knightkarr

damn dude, why you gotta be a dick?
Sound like one of those ricers that want to know, but don't listen. haha

RyoFC3S

iTrader: (1)

i'll just be basic..

i have come to understand that the fuel cut defensor basically tricks the fuel computer into thinking that you're boosting lower, so that it prevents fuel cut in the rear rotor, giving you more PSI. Theres more to it, I know, but I dont have time to prove to you I know what it does.

Btw, calling someone a ricer because they dont know as much about 7's is just beeing an *******. I've had my 7 for 4 months.. You really cant expect me to know that much. Theres no reason to rub it in or be jerks.

White_FC

So you think maybe with the above in mind that if your already boosting 10psi, what do you think that should tell you about your car and wether or not it already has a FCD?

(ps, a FCD doesn't "give you more PSI" )

JackoliciousLegs

Hey Ryo, don't listen to these guys. They get cranky sometimes.

Well, to answer your question, let me tell you my FCD story. My car, a 90 TII, same as yours, was boosting 10psi in cold weather without an FCD and just a catback. I thought there was something wrong, so i checked with another gauge. Same thing. My boost also dropped off to like 7-8psi at like 6500rpms. It was very weird. I didn't feel anything weird or harsh at high rpms. The car just stopped pulling quite as hard and felt like it was leaning out. So, I got an FCD just so I could be sure that I wasn't doing anything bad. Now my car boosts perfectly at about 9-sometimes 10 psi- through all the gears. I have seen it creep twice to like 11-12 which is why I have to be careful now in 4th and 5th until I port my wastegate.

The answer to your question, first, install your boost gauge, then get an FCD. Then port your wastegate. You'll be straight

NZConvertible

When a whole bunch of people with more knowledge and experience than you are all telling you the same thing, you listen!
Did you check to see if there was a FCD wired in at the ECU?

JackoliciousLegs

You are such nitpickers. Geeze. When I said, don't listen to these guys, I was saying, don't listen to the criticism. I caught the same flack from you guys when I started posting about my 1st gen. It's all a learning experience. Some things just didn't need to be said. Calling him a ricer without knowing anything about him for example.

Carlos said : Sound like one of those ricers that want to know, but don't listen.

NZ, I do have to say though, that since I got my TII you have been one of, if not the most helpful person on this forum (to me)... and for that I thank you. I was just defending the little guy that's new to the forum.

JackoliciousLegs

Oh, and there was no FCD at the ecu.

Evil Aviator

Good, now we are getting somewhere.

OK, you seem to understand that well enough, but I just want to clarify that the FCD does not give you more PSI. All the FCD does is keep the fuel cut from activating, and that's it. You may understand that, and your wording may have not come out right, but it is very important that you understand this, so I'm just making sure.

Now we come to the next question...

Has the fuel cut been activating when you are driving your car? (It is rather violent, so you would know if it activated).

Evil Aviator

Sorry, I'm not very well versed in the S5. Is the fuel cut activated by an absolute pressure limit or a gauge pressure limit?

White_FC

Please correct me if i'm wrong on this, but I think NZConvertible was suggesting his aftermarket boost guage read too high. (ie, '10psi' is not '10psi' according to the stock boost sensor..)
(Or possibly its plumbed in pre-intercooler?)

ilike2eatricers

NZConvertible is trying to say that his stock boost gauge is either incorrect or he already has a FCD installed and he does not know it. The reason being it is not possible to hit 10psi without a FCD (meaning he already has one) or his stock boost gauge is inaccurate. The stock boost gauge could be reading inaccurate because he may have a FCD already installed.

White_FC

Umm ok..
Sorry my bad, I obviously read it wrong...

knightkarr

haha... my bad... RICER! j/k Deep down we all have some rice in us.

Lates

NZConvertible

Absolute and gauge pressures are irrelevant to the ECU. All it knows is voltages. The ECU cuts the rear rotor's fuel when the pressure sensor sends it a voltage that corresponds to 8.6psig (23.3psia).

Evil Aviator

Yes, but in his haste to blame the boost gauge, he didn't notice that the car is being driven at an altitude of 5,280ft above sea level.

http://www.ssoar.org/outreach/underg...sure-table.pdf

12.10psi ambient + 10psig boost = only 22.10psia, which would not activate a fuel cut set at 23.3psia.

SureShot

The pressure sensor is absolute?
I had always assumed it was relative.

I drive near sea level, so I had not noticed which it was..

White_FC

Hmmm, ok, interesting, I thought thats why we had those atmospheric preasure sensors on the actual ECU itself?
I thought the voltage of the pressure sensor was somehow reference to this internal atmospheric pressure device?

NZConvertible

I don't remember that being mentioned specifically, but good spotting anyway.

I think we're all missing a rather fundamental point. If you're hitting fuel cut, you need a fuel cut defender. If you're hitting not fuel cut, you don't need a fuel cut defender. Simple as that really. Fitting a FCD to a car not hitting full cut is not going to make it run better or worse, not will it make it more or less safe.

Evil Aviator

His location is Denver, Colarado, which is known as "The Mile-High City". Aviators notice these types of things.

If you look at my questions and responses to RyoFC3S, you will see that I am trying to lead him in this direction. He needs to figure it out for himself, though. First, I need him to answer whether or not he is hitting the boost cut with the car in its currrent condition.

RyoFC3S

iTrader: (1)

I think I am hitting fuel cut.. When I push the car really hard, I hit 10 psi then it holds for probably 1 second then suddenly drops down to around 7 or 8 psi. I knew that the FCD didnt actually create PSI, but I guess I just didnt word it right.

Something I forgot to mention, which is probably really important: My boost guage is pretty crappy.. sometimes it malfunctions and says im idling at 18 psi.. again, Its a peice of crap.

If you think I should, I'll order a new one right now. I got that boost guage from the guy I got the car from.

Thanks for the help.

PS: The alititude sucks. I'm not sure what it does to PSI, but it drops me about 8 ponies. Except, since its cold outside all the time, you get a free cold air for the engine!

White_FC

Now if only you posted all that right at the start...

NZConvertible

That doesn't sound like fuel cut. All fuel is cut to the rear rotor, so you instantly lose half of your power. It is quite violent and unmistakeable. If you only think you're hitting fuel cut, you're not...

As I said before, boost dropping at higher revs is quite common for stock turbos.

fg0d

No ryo should listen, they explained it 2000x times.

Evil Aviator

RyoFC3S

iTrader: (1)

It cant be that far off though.. the first 2 times i tested it, it did fine.. I guess this means I should get a new boost guage. Any cheap accurate guages you know of? My brother is now saying when he drove it, it was dropping from 10 to 5 psi.. Bleh.

Sorry if i didn't clarify earlier.