Discussion about the difference MPI makes

[Woody]

I wanted to start up a conversation about the difference converting the 4G54 over to MPI makes. Post here about:

 

The Power difference it made. (Would be nice a before and after HP reading if that was the only upgrade)

The change to the drivability of the car.

The change in RPM where boost comes on.

 

And any other differences worth noting.

 

I think that this thread would help people deciding between MPI and a 4G63 conversion as I believe the benefits of MPI for the cost are the better option. That and you can get some pretty decent power output from our motors.

[19cturbo]

with mpi for power gains its about 10% work and 90% tune.. just bolting and running something wont work, unless its already been ran on the exact same setup, even then it needs tuned..

 

when i done my swap, the car seemed more responsive.

once the tune was dialed in drivablity was great, better than before

It did not change what RPM the boost came on.. pretty much the same.

[SOTTY]

Better mpg if you can keep yer foot out of it which is not easy , drivability/throttle response vastly improved , if Mitsubishi had done these cars with MPI from the get go they woulda had a "world beater" on their hands instead of a "winter beater".

[DieHARDmitsu.]

With MPI, you have even fuel distribution to all cylinders. You can run big boost safely and more efficently.

In TBI mode, cylinders 2 and 3 burns leaner due to the design/flow of the stock intake manifold. It doesn't matter how big of an injector(s) you add, 2 cylinders will burn leaner.

[jszucs]

When boost comes on is not really a factor of MPI. That's more a factor of your turbo and exaust side flow. You can always change or have a custom turbo made to suit your needs of when you want boost.

[Woody]

Thanks guys these are great so far. I am not looking for a debate or lecture on how to obtain this or that. I am only trying to compile a list of what benefits you can obtain by upgrading to MPI.

 

So far we have:

 

- Improved Drivability

- Improved responsiveness

- Better Fuel economy

- Better fuel distribution among all cylinders. Meaning 2 wont run leaner, meaning you don't have to pump wasteful amounts of fuel to not lean out those cylinders.

 

Keep them coming if there are more

[importwarrior]

You can run coil on plug for ignition

AKA COP's

Sequential

[Coke]

Cooler looking engine bay

[psu_Crash]

Drive-ability and the potential for more power safely, based on the better fuel distribution.

Other than that ... Huge headache LOL!

[CaliConquestAlex]

I can definitely say that one of the major upsides is that you get rid of all of the stock engine wiring and gremlins that may be hiding there. Running all new wiring with new relays takes a huge load off the stock electrics and the fusible links too. I've noticed a big improvement in low end grunt and a more usable rev range because of the better fuel tuning. I do agree with what others have said that the hard work is in the ECU settings and tuning. The mechanical setup is fairly easy as long as you plan it all out; Manifold, ECU, injectors, wiring diagrams, ignition setup, intercooler piping, etc. Edited October 9, 2013 by CaliConquestAlex

[Scotty Dont]

I'd bet that almost half of the people that attempt MPI have the exact opposite affects that most of you people have listed, worse driveability, more electrical gremlins, etc.

[jszucs]

I'd bet that almost half of the people that attempt MPI have the exact opposite affects that most of you people have listed, worse driveability, more electrical gremlins, etc.

 

No way. Not if they took there time and did it right. Even with my stupid RPM spike (and rewiring and isolating everything to no avail) I have had less headaches then all the other BS 20+ year old wireing I have ripped out of the car. Just the gestemate gages are enough to warrent redoing everything even if the car was stock.

 

With my RPM noise issue, my limited knowledge on tuning, and an ACT Extrem PP and full faced race disk (not an easy clutch to drive in traffic, or gently) the car suprised me on how drivable. Just the ablity to take real readings not computer gestemates, and then make changes on them, is totally worth it.

[CaliConquestAlex]

If someone has wiring gremlins it's due to poor planning or execution. If you don't plan out all the wire runs and power draws for everything you will want with the setup, you are destined to create electrical gremlins, voltage spikes, or worse. Before running any wires, you need to plan out the entire ECU and engine harness and try to piggyback on the stock wiring as little as possible. On my setup, I ran new 4 post relays triggered off of one wire for switched 12V from the factory harness and I have no issues.

 

In regards to drive-ability, this is solely a function of tuning. If the engine ran fine before on TBI, it should run the same or better on MPI. On megasquirt there are SOOO many settings to learn and adjust that have dramatic effect on how the engine runs or if it will even start. Getting a spark signal and getting the engine to start and idle are the biggest milestones. Every setup will need specific tuning. If two people have EXACTLY the same setup a tune can be shared as a starting point, but every car will have different fuel and ignition maps based on seat of the pants or dyno tuning.

Edited October 9, 2013 by CaliConquestAlex

[Scotty Dont]

The two people above me have proved my point, perfect reasons to just swap in something better. These engine aren't too bad, it's the fuel and ignition side that is junk even with MPI.

[CaliConquestAlex]

I do believe that it is less of an electrical and tuning nightmare to just swap in a factory engine that makes more power and use the ECU that comes with it. The challenge is that it takes WAAAY more skill to do an engine swap than just bolting on parts to do MPI. If someone doesn't have access to or skills with fabrication tools like a welder or grinder it's a recipe for a hacked up disaster. It's far easier from a mechanical standpoint to just bolt on MPI parts while the engine is in the car.

 

Also, It's soooo much easier now to go MPI because there are many options to upgrade spark to EDIS or COP and Scott87star is providing plug and play ECU's and harnesses. Finding a manifold seems to be the most difficult part, but when I initially went MPI several years ago, there was far less information and few proven setups with documented installs.

Edited October 9, 2013 by CaliConquestAlex

[TainterRacing]

scotty you might be right.... But thos same people if they did a motor swap it would still be there as they just dont do what every they are doing right or try to take on more then what they should have in the first place.

[Woody]

I believe there is more that can go wrong in an entire swap than MPI.

[19cturbo]

I'd bet that almost half of the people that attempt MPI have the exact opposite affects that most of you people have listed, worse driveability, more electrical gremlins, etc.

 

this is true, i had odd issues with MPI, and anyone can look through my MPI build section here and tell it was done right.. i cut no corners and bought everything new that i could.. still had issues.. Since the engine swap ive had no issues like that at all

 

 

and i actually swapped the 1jz cheaper than i done the MPI swap

Edited November 4, 2013 by 19cturbo

[Funky Phil]

If you're contemplating a swap or MPI, your just going to run into a problem (or a couple) and wish you had done, or do, an engine swap.

 

Decide what you wish to accomplish. Then you should work out the details.

[ZacMan]

The main difference between the engine swaps I see here, and and MPI installs, is the ECU selection.

 

People going MPI use standalone wire in ECU's, these take a non-trivial skill level to install and configure. You've got to plan everything, and make decisions regarding how you're going to provide trigger signals, how your going to configure coils and sparks, are you injectors high or low impedance... Etc, etc. Then you have to scratch build a wiring loom, which isn't straight forward to do reliably. You have to pay close attention to the heat ratings of components and wires, where to use shielded wires, current ratings, etc...

 

Most of the engine swaps I see re-use the loom and ECU from the donor vehicle, or use an aftermarket 'plug in' ECU for the swapped in engine. These are far easier to install and configure.

 

The physical fabrication side of either isn't usually too involved, but the details of the MPI swap are what make it such a challenge.

[jszucs]

Ok Ive though about it more. I would agree a swap "can" be easier and have less problems depending on what you want to swap in, and what you want from that swap. For example swapping anything in going for 600 + HP your going to develop some type of problem, when your working with a car designed for 200 HP. However a swap could also be harder and cause more problems. Some legal plating problems could be a problem in eather a swap or an MPI also depending on where you live.

 

Ether way swap or MPI it's going to take skill, and lots of planing. It also would help to have a few other builds under your belt before you take on a car this obscure to build.

[Woody]

Ok please don't get me wrong, a swap can have its benefits, but that isn't what I wanted from this thread. I wanted a source of pro's and con's for people to come here and ready when considering to do a MPI conversion. For me for instance, I want to stay Mitsubishi. So if I was to do a swap, it is going to be 4G64 with 63 head. I have a lot of those parts, but it would cost > $5k to do as the engine build alone costs a heap. I don't want to drop in a second hand engine which I have no idea how long it will last. Where as I know my 54b will last and doing MPI will cost me < $1.5K.

 

Any more pro's or con's about the MPI conversion? Thanks.

[psu_Crash]

If you have never been in a 400+ WHP Starion then you need to. Even 300HP with 350 ft/lbs torque is a blast to drive! It isn't hard to get that kind of power out of an SQ, it just takes time $$ and most of all attention to detail. For far less $$ than a swap you can build a G54B to be a torque monster and stay RELIABLE on an MPI setup. After all that's the real fun of the G54, it will (almost) always make a solid bit more TQ than HP. These motors are big bore/long stroke so don't expect 9k RPM revs from it. Even with a build top end there really isn't any reason to rev over 7k.

 

Not sure if that helps you or not but it's a little fyi anyways

 

Edit: I just noticed you are in Australia. I guess I thought yours were all the 2.0 4G63 there?? I didn't read the entire post so maybe I missed something. Either way it should be very easy for you to source a Magna intake there and get it modded up to fit your car.

Edited November 23, 2013 by psu_Crash

[Funky Phil]

If you live in Aus, Id go G54B MPI. You have access to RPW and the good Magna heads. Then you can snag up a Sigma turbo manifold that blows ours away.

 

First thing I would do, is get in-touch with Paul Testa. He has a mid 8 sec 1/4mi, Astron 2.6 powered Galant. Him and RPW will give you a HUGE advantage toward success.

[Woody]

If you have never been in a 400+ WHP Starion then you need to. Even 300HP with 350 ft/lbs torque is a blast to drive! It isn't hard to get that kind of power out of an SQ, it just takes time $$ and most of all attention to detail. For far less $$ than a swap you can build a G54B to be a torque monster and stay RELIABLE on an MPI setup. After all that's the real fun of the G54, it will (almost) always make a solid bit more TQ than HP. These motors are big bore/long stroke so don't expect 9k RPM revs from it. Even with a build top end there really isn't any reason to rev over 7k.

 

Not sure if that helps you or not but it's a little fyi anyways

 

Edit: I just noticed you are in Australia. I guess I thought yours were all the 2.0 4G63 there?? I didn't read the entire post so maybe I missed something. Either way it should be very easy for you to source a Magna intake there and get it modded up to fit your car.

 

Firstly, I have a JDM 4G54B Widebody starion. So yes I was talking about the 54B setup.

 

psu_Crash, thanks thats the kind of information I was looking for

 

If you live in Aus, Id go G54B MPI. You have access to RPW and the good Magna heads. Then you can snag up a Sigma turbo manifold that blows ours away.

 

First thing I would do, is get in-touch with Paul Testa. He has a mid 8 sec 1/4mi, Astron 2.6 powered Galant. Him and RPW will give you a HUGE advantage toward success.

 

Yes access to the Magna stuff is easy. I already have a custom exhaust manifold running a custom Garrett GT35 turbo with smaller rear housing for earlier spooling with Haltech ECU. I also have a mate who did the exhaust manifold, who is going to make me my custom inlet manifold and custom Intercooler piping for free. (Am helping him out with consultation on his app development).

https://www.facebook.com/motor.fab.1?fref=ts

 

Either way, the custom inlet and IC piping for the swap or the 2.6 will be the same for me cost wise, but that wasn't what I was wanting out of this thread.