too much boost/boost flutter in 5th gear help please!
 

hey guys,


I recently had a Forge MBC on my car for about 4 months.Car ran great,held boost fine,didnt flutter.

Recently I took the MBC off to go back to ECU boost,then get a GM solenoid installed.When I put back my stock boost hoses,connected them to the respectable nipples on the stock BCS,I went to go do test runs.My boost gauge says im hitting 25.4 lbs!!! then tapers down to 21lbs. I HOPE this is because my gauge is incorrect [prosport mechanical] ,but when I hit two step,it builds 7-8lbs,which I think is normal.I dont get boost cut,or fuel cut..Any ideas?


Also, when im around 3200rpm's, and go WOT, it spikes 24.5lbs, the tapers to 21,then flutters from 19-21lbs.You can here it through the intake.



I never had these problems with the MBC,can it be a bad BCS?PLEASE HELP THANK YOU


pj:mitsu:

why you get rid of the forge? and check to make sure you hooked everything back up correctly

because and im pretty sure all the lines are correct.I was told that for the hose running from the intake to the BCS,i can run just a regular vaccum hose.Is this correct?

did you follow this?

https://www.evolutionm.net/forums/ec...-solenoid.html

i believe unlike a mbc where you can control your boost with the controller by turning it up/down, now with this you have to use ecuflash

Tuning

DONT DRIVE UNTIL YOU HAVE ATLEAST LOWERED THE WGDC TO 50

For the tuning your gonna have to read a lot.

Here are threads to use.

The original how to I made. there was a lot of discussion on how the stock system works.

HOW TO - Control boost using ECUFLash and the stock boost solenoid

Here are some others.

http://www.norcalevo.net/forum/index...c,17318.0.html

http://www.norcalevo.net/forum/index...html#msg254039

log WGDC in EvoScan

There is others, but you'll have to find them

Also, here is a great description on how the error correction work.

Thanks mrfred

Quote:
Originally Posted by mrfred
The "Max WGDC" table is poorly named. It should be called "Baseline WGDC" table. When you are cruising, the car is at 0% WGDC (at least that's what EvoScan says), and when you stomp on the gas, the ECU looks at the engine RPM, then goes to the Baseline WGDC table, reads the WGDC number, and applies that value to the BCS. At that point, the ECU then starts comparing the actual load to the target load (BDEL + boost offset) about once every 0.4 seconds. If the actual load matches the target load, then the ECU continues to follow the WGDC value (vs RPM) in the baseline WGDC table. However, if the ECU sees a discrepancy between actual and target load, then it can/will apply a correction to the WGDC. The amount of correction depends on the values in the boost error correction table. The correction is simply to raise or lower the entire Baseline WGDC curve. So after the correction is applied, the ECU follows the raised/lowered curve. It checks again 0.4 seconds later, and if necessary, raises or lowers the curve again. This is why the correction table isn't a function of RPM. The graph shows the behavior well. The blue arrows show when corrections are made, and its apparent that the ECU is simply raising/lowering the baseline WGDC curve.

I have yet to put the GM solenoid.Nothing has been done to the ECU.no flashes,nothing.


Could this be because i installed my evo IX turbo?anyone??

You put the lines in wrong places most likely. There are pills in those. You have to make sure they are where they need to be.

lol what i said in the posts before

but you say you havent installed the GM yet?

i've called shops to ask,and according to them,i do have the lines in right....I know they have pills in them..

http://i289.photobucket.com/albums/l...29554450-1.jpg

the one with the red tip connects to the WGA,the other one connects to the turbo nipple.The other end of the hose connects to the BCS nipple closer to the front of the car.correct???


no,i havent installed the GMs olenoid,i havent even purchased it yet.

If you installed a bigger turbo (9 instead of 8) that's the cause. The ECU boost tables need to be retuned. You're hitting more airflow at the same WG duty.

that does make sense to me...


but shouldnt it be boosting up there in all gears,instead of 4th and 5th gear?any idea what causes the flutter?thanks bro..

pj

I'd recommend you get it tuned once you swapped back to ecu controlled boost. I'd be easy on the boost until then. When I swapped out to a green turbo I had fluttering/psst/psst noises at low rpm in higher gears. It would randomly happen since you're putting full load on the motor and it can't take the added air fast enough instantaneously. I just drop to a lower gear and I've had no problems.

take it to a shop get it tuned and let them have a look at it...

thats what i';ll probably end up doing.


any more info??