Ok, Here goes.
Relevent mods: 19T, Upsolute ECU @ 1.4bar (21psi), EST intercooler, Greddy Type-S BOV, blocking plate (on stock recirc valve), Samco Silicone intercooler hoses, all new rubber vac. lines. Brand new boost control solenoid.
I have 20-22in / HG at idle.
Ok, so I've been having trouble making full boost - the boost level under WOT in 3rd gear would be something like this..
1
3
5
7
12
14 (high pitched whistling noise starts - like air escaping)
16
10
14
18
16
14 (whistling noise continues to redline)
I disconnected the wastegate from the BCS to see if I could make more boost. Sure enough, no problem, 21psi (and more, but I let off).
I thought it was 1) faulty BCS (not opening and closing fast enough) 2) a wastegate issue (because of the fluctuation) or 3) a leak in the exhaust manifold.
I replaced my 11yr old BCS, and the new one is better, but I still am not able to reach full boost.
Can anyone tell me what I should do? Should I go after the wastegate? The exhaust manifold?
Boost Problems
Started by styx0r, Feb 10 2005 11:07 PM
10 replies to this topic
#1
styx0r
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Posted 10 February 2005 - 11:07 PM
1994 850 Turbo Chassis. 151,000 miles. 1995 HPT motor 15,000 miles, M56H transmission/R clutch. 19T, BSR 3in downpipe, 3in electronic exhaust cutout, IPD 2.5in cat-back. EST Intercooler, Samco intercooler hoses, custom intercooler pipe (metal replacement for stock plastic piece), Greddy Type-S BOV, Aquamist 1S 0.7mm @ 12PSI, Upsolute ECU @ 1.4bar (~21psi), Lotek tripple pod, Greddy Boost, Oil Pressure, EGT gauges, Greddy Catch Can, Greddy Turbo timer, Bilstein shocks/struts w/IPD lowering springs, IPD swaybars, OMP strut tower bar, 17in Alba wheels, 320mm front brakes, X-drilled and slotted, EBC greenstuff pads all around, Bridgestone S-03s 225/45/17s. Gemini Carbon Fiber Hood, Jewel headlights/clear corners.
#2
prasamin
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Bipedal Magnaflux
Posted 11 February 2005 - 03:40 AM
wastegate opening too soon or stuck at open?
#3
styx0r
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Posted 11 February 2005 - 04:51 AM
Yeah, I'm thinking the wastegate is malfunctioning, but when disconnected from the BCS, the wastegate does not leak. And the BCS is brand new, so I don't know what's going on...
Anyone??
Anyone??
Edited by styx0r, 14 February 2005 - 06:04 AM.
1994 850 Turbo Chassis. 151,000 miles. 1995 HPT motor 15,000 miles, M56H transmission/R clutch. 19T, BSR 3in downpipe, 3in electronic exhaust cutout, IPD 2.5in cat-back. EST Intercooler, Samco intercooler hoses, custom intercooler pipe (metal replacement for stock plastic piece), Greddy Type-S BOV, Aquamist 1S 0.7mm @ 12PSI, Upsolute ECU @ 1.4bar (~21psi), Lotek tripple pod, Greddy Boost, Oil Pressure, EGT gauges, Greddy Catch Can, Greddy Turbo timer, Bilstein shocks/struts w/IPD lowering springs, IPD swaybars, OMP strut tower bar, 17in Alba wheels, 320mm front brakes, X-drilled and slotted, EBC greenstuff pads all around, Bridgestone S-03s 225/45/17s. Gemini Carbon Fiber Hood, Jewel headlights/clear corners.
#4
styx0r
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Posted 14 February 2005 - 06:06 AM
I don't know if anyone here has suggestions, but I'd really appreciate your help. I'm quite stumped.
Is this a wastegate problem?
a boost / exhaust gas leak?
Is the ECU limiting boost for some other reason?
Is this a wastegate problem?
a boost / exhaust gas leak?
Is the ECU limiting boost for some other reason?
1994 850 Turbo Chassis. 151,000 miles. 1995 HPT motor 15,000 miles, M56H transmission/R clutch. 19T, BSR 3in downpipe, 3in electronic exhaust cutout, IPD 2.5in cat-back. EST Intercooler, Samco intercooler hoses, custom intercooler pipe (metal replacement for stock plastic piece), Greddy Type-S BOV, Aquamist 1S 0.7mm @ 12PSI, Upsolute ECU @ 1.4bar (~21psi), Lotek tripple pod, Greddy Boost, Oil Pressure, EGT gauges, Greddy Catch Can, Greddy Turbo timer, Bilstein shocks/struts w/IPD lowering springs, IPD swaybars, OMP strut tower bar, 17in Alba wheels, 320mm front brakes, X-drilled and slotted, EBC greenstuff pads all around, Bridgestone S-03s 225/45/17s. Gemini Carbon Fiber Hood, Jewel headlights/clear corners.
#5 Guest_Guest_edwardcheung_*_*
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Posted 14 February 2005 - 07:31 AM
QUOTE(styx0r @ Feb 14 2005, 06:06 AM)
I don't know if anyone here has suggestions, but I'd really appreciate your help. I'm quite stumped.
Is this a wastegate problem?
a boost / exhaust gas leak?
Is the ECU limiting boost for some other reason?
Is this a wastegate problem?
a boost / exhaust gas leak?
Is the ECU limiting boost for some other reason?
This is pretty much like the problem I am having when I had a bad acturator, I installed a MBC and a boost guage to test the actuator no matter how much turn I made on the MBC I am getting the same boost level.The Actuator may not be bad, but the spring inside the actuator is not strong enough for such high boost. mechanically, it is the spring in the actuator that control the boost level. When the car is being overboost, the BCS will release pressure into the actuator to open the wastegate to lower the boost.
And my guess is what we are having here is at WOT, the exhaust gas push the wastegate open, as a result boost cannot build up quickly, and the BCS didn't even need to releasing any pressure to control the boost. (The Spring holds the wastgate shut and the pressure from the BCS opens it)
I might be wrong, correct me if I am wrong, anyone?
#6
styx0r
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Posted 14 February 2005 - 08:25 AM
I follow along with what you're saying, but if that is the case, then why can I make 21+psi when I disconnected the BCS? The wastegate is disconnected from boost control, but the spring is strong enough to keep the gate closed to build boost...
1994 850 Turbo Chassis. 151,000 miles. 1995 HPT motor 15,000 miles, M56H transmission/R clutch. 19T, BSR 3in downpipe, 3in electronic exhaust cutout, IPD 2.5in cat-back. EST Intercooler, Samco intercooler hoses, custom intercooler pipe (metal replacement for stock plastic piece), Greddy Type-S BOV, Aquamist 1S 0.7mm @ 12PSI, Upsolute ECU @ 1.4bar (~21psi), Lotek tripple pod, Greddy Boost, Oil Pressure, EGT gauges, Greddy Catch Can, Greddy Turbo timer, Bilstein shocks/struts w/IPD lowering springs, IPD swaybars, OMP strut tower bar, 17in Alba wheels, 320mm front brakes, X-drilled and slotted, EBC greenstuff pads all around, Bridgestone S-03s 225/45/17s. Gemini Carbon Fiber Hood, Jewel headlights/clear corners.
#7
Gregg
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daniel stern lighting pimp
Posted 14 February 2005 - 08:31 AM
QUOTE(styx0r @ Feb 14 2005, 03:25 AM)
I follow along with what you're saying, but if that is the case, then why can I make 21+psi when I disconnected the BCS? The wastegate is disconnected from boost control, but the spring is strong enough to keep the gate closed to build boost...
how about bypassing the bcs altogether and just using the mbc?
Edited by gmischenko, 14 February 2005 - 08:35 AM.
#8
dons850t5r
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Posted 14 February 2005 - 11:44 AM
The wastegate actuator has a rubber diaghram in it, probably has a pin hole.
My 96r has the same prob.
My 96r has the same prob.
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#9
styx0r
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Posted 15 February 2005 - 02:33 AM
QUOTE(dons850t5r @ Feb 14 2005, 05:44 AM)
The wastegate actuator has a rubber diaghram in it, probably has a pin hole.
My 96r has the same prob.
My 96r has the same prob.
Can I replace just the wastegate actuator / diaphram, assuming I remove the 19T from the car? If so, anyone know where I can buy the assembly?
1994 850 Turbo Chassis. 151,000 miles. 1995 HPT motor 15,000 miles, M56H transmission/R clutch. 19T, BSR 3in downpipe, 3in electronic exhaust cutout, IPD 2.5in cat-back. EST Intercooler, Samco intercooler hoses, custom intercooler pipe (metal replacement for stock plastic piece), Greddy Type-S BOV, Aquamist 1S 0.7mm @ 12PSI, Upsolute ECU @ 1.4bar (~21psi), Lotek tripple pod, Greddy Boost, Oil Pressure, EGT gauges, Greddy Catch Can, Greddy Turbo timer, Bilstein shocks/struts w/IPD lowering springs, IPD swaybars, OMP strut tower bar, 17in Alba wheels, 320mm front brakes, X-drilled and slotted, EBC greenstuff pads all around, Bridgestone S-03s 225/45/17s. Gemini Carbon Fiber Hood, Jewel headlights/clear corners.
#10 Guest_Guest_edward cheung_*_*
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Posted 15 February 2005 - 07:04 AM
QUOTE(styx0r @ Feb 14 2005, 08:25 AM)
I follow along with what you're saying, but if that is the case, then why can I make 21+psi when I disconnected the BCS? The wastegate is disconnected from boost control, but the spring is strong enough to keep the gate closed to build boost...
I re-read your post again, sorry I kind of overlook some info you provided, you are able to build up boost when you disconnect you actuator with the BCS, so which means you actuator is ok, so it is neither the BCS or the ECU(which trigger the BCS) is lower the boost.
were you able to get 21 psi before?
Edward
#11
volflo
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Posted 15 February 2005 - 01:51 PM
...sorry. but if i get you correctly,
you get 21 psi with the wastegate DISCONNECTED? How is that possible? Normally if you disconnect the wastegate you have the two chambers on the two sides of diaphragm connected to atmospheric pressure. The BCS is not operating thus not being able to put pressure on the diaphragm.
This implies that your wastegate should operate/open at baseline pressure of the spring ONLY which is on my 19T somewhere around 0.7 to 0.8 bar.
So i d assume that something is wrong with your wastegate/ actuator.
you get 21 psi with the wastegate DISCONNECTED? How is that possible? Normally if you disconnect the wastegate you have the two chambers on the two sides of diaphragm connected to atmospheric pressure. The BCS is not operating thus not being able to put pressure on the diaphragm.
This implies that your wastegate should operate/open at baseline pressure of the spring ONLY which is on my 19T somewhere around 0.7 to 0.8 bar.
So i d assume that something is wrong with your wastegate/ actuator.
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