he just got full 3" exhaust installed. his car is a 88 T2 running no boost control just FCD. man his car is MOVING ran about 8-10 psi when i drove it. puts my stock TII to shame.... i can't wait to get exhaust for my TII!!!!

 

You gotta love the power gains a rotary engine gets from a simple free-flowing exhaust.

 

You gotta love the power gains a rotary engine gets from a simple free-flowing exhaust.

 

Man, I'm just glad to be done w/ my exhaust, for now anywayz!. Also, very happy to have Vosko's "thumbs" up...

 

Yah they are usually really fast for a couple hundred miles...

 

Man, I'm just glad to be done w/ my exhaust, for now anywayz!. Also, very happy to have Vosko's "thumbs" up... On the other hand, I have to prepare myself for more killer stares from my beloved neighbors...

 

his car is safe. he is gonna get walbro pump. 10psi is fine. he isn't gonna blow. i've seen much worse TII's running higher boost and not pop

 

FCD tends to lean out the car a bit
cause the computer is tricked into thinking it's running at a lower boost, so it does not increase the injectors
flow to match the boost

re-wire the fuel pump at least

 

Uhm, incorrect. As per RETed's experimentation, the pressure sensor signal does not increase injector duty cycle. He thinks it retarts timing, and I'm inclined to agree. Over spring break I'm going to be breaking out with the o-scope and finding out for sure.

Brandon

 

does the FCD lean out the ECU thru the WHOLE boost range? from 1psi up to 10 psi?

or does it just NOT let the ECU see over 8psi or so...

for instance, i have an FCD on my car...never hit fuel cut before with my mods...but put it on anyway...finally got a boost gauge, and i see between 6-8 psi on 1-3rd gears...should i take it out?

 

I think fuel cut comes on @ 8.6 If I'm not mistaken

My GXL that had the present motor my TII has
never had a FCD
cause it lacks a factory boost gauge

So the computer never knows the boost level

My GXL halled ***! 13.5
Then put the motor in a TII body with a FCD
I noticed this setup did not have the same power
as the GXL had

Maybe it's due to the NA tranny's gear ratio
I was using

But I suspect I was not getting the same fuel flow
cause of the FCD.

 

1.The ecu always knows the boost level(manifold pressure)if the boost sensor is present,connected to the harness and wiring is good.Lack of the boost gauge is irrelevent,according to my wiring diagram the signal for the boost gauge comes directly from the sensor not the ecu.
2.Mazda believe that the pressure sensor signal adjusts the fuel amount injected,according to their training manuals specifically the pressure sensor(or boost sensor) increases the amount of fuel over the base fuel map,and the atmospheric pressure sensor reduces it.I have never personally scoped the signals,but my money is on Mazda.
3.Depending on the type of FCD,fuel may or may not be reduced across the range of manifold pressure.

 

I don't think it's the fuel you need to worry about so much, it's the timing.

I think the FCD is a bad idea. I don't care how many people have run them successfully, one would never find it's way onto a car I owned.

 

Well you'd better not put exhaust on one either, unless you put a standalone on it. With my exhaust and a heavily ported wastegate, its hard to keep it under 10 psi.

 

Being new and knowledgeless to the rotary world, explain to me why this is again.. I mean, if so many peepz have run them successfully, why not use it?Thanks!

 

Standalone + PIA install & tuning > new engine

If I can't go full throttle all the way to redline without worrying about breaking something then whatever the upgrade was that caused this problem was pointless.

 

You wont catch me throwing $1500 at my car for a Haltech just cause I want a 3'' exhaust. Building the engine isnt an issure for me.

for me $Standalone > $new engine

 

FCD's don't blow engines. people running too much boost blows' engines. as long you keep boost around 10psi and under. you are fine. the only people that blow are ones to spike to 20psi and dont' let off the gas!!!

 

The FCD tricks the ECU into thinking it's running within an acceptable amount of boost, so fuel cut does not occur.

The ECU controls timing advance and retard. Since the ECU thinks all is peachy it's not going to pull timing in case a problem arises, such as a boost spike, or if the car begins to run lean for whatever reason.

Lean + too much timing advance = detonation = bye bye engine

You can compensate for this by installing a beefier fuel pump, larger injectors, and piggy-back computers out the wazoo, but the essential problem you're just throwing band aids on is still there.

The FD's computer can't even compensate for fuel and timing with a straight through turbo back exhaust, so it's not surprising that the FC has the same problem.

For a lightly modified car I guess an FCD is fine, and if you pile on enough extra **** to get around the problem the car will probably do well enough. But if it were my car I'd do it the right way, with a stand alone.

 

For lightly modified cars, like I said, IMO it'll work just fine.

But if you want to go very far with the car you have to deal with the problem.

*EDIT* -- I don't have any experience with Turbo II's, so take my opinion as such. The only thing I have to back me up is years of reading this forum and reading eMail lists.

 

i have experience with a couple of T2's none have blown up from having FCD's. if used properly on lightly modded cars you won't have a problem. now don't try and go run a T72 turbo, fmic etc. we are talking about a basically stock car with just full exhaust this is fine for just an FCD. hell my first T2 didn't even have the FCD and hit fuel cut a few times and the engine still held. it all depends how lucky you are. as long as your not going crazy you won't blow up. just be reasonable with the boost less than 10psi

 

although it seems like everyone knows the fuel cuts and such for S4's...no one really knows FOR SURE whether S5's have it...some say they've hit 12 psi with no FCD and don't hit fuel cut...others say, yes, the 89-91 T2 has a fuel cut.

my question is...lets say you have a 89-91 T2...throw an intake on it. take out on a 10F degree night. go out on the highway...floor it in 4th and it somehow hits 10psi...but no fuel cut...so you decide to throw on an Racing Beat FCD. while you have that in the car...is it gonna lean out the entire fuel mapping from when the turbo builds boost as 1psi till you hit 10psi??? or is it just never gonna let the computer see 10psi...

 

I'm about to put a FMIC, some 720s, and a TO4B hybrid (just cause my turbo is shot) on my car. I'm not even gonna put a SAFC on it. If it blows up **** it, I want a half bridge anyway. I give you permission to point and laugh when my 150k+ mile motor finally pops.

 

as long as your are just running 10psi with basically stock car and full exhuast you shouldn't run lean

 

**** I'll have that bitch up to 14 psi. I already have full exhaust, a bov, tid, fuel pump, gauges, fcd, ported wastegate, blah blah.

When it blows I'll sell the hybrid and buy the **** that I really want.