6G Celicas Forums

could you just turn the boost down for the winter?
if it spikes it wont be spiking at a high psi.
thats my band aid suggestion.

for fixing the problem id play with the boost controller first.
The bleeding hole might be clogged with oil or gunk.
if thats clogged you will be more susceptible to creep.
the thing i don't understand is, id run the ct26 with only a foot long dp and never experienced creep.


This post has been edited by x_itchy_b_x: Dec 4, 2006 - 10:50 AM

punisher i agree with manny you seem to be a tad bit trollish in your posts like you have to make sure everything you say is delivered with some controversy.

anyways what he means by not wanting to do an external wastegate for his ct26 is that the labor and money involved would be wasted if he ever chose to do a different turbo upgrade. it would be like buying new tires for your stock rims when you know that you want to buy rims in the near future. or like how i havent replaced my shocks yet because im waiting to have enough money to do springs with it.

ive been playing around with the ebc for a while now. the problem is, that if i turn it down all the way, im stuck at only about 7psi for those daily 3-5k runs. however if i go wot, ill creep to 14psi. i think this cold weather is making the problem worse. ill also have to inspect my downpipe. im willing to bet the wg is hitting the downpipe, like it has for so many other people out there.

no need to be a cocky know it all. if you have some advice to share, do it in a polite manner, and not try to talk down to everyone like your gods gift to cars or something. didnt you put your wastegate on backwards?

the wastegate is a part of the turbo. the ct26 has its own internal gate. i would have to get an adaptor to sit between my manifold and turbo, then buy a waste gate, and then redo my downpiple (no i dont want to dump). thats all time and money that wont make me go any faster. if im going to go through all that trouble, then i ll just wait untill i have the cash to upgrade the turbo as well. besides that, its cold as balls out and we dont all have moms heated garage to work in.

This post has been edited by lagos: Dec 4, 2006 - 1:50 PM

Hey Arthur. Did you fix your creeping problem?

not really. i bought a silencer as a band aid fix, but it didn't fit my exhaust. so, for now, ive just been trying to keep my eye on the boost. when it gets warmer out, im going to take my downpipe off and make sure the flapper isn't hitting it.

Why dont you just fit a restrictor plate between the downpipe and the exhaust......a 2mm`ish thick ice of metal, cut to the same dimensions as the flange, with a between 2.25 - 2.75 inch hole in it...2.5 inch usually cures the problem...very popular with st205 owners with boost creep issues.

This post has been edited by Insanity-74: Jan 7, 2007 - 8:41 AM

thats a great idea! do you have any pics of ones people have made?

This whole approach to me seem very ill-advised. We open up our exhausts to access additional horsepower. Then, if there is a boost creep issue, we restrict the exhaust?

Why spend several hundred dollars on the performance exhaust in the first place?

Creeping boost is NOT an automatic problem with a free flowing exhaust on a ct-26 equipped car. In fact, I could get the gt28rs (with a similarly sized wastegate but much more flow) to hold at 11psi on a full 3" exhaust equipped car.

Something is wrong. My recommend is to diagnose the problem and then repair it.

The problem of the boost creep IS caused by the exhaust being too free flowing and the wastegate on the CT series Turbo not being big enough to cope with the extra exhaust gases produced by modified cars and wider exhaust systems. Nothing is wrong with you car, the turbo wastegate is the problem....it can be ported, ie make the twin port of the CT turbo into one big port....that should cure the boost creep issues, but you have to be handy with a grinding stone and VERY sure of what you where doing......gt28rs turbos have a better more free flowing waste gate design, thus dont suffer the boost creep issues of the CT range.

a 3sgte engine running any ct turbo dose not need a 3" exhaust at all. 2.75" is more than enough.

Unfortunately I have no pictures of a restrictor plate, but you could very easily fabricate one....kind of like an exhaust gasket with a smaller hole in the middle.

This post has been edited by Insanity-74: Jan 7, 2007 - 1:21 PM

Or you could fit a rally style 38mm restrictor housing to the turbo inlet, which decreases BHP a little, but suprisingly increases the torque by quite alot

This sounds alot like:

"no its not"
"yes it is"
"no its not"

Here is my reply:

Q: How many people are running ct-26's with full 3" exhausts with no creep issues?
A: Alot

Fare enough...have it your way then......how about coming up with a solution and helping all the 3sgte people who do have boost creep issues.

There isn't just one solution. It depends on what the problem is.

Perhaps the wastegate actuator rod is bent
Perhaps the flapper door is not opening for some reason
Perhaps there is a leak in the pressure line going from the manifold to the boost controller
Perhaps the boost controller is faulty (a problem I had)

I am sure there are other potential causes that I am not thinking of.

x2

that is a great response.....

seriously i doubt the cause of creep is a full 3" exhaust because there are MANY 3sgte owners w/full 3" systems that get 0 creep....i mean look at mr2s....much shorter exhaust and creep doesn't seam to be a rampent problem?

find the real problem don't try to stuff your exhaust to band aid it

Thats much better 11/10...things you can check and look into and investigate and all very valid possibilities, but after working on cars now for over 15 years I can most definately assure you that an overly large exhaust diameter can cause boost creep if you have an inadequate waste gate....remember the CT series of turbo was only ever designed to cope with the standard internals producing the pressure, and with 0.9 bar...its all about exhaust gas velocity and back preasures....there is alot of physics type stuff invloved which I dont fully understand but it does happen.

A bent actuator rod is possible..unlikely due its location being out of the way, but if your not carefull when putting the turbo back on etc.

The flapper (wastegate) not opening fully is a real problem and admittedly one the most likely causes of boost creep...especially if you have one of the XS power type of down pipes which has is under designed and dosnt always allow for the full opening of the wastegate.

Manifold to Boost controller pressure leak..........highly possible in an after market boost controller set up...more likely to be a leak between the turbo itself and the solenoid for the actuator.

Faulty boost controller....the only way to find this out that I know for that is to bypass the boost controller totally and run the boost pressure dierectly off the actuators pre set pressure, which should be around 0.5 bar.

I have noticed this alot in American forums that everyone seems to jump straight on the 3" exhasust band wagon (no offence to anyone)...but unless you want to produce 400+BHP it really isnt needed, but I`m sure that noone will listen to my advice...after all I`m from England...what the F@@k do I know.

I think you raise a good point here. But there is dyno testing to prove that a 3" exhaust will result in modest performance gains at levels under that. Also, some folks initially build BPU 3sgte's with the intent of possibility upgrading later on. If thats the case, you don't want to pay for two exhausts.

BTW, I consider this a polite difference of opinion and apologize if my comments offended you. I am curious as to your opinion why some people experience absolutely no creep issues with a ct-26 (or ct20b) and a full 3" exhaust.

Likewise...most definately no offense taken at all.........its good to get a bit of "chat" between opinions and to talk them through....it can only help out people who read this as eventually we will reach a conclusion as to whats going wrong and help people in the future

I say just keep ur exhaust stock and add an electric cutout! Wanna make some noise and add about 30 +hp/tq... just flip the switch! No noise when you dont need it. Performance only when you need it.

Thats what I call sleeper!