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Old 01-11-2013, 05:06 PM   #1
darksurfing
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Question Questions Regarding my 97 STi V-Limited, something is not right :/?? boost*

Hello everyone,

Well first of all I would like to say thanks for all the help you guys are going to provide .

Secondly as you might see, I did a rebuild thread probably a year I ago. the car's been running great, it goes a lot faster than it used to.

the issue is that my car has been building a lot more boost than it used to. The car is a 1997 sti version 3, V-Limited running its stock 6s ECU. and I know it stock boost levels are around 1.1, 1.2 bar depending on air density etc, but now it goes up to 1.4 in 5th gear and on 2nd gear while brake boosting Ive seen boost up to 1.4 1.5 bar of boost and it normally holds it up to 1.1/ 1.2 bar

am I clear?

This happens on cold weather only, when temperatures are around 10-16 degrees aprox ( not that cold tho.. hahaha)

on the rebuild I did reduce compression by going to a thinker head gaskets, oem ones are 1.37 mm and I went 1.5 mm, I also went with wiseco square dish forged pistons 29.50mm, eagle H beam connecting rods, double cross drilled crank, acl bearings, etc.
That's some of the stuffs Ive got on the block.

I also have a synic Equal length Header, a turbo XS Up-Pipe and a Fujitsubo RM-01a catback. stock catted downpipe still there. I also add some heat reflective tape on the intercooler and a billion super thermo cloth on the y pipe of the intercooler and on the intake (as you can see)

I would like to install an aftermarket downpipe as well, catless would be ideal, if so i would go 2.5" cause If i go 3" I would probably have boost cut.

so my questions are...

Am I seeing this boost levels because the setup I have on the block?
Is it possible that I might have some sort of boost cut defender? because at 1.4 bar I should have boost cut, right? Ive never seen such thing on my car...
if I install a 3" downpipe the chances of boost cutting are higher than going 2.5"? I will get a ESL daughters board, but it wont be soon.

am I missing something? if so please ask me I will provide all the info you need...

ps: The car runs as fast as my mates 2011 WRX with Process west tmic, k&n typhoon intake, full 3" decat downpipe( turbo back) stock mid pipe, nameless axle back, grimmspeed up-pipe, cobb turbo heat shield, synapse and a remap.
ps2: Ive seen no det or whatsoever, but it worries me a bit, the fact it boost up to 1.4 bar, although am Happy with the results of the car, I cannot imagine how fast it will be with a downpipe and then a re-map lol
I would appreciate any help guys!

Thanks in advance.

Chris!


this is the car

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Last edited by darksurfing; 01-11-2013 at 06:15 PM. Reason: adding info
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Old 01-11-2013, 06:16 PM   #2
Rowrx11
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2011 wrx !! here... please help my buddy.
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Old 01-11-2013, 09:12 PM   #3
polaks
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So it doesn't overboost in every gear all the time? Cause that's what my 96 sti did when the colder weather hit and I believe it was the wastegate actuator... I wiggled it like no tomorrow and I guess it loosend up and doesn't seem to be overboosting anymore... odd boost spike here and there... Or if you have a boost controller try turning the boost down... that also helped with mine... Idk why but if I set mine to 14.5-14.7 it overboosts but at 14 it doesn't... idk so I just keep it at 14

Also wat kind of spark plug wires do you have on your car I am looking for new ones and Im not to sure if the 96 impreza with the 2.2 are the same wires or not...

Im also curious about the rad, what brand is that? I will be replacing mine probably in the future... Did you buy that yourself or did it come with the car?
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Old 01-12-2013, 12:31 AM   #4
blkgm8
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I see you have a built motor... I hope you have the yellow side feeds in there.
Sounds like you have a bad connection to the wastegate... There is probably an air leak somewhere between wastegate and boost source. The bleed off of air will result in the wastegate seeing less than what is actually going on. Then when it thinks it is at normal opening pressure she swings open. This is how most boost controllers work. They bleed off a little air (controlled) and you trick the wastegate into letting you get more boost.

So check all hoses. If all is good with hoses... the engine might want to overshoot (spike) because of the header and up pipe combo, basically flowing the air past the wastegate and into exhaust more efficiently than before when wastegate is open and boost could be creeping. For that you could pull turbo and port area going to wastegate hole to direct air to the wastegate hole so that it wont just want to go past the hole and cause your boost to overshoot. You could also go with an external wastegate to more effectively control boost if that is the problem.

Looks like you have alot of money in your build. I would definitely look into getting it properly mapped(tuned) right away to be sure you are not running into a lean condition
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Old 01-12-2013, 10:50 AM   #5
darksurfing
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Quote:
Originally Posted by polaks View Post
So it doesn't overboost in every gear all the time? Cause that's what my 96 sti did when the colder weather hit and I believe it was the wastegate actuator... I wiggled it like no tomorrow and I guess it loosend up and doesn't seem to be overboosting anymore... odd boost spike here and there... Or if you have a boost controller try turning the boost down... that also helped with mine... Idk why but if I set mine to 14.5-14.7 it overboosts but at 14 it doesn't... idk so I just keep it at 14

Also wat kind of spark plug wires do you have on your car I am looking for new ones and Im not to sure if the 96 impreza with the 2.2 are the same wires or not...

Im also curious about the rad, what brand is that? I will be replacing mine probably in the future... Did you buy that yourself or did it come with the car?
what you have is weird :S, is it probably because you are reaching the max boost that it can be controlled?
Mine boost up to 1.2 like it should up to 3rd gear, then on 4th goes up to 1.3, and then fifth 1.4 bar, which is around 20 psi.

on hot weather over 28 degrees Celsius, the car hardly sees over 1.3 bar on 5th gear tho..

I dont have a boost controller, the car is pretty much stock apart from the short block bluild+header+up-pipe+cat back+some heat reflective stuffs+boost gauge. apart from that, nothing else.

Im using the pfr7b spark plugs. the radiator I am not sure about the brand tho. when I used to live in NZ a mate had a performance shop called aap imports and once he gave me a sticker which I kept it until I got back to my country then when I bought this rad, because the old one got cracked i put the sicker on it hahaha. it works really well.

I bought it for like 300 usd. aprox. here in chile

and the plugs are NGK, I will take a picture of them today..
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Old 01-12-2013, 11:12 AM   #6
darksurfing
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Quote:
Originally Posted by blkgm8 View Post
I see you have a built motor... I hope you have the yellow side feeds in there.
Sounds like you have a bad connection to the wastegate... There is probably an air leak somewhere between wastegate and boost source. The bleed off of air will result in the wastegate seeing less than what is actually going on. Then when it thinks it is at normal opening pressure she swings open. This is how most boost controllers work. They bleed off a little air (controlled) and you trick the wastegate into letting you get more boost.

So check all hoses. If all is good with hoses... the engine might want to overshoot (spike) because of the header and up pipe combo, basically flowing the air past the wastegate and into exhaust more efficiently than before when wastegate is open and boost could be creeping. For that you could pull turbo and port area going to wastegate hole to direct air to the wastegate hole so that it wont just want to go past the hole and cause your boost to overshoot. You could also go with an external wastegate to more effectively control boost if that is the problem.

Looks like you have alot of money in your build. I would definitely look into getting it properly mapped(tuned) right away to be sure you are not running into a lean condition

hello, thanks for your reply mate

I have these yellos side feed injectors " Phase I 550cc 1997-1998 EJ20K STI, partnumber 16611AA231 "

I'm going to check all the hoses today, I will take pictures of everything and I will be posting them if I am missing something, by the way, I've got a video that I did last time to show how does boost behave.


the car is running faster than it did on this video.

running into a lean condition its what actually has got me worried, I have put lot of money into this build, I love the car going fast, but i would rather be safe than fast, or if both are possible it would be nice.
so if I'm having these kind of boost spike with the car, a decatted downpipe will just make things worse right?, I will probably going to have to get an EWG, that would be the best along with an engine management.


I'll check the car and I will send pictures if something is missing!

thanks for your help mate!


Last edited by darksurfing; 01-12-2013 at 11:17 AM.
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Old 01-15-2013, 12:06 AM   #7
GGSimpreza
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What are you using to control boost, EBC or MBC? I've seen EBC's do this, reach peak boost and trickle down, whereas my Hallman Pro MBC hits target boost and sticks there until I let off the throttle.
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Old 01-15-2013, 01:24 AM   #8
blkgm8
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Quote:
Originally Posted by GGSimpreza View Post
What are you using to control boost, EBC or MBC? I've seen EBC's do this, reach peak boost and trickle down, whereas my Hallman Pro MBC hits target boost and sticks there until I let off the throttle.

"I dont have a boost controller, the car is pretty much stock apart from the short block bluild+header+up-pipe+cat back+some heat reflective stuffs+boost gauge. apart from that, nothing else."


Quoted from op a few posts up...
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Old 01-15-2013, 05:52 PM   #9
darksurfing
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firstly many thanks for your replies,

I have no EBC on my car, I check all the hoses and apparently, everything is in order.

I took a few pictures of it





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Old 01-16-2013, 02:00 AM   #10
blkgm8
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I watched the video and your boost is spiking. You will notice that it hits that max boost number then goes back down a few psi as rpm rises. Either one of the solutions I presented should get you under control. Funny thing though... what is happening to your car is exactly what many tuners try to emulate. We like the boost to hit hard in the mid range and back it off at higher rpm. Get a wideband on there and see what the air fuel ratio is. If all is good you might want to leave it alone if it is fast enough for you. Weird that the car is not hitting fuel cut. Have you ever opened the cover of the ecu to see if someone has fitted a chip?

As for mapping if you do not have acess to a live mapper you might want to contact Rob for his 550 tune (very good chip tune designed for those running the yellow sidefeeds.)
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Old 01-16-2013, 04:21 PM   #11
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Quote:
Originally Posted by blkgm8 View Post
Funny thing though... what is happening to your car is exactly what many tuners try to emulate. We like the boost to hit hard in the mid range and back it off at higher rpm.
This is actually a feature of the Focus ST.

Quote:
Originally Posted by blkgm8 View Post
As for mapping if you do not have acess to a live mapper you might want to contact Rob for his 550 tune (very good chip tune designed for those running the yellow sidefeeds.)
I dont think that Rob has an EJ20K tune just yet.
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Old 01-16-2013, 11:15 PM   #12
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I'd get a wide band, I really like mine. It lets me know what my car is doing at all times. I know if it's too rich or too lean. I got a full UEGO setup pretty cheap on ebay.
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Old 01-17-2013, 09:39 AM   #13
jaxscuby
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not all tuners like oscilating boost.
i prefer flat boost to redline.

sounds like that you are overboost in the colder weather.
and the oscilation is th factory boost controller trying to
bleed off excessive boost...what it is suppose to do.

if you 3" down pipe I would match it to 3" catback.
lessen the restriction of exhaust..
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Old 01-17-2013, 10:13 PM   #14
blkgm8
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/\ I am sure you get what I am saying and definitely not talking about oscillation. I am talking about purposely controlling boost in the engine management system to give maximum gains while focusing on lessening stress on components at higher rpm. Say your flat boost Max is 20psi from 4500 to 8000 rpm... compare that to a manipulated map where we get 24psi from 4500 to 6500 then back it off a bit to the 20psi from 6500 to 8000.

Also... lessening restriction in the exhaust will make it worse because the wastegate is the problem not the exhaust. The air takes the path of least resistance and wants to flow past the wastegate hole which does not allow the wastegate to properly control boost. This is why many eventually or depending of turbo setup initially go with an external wastegate setup.
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Old 01-17-2013, 11:45 PM   #15
blkgm8
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Quote:
Originally Posted by TommyAtomic View Post


I dont think that Rob has an EJ20K tune just yet.

You are right... for some reason I was thinking of an ej20g when I suggested that. The ej20k ecu is in fact tuneable now though using ESL live mapping. http://www.enduringsolutions.com/
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Old 01-18-2013, 02:13 PM   #16
darksurfing
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Quote:
Originally Posted by blkgm8 View Post
I watched the video and your boost is spiking. You will notice that it hits that max boost number then goes back down a few psi as rpm rises. Either one of the solutions I presented should get you under control. Funny thing though... what is happening to your car is exactly what many tuners try to emulate. We like the boost to hit hard in the mid range and back it off at higher rpm. Get a wideband on there and see what the air fuel ratio is. If all is good you might want to leave it alone if it is fast enough for you. Weird that the car is not hitting fuel cut. Have you ever opened the cover of the ecu to see if someone has fitted a chip?

As for mapping if you do not have acess to a live mapper you might want to contact Rob for his 550 tune (very good chip tune designed for those running the yellow sidefeeds.)
I have never opened the cover of the ecu before, I guess it will be a good idea to open it and see if there is something in there.

And also is very weird the fact that I'm not hitting fuel cut. I should have hit it already, right?

Quote:
Originally Posted by CRX7 View Post
I'd get a wide band, I really like mine. It lets me know what my car is doing at all times. I know if it's too rich or too lean. I got a full UEGO setup pretty cheap on ebay.
Sure I will get that, I need to know how my A/F are. but at the moment I have no idea how they are u.u

Quote:
Originally Posted by jaxscuby View Post
not all tuners like oscilating boost.
i prefer flat boost to redline.

sounds like that you are overboost in the colder weather.
and the oscilation is th factory boost controller trying to
bleed off excessive boost...what it is suppose to do.

if you 3" down pipe I would match it to 3" catback.
lessen the restriction of exhaust..
it should work better and hopefully I will not get fuel cut by installing this.
what do you think?



Also I'm looking forward to install an ESL board to remap my stock 6s ecu. that would be the best solution to all my issues haha

thanks everyone for the help, I will take a pictures of the ecu once I remove the cover to see if there is something in there
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Old 01-24-2013, 11:02 AM   #17
darksurfing
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sorry for the delay of the pictures, I havent had much time to get into the car and have a deep look under the dash. However, Ive recently found that I have got an exhaust leak on one of the flex joints of my header :/ EL header will have to be removed in order to fix those crapy flex joints with plain stainless steel. and get back to the oem header.
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Old 03-13-2013, 10:50 PM   #18
darksurfing
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just to give an update, I installed a flat plate 3" catless downpipe, and my car boost 0.2+ bar on lower gears but wont go over 1.5 bar on 5th and now it goes as fast as my mates 2007 Sti Limited that has around 370-390 horsepower at the crank.

Still no boost cut or anything.
I honestly did not want to check the ecu, however I'm going to do it now, it is not possible that the car behaves like that on a stock ECU? right?

Last edited by darksurfing; 03-17-2013 at 03:37 PM.
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Old 03-18-2013, 01:54 AM   #19
blkgm8
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Quote:
Originally Posted by darksurfing View Post
just to give an update, I installed a flat plate 3" catless downpipe, and my car boost 0.2+ bar on lower gears but wont go over 1.5 bar on 5th and now it goes as fast as my mates 2007 Sti Limited that has around 370-390 horsepower at the crank.

Still no boost cut or anything.
I honestly did not want to check the ecu, however I'm going to do it now, it is not possible that the car behaves like that on a stock ECU? right?
What came about with the headers? Did you end up swapping back to OEM or repair the leaks?
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Old 03-22-2013, 12:11 AM   #20
darksurfing
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Quote:
Originally Posted by blkgm8 View Post
What came about with the headers? Did you end up swapping back to OEM or repair the leaks?

I ended up swapping back to the stock header. Money is not flowing at the moment, so I have no time to go somewhere and get it fixed.
I miss my equal length header sound tho.

this month Ive gotta get my warrant of fitness so aftermarket exhaust will have to be swapped by the stock one, once I pass I will put the header repaired and installed.

Will upload a picture tomorrow of the EL header vs Uniqual Length header.

I currently have some electrical problems with my car , low beams are not working.
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