ADVICE NEEDED ON SUBARU'S AND BOOST CONTROLLERS

[IMPREZZING]

Over here in the usa many people on sites like nasioc seem to always say boost controllers are bad for sti's . what are you guys opinions on them as this is something i might like to do.anyone have one on their's?if so what other mods you have?

[X2]

I would think that a boost controller on an STi is bad for everyone else....

[TRINIOUTLAW]

I would think that a boost controller on an STi is bad for everyone else....

...boy yuh nah easy nah! But on a serious note...aftermarket BC does seem to cause the CEL "over boost" to come on very often...but I install the Profec B Spec II in the US Spec all the time without any problems.

[IMPREZZING]

Thanks trinioutlaw.will try it out and see what happens. when i first put on the 3 inch catless tbe i always got that cel but the cobb accessport solved it for me.

[Polydor]

I would think that a boost controller on an STi is bad for everyone else....

...boy yuh nah easy nah! But on a serious note...aftermarket BC does seem to cause the CEL "over boost" to come on very often...but I install the Profec B Spec II in the US Spec all the time without any problems.

^^^^The MBC causes an overboost problem due to vac. leak and boost spikes, this will run the ECU in closed loop mode.....the EBC are better built and almost eliminate boost spike.....I'm pretty sure you spent alot of money on the
Sti ....so you're gonna need to spend a bit on the EBC.

Check this out:
http://www.modacar.com/products/Subaru/Impreza/MODAAPE
http://www.modacar.com/products/Subaru/Impreza/MODABOC/boostcontroller.html

[IMPREZZING]

This guy i know has an apexi avcr 4 sale, he wants $300. for it and another guy has a hks evc v for sale and he wants $200. my problem seems to lie in the open loop/closed loop fuel delay ,that i heard of on the 04+sti and ptfb.i have read that the cobb accessport that i already have will help with the ol/cl fuel delay,so i might get the hks evc v as the guy with the apexi avcr also want a mbc + $300 and he needs me to remove it from the car.on the other hand the hks evc v is in the box and nearer to where i live.

[JWT]

i have a manual boost controller installed and i suffer no problems with my sti

infact when i asked if to install an eletronic i was told leave the system alone

[DrunkenMaster16]

or revert to the stock system and use your stock sti ecu and rom tune it for higher boost....

Imprezzing, if someone hasn't told you about TSOC heres a link

www.scoobytnt.com

[Rx]

ROM tuning is the blast !!!!!!

[mrlantra]

I tried both a piggy back and mbc on my legacy with no luck, ecu tunning was the only way.

[InDeForest]

Yeah, the final word on boost control on these almost-300hp 2 liter engines is that they are running so close to the edge of detonation on our lower octane fuel, any added boost without specific ecu fuel/timing modification is 'bad for them'.

If you think you can just turn up the boost to beat whichever car you think you supposed to be able to beat, you gonna be in trouble.

[TRINIOUTLAW]

Yeah, the final word on boost control on these almost-300hp 2 liter engines is that they are running so close to the edge of detonation on our lower octane fuel, any added boost without specific ecu fuel/timing modification is 'bad for them'.

If you think you can just turn up the boost to beat whichever car you think you supposed to be able to beat, you gonna be in trouble.

So well said!! Very good advice....

[IMPREZZING]

ok,i think that i will hold of on this ebc thing and just wait to get a protune instead of this 93 octane off the shelf map.thank alot guys.guess i'll just put the money towards a gt35r or fp red,fmic,injectors,fuel pump and protune.

[Alpha_2nr]

Yeah, the final word on boost control on these almost-300hp 2 liter engines is that they are running so close to the edge of detonation on our lower octane fuel, any added boost without specific ecu fuel/timing modification is 'bad for them'.

Ditto. The Scubie ECu is gonna read the elevated boost as a dangerous condition, and will try to over-ride it, or run in a "safe mode" to protect itself.

If you go with a ROM tune, the entire ECU map is "tuned" to handle an elevated boost pressure etc, w/o having to worry about knock. Additionally, if the ECU map is re-tuned, then the said ECU won't read the elevated boost pressures as a "dangerous" condition.

A dyno/protune would definitely be the way to go. The Scubie ECU is a powerful and versatile unit as is.

uess i'll just put the money towards a gt35r or fp red,fmic,injectors,fuel pump and protune.

IMPREZZING, you can look at Agency Power's GT35R kit. Awesome stuff. Check www.agency-power.com

[Polydor]

We are mixing up over boost and fuel cut.

If you have the excess boost it's going to demand more fuel and will trigger the fuel cut....don't get me wrong it's not the boost solenoid triggering it's the fuel cut solenoid being triggered....

This will be the result of the single scroll turbo setup losing fuel pressure in the 3rd cylinder....the result is a seeming boost cut off condition but in actuality it's the fuel cut being triggred by the knock sensor in the motor.

The twin scroll setup helps to alleviate the problem but now the issue is the knock sensor is tuned to a different frequency for added security...if you change the intake, exhaust and filters there is more demand for fuel and hence the ECU senses this the knock sensor triggers the fuel cut and you're in closed loop no matter what.

If you use say a 02-03 knock sensor in place of the 04-05 together with removing the fuel cut and your mods ROM tuning is NOT necessary the Denso will handle all your worries.

[Alpha_2nr]

If you use say a 02-03 knock sensor in place of the 04-05 together with removing the fuel cut and your mods ROM tuning is NOT necessary the Denso will handle all your worries.

Denso handling your "worries" ?

Even stock STi's can benefit from a ROM tune, and after that, would most likely be able to run pump gas, w/o worry of knock, and would most likely make more power than stock anyways. To put it into perspective, although WRX's don't ping on 95RON octane, they still can't run the maximum IAM possible on local gasolene....so they're technically being robbed of power, as the ECU is cutting back on ignition timing to eliminate knock. For the STi's, well....they get knock no matter how much the ECU tries to retard timing.

A "Denso" won't solve that.

[Bezman]

profec Spec S - easiest to set and control, perfect for stock cars with bolt ons.

i find the Sepc B and the Apexi AVCR are better but more tedious to set up, and the blitz. well good luck, but thats an amazing unit if you have the patients to set up all teh features..

[DrunkenMaster16]

ecutek, a data cable with a laptop and your stock ecu. RS, don't talk scooby until you own one. I wish my ecu could get rom'd but its the older version so my only bets are a piggy back system or hydra (fully tune-able ecu).

[Polydor]

If you use say a 02-03 knock sensor in place of the 04-05 together with removing the fuel cut and your mods ROM tuning is NOT necessary the Denso will handle all your worries.

Denso handling your "worries" ?

Even stock STi's can benefit from a ROM tune, and after that, would most likely be able to run pump gas, w/o worry of knock, and would most likely make more power than stock anyways. To put it into perspective, although WRX's don't ping on 95RON octane, they still can't run the maximum IAM possible on local gasolene....so they're technically being robbed of power, as the ECU is cutting back on ignition timing to eliminate knock. For the STi's, well....they get knock no matter how much the ECU tries to retard timing.

A "Denso" won't solve that.

^^^^Not true at all.....

OK so I got the check engine light to go out by going up a grade of fuel. What this really means is I reduced the engine noise so that the knock sensor in turn returned less voltage signal to the ECU. Its all a trick really.

The end result was to reduce the signal being sent to the ecu. Another way was to move the knock sensor to a different location where it would still do its job but not hear as much noise.

I found that the knock sensor must be installed and must be producing sound or the check engine light will come on so I looked for a suitable location which kept the ecu happy. In my case I took out one of the short inlet manifold top bolts and fitted the knock sensor there, with its original long bolt. It is a convenient position and within easy reach of the original connector.

The way I see it, it still has a direct sound path through to the block but the sound levels are slightly reduced because of the longer distance and sound diispersion.
There is still enough ambient noise at idle for the ECU to register within its parameters so it is working OK in this location but it is not picking up as much engine knock as in the original location at road speeds.

This approach is right on.....no ill effects, I relocated the knock sensor again, but on the empty bolt hole, same 12mm head, about six inches to driver's side, where engine flange meets the transaxle housing. Aligned the pigtail at same angle as original install, must be a directional microphone, the sensor, which based on Subaru service manual is 60 degrees in relation to the line of forward vehicle direction. Mounting surface is smaller than large area prepared by Subaru, so distance plus mating surface reduced amount of available noise to sensor and timing retardation due to "phantom knock". Torqued the bolt 17.4 ft. lbs. per Subaru, and seems that OEM original install used LokTight but you can forgo that right now as the service manual did not call for it. Did the ECU restart procedure per manual, idle for 5 minutes with A/C on, off 5 minutes, restart with A/C off for 5 minutes, then shut down. Drove car at varying speeds then for about ten miles and it was a different monster with no hesitation at tip-in throttle and definitely more punch. Idle rpm at stop was about 500 w/o A/C, but frankly can't remember what it was previously.....

You also have to have the engine surge, brake boost vacuum loss problem also with Subies (surge plus brake pedal sink), so Idle Control Valve cleaning in order if that persists.

Now regarding "phantom knock".......it's a Subie thing similar to the Gti-R Pulsar problem.....So essentially the the Denso will solve the problem once the knock sensor is relocated......just gave away thousands of dollars of free tuning advice, again ROM tuning is NOT necessary

[JWT]

boi people beleive in rom tuning and i do not see how that can be better than a reflash
after all reflash people have years and went through many cars

but it is trini

aye polydor i sent u a pm but just post the stock boost level for an sti
i know it to be 1 bar or 14.7 psi

[IMPREZZING]

Polydor wrote

Now regarding "phantom knock".......it's a Subie thing similar to the Gti-R Pulsar problem.....So essentially the the Denso will solve the problem once the knock sensor is relocated......just gave away thousands of dollars of free tuning advice, again ROM tuning is NOT necessary

What is this phantom knock and what is the Denso?also what if some severe knock develops and the ecu detects less due to the new position of the knock sensor ?

[riderz]

Hey Rom tuning and reflashing is the same thing. ROM tuning means you are tuning the car by reflashing the ECU. DUHHHH. ECUTEK does the same thing, tune the ROM by reflashing it. I prefer to use the term ROM tune because it explains what I am doing, tuning for performance. Reflashing is just the action to do that.

[X2]

and all this has what to do with boost controllers again ?

[Polydor]

Phantom knock basically is a audible noise that the knock sensor is picking up that isn't knock......a prone problem to the Scubie due to it's sensor placement......well my view......

[IMPREZZING]

^^^thanks ,might try to reposition it as you did .nice idea by the way.

[InDeForest]

Polydor the fuel cut is triggered by the MAP sensor in the case of too high boost/damaged wastegate lines, independent of the knock sensor activated 'safe mode', which is ignition retard and lowered boost via the wastegate control solenoid.

[Bezman]

RS, don't talk scooby until you own one.

i dont understand why you cal;led me out on this

i never said anything about svooby or subarus etc, i stated MY personal hands on experiences with boost controllers and what i found was easiest to install and set up

i never commneted on fuel / map / knock etc.. so you can go take a chill pill...

[DrunkenMaster16]

'Advice needed on subrau's and boost controllers'

Keyword there 'subaru's', not just any turbo car or some other brand. This guy has a subaru, were talking what works and whats safe with subaru's.

just slapping on a boost controler and raising the boost won't allow the stock ecu to do its job of detecting knock and retarding the timing and cutting back on the boost as it should. Infact it will cause damnage to have a aftermarket boost controler setup on a scoobie thats reading knock.

[Bezman]

yawnnn


TRINIOUTLAW wrote:

...but I install the Profec B Spec II in the US Spec all the time without any problems.

and you can install a boost controller (one like i reccomended or any kind) and then compensate for fuel / ignition / boost cuts etc with another device (S'AFC, ECUTEk or whatever scooby guys use), JUST LIKE MOST IF NOT ALL CARS when you rasie the boost...

and any car will have detonation etc without the correct fuel / ignition adjsutments, thats why i clearly didnt get into that.. i sateed what are IMO good boost controllers and are easy to set up


again i did not mention anything about fuel / ignition / knock/ MAF etc because i know that these need ot be altered for best results and scooby owners will know what works with their cars ecu etc..

please take the chill pill, unless it is that you jsut want to find some sort of conflict in what i am saying..

[Polydor]

Polydor the fuel cut is triggered by the MAP sensor in the case of too high boost/damaged wastegate lines, independent of the knock sensor activated 'safe mode', which is ignition retard and lowered boost via the wastegate control solenoid.

^^^Exactly but once it's bypassed to raise beyond the set boost limit of 18 PSI @ 220 KPa (Absloute) then it's next defense is the knock retard signal sent to the ECU which strangely enough ambient engine noise becomes more noticeable @ higher boost levels.

When I say bypass the MAP I'm talking about replacing the stock unit with another say a 1.05 bar or even a 3 bar suitable up to 2 bar-s of boost.....or even using a HKS boost cut defender on pin 22 plug c (136) to the MAP sensor to clamp it's voltage on the original unit....a cheap fix to overboost but not ideal for a serious tune....again fuel cut will come into play as long as the knock is a factor, ignition will tll the ECU to go into limp mode.

In effect, it seems the overboost cut is actually an ignition and/or fuel cut that occurs at approximately 18psi of boost in a standard STI engine. Essentially, 2 signals are monitored by the ECU.

'PIP' signal from ignition (strength, length and frequency of spark) and Air Flow

Using these 2 signals, the ECU determines the load the engine is under, and a boost cut is activated.