[slysolid]

Hi guys i was looking near my ecu a sec ago and found a fcd hooked in there...then i looked at mkiv.com and they do not reccomend this part??why???


thx.
brad

 

[SpdRcr0]

I have talked to a few people.. and the thing is.. both are the same.. at least on basic BPU cars...they run the exact same..

I called (dont remember, but the big supra tuner) and I ask them the same quetison... and what he told me was this... "If you were running 800+ RWHP, then every little bit of tuning would count... but considering that you will be running about 400-500rwhp, then the basic setup of either unit will perform the same..."

Hope this sheds light on your question...

 

[Ranger498]

guess its just a preferance power house recomends the hks fcd

 

[deavenly1]

THIS HAS BEEN DEBATED AT LENGTH AND MOST PEOPLE SAY BCC IS BEST, BUT IM NOT SURE, DO YOU THINK HKS WITH ALL IT'S R&D AND MULTI-$ WOULD SELL A PRODUCT THAT DID'NT WORK RIGHT.

 

[pwpanas]

WHY THE HKS FCD DOES *NOT* WORK!!!! (For BPU MKIV's w/sequential turbos)

http://www.mkiv.com/techarticles/bcc/why_bcc/Why_the_GReddy_BCC.htm :rant:

 

[ekool]

the HKS FCD works fine.

 

[SpdRcr0]

no no.. Im sure that the BCC works excellent... technically once again.. they work the same...

one determines fuel cut from boost, the other from the actual fuel cut of the ECU

 

[pwpanas]

no no.. Im sure that the BCC works excellent... technically once again.. they work the same... one determines fuel cut from boost, the other from the actual fuel cut of the ECU

Again, read the article - the HKS FCD is no better than the FFCD. The FCD and BCC do prevent fuel cut, but that's where the similarity ends. Only the BCC properly supports sequential operation of the oem twin turbos.

 

[ekool]

For some people, that is not a problem.

People that are TTC, ETTC, Single, etc.

The fact that people throw around the "idea" that the HKS FCD is broken, is just plain wrong.

It works, it does what it was intended to do, and it allows you to have greater control over where fuel cut happens, UNLIKE the BCC.

The HKS FCD works absolutely fine.

If someone wants boost cut to happen at a certain psi still, they can adjust where it happens. Some people would prefer this over not having a cut mechanism at all. And, if you decide you want to raise it just slightly for a race, then its just a turn of the knob. No need to bust out a volt meter and do any calculations/conversions, etc.

Just like anything else in this world, its all a matter of opinion. But to say that the HKS FCD "doesnt work" as you put it, is a lie.

 

[pwpanas]

The fact that people throw around the "idea" that the HKS FCD is broken, is just plain wrong.

I agree. I never said it was broken. I did say it doesn't properly support the sequential operation of the oem twin turbos.

The HKS FCD works absolutely fine.

Again, I agree, but only for TTC and single turbos.

Just like anything else in this world, its all a matter of opinion.

When someone's #2 turbo blows because they're running the HKS FCD, the $ he has to spend fixing it becomes much more than a matter of opinion. Not giving all the facts when you say "the HKS FCD works fine" is just as much a lie.

 

[ekool]

Can you point me to anybody that has blown the 2nd turbo due to the FCD please?

As with any other mod, do your research before applying a mod. If you blindly do something like this to your car and something breaks, you deserve it.

 

[pwpanas]

Can you point me to anybody that has blown the 2nd turbo due to the FCD please? ...

For years, mkiv owners have not blown the 2nd turbo because they've known not to run the FCD with the oem twins in sequential mode. Most have sold their FCD and replaced it with a BCC, or have gone single turbo and run the FFCD. You're the first in a long time that I've heard trying to tell people the FCD is just is just as good.

...As with any other mod, do your research before applying a mod. If you blindly do something like this to your car and something breaks, you deserve it.

I agree. Read the article, and make up your own mind.

 

[SpdRcr0]

hmm.. very intersting.. considering Im auto and going to stay with the stock sequencial turbos, I made up my mind and am going and getting a BCC...

thanks guys!

 

[ekool]

Controlling the boost limit is the job of the boost controller (not a fuel cut prevention device). Fuel cut is only an oem 'safety measure' that should be competely disabled if an owner wants to be able to achieve maximum performance. I don't know anyone that is satisfied with only "controlling where fuel cut happens". When the BCC completely and permanently eliminates fuel cut, I call that a good thing.

I agree, controlling the boost is the job of the boost controller... However, some owners would prefer to be able to control when boost cut happens, to give themselves added safety. For example, on a cold night....

If you dont want it to be there, then thats adjustable... but at least you are able to have control over it.

 

[Nivek]

For some people, that is not a problem.

People that are TTC, ETTC, Single, etc.

The fact that people throw around the "idea" that the HKS FCD is broken, is just plain wrong.

It works, it does what it was intended to do, and it allows you to have greater control over where fuel cut happens, UNLIKE the BCC.

The HKS FCD works absolutely fine.

If someone wants boost cut to happen at a certain psi still, they can adjust where it happens. Some people would prefer this over not having a cut mechanism at all. And, if you decide you want to raise it just slightly for a race, then its just a turn of the knob. No need to bust out a volt meter and do any calculations/conversions, etc.

Just like anything else in this world, its all a matter of opinion. But to say that the HKS FCD "doesnt work" as you put it, is a lie.

I have done my own research on both the BCC and FCD. I have my own electronic test equipment(iam a eng tech by the way) at work and got ahold of both devices. THE FCD IS SHIT. First off the FCD sends a CORRUPT signal to the ECM, this is a false reading and the ECM can not read psi properly. If you dont know, there is a switch triggered by the ECM that tells when the #2 turbo should come on. Also there are 5 other signals that are tapped into the TPS line. These 5 other signals are now corrupted as well. HKS makes FCDs for other turbocharged cars and took those principles and applied them into the FCD used for the Supra, not taking into account how the sequential system works.

The BCC on the other hand DOES NOT CORRUPT any of these signals. The BCC acts as a window to the TPS line, only allowing what the ECM is able to see. How it specifically works is it clips the PSI voltage reading, it will not pass a voltage reading that intiates Fuel Cut(voltage over 4.3V). This is why you should fine tune the BCC with a volt meter. The BCC is a much higher techincal design over the FCD. The FCD does work, it just does not work how it should on a Supra.

This agruement comes up at least twice a year on here and on the mailing lists. With the same out come everytime. If you dont believe what I have to tell you, then you can also contact Lance W who is also in the electronics field and will tell you the samething.

 

[ekool]

Can you please define what you mean by corrupt?

The FCD (according to all documentation i've ever seen on it) alters the voltage based on a percentage.. the percentage is adjustable via the dial. Is this what you mean by corruption? That the signal can be altered?

Ie. the FCD is seeing X voltage, Y adjustment is made on FCD and Z is seen by the ECU.

I have adjusted my FCD and can adjust where fuel cut happens... my fuel pump is hot wired, and I am single... i dont think that an FCD is causing me any problems, and the car has been chugging along happily for over a year setup this way.

 

[Nivek]

Can you please define what you mean by corrupt?

The FCD (according to all documentation i've ever seen on it) alters the voltage based on a percentage.. the percentage is adjustable via the dial. Is this what you mean by corruption? That the signal can be altered?

Ie. the FCD is seeing X voltage, Y adjustment is made on FCD and Z is seen by the ECU.

I have adjusted my FCD and can adjust where fuel cut happens... my fuel pump is hot wired, and I am single... i dont think that an FCD is causing me any problems, and the car has been chugging along happily for over a year setup this way.

A corrupt signal as in NOT A TRUE SIGNAL. A percentage of a input signal is not a true signal on the output. The signals passing through a BCC are all actual and true signals with no interferance.

You are running a single turbo so you do not have anything to worry about.

 

[ekool]

I guess we are arguing about pedantics here, but...

The signal that the BCC offers to the ECU _could_ be considered corrupt by that definition as well.

The BCC is modifying the voltage seen by the ECU just like the FCD, the only difference is that it is by a set, solid, wall. It will now allow >X voltage through... unlike the FCD.

I see what you are saying, but I definetly think the word "corrupt" is not the appropriate word in this situation.

Regardless tho, we have hashed out what the pro's and con's of the units are.

 

[vande17941]

Here's the facts!

The HKS FCD reduces the voltage by a constant percentage....therefore the output signal IS ALWAYS CORRUPT.

The Greddy BCC limits the voltage only, so it is ONLY CORRUPT WHEN THE TURBO PRESSURE SENSOR OUTPUT EXCEEDS 4.3v (OBDI) or 4.1v (OBDII). When the TPS output exceeds 4.3v, the Greddy BCC holds tight at a MAXIMUM 4.3v (when adjusted properly).

DO you want a cheap BCC that never goes out of adjustment, is simple to hook up, and costs 59 cents?

Go buy a 4.3volt (4.1volt for OBDII) Zenier Diode from your local electronics and solder it into the wire from the turbo pressure sensor.

The banded end of the diode should be soldered into the turbo pressure sensor's output (pim) wire, with the other end of the diode is soldered into the ground wire.

This works EXACTLY like the BCC, without the adjustability. We don't want adjustability...we want it exactly at 4.3volts. Greddy makes the BCC adjustable so it fits many different cars! We're paying for a feature that WE don't really need.

NOTE: GREDDY BCC USERS. Open your unit and set it for the right voltage. Every BCC I've seen is set too low from the factory (3.5-3.7v). This is not optimum for a number of reasons.