looking for someone to give me advice on my build

[elplatanudo]

Ok guys i currently have a 97 eclilse gst.. my mods are: evo 3 ported 16g turbo, o2 dump tube, fp race manifold, act 6 puck clutch, intake pipe with filter, front mount intercooler with piping, 3 inch turbo back exhaust, walbro 255 lph fuel pump .. currently with my ported turbo i sit at 16 psi the first three gears, then at 4th gear it spikes up to 17 psi....with no boost controller, and afc neo (zeroed out)..


Items i have that i havent installed: hallman mbc, evo 560cc injectors, 255lph rewire kit...

now my goals are for my car to run well at 17 psi.... My problem is that with my current set up on cold days i get fuel cut, now if i install the injectors i will have to tune it? Or will it run fine or a lil rich? Do i install the rewire kit and test it out to see it that helps with fuel cut? I do want to tune my car but the closest tuner lives 4 hours from me so that has to be pretty planned out....

Any advice will be appreciated.... Thanks guys.

 

[JayB12]

First of all, you shouldn't be running that high of boost without any fuel mods on the car. Second, you will need an aftermarket fuel pressure regulator because the 255 will overrun the stock one making you run rich. Last, you can use the neo to correct for the 560s, if you don't, you will run rich. Another thing, you'll want to get some logging software and a WBo2.

Also, I'm not really sure if you have a messed up wastegate or an aftermarket one, or if your overboosting..without a boost controller you should be seeing like 10psi..

 

[gofer]

You need to get some sort of logger and a wideband o2 sensor before you can effectively tune your cars current setup. Below is a tech article I pulled from our site, its a good read if you plan on tuning with an SAFC and will more than answer your questions.

Tech Articles: SAFC Tuning How and Why

Normally with the SAFC, this involves adding fuel in the affected rpm range. But you have to be careful, because there is also rich knock. So, you make the appropriate adjustments on the SAFC and make another pull. If the knock goes away, great! If not, we need to keep making adjustments.

Using the SAFC is like ice skating uphill. As you use the SAFC to molest the mass of air the ECU "sees", the ECU increases timing. Remember, the lower the mass of air seen by the ECU, the higher the ECU will allow the timing to increase. This causes a problem, because we really aren't running a lower value of air, we are just telling the ECU that we are. So as you increase the size of your injectors, you need to remove more and more fuel. See, when you add larger injectors, the ECU doesn't know, and frankly, doesn't care. It treats them as stock and continues to use the programmed IPW. But since the injectors are larger than stock, the same IPW results in additional fuel that the ECU interprets as a rich condition. Seeing a rich condition, it decreases the STFT and LTFT until it runs out of adjustment range. I believe this occurs at -12%. When it hits it's adjustment limit, you get the good old P0170 CEL, Fuel Trim Malfunction (Bank 1).

This is where the SAFC comes in.....By lowering the airflow value before it reaches the ECU, we can manipulate the IPW. Now that the ECU sees less air, it drops the IPW and basically compensates for the larger injectors. This is also what causes problems at WOT. You want larger injectors to support additional flow generated by a turbo upgrade, right? So now we have a turbo that flows significantly more that stock and larger injectors to support the additional flow. So what do we do??? Add a SAFC and manipulate the airflow to the ECU. This works, but causes a big problem. The ECU is now seeing significantly less air than is actually being "ingested" and allows for additional timing over the 2.1g/rev cap of 16 degrees. High timing + high airflow = knock.

This is the problem with running the SAFC, over something like DSMLink. It is "doable" but is definately not the best way to approach the situation. I am running 650cc injectors and a SAFC and have a pretty good tune, so it can be done.


Let's talk a little more about the SAFC's manipulation of airflow since the question of g/rev was brought up.

The Karmen sensor inside the MAS sends a frequency to the ECU based on the mass of air flowing into the system. The sensor contains a vortex generator that creates small swirling within the intake stream. When properly detected, the frequency of the vortices are proportional to the mass of air passing through the sensor. As the vortices are created, they are directed to a sensor within the MAS and begin to vibrate a piece of reflective, metallic foil. As the metallic foil vibrates, it causes light to be reflected to, or away from a photoelectric sensor. This creates a square voltage wave within the sensor that is transmitted to the ECU. The faster the airflow through the intake, the faster the foil vibrates, the higher the frequency value passed to the ECU.

Wow, that was fun, wasn't it.....This is what I get for paying attention durning physics class. Alright, so what do we do with this frequency once it gets to the ECU?? Well, why don't we screw around with it and see what happens. Remember that SAFC stands for Super Airflow Convertor and only alters fuel delivery indirectly. So, as you drop the airflow signal with the SAFC, the frequency is manipulated to a percentage lower than what we started with. An opposite effect is produced when you add airflow with the SAFC. As I decribed in my initial post, this leads to a increase or decrease in the fuel delivered by the ECU. We use this ablility to manipulate the airflow signal to compensate for larger injectors or lean out the AFR from the factory 9.5:1.

So now that the SAFC has minipulated the airflow frequency and the ECU has used that information, it gets output to the OBD-II port. One thing everyone forgets, is that the airflow shown on your logger, isn't the actual airflow value. You are getting this airflow value after it has been molested by the SAFC. So, if you want to find the actual airflow, we need to convert using the highest airflow value output to the logger, the rpm at which that airflow value occurs and the corresponding SAFC Hi Throttle correction factor.

Here is the calculation:

Airflow (Value from logger) / ( 1 - SAFC Correction Factor in decimal form corresponding to peak airflow rpm) = Actual airflow

So, for example, let's say your logger shows 26lbs/min of airflow at 6200rpm. You check your Hi Throttle table and see that you have a -21% correction factor at 6200rpm. So, the calculation becomes:

26 lbs/min / (1 - 0.21) = 32.91 lbs/min

What do we do with that number you might ask? I use it whenever I am increasing boost and also to determine what boost I should be running. Why boost more when you aren't getting a higher flow. Higher boost increases the temperature of the intake charge and leads to an increased chance of knock. So why push 20 psi when you can create the same flow at 17psi.

You can also use this to evaluate the effectiveness of an upgrade. Back when I installed my UICP, I made a baseline log after the installation at 17psi and was flowing 30.26 lbs/min. Prior to the upgrade, boosting 17psi I would see a peak airflow of 28.50 lbs/min. I cranked up the boost to 19psi and saw an increase to 32.15 lbs/min. Before installing the UICP, I was seeing a minimal airflow increase when upping the boost, so it would have been self defeating to increase the boost and not get a proportional increase in flow.

So, let's say that we want to determine if we have been placed on the ECU's highest timing map. If so, we can definitively see if we are knocking, which is always a hard thing to determine on a 2g.

We need to convert the airflow value from lbs/min to g/rev, but which airflow value do we use. We need to use the airflow displayed on the logger, not the value after the calculation.

To convert to g/rev you need to use this equation:

(A * 453.59) / R = Airflow in g/rev

Where:

A = maximum airflow displayed on the logger
R = rpm value of A

 

[elplatanudo]

First of all, you shouldn't be running that high of boost without any fuel mods on the car. Second, you will need an aftermarket fuel pressure regulator because the 255 will overrun the stock one making you run rich. Last, you can use the neo to correct for the 560s, if you don't, you will run rich. Another thing, you'll want to get some logging software and a WBo2.

Also, I'm not really sure if you have a messed up wastegate or an aftermarket one, or if your overboosting..without a boost controller you should be seeing like 10psi..

Thanks for the heads up... Now when i first got my turbo i would have the nightmare boost creep and it wouldnt regulate at all... I had fp port my turbo and when it came back thats how much it pulls on my stock settings... I have had two more friends that theirs does the same after porting. My wastegate is fine..u can hear it open and close....i will install the mbc and bring down the boost... What psi do u think is safe? 15?
Again thanks.

 

[JayB12]

Your boost controller won't bring your boost down below the wastegate spring pressure. I would say 10-11 psi is a safe place to be with stock injectors. But you really should address the overboost issue first, it seems to be the major problem here. Seeing as you have ported the turbo and added a open dump o2 the only other thing I would even know is maybe welding the internal wastegate shut and adding a tial or similar on the manifold. I'm not 100% on this though as I've never dealt with this issue personally.
After searching, I found that you could probably just get supporting mods to run 17psi as you stated, as opposed to trying to "cure" the overboost.

 

[elplatanudo]

Anyone else?

 

[1qkfwd]

If your still running the stock bsc, you can eliminate it and run the wastegate straight off the pressure source to run straight wastegate pressure. Good way to test if it's the wastgate or vacuum lines causing your boost creep.