Yes, absolutely. But MBCs can also control it. The game is won or lost in controlling not just max boost, but boost-at-any-given-RPM. You don't want boost to come on too early. I'll try to note what PSI my 850 is at at say 2000 RPM, for reference.
Fast Fridays have lots of information about boost:
Fast Friday#12: Turbos and Exhaust
"... but first let’s understand why the larger turbos in the TD04 family can be prone to boost spike or rapid early RPM boost development."
Fast Friday #4: The Boost Variance Problem
"The BPS in these models is more for control of max boost target (I.E. over boost or spiking) rather than as a feedback..."
Fast Friday #3: Lucky talks Chip vs. MBC
"... If your intention is to use the MBC to control spikes then you have it setup correctly."
Lucky has forgotten more about this than I'll ever know, so take what I say with a grain of salt.
Recomended MBC for Volvo 850 Turbo
This topic is in the MVS Volvo Repair Database »
Recomended MBC for Volvo 850 Turbo
- matthew1
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Re: Recomended MBC for Volvo 850 Turbo
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1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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1998 V70, no dash lights on
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2004 V70 R [gone]
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boosted5cyl
- Posts: 1100
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Any thoughts on an electronic boost controller? Boost gauge, boost controller and a new TCV to boot:
http://www.ebay.com/itm/2012-new-HDi-el ... 71&vxp=mtr
http://www.ebay.com/itm/2012-new-HDi-el ... 71&vxp=mtr
'04 XC90 2.5T AWD (Angus) 134K.
'99 S80 T6 (Medusa) 214k. On borrowed time LOL
'98 V70 T5 (Vivienne). RIP @ 228K. Spun rod bearings.
'99 S80 T6 (Medusa) 214k. On borrowed time LOL
'98 V70 T5 (Vivienne). RIP @ 228K. Spun rod bearings.
I'm considering one of these. You can find them on Amazon for less than $30 so I'll probably order from there.
These seem to work well (something as simple as an MBC should) from what I've seen on other forums.
http://www.zenboost.com/boost_controlle ... oo_IV_MBC/
https://www.amazon.com/s?ie=UTF8&page=1& ... odoo%20MBC
These seem to work well (something as simple as an MBC should) from what I've seen on other forums.
http://www.zenboost.com/boost_controlle ... oo_IV_MBC/
https://www.amazon.com/s?ie=UTF8&page=1& ... odoo%20MBC
- matthew1
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I'm a big fan of MBCs. Watch that boost! 
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1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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Also -> Amazon link. Click that when you go to buy something on Amazon and MVS gets a cut!
1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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boosted5cyl
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What initiates the fuel cutoff? ECU sees airflow outside normal range and cuts the juice?matthew1 wrote: I do not get fuel cutoff until ~90mph / full throttle.
'04 XC90 2.5T AWD (Angus) 134K.
'99 S80 T6 (Medusa) 214k. On borrowed time LOL
'98 V70 T5 (Vivienne). RIP @ 228K. Spun rod bearings.
'99 S80 T6 (Medusa) 214k. On borrowed time LOL
'98 V70 T5 (Vivienne). RIP @ 228K. Spun rod bearings.
- matthew1
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No idea, but that'd be my guess.
Jimmy? JDS60R?
Jimmy? JDS60R?
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1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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- matthew1
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I should clarify my sentence from a couple months ago:
CORRECT:
I do not get fuel cutoff until ~90mph@full throttle.
Without the @ symbol it makes my sentence read like fuel cutoff happens at ~90mph OR full throttle, which is incorrect. It's ~90mph@WOT.
CORRECT:
I do not get fuel cutoff until ~90mph@full throttle.
Without the @ symbol it makes my sentence read like fuel cutoff happens at ~90mph OR full throttle, which is incorrect. It's ~90mph@WOT.
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1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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Also -> Amazon link. Click that when you go to buy something on Amazon and MVS gets a cut!
1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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jimmy57
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Mot 4.3 and 4.4 use MAF vs RPM and a factor to decide when to shut down for inferred overboost.
I'm not sure if that is an answer you're looking for as there isn't a road speed shut down on the 97 until 155mph.
If you are over boosting then 90 MPH may be where you get enough load to have an overboost where the air consumption goes off the allowed map.
BTW, you'll go off the map more readily at lower altitude and in colder air temps. THe MAF signal goes higher with denser air.
I'm not sure if that is an answer you're looking for as there isn't a road speed shut down on the 97 until 155mph.
If you are over boosting then 90 MPH may be where you get enough load to have an overboost where the air consumption goes off the allowed map.
BTW, you'll go off the map more readily at lower altitude and in colder air temps. THe MAF signal goes higher with denser air.
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97_boostedgLt
- Posts: 6
- Joined: 15 December 2013
- Year and Model: 850 Glt 1997
- Location: PA
Look at Turbosmart "T" MBC (89.95) wanna spend the momey on a MBC if u cant afford a EBC. That said, running the T MBC with ARD white tune, at 12lbs 253 HP, on my 1997 Volvo 850 GLT, Absolutley STOUT and made the car a whole new animal.been about a month and no spike in boost, doesnt boost to high in low rpms. All u need is a proper tune and a MBC is the quickest and easiest way to up your HP, Tq, etc.
hope this helps!
hope this helps!
"...doesnt boost to high in low rpms." Do you mean low GEARS? And if so, how is the MBC "bypassed" in the low gears??97_boostedgLt wrote:Look at Turbosmart "T" MBC (89.95) wanna spend the momey on a MBC if u cant afford a EBC. That said, running the T MBC with ARD white tune, at 12lbs 253 HP, on my 1997 Volvo 850 GLT, Absolutley STOUT and made the car a whole new animal.been about a month and no spike in boost, doesnt boost to high in low rpms. All u need is a proper tune and a MBC is the quickest and easiest way to up your HP, Tq, etc.
hope this helps!
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