OK, a little background.... Im running a built 81.5mm LS, SFP race mani, tial 38mm w/ .6 bar spring, PTE SC6152S turbo, and Blitz SBC-id boost controller...

Well, here goes... About a month or so ago, we put my car on the dyno to get it tuned up for the 1000cc injectors, and see what we could do on pump gas... Well, we safely got it up to 18psi, and thought it definitely had some more power in it (currently makes about 350-360 on 18psi)... Well, we tried to turn the boost up, in 1psi increments, and when we did so, it would hold til about 6500-7000 rpm, where the boost would spike anywhere from 25-35psi..

Now, it has been my belief, that if I uprade to a 1 bar spring (since I am going over double the .6bar), I should be ok, and that will eliminate these issues, because it is safe to run nearly double what the spring is rated, but not over double... My tuner, as well as many other people have said the same thing...

My question is, what exactly causes this erratic spiking/creeping in the higher rpms??? I thought that the spring being rated too low, would cause boost to drop if anything. But apparently I was wrong..

Im just looking for a simple explanation as to what is causing this, and if I am going about fixing it properly...

Thanks,
Chris

 

i would think a larger spring will improve the issue, if you're going to run no less than 18 psi, get something close to that.. also, check the wastegate diaphragm and for leaks.. and your boost controller should have the overboost feature and that should work all the time unless vacuum line loose.

 

What is the gain set at on your EBC ? and have you tried to set it up to control boost with the settings ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PK SPEED &raquo;</TD></TR><TR><TD CLASS="quote">What is the gain set at on your EBC ? and have you tried to set it up to control boost with the settings ? </TD></TR></TABLE>

i have dual sbc so its somewhat diffeent from sbcid, i'd have to look at it again, basically, i have to dial it where its in the red, then set the level where you want it to cut the boost, after that set how much do you want to subtract like -10, -20 and so on.. and if i remember about gain, i have that set at 0, i guess that can allow for faster spooling but i never messed with that one.

when my wastegate diaphragm ripped, it saved me more than few times or when weather changes dramatically, it will still stop from overboosting and let me readjust settings

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtec.dc2 &raquo;</TD></TR><TR><TD CLASS="quote">i would think a larger spring will improve the issue, if you're going to run no less than 18 psi, get something close to that.. also, check the wastegate diaphragm and for leaks.. and your boost controller should have the overboost feature and that should work all the time unless vacuum line loose.</TD></TR></TABLE>

I would like to get the 1 bar spring, so I can have that 14.7 psi to run through first gear... With the .6 bar, I run 11 psi in first, and thats about the most I can run without annihilating the tires, so even 14.7 may be a challenge, but bigger tires should help that... Also, the boost cut on the boost controller is disabled, as I prefer the boost cut on my EMS

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PK SPEED &raquo;</TD></TR><TR><TD CLASS="quote">What is the gain set at on your EBC ? and have you tried to set it up to control boost with the settings ? </TD></TR></TABLE>

We adjusted the gain both ways (we played with it for a good 45 mins. on the dyno) and it still did it no matter where it was set... The boost controller is set up fine and works perfectly at all four boost levels... I just have problems taking channel 4 above 18psi... as it is right now ch1=12psi, 2=14psi, 3=16psi, 4=18psi...

Set up like that it works perfectly...

 

 

No more input???????????????????

 

check wastegate diaphragm for tears?

 

wastegate is fine. Like I said, it holds all the other boost levels perfectly... Its just when I go over double what the spring is rated

 

turbo turbo turbo

 

yeah I got the same EBC as you and cant think of anything.. What about how you got the warning set up, ??
Well good luck with your stiffer bar wastegate spring,,,,,,, possable making the controller control it to hard and holding it harder than needed, causing a bit of overspike ????????? but never had any issue like this with my blitz before, so Ill rule on it being wastegate spring being

 

Chris,

I do not recommend upping the boost past 18 lbs on pump & or without more tuning

The new spring/checking for leaks/issues would be a good idea.
If it comes down to it, try borrowing a friends MBC to see if the boost controller is the cause of the issue.

Good Luck :-)

 

interesting... im having the same problem with mine.... except i have the apexi avcd. i think its my WG though... it use to hold fin but now when i turn it up just one lil notch on the controller itll go up like 6psi or more.

it ise to hold fine at 9 psi... WG spring.... but now ill bypass my controller and itll go to 15 instead of 9. but it holds fine at 15

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mtber &raquo;</TD></TR><TR><TD CLASS="quote">Chris,

I do not recommend upping the boost past 18 lbs on pump & or without more tuning

The new spring/checking for leaks/issues would be a good idea.
If it comes down to it, try borrowing a friends MBC to see if the boost controller is the cause of the issue.

Good Luck :-)</TD></TR></TABLE>

Im saving up for ya man... Once I have the money, Im gonna do the meth injection, and then were gonna find out how much this thing will hold

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by booja &raquo;</TD></TR><TR><TD CLASS="quote">interesting... im having the same problem with mine.... except i have the apexi avcd. i think its my WG though... it use to hold fin but now when i turn it up just one lil notch on the controller itll go up like 6psi or more.

it ise to hold fine at 9 psi... WG spring.... but now ill bypass my controller and itll go to 15 instead of 9. but it holds fine at 15</TD></TR></TABLE>

Thats pretty close to what mine is doing... Normally, 2 clicks equals out to 1 psi, but past 18, 1 click = like 10psi lol... Only thing I can really come up with is the darn wastegate spring...

I just wish someone could explain to me WHY it happens....

 

yes i wanna know too.... i was gonna take that wastegate off today and take it apart to see whats wrong with it but my WG is in a hard to reach spot and its hot outside....

so an answer sould be nice b4 i go taking my stuff apart

 

bump for more info.