Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: T88C on August 26, 2007, 06:56:57 PM

Title: new exhaust and slow boost
Post by: T88C on August 26, 2007, 06:56:57 PM
i just installed a stinger exhaust on my 88 TC and now when i step on the gas the boost gauge shows that its boosting really slow.  the only thing that i have touched besides the exhaust is the intercooler to move it so i could see the downpipe.  i just checked and everything that i disconnected is tight.  i the car sounds like it builds boost but it goes nowhere, it feels like a dog now.  when i put the K&N on it really woke the car up... but now its slower than it was when it was totally stock.
 suggestions??? or boost leak somewhere?
Title: new exhaust and slow boost
Post by: SLEEPER T-BIRD 87 on August 26, 2007, 07:39:26 PM
boost leak
Title: new exhaust and slow boost
Post by: martin0660 on August 26, 2007, 07:49:30 PM
Quote from: SLEEPER T-BIRD 87;172167
boost leak


X2 - anytime you touch the intercooler, there is a change of not getting one of the couplers or clamp on there right. The other thing to look at, make sure you didnt knock the wastegate rod loose. Its down there where you were messing with the downpipe bolts.

Bob Myers
Title: new exhaust and slow boost
Post by: daboss351 on August 26, 2007, 08:21:16 PM
yea the exhaust would make it spool way faster, so theres a boost leak in there somewhere.
Title: new exhaust and slow boost
Post by: 88turbo on August 27, 2007, 01:30:21 AM
I am running the stinger exhaust installed by stinger himself.  check all of your boost/vacuum connections and fittings and lines to make sure you dont have a leak and also check to make sure that your intake tube isnt sucking closed under boost.  keep us posted
Title: new exhaust and slow boost
Post by: T88C on August 27, 2007, 12:51:26 PM
ok so i should check ALL  of the vacuum lines???
88turbo- what do you mean by the intake sucking closed under boost?

martin0660- should i check for play in the wastegate rod and what do i do if it is loose (dont think that i touched it though...)
Title: new exhaust and slow boost
Post by: daboss351 on August 27, 2007, 12:53:08 PM
Check all vacuum lines and intercooler couplers!
Title: new exhaust and slow boost
Post by: T88C on August 27, 2007, 01:30:30 PM
YAY i cant wait....
Title: new exhaust and slow boost
Post by: 88turbo on August 27, 2007, 01:39:17 PM
the intake tube going from your airbox to your turbo. there should be a spring inside to keep it from sucking closed under boost
Title: new exhaust and slow boost
Post by: T88C on August 27, 2007, 07:01:40 PM
ok just retightened everything down and replaced some hoses now it boosts like crazy!!!

now im new to turbos and do not fully understand them so i have a ?... when i stomp the gas to accelerate the car gets up to a certain boost level then goes back down to 0.  is this typical of turbos or is something releasing the pressure unnecessarily??
Title: new exhaust and slow boost
Post by: daboss351 on August 27, 2007, 07:19:01 PM
you have an IHI. Your boost drops out? Somethings not right it should hold full boost till you let out of the gas.
Title: new exhaust and slow boost
Post by: T88C on August 28, 2007, 06:27:44 PM
boost leak maybe???
 i dont have a BCS but i ordered a manual boost controller should that help at all?
Title: new exhaust and slow boost
Post by: daboss351 on August 28, 2007, 06:35:37 PM
You dont have a bcs? thats boost control soliniod right? You should have one, or the turbo is just going to boost as much as it can, i believe. How much boost is it making?
Title: new exhaust and slow boost
Post by: T88C on August 28, 2007, 08:20:51 PM
it keeps going up but i wont let it go past 18lbs  i have to shuft kinda quick lol

so shoulda manual boost controller solve that problem?
Title: new exhaust and slow boost
Post by: daboss351 on August 28, 2007, 08:50:36 PM
Yes. It will let you set the boost. Just make sure you put it in the right way
Title: new exhaust and slow boost
Post by: 88turbo on August 28, 2007, 10:06:25 PM
Quote from: daboss351;172835
You dont have a bcs? thats boost control soliniod right? You should have one, or the turbo is just going to boost as much as it can, i believe. How much boost is it making?


wrong......  what you need is a wastegate actuator this is what really regulates your boost.  a boost controller is what regulates the actuator.
Title: new exhaust and slow boost
Post by: bhazard on August 28, 2007, 10:08:35 PM
Hook something up to the WGA, anything, even if its just straight vacuum/boost source.  Having nothing hooked to the WGA is just asking for a boom.

A mbc would be best though.
Title: new exhaust and slow boost
Post by: 88turbo on August 28, 2007, 10:11:31 PM
:iagree: listen to the man:flip:
Title: new exhaust and slow boost
Post by: daboss351 on August 28, 2007, 10:31:50 PM
shouldnt the turbo already have that? So if theres no reg for it it will keep boosting?
Title: new exhaust and slow boost
Post by: 88turbo on August 28, 2007, 10:45:40 PM
if there is no vacuum/boost getting to the actuator it is pretty much useless and will do nothing.
Title: new exhaust and slow boost
Post by: ipsd on August 29, 2007, 01:30:13 AM
That or the Actuator could be blown out. They are a rubber balloon on the inside the inflates to push the rod to open the waste gate. Yon can use shop air to push it open to see if it works. Also make sure that is really moving the little arm that the rod hooks onto. Then If all that works right then you should have a non BCS controlled boost level of about 7-8 psi unless you have something other that a factory actuator.  Then 87-88's got a BCs maybe a few older one but the early models got none. The later models with the BCS is just a computer controlled way of tricking the 7-8 psi actuator into running more than its rated boost level. Then if you run a Manual boost controller you can trick it into run a lot more boost. The  MBC will help it spool a little quicker due to the fact that it delays the air signal from reaching the actuator until it has enough boost to raise the ball inside and make it to the actuator. The BCS does this sort of it is just a motor that opens and closes to bleed of the signal to the actuator. Kind of like an adjustable opening in the vac line to the actuator.
So if you are boosting 18psi with foot control maybe the waste gate flapper is rusted shut on the inside or maybe the actuator rod isn't long enough to open the gate all the way.
Title: new exhaust and slow boost
Post by: T88C on August 29, 2007, 10:04:13 AM
i use premium gas so it should be boosting more than 8 psi anyway.  but is the actuator replacable and should i upgrade it so a better one???
but im only working a half day today so when i get home im going to check and make sure that everything is in working order

and does anyone know about my other problem with the boost not holding when i accelerate??

thanks for the replies.....

oh... and ipsd where would i hook the air up to to test the actuator???
Title: new exhaust and slow boost
Post by: ipsd on August 29, 2007, 11:23:32 AM
Ok the actuator should be bolted to the inlet housing of the turbo.Don't forget about the little E clip that holds the arm to the waste gate flapper. Yes you can replace them. The stock unit is fine. Mine is the factory 84 unit. I'm only running 15psi but I haven't heard much about needing to upgrade the stock unit. To test the one you have pull the Vac line and use compressed air sprayed into the vac line going to the actutator and see if it moves the arm. Kinda need a mirror or to be under the car to see the arm move unless it is off the car. As for the boost not holding while you accelerate maybe the arm that hold the flapper shut isn't holding it shut tightly to start with. Check to see if the flapper can me push closed more with out the actuator arm hooked to it. The actuator is held to the turbo with sheet metal bracket that is welded to it. It could have gotten bumped during the exhaust work. If the arm isn't adjustable you can take a pry tool and bend the bracket so it holds the flapper shut nice and tight. Also if you removed the BCS and the computer is no longer in control of the boost level how does having premium gas and being in premium mode help. The stock actuator is made to allow 7-8psi with out and added help from the stock ECU controlled BCS. So 8psi sounds right on the money with out the BCS. If you want more boost get you a MBC or you can make one like this. 
http://forums.turbobricks.com/showthread.php?t=59089

Also if you plan on running much stock I tell you to put zip tires on all the vac lines also start replacing them before they blow on you.
Title: new exhaust and slow boost
Post by: T88C on August 29, 2007, 03:19:50 PM
just so you know i didnt take the BCS off i bought it this way.  and i didnt even know about it until i was following vacuum line diagrams and wondering why there were a few that were capped off. 

so your saying that i shouldnt be able to run more than 8 lbs of boost?? and because i am there is something wrong?

well.... im going to go and check all the lines again and the actuator
Title: Updated!!!
Post by: T88C on August 29, 2007, 05:18:29 PM
so i went searching for the vacuum hose for the acctuator and come to find out the previous owner (***hole) cut the effing hose right off it!!!!!!

so im off to get a new vac hose for it and i was wondering what line should i cut into?????
Title: new exhaust and slow boost
Post by: CougarSE on August 29, 2007, 05:20:56 PM
Any line that is after the turbo on its way to the throttle body would work.. I think there is a fitting on the compressor outlet, and if not there is one on the corner of the intercooler.
Title: new exhaust and slow boost
Post by: T88C on August 30, 2007, 09:49:30 AM
well the WGA vac line is connected now and i didnt really get a chance to drive it to test it out because the traffice this morning was unbelievable.  thanks for the replies and the help guys....
Title: new exhaust and slow boost
Post by: ipsd on August 30, 2007, 10:01:31 AM
No problemo; Us Turbo coupe owners have to stick together and help each other out. With out the help of others we would get pissed of and shoot the  cars.
Title: new exhaust and slow boost
Post by: T88C on August 30, 2007, 06:17:54 PM
i had the gun cleaned and loaded just in case....:D

luckily replacing the vac line solved the problem of the boost dropping off  too

now i just have to find out what part of the suspension is squeeking under the front drivers side fender.....
Title: new exhaust and slow boost
Post by: bhazard on August 30, 2007, 10:18:57 PM
check the ball joints.
Title: new exhaust and slow boost
Post by: SLEEPER T-BIRD 87 on August 31, 2007, 11:30:25 AM
Quote from: bhazard;173511
check the ball joints.


yup #1 suspension noise in the fox family line