Help Needed:STI 8

[fai17]

I have fitted a APS cold air induction kit & a full decat snakehead back 3" system & uprated Bosch fuel pump.Its on standard ecu map the now.

I have a problem : a flutter like noise when coming on boost in 4th ,5th & 6th gear at low RPM(e.g 3000rpm).

on my Defi boost gauge, the needle flickers like mad when at peak boost(1.8bar).

the peak boost has been reduced to 1.5bar then settles to 1bar by Greersport.

there is hesitation when its making the above noise but goes away when boost drops back down to 1bar.

with the boost decreased,it's alot better but not cured.

i am having the GEMS ecu put in in 2 weeks with a new map.

will this cure it aswell as added BHP with the GEMS ecu?

is the induction kit flowing too much air?

will i need to put the standard air box in to get it run normally?

is the induction kit the cause of the problem?

if so i will get rid of it.

I need some much needed advice please from yous tech head out there..PLEASE & THANKS

if you need more info please let me know as i can't sleep at night thinking about it....HELP...

[Gee Wr1]

The Wr1 makes fluttering noise at around same RPM seems it's just turbo spooling. Less so now since the turbo hoses were changed under a recall but it's still there, seems after discusion all the WR1's do it though.

Sounds like boosts spiking due to new unrestricted exhaust system, but 1.8 bar

When you get the GEMS fitted it does away with the MAF sensor & uses MAP sensor instead so the induction kit will be fine.

Should all be sorted when the GEMS is fitted & mapped.

Gee

[Edinburgh-Chris]

1.8Bar in any subaru without an aftermarket map is Engine suicide!!

1.8bar = 26.1psi

Engine knock must be near the level of actually hearing it!!!

STI8 with Gems is great fun, GET Antilag, great fun to be had.

[john_robertson]

As already said, runningthat boost on a standard map is asking for trouble.

The fluttering you are hearing could be one of several things,

Waste gate chatter due to the high boost pressure or the standard D/V is struggling to hold the pressure and leaking some, added to that the fact that you have the APS system you will hear it more.

John.

[the squiggle]

Way to much boost, AFAIK it should be about 1.4 bar dropping to 1.2 bar. The std map will not have a reference point for that level of boost.

Do you have some sort of Knock monitoring or Air/Fuel Ratio monitoring as the hesitation you descibe could be DETONATION.|

Is the APS cold air induction filter situated in the inner wing or located where the std air box was located?

Agree with Mr NTS, the Dump valve will be stuggling to hold back the pressure at that kind of boost level.

Grant

[Johnny50]

Thats a fair bit of boost !!!

When i was running Gems, mine would boost to 1.9bar.

Car went great, but does nothing but harm in the longrun..lol

[sma01]

the aps induction kit is one of the best around mate, it flows air extremely well....GEMS ecu will cure the problem you are referring too no problem. had similar with mine when first got it fitted but its ok now that the turbo is on, altho am still to be mapped. gems would be v nice, but budget cant stretch to that just now unfortunately.....will be interested to hear how you get on with it

Scott

[sma01]

grant - aps induction kit sits in the inner wing....

[fai17]

Thanks for much needed advice

What does engine knock sounds like?

Should i fit a lamda & knock link?

Mr NTS:Its does sound like the D/V may be leaking at such boost.What after market D/V should i fit to help as i had a similar problem with a APS twin vent D/V which i have returned to seller.The APS D/V was adjusted as far as poss and it was still leaking boost(making that same fluttering noise)

As i said the boost now has been reduced to 1.4 - 1.5bar.

The car is prob running rich as the exhaust fumes is minging.....

So does most of you think the GEMS ECU should sort it out , no problems.what a relieve

Cheers everyone.More info still needed

[john_robertson]

Engine Knock normally isn't that audible to the ear, it normally needs DET cans or a knocklink to detect it acurately, if you can hear it " which is worrying " it sounds high pitched, if you take a spanner and gently tap it against something solid like a vice or year inlet manifold you will hear a similar sound.

A Knocklink a an advisory addition to any mod'ed engine it can be got for approx £140 from BR Developments, it is a sensor that bolts on the block above No 3 cylinder, this sensor plugs into a box with LED's on it, the higher the LED's light the more knock it is sensing and potentially the more damage you are doing to your engine. The Lamda Link is a nice to have, basically shows your fuel ratio via a sensor in the exhaust and gives you an idea of how rich/lean the engine is running, as I said nice to have but if it was a choice get the knocklink first.

Seems strange that the APS D/V was leaking most of the APS gear seems to get a good right up, the next choice would be HKS but once again you could run into problems as this is a VTA unit and these can cause uneven running and possible lean running due to the closed loop design of the scooby fueling management " I'll leave Grant to explain this one " but if you have hte GEMS fitted you may be able to overcome this in the MAP.

Boost still sounds high to me considering you don't have the GEMS fitted yet, something around 1.4 peak and 1.2 holding might be better, you don't mention your IC or fueling, have they been touched? you'll need an uprated fuel pump and possibly an uprated fuel regulator.

The car is probably running rich the now as the standard ECU is trying to cope with the higher boost pressure, its probably only rich at idle one on boost there is a good chance the car will be lean, which takes us back to the engine Knock again.

The GEMS ECU should sort it all out provided it is mapped well.

John

[fai17]

i have the standard I/C & an uprated Bosch fuel pump .

it is at idle when i can smell the fumes.

a knocklink should be on my list to do.

cheers

[johns]

I'll just add to the comments above to say that you are very lucky that you haven't seriously damaged the engine by running at peaks of 1.8 bar and not had the ECU remapped to cope. The hesitation could be due to det, and the noises are most likely the turbo, as it wasn't designed to be run at that boost pressure and will be well outside it's efficiency range. The fuelling and timing will likely be well off, and by default the ECU will most likely pour in lots of fuel to try and make it safer, which in itself will cause hesitation and poor running.

On the standard turbo, I'd recommend no more than about 1.4 - 1.5 bar peak (when properly mapped), dropping down to about 1 - 1.2 bar at the top end.

John