North American Turbocoupe Organization



Hmm.. boost / cat. converter questions.
Ryan H Offline
Posting Freak
#11
Idle vacuum is a steady 17" from my AutoMeter gauge. Boost raises to ~14 PSI just before it hits the rev limiter and I let off. It only happens if I go WOT. I'm going to try putting on my spare downpipe that has the gutted cat and see if it makes any difference. Could really use some insight here guys...
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Ryan H Offline
Posting Freak
#12
I just bolted up my spare downpipe that has a gutted cat and the issue is still there. I am now leaning towards a worn valvetrain. I will try the "string" timing method tomorrow and see what happens. Hopefully my plastic marks are just out of whack.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Gulfdiver Offline
Senior Member
#13
Def. an interesting scenario... please keep us posted.. the suspense is killing me... (anyone read the last chapter of this? I'm dieing to know how it turns out.. Was it Capt. Crank with a worn valvetrain in the garage? Maybe it was Scarlet Timing with a crowbar in the timing booth) Your guess is as good as mine..
!!!!! MINE ALL MINE !!!!!
1988 TBird Turbo Coupe Mach 1 Special Edition
K&N airfilter; Spec Stage 3.. More mods to come!
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Ryan H Offline
Posting Freak
#14
OK ladies and gents, this was keeping me awake so I decided to pull everything apart and use the string method. I lined my marks up and made sure my rotor was pointing at #1, and then proceeded to use the string. I found that my marks ARE a little off as suspected, however my actual TIMING is dead on. I suppose this means my valve train is shot, unless anyone here has any suggestions!
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Huey866 Offline
Posting Freak
#15
I vote valvetrain. My car would build boost in neutral too. So i yanked the valvecover off and... well.... Lets just hope you dont find what I found.
87 TurboCoupe - silver, 137k, 5-speed, 3.73, 5 lug swap, MM... Evertything, 03 Cobra Brakes, Griggs Subframe connectors, Bo 1.5, Big Valves, massaged 79 turbo head, Essy Cam Gear, Boblog + Elbow, .63 T-3, Stinger Exhaust/FMIC

Currently dreaming about ball-bearings and Pimps
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Pete D Offline
Administrator
#16
I'm having trouble see a worn valve train allowing boost to build so high in neutral. I can understand vacuum being down some and of course, power being down
Pete Dunham


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Ryan H Offline
Posting Freak
#17
Just tested compression to check for blown head gasket, my numbers are:

cyl 1: 155
cyl 2: 155
cyl 3: 154
cyl 4: 155

SO I think that rules out the head gasket..? I guess I'm gonna have to raid the junk yard for a roller cam and slap some new valve seals/springs in there. If anything, I'll at least get a little lift back because my cam lobes and followers were shot about 20K miles ago. I think they're just finally done in.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Jeff K Offline
Administrator
#18
Slider cams are surface hardened only. Once they wear thru the hardened surface, they will go down hill REAL quick.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Gulfdiver Offline
Senior Member
#19
Just a beginners thought.. but why is building boost at idle a bad thing? I know it's not the intended operation of the car.. but I think having 14lbs of boost would be pretty kewl... kind of like cutting the rear brake lines on a car to make a "cheapy line lock vehicle"

Just wondering what the downside is...
!!!!! MINE ALL MINE !!!!!
1988 TBird Turbo Coupe Mach 1 Special Edition
K&N airfilter; Spec Stage 3.. More mods to come!
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trashline Offline
Posting Freak
#20
Quote:Originally posted by Gulfdiver:
Just a beginners thought.. but why is building boost at idle a bad thing? I know it's not the intended operation of the car.. but I think having 14lbs of boost would be pretty kewl... kind of like cutting the rear brake lines on a car to make a "cheapy line lock vehicle"

Just wondering what the downside is...
I dont think there is a downside to building boost without having a load on the motor, but it is the fact that it indicates something is wrong with the car.

For instance the one time I was able to build boost with the car not moving was when my headgasket blew between #2 and #3 cylinders, forcing me to invest in a new head.
Brian

www.BCPCustom.com

06 Cobalt SS
66 mustang 289 C4 handfully modded

Stingers IC install and tbird photos
http://community.webshots.com/user/trashline
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