how safe or not safe is this?

[trybal]

I just installed some 550cc injectors on my sr. I have stock t25, 3inch from turbo back, boost controller and thats about it for the motor as of now. I just got the injectors for a really good deal so i installed them. The car seems to idle solid, just high, at about 2k.

Would it be stupid to drive running that fat or no? I also have a safcII i just haven't installed it yet

[HyperTek]

should be ok.. install the safc if you can to prolly decrease teh fuel ratio?? i dont know

[trybal]

i just don't wanna overfuel the slut and mess something up, and the nearest dyno tune is about a 45 min drive...

[gear]

im pretty sure you'll be fine, i just wouldnt drive it hard until its tuned. Excess fuel makes the car run like shit, fouls the plugs, makes the oil foul quicker, and ruins catalytic convertors. (not necissarily all those at the same time, but it can be any combo) Id get it fixed relatively soon if possible.

[trybal]

yeah, i hooked up the safcII today, guess its time to decrease the fuel by 30%.. and i have no cat so that rules that out :-D

[trybal]

so i hooked up the safc but the car won't start with it hooked up, and i don't wanna mess with tuning it till i can afford to have someone else do it. So i disconnected the mafs from it. So running with the 550's shouldn't cause hydro lock or anything? The oil does look alittle thin right now and the oil smells abit gasy in the valve train

[DJ_Sunrise]

its gonna foul things up. have u ever done a compression test where the fuel injectors are still connected? if u have, congratulations! its how you blow your piston rings . imagine the same effect. all that gas is getting into oil. if u so much as have the motor running besides going for a tune, make sure it has fresh oil. keep trying to lower that fuel if u get the safc to work.. i would honestly try to get the car towed for someone to tune.

[shayrgob240]

I think you're just gonna waste gas. lol. But do get it taken care of asap

[johngriff]

Yeah, Um, YOU DONT NEED 550CC INJECTORS FOR A STOCK TURBO. What is the point? Since the 370cc injectors can handle the stock turbo @ 14psi, there is no reason to change injectors until you upgrade the turbocharger.

So, shelf the 550cc's until you uprgrade the turbo.

Oh yes. With the MAF unplugged, the ecu will send MORE injector open time, than with the maf connected, so you are once again hurting the engine more.

If the car does not start, after the AFC install, you have incorectly installed your SAFC. I would also suggest, selling it, burning it, or trashing it, because it is the WORST Air Fuel Computer Solution with vehicles with a DIS Load Based Ignition system.

[trybal]

yikes.. no love from you guys i see. Well i just picked up a z32 mafs and a fpr. Im keeping the injectors on here. I don't have stock ones anymore, 2 of them were shot. And how would hooking up the safcII wrong make the car not run? I know i hooked it up right. Thanks for attempting to make me feel like a douche though

[Wei240]

well, you see, people here are saying, unless you upgrade other stuff (like the turbo AND some type of good fuel management), it's kinda pointless... because the stock t25 maxes out around the same time the 370 injectors and maf, so if you upgrade your injectors, maf and not the turbo, what's the point... (besides potentially fvcking up everything else big time)

[trybal]

because i can. Whats the difference between my running 10lbs of boost with these mods, then someone with a 2871 runinng 8lbs on the same mods..? nothing... I upgraded because i had the chance to upgrade for cheaper than fixing with stock parts. So i did it, which im sure most of you would do also.

[S14DB]

Cause the 2871 flows a lot more air at 8psi then a T25 at 10.

[steve shadows]

Originally Posted by HyperTek

should be ok.. install the safc if you can to prolly decrease teh fuel ratio?? i dont know

should be ok?

Are you out of your fing mind?

Have fun soakingthe rod bearings.

It will ONLY* be ok if you install the afc and dial down fuel correction at least 35-38% across the board. I typically suggest people run 40 psi with vacum connected on sr and even then typically i need to pull an afc down to -40 or -42% all the way across the board.

NEVER install oversized injectors on any engine without a surefire way of properly controlling the open timeo or ecu.

Power FC or other more invasive management would be a much better bet to safley tune for this scenario even with the setup you have.

[steve shadows]

Originally Posted by trybal

yikes.. no love from you guys i see. Well i just picked up a z32 mafs and a fpr. Im keeping the injectors on here. I don't have stock ones anymore, 2 of them were shot. And how would hooking up the safcII wrong make the car not run? I know i hooked it up right. Thanks for attempting to make me feel like a douche though

ok...

douche or not using an AFC is simply a bandaid.

It will allow you to do a ruff pulldown of injector via tricking the MAF sensor signal to the ecu, but it will not allow you to properly control and tune for appropriate timing and injector open time as a ems like a power fc or a aem etc would.

If you dont want the help so be it but John is right on most of what he said.

Use the afc to run the z maf, but IMO all you really needed to safely turn up the boost with an AJD fpr for your stock rail and fp gauge with the 370cc.

When you get the chance go pfc or haltech.

[trybal]

See, thats more of the helpful info i was looking towards getting. A gt series turbo is just a paycheck or 2 away, but in the meantime i would like to have a car to drive ya know. And lets say i do have a gt series turbo. And i drive around town all day without hitting boost, with the mods i have. Why would that be different than running what i have with the t25. It sounds strange to me that you need a bigger turbo to run this.

[NemeGuero]

You don't need a bigger turbo.. its just pointless to have 550s with out it.
370s are more than enough for your *current* application.

[trybal]

Thank you^^ kinda the answer ive been looking for. I did the injectors because i got a deal and i plan to upgrade my turbo very very soon, so why not get the supporting mods outta the way ya know. I don't consider myself anywhere near a expert in cars or turbos for that fact, but i know my way around a car. Im just looking for some advice on what to do to be able to run with these injectors. not how stupid i am for putting them on there. I know they are to big for my current setup, im not that stupid.

[johngriff]

Well..

The way the ecu determines fuel is pretty simple. It uses a table, that could resemble a MS Excel Spread sheet. Across one side runs RPM values, say from 0-8000. Across the Bottom runs load values, say from -30psi(vac) to maybe 14 or so.... err (map sensor will type settup will be used for example). There are typically 20x20 cells on the spread sheet, with each cell representing an injector open time. When two values intersect (rpm vs load), the ecu referances the corresponding injector open time as the signal to send to the injectors, measured by legnth. Typically with side feed injectors, you useable injector open time will be between 1.5-45ms.

At say 2000 RPM w/ -10(vac) at non WOT TPS the injector open time for a 370 is probably 8-10ms (milliseconds). If you plug in the 550cc injector, at the same rpm vs load point it will dial the same injector open time for that point, 8-10ms. You have now just injected about 35%-40% More fuel into the engine, making it VERY rich.

The solution to controlling the larger injector will be to "re-referance" the injector open time for this point. The SAFC accompolishes this goal by interfering the MAF/MAP signal. You use the afc to make the MAF signals referance to -20(vac) equal to -40(vac).

Doing this will force the ecu to reference a different cell on our fueling table. In which case this cell might contain 5.5-6ms injector open time, this will bring our AF/R on to target.

BUT! Using a dis ECCS car there is a very large catch. Because the ECU also completely controls the ignition system, it to is referenced the same as the Fuel Table. Actually the two stack onto each other the same. The ecu uses the same data LoadvsRPM to reference each ignition cell as well. SO, if you NEED to use the cell for -40 when you are actually at -20 you will also be using the cell for -40 ign timing.

This is where everything gets VERY f'd up. Your ignition advance and retard curves will now be permanently 35-40% behind where they should be. So when the ignition should be advancing for light load boost to help the Motor accelerate, it will still be using a vacum timing (32adv for mid range vs 15adv for vac/idle). This will have drastic effects on your fuel economy.

But wait, there is more. After the ECU Starts to reach full load, it will trim advance (retard timing) to keep the engine safe from detonation. Keeping in the therory that we are 35%-40% behind our loaded ignintion curve, where the timing should be 20-25adv you will be at 30-35adv. Too much advance timing promotes Knock, Ring failure, over heating, and head gasket failure.


All in all, you have hurt yourself much more, by upgrading the injectors, then proceeding to you use a dangerous fuel contoller. If serious engine damage does occur you could be out as much as a comparable EMS system when taking into account the cost of injector upgrade + SAFCII+Engine rebiuld or new JDM engine.

In short. IF this is your Daily Driver, Replace the 550cc's with 370cc's and cruise it stock. Peice the parts together for a good setup on the shelf, then install all at once. Purchasing the correct components the first time will always save you time money, and hapiness in the long run. Also, do not be afraid of systems like the PFC (i recomend against), or the Haltech. These systems have become very easy for the beginner to tune, with base maps loaded, and a efi book or two, you will have your car streetable in a matter of hours. There are also more AWESOME resources for you to read up on, to make an informed desicion on EMS systems. www.efi101.com is a great place to start!

Have a great day.

If you need any other help, dont be afraid to shoot an email at me as well.

John

[email protected]

[trybal]

Thank you so much^^^^ props to that write up for me. I never looked at things that way till now. Well i guess i will go out and buy another set of stock injectors. On the other hand, do you recommend slapping the z32 mafs on there with the stock injectors?

[johngriff]

If you decide on the Power FC I would keep the Z32 AFM, but the pleasures of using a MAP sensor over a MAF are comparable to illicit street drugs. I would hunt for a Power FC DJetro, or the Haltech, which both use a 3 bar map sensor. Yet, a little known fact about the PFC is that you will need a Certified Excel Tuner to make significant modification to your PFC. You can locate one on Apexi's website. The labor rate (ie dyno time + power excel tunner) is from $250-$400 per hour. The only other current solution is the Data Loggit out of NZ/Austrailia which is a third party component that will void your Apexi PFC warranty.

For the Stock T25@14psi the Z32 Air Flow Meter will be moot. The OEM SR or KA maf will suffice in this instance. Plus you get to run open turbo, or just turbo w/an air filter with the MAP, which always looks tits.

There is also a couple other things to say about EMS systems.. the EXTRAS, anti lag, all in one boost control, nitrous control, fan control, DATA LOGGING (LIFE SAVER!!) plus alot more.. there are alot of really cool things that would take 2 s13 dashboards of small boxes to make up for with just one good Haltech.

Give me a call i have some "unreleased" equipment for the haltech you might be interested in.

John
714 493 0293

[johngriff]

I am bumping this, because people NEED to READ this.

Don't get an AFC / AFM manipulator.

[nicku]

My setup is redtop, s15 t28, nismo 555cc, stock maf, boost controller at 12psi, safc, plx wideband. Right now my safc is set at -30 across the board. And the car is running fine. Do you think I can boost up a little more? When will the stock maf max out at this kind of setup?

[DarkPhoenix]

Originally Posted by johngriff

Don't get an AFC / AFM manipulator.

Besides not having enough resolution, why would running an SAFC be a bad thing? Sorry, I have been running turbo cars for ten years, and everyone of of them either had the old school AFC (5 knob) or an SAFC2, with great results. My last car was a 1992 Galant VR4, with an HKS VPC and an SAFC2, and I will able to tune it for 400+ whp on 720cc injectors, and still get 30 mpg on the highway. This was a street tune, with a wideband and EGT.

Haltech would be great and all, but when you can tune a street car with a fuel controller and it would be cheaper (Around $200 for the AFC and the Haltech is about $1100+ for the E6X), why not go that way? I'm not trying to bust balls here, but I am curious.

[SlideWell]

^^^^ +1 on that. shiet, Keisuke didn't say anyhing bad about my friends s14 when he was tuning it out to over 400hp. ive only heard great things about using an AFC. if you could explain why thatd be great.

[johngriff]

The reason why is because the nissan ECCS system changes the ignition timing based on the AFM load input into the ecu. You need to have control over the ignition timing to prevent knock. Without knowing the base settings of the ignition you are flying blind when doing an SAFC tune.

The emanage is a good low cost solution to this, so is the Perfect Power.

http://www.perfectpower.com/

Basic Air flow meter manipulators are junky at best. And DSM's are known for responding VERY well to AFC's, this is probably because of the linear design of their ignition maps, compared to the non linear loaded/unloaded points in most nissan maps.

[DarkPhoenix]

Originally Posted by johngriff

The reason why is because the nissan ECCS system changes the ignition timing based on the AFM load input into the ecu. You need to have control over the ignition timing to prevent knock. Without knowing the base settings of the ignition you are flying blind when doing an SAFC tune.

The emanage is a good low cost solution to this, so is the Perfect Power.

http://www.perfectpower.com/

Basic Air flow meter manipulators are junky at best. And DSM's are known for responding VERY well to AFC's, this is probably because of the linear design of their ignition maps, compared to the non linear loaded/unloaded points in most nissan maps.

But DSMs have the same issue with ignition control that the Nissan's have. On a 2G it's worse due to the OBD2 configuration, making any timing changes impossible without either a NEO, or another separate timing controller. I was just curious because of my success with them, in my DSMs and my Z31s and Turbo S301s.

[nicku]

so John, you are saying that if I keep using safc, enventually , i will blow my engine?

[johngriff]

AFC NEO? I did not know they can control timing, and am 99.999% sure they can't. My experience with the neo was that of a dressed up fat girl. I would rather just have the plain old fat girl with the safc-II than the neo, it was much easier to tune.

I am NOT a DSM expert, so don't quote me, in my experience, what I've seen, I have seen allot of DSM's go fast with AFC's.

Will you eventually blow your engine? Who am I to judge, it is really dependent on so many variables, I can't start. If you are knocking, then yes, you will blow your engine. That can be from timing, lean af/r's or and ESPECIALLY HEAT.

I just like to know WHAT my ignition values are, and to view the tractive effort output (tq) of the engine, ensuring it is making the most power before the detonation thresh-hold.

nicku: what is the end result of your concerns? Take the car to a dyna-pack or a dynodynamics, get the tune checked out, have the technician check it out with with an advanced knock detector, you will have your answer from there.

[tgd89]

What about something like nistune, as compaired to a haltec? Though I don't think you can use a MAP with it.