Hey guys i am running a tial 38mm wastegate with my setup. I had an 8psi spring and wanted to turn my boost up to 10psi. The turboxs boost controller could turn it up, but it would fall back a couple of psi after vtec crossover...so i ordered a 10psi wastegate spring. I installed it and my boost didn't really increase. The first night it looked like i was boosting maybe 1 psi more, but now it doesn't seem to be anymore different than the 8psi spring

 

How new is the turbo and are you reading boost from an electronic or mechanical gauge.

 

the turbo is fairly old..its from a wrx and is very small. The turbo isn't messed up though because i can boost plenty with a boost controller..it will just drop back a couple of psi.

I am using a mechanical boost gauge and I am also datalogging my map signal.

 

Do you have any idea why your boost is dropping back down a couple psi??

 

I'm not sure. I'm assuming it has something to do with running a boost controller on a small *** turbo...it seems like lots of people have this problem..with setups like the greddy kit. If i run right of the 8psi wastegate spring then i will hold 8psi very steady...if i hook the mbc up with it set at 0 increase i will boost 8psi and drop down to 7psi or something after 5500 rpms.

 

where is the pressure source from for the bc?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrettyLude &raquo;</TD></TR><TR><TD CLASS="quote">where is the pressure source from for the bc?</TD></TR></TABLE>

the above question and the type of vaccum line you are using seem to be the question. also how the mbc lines are seccured...zipties, hose clamps, etc.

 

you sure u don't have a boost leak?

i had a super small crack in my clamps and it did the same thing to me, not able to hold boost with my old sold setup.

 

I had the same problem on my last turbo setup.. There was a 6psi spring and I wanted 8-9psi but it would go up to 8-9psi and drop back down.. I then turned it up to 11psi and it would go straight to 11psi and stay there..

 

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

the above question and the type of vaccum line you are using seem to be the question. also how the mbc lines are seccured...zipties, hose clamps, etc. </TD></TR></TABLE>
the pressure source is coming from the brake booster and it is secured with a zip tie. I don't think i have any vacuum leaks because my vacuum at idle has always been right where it needs to be.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Quad-Damge &raquo;</TD></TR><TR><TD CLASS="quote">you sure u don't have a boost leak?

i had a super small crack in my clamps and it did the same thing to me, not able to hold boost with my old sold setup.</TD></TR></TABLE>
no boost leak because when i used to just be internally gated i've had the boost creep up way past 8 and 10psi before.

 

One other thing is that when i was replacing the spring i kinda smushed one side of the orange diaphram thing that was in there with the spring. Could that effect anything? I thought that if that got messed up then my boost would creep.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">One other thing is that when i was replacing the spring i kinda smushed one side of the orange diaphram thing that was in there with the spring. Could that effect anything? I thought that if that got messed up then my boost would creep. </TD></TR></TABLE>

lol, pull it back out and un-smush it.

not only that but you could have torn it when you "smushed" it.

 

well i tried unmushing it, but it didn't really want to unmush. I checked for tears and didn't see any. I think its still doing its job though because wouldn't i be overboosting or something if that was messed up? Its sill holding 8-9psi pretty steady.

 

yeah, if it was mushed and untorn you'd be overboosting. I just thought it had a tear in it was all.

you happen to know the trim rating on that turbo?? I'm pretty sure with it being a small turbo, probably whats happening is you're reaching the outer limits of it's efficiency range on the high end of your rpm range. Probably just time to start looking for a bit of an upgrade.

probably a .60/.48 or .60/.63 from a ford 2.3t engine is where you want to be.

 

i'm not sure..its tiny as ****. Its a tdo413t or something like that. Whatever comes in the regular wrx's. I wouldn't think that it would be running out of its efficiency at only 8psi. People push these turbos to like 18psi on wrx's and i have seen mine go to over 15psi before

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SOHC_MShue &raquo;</TD></TR><TR><TD CLASS="quote">i'm not sure..its tiny as ****. Its a tdo413t or something like that. Whatever comes in the regular wrx's. I wouldn't think that it would be running out of its efficiency at only 8psi. People push these turbos to like 18psi on wrx's and i have seen mine go to over 15psi before </TD></TR></TABLE>

was it able to hold that pressure or was it just a quick spike?

Is there any "T"'s in between the compressor housing outlet----to----wastegate line?? if so, unhook them and run a brand new line and clamp it at both ends and try that.

also, try hooking your boost controller straight to the vacuum tree at the intake manifold, again with a new line.

I've seen/had some interesting problems in the past with these two lines when I or friends would start playing with them.

some things are just best left with dedicated feeds heh.

 

It would hold 15psi.

there are no t's near the compressor because i'm running the source from the brake booster instead...however there is a T at the brake booster. Maybe i'll have to just fool around with the lines and see what happens.

 

bump for anymore info