rotary_fan

Hello all,
I picked up a completely stock 87 TII with 80k on the car. I've been working on getting it back on the road, rather slowly. The car has no exhaust at all, so yesterday I ordered the RB RevTII complete exhaust. I've read where I need an FCD or something else to trick the ecu into not cutting fuel but also about the S4 wastegate's weakish spring?

I am trying to piece together the next steps due to the above mentioned situation so that I have a safe mostly stock car.
Does the following steps make sense ( and the order) or is there something I'm overlooking or better options I'm not aware of?

1. I spoke to BNR about what we can do to fix the S4 turbo and sounds like their stage 1 would take care of the wastegate situation and I'd have a fresh S4 turbo? Thats all over $900

2. Is buying an FCD really the best choice? Would an rtek or something else be better to address the fuel cut situation and also gain some other features?

3. Then I remember reading something about possibly needing to upgrade my fuel pump or maybe rewire it to make sure that isn't going to contribute to a lean condition? Is this necessary or recommended what which is best.

This is all because I don't have an exhaust and went with a free flowing one.. I'm definitely still learning trying to piece this together but just not confident in what needs to be done to make this a safe setup.
Please let me know if there are any other details I could provide. I did search and found some helpful threads but nothing definitive and they were much much older.

Thanks

j9fd3s

iTrader: (3)

#1, the stock turbo wastegate is small, but so is the turbo, so there is a balance there. ive usually ended up with something that doesn't boost enough

For #2 i've always used the old HKS F-Con's, they work great. it basically plugs in between the stock ecu and injectors and it has its own maps in it with a 0-9 potentiometer. 0 is stock, and 9 is as rich as it can go.

for #3 i've just put in a used FD fuel pump, usually if you find a guy with an FD, they will have a perfectly good one. i'm not sure a fuel pump is really needed though, my current car is an FD engine in an FC chassis, and it was running an FC pump for years and it was ok. you should change the filters, and it wouldn't hurt to check the voltage drop.

Chandon Pierre

1. BNR Turbo is a great option because he welds on a bigger waste gate flapper. If you're not planning on using an aftermarket boost controller, you can get by with porting your existing turbo. Port where the flapper sits , and port the cover that sits behind the flapper to allow it to open more. I also like to port the runners leading to the wastegate hole but that's more optional. This will prevent you from overboosting in colder climates.

2. FCD is the better of two evils. It basically just stops the ECU from cutting fuel when you overboost so you don't instantly lean out, but the ECU doesn't have any fueling map past 9psi I believe. So it's still ideal, you can still lean out. On the easier end you'd use FCD+SAFC to correct fuel trims, or an RTEK. RTEK has does not have a boost limit, so no FCD needed. On the more difficult but "best" end of the spectrum, full standalone.

3. There is a fuel pump resistor that reduces fuel pump voltage in low engine load conditions. This, coupled with relatively low gauge wire in the stock harness has been found to reduce fuel pump voltage in full load conditions causing lean out events. Personally, I wire in a 10AWG power wire to an added relay to bypass the resistor altogether. There are a few different ways to go about doing this so be sure to read up and think about the pros and cons of each.

rotary_fan

Thank you both for the suggestions and guidance.. i've been looking around for both the f-con and I guess an rtek1.5 or maybe the 1.7 if I can get some 720 secondaries.
The f-con has been a little tough to track down but the rtek seem to pop up more frequently....

rtek install seems easy is the fcon about the same or a little different?

Do either of you have any experience with the rtek 1.5 vs the 1.7. I see the primary difference is just that you have to run 720s on the secondaries but you also gain the in car deflood feature with the rtek 1.7.

Does having the deflood feature in the rtek 1.7 make that a no brainer in the choice even with having the upgrade secondaries?

Just to recap what I currently have...stock 550s all around and RB full exhaust and S4 Turbo that I guess will need to go BNR for rebuild and wastegate porting..
Thanks!

j9fd3s

iTrader: (3)

install is about the same, the Fcon has its own pressure sensor you need to install, but that's it.

with my last t2 i was running basically the same setup, stock engine, S5 turbo, RB exhaust, cone air filter, and it would hit 8psi, and hold 7psi all the way to redline, no need for any fuel mods, lol.

these turbos can be a balancing act.

Chandon Pierre

I've had both the PFC F-Con and RTEK 1.7. Already got rid of the F-Con and getting rid of the RTEK and injectors soon as I'm going standalone. Let me know if you're interested.

RTEK is the simplest way to improve your safety margin. You'll want the additional fuel of the 720s to compensate for the higher boost pressures, and lowered secondary staging RPM (3300 vs 3800 RPM IIRC)

Robert Stanton

iTrader: (2)

RTEK 1.7 worked very well on my car. I had nearly the identical setup you have. Porting the wastegate is well worth the effort IMO. I made the wastegate as large as I could (housing limits size) and welded the head of an old exhaust valve from an ATV onto the OEM flapper to cover the hole. I use an old valve because of its ability to resist the heat.

rotary_fan

thank you all for confirming this is the correct path, i'll see if I can source an rtek locally.

KompressorLOgic

iTrader: (6)

You can easily port the wastegate your self, keep boost levels at the stock level and run it as is with the racing beat exhaust.

If you dont port the wastegate boost creeps higher than stock and leads to fuel cut, an FCD is a cheap older tech that intercepts the boost sensors signal lies to the ecu about how high the boost actually is, which leads to more advanced timing than desired, and the stock injectors run out of steam quickly anyway.

good setup to run more boost
port the waste gate your self
get a manual boost controllor
walbro 255 fuel pump
rtek 1.7 ecu
720 cc secondary injectors.
And u should be good to run about 12psi with the stock intercooler being the next limiting factor.

No need to upgrade the turbo if your not looking for big power