. This is a direct relationship. So you will need a larger radiator when you get up into the higher numbers. The VR4 radiator is very efficient as stock and the fans are also very effective. In fact many higher HP cars prefer the stock fans over the FAL brand (Flex-O-Lite). The FAL is very popular too though for close to direct drop in and where the limited space (like for larger turbos) is crucial.

Most go with a multi-pass Aluminum Radiator like Koyo brand. And many go with the FAL dual fans because they have to fit in there! The bigger radiator gives problems getting in the stock fans.

Another important factor is to keep your radiator shrouds and under engine panels all in place to keep the effectiveness of the fans and their air flow. On older cars that might have been subjected to careless maintenance over the years, examine the cooling system for scale build up. Many times this can be the main contributor to overheating problems.

If you are going for a very big build (~ over 700-800 AWHP)I recommend the Derale brand fans. They pull a lot more power though so you cannot use the stock wiring harness by itself. But they cool like no other fan I've ever used. You'll just have to do custom fabrication to install them.

Also see the information on your COOLING SYSTEM and proper maintenance plus other information.

Harmonic Balancer

Make sure your harmonic balancer on your engine is in good condition. Unfortunately there are not SFi high performance balancers available for our engines except special order. So OEM is the next best thing. Do not replace this with some aluminum pulley. You want this on your crank. I'm not going to go into specifics as there's enough on the internet if you're so inclined. Also make sure your engine builder does his balancing for you with your balancer installed (IOW - make sure your machine shop has your balancer that you are going to use on the engine so they can use it, along with the flywheel, crank gear, etc. when the balance your engine)



Planning for tuning costs is part of the build process. I've seen several people spend all their money on the car and/or engine but be left with no funds to get it tuned properly. Set aside some of your budget for getting tuned professionally on a dyno.

Make sure and talk to other owners about the tuner and results!!!
Do NOT take for granted they know what they are doing if you cannot confirm from some other car owners the results and satisfaction. A tuner can destroy your engine very fast and that's that. You don't get a second chance and you will be stuck.

So - VERIFY who you are going to let tune your system. YOU can do it yourself later but you cannot just open the book and all of a sudden be a car tuner. Nor will there be any map that will work from another car in your car.

If you are going to be upgrading to the point of needing to protect your bottom end internals from a much higher HP output then you have to decide when you will be wanting to do this. Usually it is a good idea to get this done sooner rather than later because you really cannot seek that higher power output without risking damage to your bottom end/internals. So this area is separate as it is more the 'shortblock' build plan for a performance engine. Meaning if you are going to be going over ~500 AWHP or more then this is something you want to examine now. If you are not but you have high mileage then this work will probably be a good idea too but not necessarily all the parts like the pistons and rods will be necessary. Again this is very subjective to your overall goal, timeline, and budget.

6G72 twin turbo engine


If you have what's called a 4 block main block then you will likely have a forged crankshaft (some 1993s and all 1994-1999). If you have an older car then you probably have a cast crank. Most would agree that you should just put in a forged crank now if you are gong high performance. Sometimes the old cast can hold a lot of power so it's up to the owner. Just realize that if it does then you will have to rebuild all over again. A new forged crank from Mitsubishi is about $1,000 with tax, shipping, etc. (ballpark).

I am not going to address custom cranks or things like that here. If you are going that route then there is more to talk about than there is room for here.

Pistons Forged Pistons are a standard upgrade to a performance engine build. Ross makes some nice ones for our engines.
Rods Forged Rods are a standard upgrade to a performance engine build. There are several good brands available.
Bearings, Rings Standard new parts for your rebuild. Clevite's "coated" bearings are now available for our engines. For rings I have always like the PerfectCircle brand.
Head studs

The stock head bolts are pretty good up to a point. When you start getting into the higher boost pressures though you may decide you want stronger studs to hold your heads down. I recommend A-1 Technology head studs. A set runs about $800.

Cylinder Heads You will have to decide how much higher you want to go on your head specifications. Ported for sure. Oversized valves are also a good performance addon. High Rev Springs are a plus if you are going to be racing or squeezing that power out on a dyno.
Lower Intake Have your lower intake ported. Make sure the person doing it knows how to do this right. Like many things in life there is more to it than meets the eye.
Cams More aggressive street or race cams will get you some good power numbers.
Adjustable Cam Gears Not really needed if unless you have stock cams, or, you have a tuner and the time to dial them in for the race cams.
Performance Coating

Ceramic coating or performance coating is a nice way to contain the heat in a turbocharged system. Increased performance is seen by keeping in the heat. Heat wrap is also an option. High HP builds get nice gains from this and the time to do it is when your engine is apart and getting rebuilt. Performance coating of pistons is not advised.

One of the biggest performance coating companies is right in Auburn, Washington. PerformanceCoatings

Larger Throttle body Increase throttle body size can make a big difference but you must have other parts to work with it or it is pointless. Stock size is 62mm and you can increase to 90mm using a Q45 one (most popular) and matching up to a new upper plenum (intake). But you will lose much functionality of your stock system. Not advised except for racing only.
Things not discussed here and beyond the intended scope of this list.
Nitrous Oxide N2O systems are pretty common in the race world and non-turbo charged street cars. It isn't too common for turbo street cars. It is beyond the scope of discussion here but it is something that comes into play for performance planning. In short - it allows for more fuel to be burned by making more oxygen available to your engine.
Water Injection

Also called Water / Methanol or Water/Alcohol Injection - used to cool down the cylinders and allow the boost to be turned up without getting knock. Developed back in WW II actually. Again - the full operation, theory and application is beyond the scope of this guide. But if you're wanting to get in to the upper HP ranges on pump gas (rather than race gas) and turn your boost up high then WI is something you might consider helping you achiever that. If you can run race fuel then there's not as much need, if at all, for WI.

There is lots of good info and the best place to start is understanding the theoretical methodology. How does it work and why. A big red flag is when someone insists on continuing to use the words "meth injection". Yeah, sounds real cool. But in reality the technology is WATER injection. The methanol is there to support the process but it is not the process itself.

Also be aware that if you plan on running race gas then WI is most of the time redundant and not warranted at all. No need. The higher octane race fuels do not need or benefit from WI.

Race Fuels

As mentioned above, using race gas is a consideration for high HP builds. Not just racing. Of course if you are going to drive your car everyday then this isn't always an attractive option. But you CAN have two maps available if you run a standalone EMS (eg - AEM EMS) and use the pump gas map for normal driving and then switch to race gas for the track. A minor drawback is that you do have to drain your fuel tank to switch over each time.

There is a lot that can be written on race fuels. I personally prefer the VP brand fuels but they are also the most expensive (as in $15-20/gallon). But enough to note here that not all race gas is the same. Not even close. And you will have to dyno tune for the fuel so choose your fuel wisely. There is enough difference in them that you cannot tune on one brand and then switch to another without potential problems. I order my VP Race fuels and they deliver them to my door so that is convenient. Or if you always go to the same track, see what they might carry if you prefer. For more info see VP RACE FUELS or any other equally large supplier like Sunoco, Torco, etc.

Basics: Race fuel has a much higher octane (as in the 110-120 ranges). It burns slower. It prevents knock at levels that lesser octane fuels cannot. (note: this is also why your VR4 says PREMIUM FUEL ONLY - to prevent knock that the 92-93 octane can prevent and the lower octane pump gas cannot). It can help cool the cylinders (which is why WI isn't always needed on race fuels). You can also go with a leaded race fuel, but you should be committed to your car being race only if you do that (in my opinion). Those are just a few basic reasons for using race fuel. If you understand the differences and why it is used over pump fuel then it can help you decide on adding it to your overall goals/plans or not.

Don't let running race gas intimidate you. It isn't that complicated and if you have an AEM or other standalone you just have two maps. When you want to race and use the race gas you upload the racing map. If your car is a street car and you want to go back to pump gas you just upload the pump gas map which is a different tune. There you go.

Ethanol - some like this and can get some nice results. However the majority abandon it when the hassle of obtaining it sinks in or the fact that you have to build to supply so much volume to match the power of a real race gas. Not to say it isn't great for some just make sure you don't jump on a bandwagon only to find out the downsides later (and there ARE many downsides to it, which is why many at the track are still running good old race gas and not ethanol - think about it).

Cryo Systems Uses supercooled method on intercoolers, fuel systems and other components to help lower the charge air to increase power.
Full build buyouts

In the racing world you can sometimes find good deals on those getting out of the biz or moving on to another platform and such. For the 3000GT VR4 platform you can also sometimes find deals where people did not budget, listened to the wrong people (ie - did not read this build guide, lol) and in the end ran out of money, ruined the car, blew the engine, or combination of that and more, etc.

The end result is that you can pick up a lot of the parts for a fraction of the cost when they realize they have to get out from underneath all that money sitting there.

A few things to keep in mind when buying a whole car:

1 - when they list things like what spark plugs are in the car that is just trying to stretch the list of mods and indicates desperation or that the list really isn't that big. Who cares what spark plugs are in it. Seriously. How ridiculous. Or what coolant is in the car or engine oil and other such silly overly-basic info.
2 - many will try to represent the car as doing really well and only selling because of (insert basic excuse here). Don't believe it. Chances are 10:1 that there is something wrong with it. It's been heavily mod'd and something went wrong most likely. That is still okay for your purposes just don't buy into that BS.
3 - considering the car a "parts car" is not the same as fixing it all up yourself as a car. In other words: getting it for parts for your car (one you know what's been done and you want to upgrade or mod or performance addon to it) is one thing. Buying the car to fix it is another. Why? Because buying parts to pull off, verify and refurbish as needed is not the same as buying a car with unknown things wrong that you may very well have to fix!

So look at the parts costs and add up the PARTS. Not the car. The parts that you want. Then, depending on the miles or amount of use on the parts take anywhere from 60-85% off new cost. IOW - if 100,00K in "useable" parts then a 'good deal' would be 20k. This is especially true of electronics (that are hard to verify if any problems) as well as parts that wear fast like a clutch. Unless it is a RPS rebuildable or something similar then a used clutch isn't worth much. Yes I know, the guy only drove it twice and the little old lady on weekends,,,lol......Remember, it is not a 'good deal' if half the parts are worn, the turbos are blowing oil, the ECU has quirky problems, etc. Don't kid yourself - people sell off their 'project cars' like that all the time. They know there's another multi-thousand dollar rebuild needed and are now looking to unload.

In the end if there are parts that you would BUY ANYWAY and the entire cost is over 75% off of new cost (for just the parts you want, not everything) then it is worth considering. If not then be careful you don't talk yourself into it being a good deal when it really isn't once all said and done. Spending all your money on something like that and turning around to find it has a blown set of turbos, cracked crank, and so on, is not something that you want.

Note that I am talking about performance mod'd cars. Not stock with some bolt ons. The more heavily mod'd the car is the higher the discount if trying to unload. BE SKEPTICAL! Nothing personal to the seller, it is just good business.

USED PERFORMANCE PARTS - BUYER BEWARE. IF ONLY 10-20% off (or thereabout) you are better to just bite the bullet and buy new. Otherwise you are buying on faith with no warranty and could be one of the many people stuck with worn out, shot, or just plain ruined parts.

Future Use?

I'm sure there are things I may have missed and someone will tell me. Some things I have purposely left out.

NOTE: this isn't a DIY but a guide for those that are newer to the platform or performance concepts so there are things not included here.

So if anything comes up that I forgot to mention, or added info deemed helpful, I will add in here. I'm sure many will disagree with things I've said and some of them will not bother to want to correct me but instead want to flame me. Part of the deal I guess :)

I hope this information has been helpful and informative for you.

If you have any constructive feedback or corrections feel free to email me.
If you have further questions or elaboration feel free and if I am not too busy I will reply back to you.


Enjoy making, and keeping, your VR4 in nice condition and a high performance sports car like it deserves!

In summary, if you get nothing else from this site / writeup:

1) Know your goal ahead of time or at least the REAL expectation of what you want to end up with and what you can truly afford. FACT: Most "builds" end up costing 2X or more than what the new builder thought. Many are left with half done projects because they ran out of money. So.....

2) PLAN your build out on paper first (*I suggest a spreadsheet like Excel that will to the math totals for you as you work). Add in the little things the best you can. These "little things" add up and can push you well over your budget. Do this BEFORE you spend money buying parts!!! Round UP because there will be things that you forgot or will run into once you start disassembling your car/engine/trans. It's just how it goes. Plan on it accordingly with a buffer on your budget. If you don't then you will run out of money before completion or will have to take short cuts that sometimes have sad outcomes.

3) Get off the car forums that are mostly huge collections of BS and and many times totally wrong. There are certainly times when there is good information there but be aware of knowing the difference or take into account the person handing out the advice. 90% of the time you get ridiculous advice from the nut-swingers and dreamers. If you know (or know of) someone that has a proven record of building and success then reach out and contact them.

Sort of a "trust but verify" attitude is in order. It's nothing against anyone personally but is just wise to keep these things in mind, especially on big builds that will exceed 10's of thousands of dollars.

Good luck on your build, whatever the level. Enjoy the process too!
I hope this has helped you out.
If any questions or mistakes that are mine please let me know.




©cjbyron.com 2012
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