DJ_Merle

iTrader: (6)

Hey guys,

I was hoping I'd be able to do enough searching throughout the forum to find all the answers I was looking for so I wouldn't have to make this thread, but that didn't happen lol. So for those of you who browse the Non-Technical and Pictures section, you may have seen I picked up a 1990 Turbo-II last spring.



Since I've purchased the car, I've been doing tons of research to get a better understanding of what to look for how and how to maintain a turbocharged car. Right now all I've done to the car is install a HKS Turbo Timer. Now that spring is approaching, I've tucked a bit of money away to do some things to the vehicle. One of which being the Racing Beat Rev-TII Exhaust system.



As stated on the website, it states that the unassisted boost pressure is increased to 10-11psi. I've searched using different tags and have found that people are needing to port the wastegate in order to stop boost creep. I contacted Racing Beat, and they stated it's necessary to get the FCD, but I've read that doing this is not the best idea as this will let the boost spike uncontrollably. I've looked into what can be done to help control boost, and I've found obviously there are boost controllers and such.



I've also found that you can purchase adjustable actuators which can adjust boost. does this help?



What I'm asking is, what are the necessary things to do when installing this exhaust? I'm not really looking to go standalone (which I've read some people hae done), as I'm not looking for massive power gains, just a nice increase in power while keeping the car reliable, and drive able. Thank you for looking and for any help you have to offer!

arghx

iTrader: (3)

nothing else matters if the wastegate won't flow enough (as in, requiring porting). no actuator or boost controller will do you any good. Even a heavily ported s4 or s5 wastegate can still be overwhelmed depending on your level of modifications.

SpeedOfLife

iTrader: (16)

I spent the last two days porting my S4 turbo to 30mm (stock is 12mm diameter! TINY!) and I'll reinstall it tonight. There's a thread I'd been discussing this with another guy, florotary I think, I'll post pics and an update in there before long.

walken

iTrader: (6)

I've owned several s5 T2s. on all of them the REV II was just a bolt on affair. no mods needed, even with the factory boost controller working. I still would recommend a rtek 1.5 just in case.

Brody8877

iTrader: (10)

Stock ecu cuts the fuel before you can even boost creep. I would highly recommend porting the wastegate, S4 turbo like stated above is tiny, S5 have bigger waste and flapper. Getting the FCD with no larger injectors, or way of controlling them is all bad. What if you creep up to 18-20psi and your injector max out duty cycle, you will run lean potentially destroying your engine. Boost controller can only raise boost but will not lower boost or way to control creep. The wastegate actuator will change your boost setting, if you're planning to boost off the wastegate, but still will not able control or eliminate creeping.


I would highly suggest going 720cc secondaries, upgrade fuel pump, port the wastegate, and some sort of EM such as rtek 1.7 to control the larger injectors.

HOZZMANRX7

iTrader: (43)

I'm going to deviate a bit from Brody regarding the FCD. As Brody indicates, what the FCD does is keep the rear rotor from leaning out at the higher boost the Rev II will allow. This "interesting" design into the ECU creating rear rotor stress is the culprit of why you hear about folks finding low compression in the rear rotors when the front is still fine. What the FCD essentially does is trick the ECU into not leaning out the fuel to the rear rotor. So in all cases, with the Rev II you do want a FCD. And make sure you get a new FCD as it's almost impossible to tell if the FCD is bad.

Now since you have a S5 TII, thus an S5 Turbo, I'm not so sure porting the wastegate is all that important in your situation. If you were running a S4 TII, absolutely you should port.

And, one more time I'm going to deviate a bit from Brody. If you're running the stock ECU, go with 680cc injectors in the secondaries. First hand testing found that the 720's will bog things down where the 680's don't. You wouldn't think 40cc's would make that much difference, but there you go. 720's and I absolutly agree you'll need to upgrade your EM.

Do up grade your fuel pump to a Walbro or Denso (my choice). Also, I followed a tip from my Tuner and ran a larger gauge wire directly from the battery positive to the fuel pump to insure consistant power to the pump. A simple bosch relay using the stock fuel pump power source as the trigger is all that's needed.

The HKS wastegate is a good thing, but unless you do some minor upgrade of your Turbo to, say, a T04*, might be a bit of overkill with modest if any additional benefit.

Summary, what you need when adding a free flowing Exhaust such as a Rev II (which I have on two of my T-Verts) are all pretty much bolt on things:

Do buy a NEW FCD.
Do consider 680cc injectors for your secondaries if you're staying with the stock ECU.*
Do upgrade your fuel pump to what ever your own research concludes.
Do run a dedicated power to the fuel pump connector.

You might want to consider upgrading your air filter as well. It's all about making it easier for your engine to breath. The Rev II takes care of the free flowing exhale, but if the inhale isn't also improved, you dilute the benefit of the REV II. I have a K&N drop in my S4 T-Vert and a K&N cone on my S5 T-Vert since it comes with a CARB sticker.

*You can use GSL-SE injectors despite they being low impedance (you have a high impedance system) by soldering a resistor to the power wire for each secondary injector.

Grip

iTrader: (9)

here is my setup:

RB REV TII turbo back
Rtec 1.7
RC 750cc secondary injectors
walbro 255 fuel pump
K&N air filter (in stock air box)
S4 wastegate ported to 32mm

thats about as muich as im doing as far as power to my car this year.

therotaryrocket

I suggest you get the exhaust and get a wideband oxygen sensor and gauge. I have the AEM UEGO unit, this will allow you to monitor your air/fuel ratios and make sure your engine is in a safe running condition. Well also you'd probably want an aftermarket boost gauge as well to show a more accurate representation of what boost your at.

Anyways, I run an S5 turbo with stock wastegate, I've ran my car with only a 3" down pipe and no other exhaust, I still didn't get a bit of boost creep out of 1st, 2nd, or 3rd gear. I also have an FCD and an NXS (ebay) boost controller. Stock fuel pump and injectors in my car, and my a/f ratios stay around 11.5:1 full throttle all the way up.

Basically you don't want your engine to run lean (higher numbers like 14:1 or 15:1 are scary at full throttle especially in boost), because it may lead to detonation and then engine failure. So if you have the wideband setup and boost gauge, you'll know what's going on and only if necessary will you have to upgrade your injectors or pump or whatever.

But you may want to consider rewiring your fuel pump, it's a pretty common modification to ensure proper voltage gets to the fuel pump and it's a pretty cheap mod too.

Vr6Jason

ah it was my understanding that i could run the turbo-back with just a ported s4 turbo, and rtek 1.5(for the fuel cut defenser) and i wouldn't have to worry about running lean? or i was told that i could stick to the stock fuel system for now? but by reading above it sounds like i need to port the waste gate, get the rtek 1.7(along with 720cc secondaries and the 255 walbro pump) does that sound correct?

RotaryRocket88

iTrader: (7)

Depends on how much boost you intend to run. The stock fuel system will make you run lean if you push it beyond about 9 psi. The pump can't flow enough and the injectors max out.

SpeedOfLife

iTrader: (16)

Mine's similar.

REV TII full system
Rtek 2.1
720cc secondaries
high flow pump (not Walbro, something else I forget)
custom CAI (in a thread titled "my cheap cai")
S4 waste gate ported to 30mm

I finished the waste gate port yesterday. I STILL creep a little in 4th gear. I have the stock actuator hooked up, no boost controller, so it's as low as it gets without disconnecting the rod and leaving it open all the time. I can run WOT through 3rd hitting about 10-12psi then in 4th it'll try to go to 14-15psi. Haven't fiddled with 5th yet, but it won't be any better. I'm disappointed, but it's better than it was.

therotaryrocket

Idk what kinda car your talking about or where you got that info, but I have ran my 87 T2 (jdm s5 engine) with the completely stock fuel system to 10 psi at least without running lean at all (staying under 12:1 a/f ratio). I'll give you some though, I didn't really boost in 4th gear so I guess it could start to lean out then...

Anyways, if you get a wideband you'll know if your car is running lean. If it starts to go lean at all then back off until you can appropriately modify/tune the car. See how useful it is? I've blown one 13bt due to plain stupidity. I felt this time around that getting a proper boost gauge and a real wideband o2 sensor were essential when increasing boost. btw, I usually get a friend to ride with me and watch my boost and a/f gauges while I do a few pulls until things are set correctly.

One more thing that's important to keep your eyes on is the turbo itself. If you do a few hard boost runs up and down the street and pull over with the car still idling, pop the hood and see if the turbine housing is glowing, don't let it get cherry red! A lot of people get an EGT sensor to monitor this, and when the money flows in I'll get one too, but for now I just hop out and check things out.

RotaryRocket88

iTrader: (7)

Obviously I'm talking about 2nd gen TIIs. Back when I was young, and mistakenly took the advice of a local "rotary expert", I blew an S5 TII engine by running 10-11 psi with stock fuel and an FCD. It lasted about a month before taking a dive at WOT on the freeway.

First you have the false pressure data the FCD sends the ECU. Then there's no getting around the low flow of the stock pump at increased fuel pressures, or the limitations of 550cc primaries. At about 10-12psi on the stock turbo, they will max out before 3800 RPM when the secondaries come on. This gives you a nice lean spot right where the engine is creating peak torque & max chamber pressures. I've logged this with my Rtek, and compensate by having the secondaries able to come on as low as 3100 RPM instead. Glancing over at a wideband won't show you this lean spot in the midrange, the display just isn't going to update quickly enough. If you have some logging software, you'll find it. People blowing TII engines on stock fuel isn't exactly rare. It's part of where the horrible reliability reputation comes from (that and the FD lol). You can find a ton of threads on it.

It sounds like you tried running 10psi once or something. Well as I mentioned, it can work...for a time. Crank the boost controller up and go step on it in 4th or 5th gear. Chances are you'll be doing a compression test soon after.

therotaryrocket

alright, well I didn't really realize that this mid range lean out might not show up on my a/f gauge. I have been keeping my boost around 8-9 psi anyways because I'm still working out some other issues so maybe I'll just leave it there until I have the money to upgrade my ecu. Good thing my intercooler hoses have been blowing off lately, it's probably saved my motor, but I need to get an ecu, stock sucks!

Definitely appreciate you educating me on this issue. Sorry about before, guess you were right.

Vr6Jason

thanks guys this thread has defiantly convenienced me to go with rtek 1.7 720 secondaries and the fd fuel pump. i'm trying to soak in as much info as possible before i do anything. and even with that setup i'd still be kinda worried to go over 9 lbs.. is a manual ball and spring boost controller effective enough for now.

DJ_Merle

iTrader: (6)

+1 Thank you everyone for the fantastic info! Looks like an Rtek 1.5 and some fuel goodies are going to be needed for this exhaust. Feel free to keep adding info to this page!

Furb

iTrader: (2)

boostcontrollers are meant for raising boost pressure...
wastegate size and spring pressure control the minimum boost pressure.

port the wastegate and get it tuned so it doesnt blow up

SpeedOfLife

iTrader: (16)

That depends. They're manual controllers and will all operate slightly different. Make sure your boost will never creep above 'x' psi first before installing a controller, as it will not go any lower than that, a controller can only raise it. Even on a manual controller's lowest setting it can potentially raise the boost too high. This was the case with mine when I was checking out how my new waste gate port worked, so I'm running a vac line straight from the compressor side to the actuator (just like stock).

Vr6Jason

oh good that's what i thought, so right now i need to buy a good boost gauge and port the waste gate, and just make sure i'm not creeping up above 9-10 lbs?

midnightbluefc

iTrader: (19)

good info here for minor power upgrades

cone_crushr

iTrader: (18)

WELCOME to the rotary world, where apparently simple questions induce complexities that boggle the average mind. You may want to stay at a Holiday inn for a night or two.

Just to add yet more fuel to the fire regarding rewiring the fuel pump, note that by running a relay off the stock pump wiring to deliver full battery voltage, you negate the dual speed (voltage) function of the pump used to reduce the flow during low load operation. In my case that also caused the Fuel Pressure Regulator to be overwhelmed due to the increased return flow. Frankly, while replacing the stock pump is mandatory, rewiring it has implications that start adding up (although the fuel pump resistor is unreliable at elevated temperatures).

Tread carefully dude. Hope your head doesn't explode.