Deegee

iTrader: (1)

So my shop is installing a 2JZGTE single turbo into my SC300 and we're aiming at roughly around 400HP with the current setup. I've been told by a few friends who know very little about 2JZ and Toyota's in general that I'll more than likely need a tune and that I cannot run 10-15lbs of boost without eventually breaking something on a STOCK Ecu (JDM Aristo).

So I'm in need of some help, where do I go next?? The shop where my car is getting worked on doesn't do tunes, and even if they did what am I needing to get to make this engine work with that kind of power?

I've also been told in passing to check out Haltech, and Proefi engine management systems to replace my stock ECU and find a tuner in my area to make this all work properly because "it's not possible to run 15lbs of boost, on a big single turbo reliably without a tune"

So Help CL, what kind of recommendations and advice should I ask my mechanic once he puts everything together?? What kind of EMS system are most of you guys running on their JDM 2JZGTE setups?? As far as the engine goes, it sounds like I'm going to be fine in that department with the minor upgrades that are being done to the engine, but the electronics/tuning is where I'm completely lost.

Edit: Another question I've come up with, how much boost is "safe" to turn on a stock ECU?? I've read anywhere between 10-15psi. Right now I'm kinda strapped for funds and don't wanna throw another 1K-5K for an EMS, so if I were to stick with the stock ECU, would my car run like **** between 10-15 boost?

Dexter72

Do a search on the forums and do a lot of reading. The turbo engine and turbo ecu your shop is installing should be able to handle, 10 psi on 440cc to 550cc injectors. I would listen to your friends but also find out for yourself, to make sure your getting good info.

Kris9884

iTrader: (7)

I want to say the magic number is 14psi with no mods, but people have gone up to 18 or more so its hit and miss. Your ECU will be just fine up to almost 500HP if you have the 550cc injectors and maybe an AFC to get the A/F right. I suggest a fuel pressure regulator too. You'll run into boost/fuel cut before anything else goes wrong so you may need a BCC but you'll be fine. Just always run 93 octane, the stock ECU can def take a beating.

If you are dead set on an EMS then I am huge fan of megasquirt, if you wont be doing any tuning yourself then AEM or Haltec but you'll pay far more for the brand name and really no further benefits at your 4-500 hp range..

Vrank

iTrader: (4)

Your friends are idiots. Hopefully your shop is not. Stock twins with fcd should be fine 15-17psi without corrections

Deegee

iTrader: (1)

When you so no mods, do you mean mods like exhaust, aftermarket intercooler, etc.? I believe the magic number we're trying to stay around is 400HP or LESS. I'm familiar with AFC, perhaps that should be my next mod to get the air flow correct? What kind of fuel pressure regulator should i be looking at? Can I install this myself? How bout the boost controller cut?

We did away with the stock twins and went with a single aftermarket turbo.

Dexter72

Megasquirt 2... Megasquirt pro are good standalones. You have to do more work with Megasquirt 2 but you also learn a lot about how your standalone works. I have used a Megasquirt 2 for 8 years now.

Deegee

iTrader: (1)

Is Megasquirt a standalone or piggy back system?

I'm a novice as EMS systems, any more info on these things? They're relatively cheap in compared to AEM, Heltech, etc.

Forgot to mention, this is on a stock JDM Aristo ECU

Ali SC3

iTrader: (10)

you have to tell us what kind of turbo, a certain psi on one turbo can be a completely different power number on a different turbo. that being said, they are just trying to talk you into a more expensive ecu. you can put down 400hp on the stock JDM ecu with 440cc injectors, and you can put down 500hp on the JDM ecu with 550cc injectors and a simple piggyback. what psi that equals depends on the turbo, but people run 500+hp on the stock JDM gte ecu with larger injectors and a piggyback all day long without even a thought of breaking something engine wise (JDM twin turbo's arent that great at high psi, but you are going single so thats moot).

megasquirt is a sort of DIY standalone, it controls everything like others aem ems, pro-efi, Motec etc..
a piggyback is what you need on the stock ecu to run larger injectors, think safc, emanage, map ecu, aem fic.

on my na-t I have a supra JDM 2jzgte 6 speed ecu with 550cc injectors and a map ecu piggyback.
I have a single turbo on there and am usually running 16-18 psi with no issues but at this altitude thats probabaly only mid 400's power wise, easily above your 400hp power goal.
I wouldn't go standalone unless shooting for over 500hp, cause you can just use the stock ecu and a piggyback and 550's and you are right there with no complicated systems to tune.
standalone you will literally be tuning everything on the car and it takes alot of tune time to get that factory feel back, above a certain power goal its worth all that, but I can tell you its not worth it at 400hp the stock ecu with 440's can even do that but its at the upper limit on fuel. I would recommend 550's and a piggyback in case you get an itch to raise the boost after you get used to 12-14 psi, but if you have a dependable setup you can just run 12-14 psi on the 440's and see what it gets you power wise, might be enough.

Deegee

iTrader: (1)

Thanks for the informative post!!

Yes, I'll be running 550cc injectors on a single 63mm (I think) ceramic Borg Warner turbo.

When you say it's an upper limit on the fuel, what do you exactly mean? I'm glad that 400HP will be attainable with the stock ecu. I may consider getting an SAFC because they're some what cheap, out of all of the ones listed, which piggyback would you say is the "easiest" to DIY tune?

Ali SC3

iTrader: (10)

ok so the stock ecu normally has fuel cut at around 14-16 psi.
pretty much you wont run out of fuel on most turbo's at this psi even on 440 cc injectors, lets say at 12psi you have an air fuel ratio of 11-12 on the gauge. that is what most turbo setups are tuned to run ruch in the 11-12 range and the stock ecu is programmed to run very rich so with the bigger turbo leaning it out maybe a point or so you are still in a healthy AFR range.

so now what happens is you want a little more boost, so you get a boost cut controller to let you run more boost or some piggybacks have that option, so you crank it to 16 psi, now the stock ecu only sees up to 14 psi then its "tricked", so as you run more boost things start to get leaner. at 16 psi you might be in the 12 range and ok, but maybe at 18 psi you will dip into 13 AFR range and then I would say "hey you are on your upper limit of fuel at somewhere between 16 and 18 psi, the ecu cannot maintain a healthy air fuel ratio at that boost.

so on 440 cc you need to watch your wideband like a hawk if you are raising the boost that high. the fuel pressure regulator adds a pound of fuel pressure for each pound of boost, but with 440's its not enough to keep up with the bigger turbo's at the higher psi's.

Lets say now you want more "fuel overhead" (common term)
what that means is you install 550cc injectors, and then with a safc or map ecu, you adjust it so it lowers the map sensor value and that makes the ecu deliver less fuel so it drives normally with the larger injectors.
This is a really good thing is because when you do that you are lowering the map value, so that also means you can run more boost until boost cut and now when you reach higher boost levels, you will have that whole 100cc more fuel delivery power and can actually adjust it with a piggyback. you will see where it was dipping into the 13's before and going lean (running out of fuel) will now be running much richer, like 10-11 range or even richer.

so with the stock ecu when someone says you are on the upper limit, that means the ecu is close to going lean usually below 12 or 12.5 AFR. When people say they install larger injectors to get more fuel overhead, they mean it corrects that problem in boost because it delivers so much more fuel.

so in the end you can see how important it is to have a wideband AFR gauge on a turbo car.
if you have one of those, then the correct answer for how much boost you can run is what your setup can handle, and where you still have a healthy AFR ratio under all weather conditions. I like to be in the 11 AFR range personally as the extra fuel is a little extra insurance to supress detonation, but something like a 10:1 afr would not be desirable as you wuold be loosing power. 12.5 AFR makes great power but can also heat things up and is on the verge of going too lean, I would only run this at lower boost levels.

SAfc is the easiest to setup, takes like 5 minutes and you will be off and running with the 550's.
The map ecu is a bit more complicated, but has more features like you can actually set where you want your new boost cut to be at, the safc can kinda do it but with alot of guesswork cause the safc uses the stock map sensor as an input and then on the safc you adjust percentages. on the map ecu there is not stock map sensor, but the map ecu has a table and you can enter exactly what you want it to ouput.

normally for simple injector changes you would be doing a percentage across the board, and fine tuning percentages in boost if needed.
on the map ecu you scale the whole map up or down to fit your needs.