North American Turbocoupe Organization



boost levels
Noname
Unregistered
#1
in my 87 turbocoupe (5-spd) when im at 3grand i get about 5#s of boost at about 3500 rpm boost is at 10 #s and at 4 grand i hit 15 #s of boost. eventially i get to 18 #s.

i have no vacuum leaks, all my hoses are tight and have no holes. stock boost controller with bleed valve. cut air box with new filter. just flushed intercooler and cleaned t/b. car runs good and has plenty of power when boost finally comes in, but by the time boost comes in it's time to shift.

where does your boost come in at?

any help will be fully welcomed.
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SteveX82 Offline
Posting Freak
#2
Quote:stock boost controller with bleed valve.
[/B]

so are you running the stock BCS or an aftermarket valve (like the gillis valve)? i don't see how it'd be possible to run both. but anyways.......with my gillis valve and k&n i hit 18 lbs of boost by about 2700rpm and am up to about 5lbs of boost by 2000rpm, so your situation sounds a little bit awry. have you ever checked the turbo itself to make sure nothing's wrong?
Estoril blue 1987 TC 5spd, 148k mi, a237, Bailey BOV, spec stg3 clutch, spearco FMIC, 50 trim t3/t4, 3" exhaust, Bamafuel, LM1, 55pph
Best 1/4 mile: 12.31 @ 110mph on 25psi
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Dan E Offline
Posting Freak
#3
This doesn't sound too unusal to me...

Boost isn't either off or on...it is incremental with rpm's. I experience the same thing. Boost builds to its maximum level about the time when it comes to shift to a higher gear. Then the process begins again building boost pressure as the revs increase.

It does, however, sound like you boost is a little slow to build...this may be due to a WG door that won't 100% close...or a bad WG actuator...?

------------------
Dan Eaves
88TC 5spd, Shortblock with Crower 5.5" Sportsman Rods and Short Wiseco Pistons bored .030" Over, Ported Head with Polished Combustion Chambers, Gutted & Polished Upper, Ported & Polished Lower, Polished T/B, Ported E6, SVO T3 Turbo, 3" DP w/No Cat, RR Cam, Adjustable Cam Sprocket, K&N in Fenderwell, Gillis Boost Valve, Centerforce I Clutch, Removed A/C, Polished Wheels, Polished Valve Cover, Polished Crank and W/P Pullies, and the DAMN Heater Core is new too !

[This message has been edited by Dan E (edited 06-12-2001).]
Dan Eaves
88TC 5spd Vermillion Red, Polished...everything...
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Pete D Offline
Administrator
#4
Please clarify if you factory BCS is still in the vacuum/ boost circuit - still hooked up.
Like Steve, with an aftermarket boost control
valve hooked up right, a freel flowing air filter and maybe some exhaust mods you should get most of your boost by or below 3k rpms.

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88 TC X 2, 86 SVO, Main TC with K&N, 3"DP to 2.5"duals through Dynamax, Ric valve at 17+ and disconnected KS.
Elite Bodega 16" chrome wheels. Autometer pod w/ A/F and Vac/boost gauges. New engine shortly, ported head and
manifolds, polished and cc'd chambers, A-230 cam, Race Engineering Adj Cam Sprocket, Crowlers, ARP head studs, Walbro 190 pump and T-3 for starters. KB subs
and jack rails.
Pete Dunham


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Noname
Unregistered
#5
the factory bcs is still in the vacuum/ boost circut. the bleed valve is a small manual valve kinda like a fish tank air line valve. (it was used on a friends grand national and was fine). there is not any type of gillis valve or anything like that.

i've only had the car for about a 2 months so there is nothing major performance wise. i havent checked the turbo other than the obvious visual inspections.

i also have a 87 tc drive train in my 87 stang and it will hand the tc's ass to it at anytime. the stang hits 20#s by 3500 with a front mount and ihi. i'd like the tc to atleast have a chance. the stang was built to play with the gn, but the gn's owner just upgraded his turbo to a ta49 (i believe) and has been looking for a powerstroke ic for awhile, so the stang will need more work already.

the tc is a daily driver but it also needs to be not beaten too badly by the gn on the way home from work. i can kill him in the corners but as soon as the road straightens out all i see is taillights. i'd like to be able to atleast read the tag. lol

will making the wg actuator rod adjustable be a fix, or will i just be masking a problem?

sorry for the long post.
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Pete D Offline
Administrator
#6
I'm guessing the stock BCS is still influencing boost and part of the way it was designed to work was to gradually bring in boost but not give full boost until 4000+.
I would take it out.
The TC is never going to run with the mustang or a reworked GN. The Mustang has a 3-400 lb weight advantage and the GN has cubic inches.
The IHI in either vehicle is a limitation compared to the GN.
An adjustable waste gate arm can have value, but you need to determine if you have a problem there first. There may be some reason it is partially open that an adjustable arm won't fix.
I can send you some instructions for installing the fish tank valve and taking the stock BCS out of the circuit. E-mail me off line

------------------
88 TC X 2, 86 SVO, Main TC with K&N, 3"DP to 2.5"duals through Dynamax, Ric valve at 17+ and disconnected KS.
Elite Bodega 16" chrome wheels. Autometer pod w/ A/F and Vac/boost gauges. New engine shortly, ported head and
manifolds, polished and cc'd chambers, A-230 cam, Race Engineering Adj Cam Sprocket, Crowlers, ARP head studs, Walbro 190 pump and T-3 for starters. KB subs
and jack rails.
Pete Dunham


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SteveX82 Offline
Posting Freak
#7
wait, so let me get this straight......you have a bleeder valve installed along the same vaccuum circuit as the bcs? maybe that's why it takes so long for the boost to build? i mean, if the bcs is trying to determine how much boost to allow and then the bleeder valve is further restricting it......hmm...
Estoril blue 1987 TC 5spd, 148k mi, a237, Bailey BOV, spec stg3 clutch, spearco FMIC, 50 trim t3/t4, 3" exhaust, Bamafuel, LM1, 55pph
Best 1/4 mile: 12.31 @ 110mph on 25psi
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Noname
Unregistered
#8
it did the same thing before the bleeder was put in. since the bleeder was installed i just get about 18 psi, as before i could only get 15 psi max.

thanks pete, you'll have mail really soon
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Noname
Unregistered
#9
thanks to all who helped. i grabed the wastegate actuator from the stang and used it to replace the one on the tc. now i have full boost (16 psi) by 3200 rpm on the tc.

i feel much better now

thanks again
jason
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