JustJeff

iTrader: (13)

A related thread reminded me that I also needed advice. I figured it was better to start my own thread about my setup and needs. I'm looking specifically for boost control advice, but would love some general feedback about the overall build.

My stuff is in my signature and mostly stock....Only thing to add is that I have my Rtek 1.7 shipped and will be ready when my rebuild is done. Car is mostly stock..not doing any porting.

Before detonation and rebuild I was maxing out at 12-15psi which IIRC is maxing out the S5 turbo. The Rtek 1.7 will control timing and fuel up to the max the ECU can read which IIRC is 15 psi.

I was told I could remove my boost duty solenoid because I was boosting above OEM settings. A related thread leads me to believe that the OEM duty solenoid does help with controlling the wastegate up to factory levels? Is this true?

I have been undecided about a boost controller..and that is where I need the most advice.

My thinking behind not using a boost controller is this:
-Rtek will provide me controls up to the max the turbo can hit and also the max the ECU can read (15psi).
-Boost spikes/creep/etc are more a problem with S4 turbos than S5...so I should be safe from spiking over 15psi.
-I rarely pushed the engine hard and won't be pushing the max and risking overboosting as much...so control isn't as needed.

My thinking behind using a boost controller
-If I get a simple manual one I can set it at 11 or 12 psi and not be as hurtful to my OEM turbo. From what I've read pressing a turbo to it's limits isn't healthy for the turbo. It accelerates bearing wear and such.
-I'm an extremist by nature so my instinct and rationalization is to wait and get an electronic controller a little down the road after some of the rebuild costs are deferred. Though I can get a no name manual controller for $20 on ebay.
-I need to do more research and get more advice before I'm ready to decide which is better manual or electronic controller. From what I understand a spring and ball type manual controller is the same regardless of name brand or no-name. Electronic ones are easier to setup. But I need to research and find out which brands are reliable. I seem to remember reading about one of the Profecs having problems with the solenoid.

Any and all advice is greatly appreciated

siikduke

iTrader: (5)

I didn't see you mention this anywhere, but the #1 thing you need to do first is you need to make sure you port your wastegate LARGE. With your current setup a boost controller will not help you stop at 11-12 psi. The wastegate port allow for flow away from the turbine thus allowing you to control your boost properly. Not enough flow means more boost. Once you have your wastegate ported, you will get rid of that Duty Solenoid. Reasons why? One, you are already over boosting, it was meant to control boost at stock levels. Two, it's not doing you any good and by removing it you will simplify your vacuum lines since you will be adding a boost controller.

Make sure you port it large enough! Search the forums to see what others have done. I ported mine, but I didn't measure how large I made it, all I know is that it was much much larger than the stock port. Even with that port, it still over boosts in 4th and 5th gear. I pull 8 psi fine in 1st-3rd gear and then in 4th and 5th I can reach 12-14.

After you've done this, you can go ahead and choose what type of Boost controller you want. A manual controller will take you a little more time to setup, since you will have to adjust it, and then make a run, and watch your boost, park and repeat till you have your desired boost level. An electronic one will make it easier to set your boost level, and is much easier to use when you want to up your boost or lower it to a "safe" level. I run a manual Hallman boost controller in my car and it works great.

JustJeff

iTrader: (13)

^I'll do some more reading, but from what I remember porting the wastegate is more of a benefit for S4 than S5.

R.O.D

iTrader: (3)

im running the apexi avcr and the rtek 2.1

its nice to be able to tune the boost at lower rpms, and keep the wastegate shut longer
to build boost sooner.
also it has an A ans B setting, so u could have 8 psi on one and 10 on the other.
on top of that u can create a scramble boost for 15psi if u wanted.

ive been using the avcr for 3 years, and compared to others ive seen and used its def #1



ooo, almost forgot, u can also control boost per gear.
its hard to figure out at first but after that, its pretty damn easy to use.

siikduke

iTrader: (5)

Yes it is more beneficial for the S4, but again, with your current setup that boost controller will do nothing and will not stop you at 11 psi, the stock wastegate port will not flow enough to stop it.

arghx

iTrader: (3)

The problem isn't the OEM duty solenoid. The factory N370 ECU boost control programming is designed for a stock engine with stock intake and exhaust. The problem is that there is no way to reprogram the duty cycle maps unless you have a Power FC, AEM EMS, or other plug-and-play standalone engine management system. I have controlled boost with Mazda OEM solenoids before using a Power FC, on both FC and FD applications. If you buy an s5 Power FC kit it is already wired up to control boost with the stock solenoid. If you buy an Evo or STi, they have a factory duty solenoid just like the s5 (2 port bleeder solenoid). On those cars though you can reprogram the duty cycles by reflashing the ECU

If you remove enough restriction from the intake and exhaust it is problem on both s4 and s5 turbos, especially in higher gears and in colder weather. I have personally spiked to 18psi on the stock turbo with an MBC in 3rd gear, in near-freezing ambient temperatures. The result was audible detonation (good ol' marbles-in-a-can sound) but the engine survived.

they work the same way but there is at least some difference in quality of the materials used.

Only if you truly understand how they work. They can be very frustrating if you don't. One advantage of an EBC is that most of them let you set an overboost value so that if you overshoot enough, it will disable the boost controller. Now that doesn't always stop the overboost completely but it helps. The Rtek disables overboost fuel cut which is your last line of defense. Only a standalone will let you configure additional overboost protection (fuel cut, ignition retard, etc).

Most people can't figure out how to tune them, often due to poor instructions. There are two types of external boost controllers: those using a solenoid and those using a stepper motor. Solenoid-based controllers have become much more popular over the years. All the Japanese EBC's (Greddy, HKS, Apex'i) use literally the same solenoid made by Denso.

When I had an s5 turbo I easily overwhelmed its wastegate even though it had been ported to the limits of the stock flapper. This was with a catless 2.5" exhaust, large street port, TID, and FMIC. If you have a more restrictive exhaust or intake then overwhelming the wastegate is less of a concern.

It can be very difficult to control boost with an internally gated turbo, no matter how much the gate has been enlarged. But it all depends on your setup.

Rob XX 7

iTrader: (8)

the profec when properly tuned is awesome

does the rtek have full boost control ability? If it does I would go with that, my wolf controls boost and its extremely adjustable

arghx

iTrader: (3)

I don't believe the s5 T2 Rtek can control the boost control solenoid

JustJeff

iTrader: (13)

I've got a 3" TID and REV TII exhaust with the presilencer. I'm not planning any porting of the intake or exhaust ports.

I wasn't going to do the wastegate partially because I don't own a die grinder. I've put some feelers out with friends, but so far no one I know owns one either. I don't want to buy a die grinder because it will be a one job purchase. I suppose I could take the hotside off and take it to a machine shop. I'm having my flywheel resurfaced and tapping for a fan thermoswitch so I'll have parts there anyway.

I could use my dremel, but I've never had much success with those little grinding bits.

Everyone has given me food for thought and I'm thinking things over.....again.

As far as boost controllers is concerned, I'll keep an eye out for used ones. If one doesn't turn up I'll get a manual controller. If I do a manual one I'll probably either get a Hallman or one from Prosport (I'm getting some parts from them anyway).

About Rtek
Rtek 1.7 doesn't have boost controls. Here's why I got it
FCD:
The stock ECU will cut fuel to the rear rotor when boost hits the fuel cut threshold of about 8.6 psi. Although this was put into the stock ECU as a protection mechanism, it's a quite harsh mechanism and not required for mild improvements in boost.

Up until now, a Fuel Cut Defensers (FCDs) have been external devices wired into the engine harness that interrupt the signal from the boost sensor to the ECU. The Rtek7 goes goes right to the source by removing the code responsible for Fuel Cut from the ECU altogether. This has the additional benefits in that it doesn't alter the boost signal to the in-dash gauge, there are no wires to splice, and no additional box to clutter the engine bay.

Lower secondary staging rpm:
Normally the secondary injectors start adding fuel at 3800 RPM. The problem is that the secondary injectors will not come on below this rpm regardless of the boost being run. This can lead to cars running lean below 3800rpm even if they have larger injectors, fuel pump etc. Lowering the RPM at which the secondary injectors come on allows them to add fuel before the primary injectors start to max out.

Timing retard above 9psi:
The stock ECU has no additional timing control for above around 9-10psi. This mod extends the timing control to give a little more safety for those running 9+ psi. Timing is pulled about one degree per PSI.

siikduke

iTrader: (5)

I actually used a dremel to port my wastegate... I think I had to use 2-3 of the smaller circular ones to get the job done~

arghx

iTrader: (3)

Catless exhaust without a ported wastegate is risky, even if it's an s5 turbo. A motor is more expensive than a die grinder.

JustJeff

iTrader: (13)

^True

One of the reasons I'm hesitant is that I've never seen my boost creep on me. It's never gotten higher than 12-15 psi. I've never held my foot constant on the throttle and watched my boost keep rising. But I do mostly city driving. Really the only time I see alot of WOT are country roads and entrance ramps.

Rob XX 7

iTrader: (8)

get a good electronic boost controller, I gained 30hp across the entire midrange when I switched over. The issue was the manual one would start to bleed off early. Might have been the one I had but I really think for a street driven car that is not FULL boost all the time like a drag car a electronic unit is the way to go

JustJeff

iTrader: (13)

^which profec are you running Rob? I'm eyeballing Profec B simply because they are so cheap. A used one isn't much more than a nice MBC.

Rob XX 7

iTrader: (8)

I no longer have a greddy, I now control it with the wolf v500.
I used the greddy after the manual when I was still wolf v3

all the reading of the greddy manual does is confuse you, you pretty much HAVE to drive the car on a safe road with someone else adjusting the controller and go increments at a time, as you get into it starts to make sense and you see instantly whats happening.
Just obviously set max boost first so you dont over boost

j9fd3s

iTrader: (3)

i had a bunch of different setups on my t2, i notice with a stock turbo there is a balance between

for instance the last setup was a stock S5 turbo, on an S4 motor, RB turbo back exhaust, and an open intake, it would solidly boost .4 bar, all the way up to redline.

adding a cat to the exhaust, added a bunch of lag and some boost creep, not bad it would do like .5.

i had a similar experience with the S4 turbo, boost creep with the stock exhaust and an intake was worse than with the 2.5" DP. with the stock exhaust it would hit 13psi on cold days!

ymmv though!