SOHC_MShue

I just recently got around to hooking up my turboxs manual boost controller and I'm having problems keeping steady boost. My setup is a tial 38mm tial wastegate with an 8psi spring coupled with a hf mani and a small wrx turbo. The boost will shoot up to 10psi, but around vtec crossover it drops back down to 8-8.5psi. I know that I don't have any vacuum leaks because my boost gauge reads very high in vacuum at idle and hasn't varried ever. Also its strange because sometimes like when I do a 3rd gear pull from about 40mph the boost will go up to 10psi, then drop down to 8.5, and then shoot back up to 10psi again really quick. This makes for a not so smooth powerband . Is this just because I have a small turbo?

Also without the boost controller my boost was very steady at 8psi running off the spring. I also have the vac line hooked up to my intake mani incase you are wondering.

B20luda

hookin the vaccum line up from the compressor housing has givin me better reliability boost wise with my car...my WG would "flutter" when i had it hooked up to my manifold...the boost guage would go crazy...from 5-9psi.. thats just my experence...i was also using a 35mm deltagate..BTW all those problems stopped when i hooked it up to the compressor housing...GL

SOHC_MShue

for real? Thats interesting. Usually i hear its the other way around. Maybe i'll have to give it a try...

SOHC_MShue

i just drove it again and it does seem like it has a flutter. So annoying

PrettyLude

try switching the vacuum to the compressor like he said, and see if it works

SOHC_MShue

well i just tried that and the boost controller did an even worse job of holding boost. It spiked to like 9psi and then fell to 7psi all the way to redline. It didn't fluctuate quite as bad, but it dropped back so low..

PrettyLude

i had the same problem with that turbo xs manual one, i finally ditched it, and when with the sbc-id from blitz

093turbo16

iTrader: (2)

my dad is having that problem with his turbo XS. It never use to do it, it goes to 22 then backs down to like 18-19. Makes me mad.

SOHC_MShue

yea man this pisses me off. I have another one I can try out though.

SOHC_MShue

anyone else found a fix for this?

tub_sephiroth

I've got the same problem. It'll boost to 8 lbs. then after 6000 rpm, it'll drop to 5.5 lbs only. This was after I put on the turbo xs mbc. It held steady boost off the spring only.

Off topic... Is it normal to hold boost at 1 lb. under the spring rate?

t3h_sl0w

My turbo XS dual stage has no problems...solid 10 pounds on first stage and 15 on second stage, not fluctuating...(unless i have a ******* boost leak which i have another one today, after i just fixed one yesterday, i HATE charge pipes)

SOHC_MShue

do you guys think that if I got the fine adjustment turboxs mbc rather than the cheapest model it would work better?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tub_sephiroth &raquo;</TD></TR><TR><TD CLASS="quote">Off topic... Is it normal to hold boost at 1 lb. under the spring rate?</TD></TR></TABLE>

are you running your vac line from the turbo's compressor and not the intake manifold? If you are then this is probably because you have a 1psi pressure drop across the intercooler and the wastegate is seeing say 8psi, but your car is really only getting 7psi. If you have it hooked to your intake manifold then your wastegate isn't going to open until you actually have 8psi at the manifold.

tub_sephiroth

Yeah, it's off the compressor. Where on the manifold do I hook it up too?

Calvinator

did anyone find a way to fix this, im having the exact same problem with my turbo xs boost controller. It pissed me off, so now i have to settle with 6 psi until i can get the MBC to work properly.

SOHC_MShue

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tub_sephiroth &raquo;</TD></TR><TR><TD CLASS="quote">Yeah, it's off the compressor. Where on the manifold do I hook it up too?</TD></TR></TABLE>
you can hook it anywhere on your intake manifold. Just T it off the brake booster is what I would do.

tub_sephiroth

After the throttle?

SOHC_MShue

yes after the throttle body on the intake manifold. The brake booster line is the big one coming out the back of your intake manifold. Make sure that you T into it after the check valve inside it.