TD04 boost drops around 4-5k rpms

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Thesubielover
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TD04 boost drops around 4-5k rpms

Post by Thesubielover »

Hey there. I just finished my swap about 4 days ago of my td04, hallman pro mbc, boost gauge, tmic, and blitz bov. I was wondering, before installing the mbc I hooked up my td04 to my stock boost solienoid and was observing around 10psi on my gauge. I was also noticing that with more gas in higher rpms I would all of a sudden come out of boost like it was hitting fuel cut. I put on my mbc and dialed it all the way down to hallmans stock setting, which read 4 psi on my boost gauge. When test driving, I didnt feel anything as I explained before. I went ahead and began turning the mbc up 1/4 turns until I was finally at 8psi. When I was up there, i felt that whenever pulling in 2nd or 3rd gear at a high rpm with my foot more then half way down on the throttle, I would feel some kind of lag again like it would drop boost. Sop I turned it back down, to where it reads now, 5psi on my gauge. Am I supposed to install a fcd? I thought that my stock cut off was at 10 or 11psi, am i wrong? Am I having boost spike? All info is welcome, other then that, the car feels quick, pulls nice and long in 2nd and 3rd where it is now, at 5 psi :(. Maybe my gauge is off and is reading a low psi? Vaccume reading id right in the middle of 25-28 when its running at idle.

Thanks!
Last edited by Thesubielover on Fri Aug 03, 2012 5:27 am, edited 1 time in total.
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Rubasu
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Rubasu »

ya try a new gauge. on brand new motors they pull like 20 psi in vacuum and around 15 on used motors. ive never seen a old subie pull 25-28 psi at idle. if you get a new gauge dont go cheep.
90 legacy Wagon LS Special, JDM closed deck 20g, custom 25d heads f/ metic motors, APS GC FMIC, 740cc, VF34, 4.11 F/D, Turboxs RFL blow off valve, now with piggyback.
94 Legacy SS R.I.P (parts car now for 90)
97 Legacy Outback (sold)
Legacy777
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Legacy777 »

I don't necessarily agree that all old motors will not have around a 20 inches of vacuum. If the engine is in good health, AND you are at sea level is should be around 19-20 in-hg of vacuum.

I too would suggest trying a new gauge. It sounds like you may be getting boost creep in the higher gears (higher load). What exhaust do you have on your car?
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

I'm running a 3in tbe with no cat or resinator. i'll return this one for a new one i guess and see. the motor only has 117k miles on it.
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

Also, how do I adjust my bov spring? If thats even what needs to be done. It's hooked up properly with my small diverter valve vaccume line hooked up to its barb, but again when im on it or rev it at a stop light, it doesnt seem to make any pressure releasing noise.
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Joined: Tue Feb 14, 2012 11:20 am
Location: Seattle, WA

Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

Just swapped gauges for a new one and what was once 4psi on the old gauge is actually 7psi on the new on. Gave is a couple small turns and left it at 9psi.... shiiiits quick!
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

Vacume now is about 18-20. much better i think
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Location: Seattle, WA

Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

now to resolve the bov. any tips? no noise coming from it when im on boost changing gears or when im at idle and rev it up
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
CAV3MAN227
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by CAV3MAN227 »

I thought that my stock cut off was at 10 or 11psi, am i wrong?
-Stock fuel cut is around 12-13 psi, depending on elevation.
Am I supposed to install a fcd?
-You can if you want but I personally wouldn't do it unless you have a wideband to watch you air/fuel ratios. A td04 is good up to 16psi but if your not around 10.8-11.2 in afr's, (at wide open throttle, 5th gear) back the boost down. I run 15psi with my td04 and turbo-xs fcd.

-Joe
-I'd rather loose by a mile because I built my own car, than win by an inch cause someone else built it for me. Your car, is your story, so don't let someone else write the book. ~Moog
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

I see, cool. Where did you buy yours from? The FCD? I was also wanting to post the link I found on how to adjust my blitz bov. Here it is

http://www.blitzpowerusa.com/techsuppor ... versal.pdf
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
vrg3
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by vrg3 »

What did you connect the vacuum port from the BOV to?

Also, you say you're not hearing it blow off -- are you hearing the compressor surge during shifts instead? Compressor surge sounds kind of like a clattering sound.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

My bov has a vaccume 90 coming off of it and i attached my small vacume line from the stock bpv to that 90. Should source? I dont hear any clattering either, other then the turbo spool noise which sounds like sucking alot of air. thats really all the sounds im getting. everythng seems to be running just fine, and quick too with the new upgrade.
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Joined: Tue Feb 14, 2012 11:20 am
Location: Seattle, WA

Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

CAV3MAN227 wrote:
I thought that my stock cut off was at 10 or 11psi, am i wrong?
-Stock fuel cut is around 12-13 psi, depending on elevation.

-Joe

Is this true? Everywhere on here, I've read that its in the 10-11psi range.
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
vrg3
Vikash
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by vrg3 »

You would hear the surge at the time when you would otherwise hear the blowoff -- just as you lift your foot off the throttle to shift when you're on boost.

If you're not hearing clatter, I have to imagine your blowoff valve is actually working but is just quiet. Compressor surge with the TD05 ought to be loud enough to hear.

Maybe you could get a friend to help you test it. Put the car in neutral and have it running with the hood up. Get your friend to put their hand by the blowoff and then you floor the pedal really fast and release as soon as you hit redline. That should allow you to build enough boost to activate the blowoff valve. They should feel air coming out the valve as soon as you let go of the pedal..
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
CAV3MAN227
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by CAV3MAN227 »

Thesubielover wrote:Where did you buy yours from? The FCD?
-I got mine thru a friend but I'm sure they sell them on turboxs's website.

-Joe
-I'd rather loose by a mile because I built my own car, than win by an inch cause someone else built it for me. Your car, is your story, so don't let someone else write the book. ~Moog
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

[quote="vrg3"]You would hear the surge at the time when you would otherwise hear the blowoff -- just as you lift your foot off the throttle to shift when you're on boost.

If you're not hearing clatter, I have to imagine your blowoff valve is actually working but is just quiet. Compressor surge with the TD05 ought to be loud enough to hear.


I followed the link I posted and there was no change in bov sound. I adjusted it all the way to the left, and not even a slight change. Should I try using a defferent bov? Just wondering what I can do. Also, im only pushing the td04, not the td05 (yet) ;)
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
vrg3
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by vrg3 »

Hmm, you should be able to hear the TD04 surge too, I'd think. Maybe not though; never tried it myself.

Wait, you turned the adjustment screw all the way counterclockwise and the car still ran okay? The valve should be leaking like crazy at idle if you do that.

It does sound like maybe this particular blowoff valve is defective.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
Legacy777
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Legacy777 »

Thesubielover wrote:
CAV3MAN227 wrote:
I thought that my stock cut off was at 10 or 11psi, am i wrong?
-Stock fuel cut is around 12-13 psi, depending on elevation.

-Joe

Is this true? Everywhere on here, I've read that its in the 10-11psi range.

Around 12-13 psi at sea level is accurate.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Legacy777
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Legacy777 »

Thesubielover wrote:I'm running a 3in tbe with no cat or resinator. i'll return this one for a new one i guess and see. the motor only has 117k miles on it.

You description of the problem in your first post and the fact you have a 3 TBE with no cat or resonator would indicate to me you are experiencing boost creep. It doesn't have anything to do with the BOV. You still may have an issue with the BOV, but if you overboosting in higher gears, that's usually caused by a very free flowing exhaust and inadequate boost control.

MBC's typically can not compensate for the added load in the higher gears, so you have to compromise the setting of the MBC so you don't overboost in the high gears, which causes you to make less boost in lower gears.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

So adding a resinator or cat will help with boost creep and help me get closer to 10 or 11psi? i turned the mbc down to 7 and im not experiencing the symptoms anymore, but would love a few more psi
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Joined: Tue Feb 14, 2012 11:20 am
Location: Seattle, WA

Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

Bump. What size resonator would be good to install?
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Legacy777
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Legacy777 »

You're going about this the wrong way. You don't want to add more restriction to your exhaust if you don't need to.

Get a better boost controller. An electronic boost controller should allow you to set a desired boost pressure and it will adjust things so that it maintains that boost regardless of what gear you're in or whether the ambient conditions change.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Thesubielover
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

Oh i see, thanks josh
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Thesubielover
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Posts: 709
Joined: Tue Feb 14, 2012 11:20 am
Location: Seattle, WA

Re: TD04 swapped/mbc, hitting fuel cut?

Post by Thesubielover »

So Im thinking of getting the aem tru boost electronic boost controller
93ss 3inch tbe, Hallman mbc,06 wrx td04, tmic, bov, bugeye seatsStolen x2, sold
93ss Stroker,440cc inj, VF39, '06 TMIC, EJ20G heads & intake, EJ25 crank, 4.11Traded
93ss 4eat, coils, stanced, wraped, flat black, stock show car
Rubasu
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Re: TD04 swapped/mbc, hitting fuel cut?

Post by Rubasu »

i was going to get one of those. i have good things on this one.
90 legacy Wagon LS Special, JDM closed deck 20g, custom 25d heads f/ metic motors, APS GC FMIC, 740cc, VF34, 4.11 F/D, Turboxs RFL blow off valve, now with piggyback.
94 Legacy SS R.I.P (parts car now for 90)
97 Legacy Outback (sold)
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