Djhoon

It was recommended that i get an A/F gauge for my build and im just looking at any opinions people have.

Hks downpipe, stock main cat, and apexi N1 exhaust, also an apexi dual filter intake. Stock ECU.
Im fine with stock boost levels but I worry about boost creep with this setup, im planning on porting the wastegate.

All that being said, how strongly would you guys recommend an A/F gauge?
"How much is peace of mind worth?" i know but im also not building a racecar here.
I can fit it in my budget but my list of accessories is so long already.

Cheers

deanofay

I am wondering the same thing.

angel824

iTrader: (8)

I think most would deem it necessary

Banzai-Racing

iTrader: (11)

A wideband is a great tool, but on a relatively stock car it requires an addition bung to be welded in. Additionally if you are not going to monitor it then it is a waste of money. You can take your car to a tuner, have them install their wideband, do a couple pulls and verify that your AFRs are ok. It would cost you about the same as a wideband.

You should not have boost creep with the stock main cat.

TomU

iTrader: (11)

i had boost creep on my 100% stock FD

Banzai-Racing

iTrader: (11)

Then obviously you had an issue that had nothing to do with air flow mods (since you claim you had none) more likely a mechanical issue with either the wastegate actuator or the vacuum line(s) going to it. However I am not going to pretend to know anything about your car, since I have never seen it. I do know from personally building 100+ FD's that a properly functioning car with an OEM main cat will not creep.

Djhoon

Appreciate the response!

jasonn

iTrader: (10)

Yup, unless you have an ecu that will warn you of lean condition under load/throttle, it won't do much :\

Marf

Without a mappable ECU to allow you to adjust the fuelling based on logged A/F readings, a wideband is just another distracting gauge with pretty flashy blinky lights to sit on your dash and cause you worry as you glance at it whilst driving thinking "Is that reading ok?".

Basically, get one if you get an ECU, otherwise if you want your a/f checked get it on the dyno.

I just installed a PFC+datalogit and plan to pick up a gaugeless sensor loom like the Innovate LC-2 to go with it

IRPerformance

iTrader: (41)

A wideband is always a good idea. An issue with the fuel or ignition system will often show up as an overly rich or lean condition. If you know what a/f your car usually runs at, and one day it is different, you may be able to catch it before you hurt the motor. You can also get something like the AEM Wideband Failsafe which can be setup to open the wastegate if it leans out.

Montego

iTrader: (1)

Do you need one? With your mods not at all. Why I say that you do not need one: and lets break this down in a logical fashion.

Fist of all the main concern here is A/F ratio... If you keep your boost at the 10 psi then you should not have to worry about your mods creating a dangerous situation.

Hks downpipe:This mod decreases BACK PRESSURE in your exhaust. The only way it can affect your A/F ratio is if you experience elevated boost or boost spikes from it. Remember turbos spool from the exhaust gases and therefore affects the boost pressure. Keep your boost at the stock level by adding a boost controller and not worry about it.

stock main cat: it's stock. Enough said. Usually most people who retain their stock cat do not suffer from boost creep even though they have a DP and Catback combo. The cure for controlling boost creep is porting the wastegate.

apexi N1 exhaust: This mod decreases BACK PRESSURE in your exhaust. The only way it can affect your A/F ratio is if you experience elevated boost or boost spikes from it. Keep your boost at the stock level by adding a boost controller and if for some strange reason you are creeping then port the wastegate.

apexi dual filter intake: A hot air intake.... Not really sure what the gain is of this puppy given that it sucks hot air straight from the engine bay. But lets say it is a true CAI. Then you should experience elevated boost which is controllable via a boost controller. Again keep at ten psi and you are good to go.

The same applies to adding an IC: As all it is doing is mimicking a colder climate. Keep note that adding an IC causes elevated boost due to a lower pressure drop and colder AIT's. The fix is a boost controller.

Stock ECU: Using the stock ecu guarantees a proper fuel curve and A/F ratio at stock 10 psi of boost. So if you are keeping stock boost levels why would you need to monitor the A/F ratio?


What you really need is a boost controller and boost gauge that you know is accurate.

In spite of what I just said I still believe that it is not a bad idea to get a wideband. The reason being is that it indirectly monitors fuel delivery that has nothing to do with your mods. For instance: a clogged injector, or weak pump. That's what happened to me: All of the sudden my AFR's went from a nice tune of low 11's to low 12''s under WOT. Turns out a problem had developed in my delivery fuel system and I caught it in time thanks to my AFR gauge.

Djhoon

Now there's an explanation, I appreciate it! Looks like I'm in the market for a profec b. I have a good defi boost gauge/water temp/oil temp, but I think I'm at the limit of how many gauges I want.
Cheers

Montego

iTrader: (1)

Just remember the most important thing is not to exceed 10psi (no creeping nor spiking) on the stock ecu. Going past it will cost you an engine.

Banzai-Racing

iTrader: (11)

Installation of a boost controller is not a good idea with the stock ECU, raising the boost will yield leaner results and boost/fuel cut.

Tem120

iTrader: (5)

cheaper solution is DRIVE , if you see creep or anything of the sort , then take out your Pills on the turbo pre control / waste gate lines , Port the little pills a tiny bit so they let a bit more air bypass . that should maybe help with the over boosting .

Montego

iTrader: (1)

I think you misunderstood my comment. Given that he has mods, the reason to get the boost controller is NOT to raise the boost, but to control the boost DOWN to 10 psi.


Edit-
Porting the little pills will definitely work for elevated boost but it won't do anything for creeping. Not sure if it will do anything with spikes either

Banzai-Racing

iTrader: (11)

If boost creep exists and removing the pills does not keep the boost at a range lower than 10psi, then a boost controller will be useless. A B/C will not control boost down, only up. If a wastegate is too small, the only fix is a larger wastegate or a more restrictive exhaust.

Montego

iTrader: (1)

Exactly. That is why I said this:

For those that may not know: There is a huge marketable difference between elevated boost, boost spikes, and boost creep. Meaning they are not the same thing.


Just expand on what you said. A boost controller on a properly working setup (meaning no creeping) will adjust boost down to the wastegate spring but NOT below it. On a stock twin FD that means 7 psi.

M-

Tem120

iTrader: (5)

I thought porting the pill tricked the ECU into opening up the wastegate earlier

IE if it opened up at 9 PSI with the stock pills , and then creeps to 11 , by the time it reaches redline .

if it was ported a bit it might open up at 8 and rather hten creep to 11 , it creeps to 10 , ideally you'd want a larger waste gate so the creep is less , and you can hold 10 PSI rather then 9 and slowly creeping to 10 .

But I could be wrong . as I've never used the stock ECU , I have always had the power FC , and always used the Power FC's boost control .

When I first got my car running Car would not boost past 8 psi , and I was going crazy trying to figure out why . had the duty cycles closed up to 90% , and then i tried putting the stock pills in and I saw 16 psi .

So the stock waste gate would creep to 8 psi primary , and even 10 when both turbos were operatng despite running off the 7 psi spring ,

So thats when using the Duty cycle on the power FC lowering the duty cycle alowed me to control what PSI I ran the turbos .

I figured porting the pill would replicate lowering the duty cycle by tricking the system

Banzai-Racing

iTrader: (11)

On a properly functioning system (meaning no creep)...... there is no reason to install a boost controller, since the car will be at 10-8-10, there is no reason to lower the boost to WG spring pressure (7 psi), and even if someone wanted to all they need to do is remove the pills and save themselves the cash for something else.

Not to mention the stock ECU does a fine job of controlling the sequential system at a stock level. I have seen countless threads where people have 12-7-0 (or some other problem) after installation of a B/C on twins because they have it installed wrong or do not know how to tune the settings properly.

We do not install boost controllers in customers FD's unless they are single turbo or want to run the twins higher than 14psi. Even with these situations we have found that the PFC will control MAC valves very well. The only real plus to an independent B/C is having multiple high boost settings that can be changed on the fly with the push a single button instead of fiddling through a few screens on the PFC just for 1 high boost setting.

Montego

iTrader: (1)

Sure there is . Take me for example: I started with a 100% stock car and I mean 100% stock. So @ 108K my engine died due to carbon lock, warranty had run out so I was free and clear to mod my car as I pleased without any fear of voiding it.

So I got my engine rebuilt, installed a boost gauge. Soon enough I got a DP. I experienced a slight elevated boost so I got a boost controller to keep it at 10 psi. Later on I got a MP (with a stock cat). The result was elevated boost but this time it also came with spiking. But that was ok, my boost controller took care of that problem too. So back down to 10 psi with no spikes and happy motoring . Alright, some time later I got a CAI and frankly, I don't remember what was the outcome so I'll skip over that. Next was the addition of a PFS SMIC and the end result was a 2 psi of elevated boost. And once again I used my boost controller to lower it back to 10 psi. All of this was done on a STOCK ECU and as expected the ECU did not control my boost. Hence the reason I purchased a boost controller in the first place. Granted, there are different ways of controlling boost but that's the method I chose.

Maybe a family member wants borrow my car so I purposely set the boost down to 7 psi (slow mode). There could be various reasons to do so, rainy day, filled up with 87 octane who knows. The thing is that ultimately it is not up to you nor I to decide what a good reason is. In any case, a boost controller is a handy tool to be able to adjust boost on the fly for whatever the reason.

Now the only reason I mentioned it was because you stated that a boost controller can't control boost down. I know what you meant but others might get the wrong idea that a boost controller cannot lower a boost response which as you know is false. So I was just clarifying.



How does the stock ECU control boost? I’m seriously asking. So if you can please enlighten me I would greatly appreciate it. Because I have always been under the impression (and from what I’ve seen) that the stock ECU does not control boost. Granted it has fuel cutoff capabilities when a certain boost level or RPM is reached but that’s it. Thanks to wade and his lambda tests, it came to light that the stock ECU runs rich enough not only for different environmental situations but also for boltons @ stock boost. But again I've never seen nor heard any mention that the control of boost comes from an electronic input from the ECU

Banzai-Racing

iTrader: (11)

You must really be bored, sorry but I do not have time to argue, and you can do whatever you want with your car. However telling someone to waste money on a boost controller is irresponsible. Don't you think if it were the fix I would be trying to sell him one?

Seriously? Of course the ECU controls the sequential turbos. Read the factory service manual. Why do you think there are wastegate and precontrol solenoids, charge relief, Turbo control, and charge control solenoids? For that matter the PFC controls the sequential twins the same way the factory ECU does. Boost transition and secondary turbo operation are completely controller by ECU.

OP- if you have creep, port your wastegate, a boost controller does absolutely nothing to stop it from happening. Keep the main cat and you will not have an issue. Good luck with your car.

Djhoon

Appreciate all the info here!
From what I understand, il let my stock ECU worry about controlling my boost, and il port my wastegate just in case, it seems a boost controller won't do anything for me at all at STOCK boost levels. I can't discharge air any faster than it can exit the wastegate.

If I ever go nonsequential or aftermarket ecu than a boost controller will be #1 on my list. In the meantime il keep an eye on my gauges.


Cheers everyone for the insight!

JBarnett'92

iTrader: (1)

The first thing i purchased for my car was a boost gauge and A/F gauge.

I knew i would be modifying my car, so in that situation it was money well spent to keep an eye of things while driving my car hard.

If you plan to just drive it on the street then don't bother.

limepro

iTrader: (2)

I see what Montego is saying, take a stock turbo system and say you are boosting to 12psi with your mods. Take out the pills and you are still hitting 9psi but, you want the 10psi so you take the pills out and add a boost controller and you can keep it at 10psi.

In this way a boost controller can lower your boost because you are removing the pills that are designed to keep you at 10psi along with the wastegate by restricting air flow as they are no longer allowing enough air through.

Saying that, porting the wastegate is the better route.