[paddlenbike]

I drove another forum member's car last night and his boost seemed to come on a lot sharper than mine (both of us have stock CT26s and Profec B boost controllers with identical settings). I'm thinking the spring on my wastegate is hosed since I only pull slightly less than 6 psi with the boost controller off. Can I replace/upgrade the spring?


Note: I had the turbo off the car 13,000 miles ago and didn't see any cracks around the wastegate port.

 

[Trent]

There is no wastegate spring really. If you can remove the actuator and somehow get it taken apart, then you might be able to replace something in there. The only spring anywhere would be inside that actuator.

Even though you both have stock turbos and Profec B's there are still MANY variables that come into play regarding the spool of the turbo. I wouldn't judge it based on his turbo and boost controller. It can depend on exhaust, intake, health of the motor, health of the turbo, timing, etc.

 

[paddlenbike]

I just remembered something else...some people have trouble shimming their wastegate because of the force on the actuator (which is why I assumed there was a spring in there). I had NO problem whatsoever. You've met me Trent--you know I'm not a big guy! I think something's afoul here...LOL.

 

[MK3Brent]

It is stiff... but do able.

There is a squarish metal "leaf" type of spring metal.

It really just holds it closed. I think it has a tension to it... but it isn't a spring.

 

[ZaZZn]

Depending on settings it has nothing to do with the wastegate spring... Since the EBC doesn't give any pressure to the WG line until you reach you're desiered boost.... It all depends on how you set up the profec I would guess... I know it's like that on the avc-r.

 

[conundrum07]

Perhaps your spring is shot or there is somehing broken in the actuator. If there was little/no force holding the wastegate closed, it seems likely that the exhaust gasses would push open the wastegate.

 

[Trent]

What you might want to do paddlen is get under the car and see if you can grab the actuator arm and open the WG yourself. You should have to try very hard to open that thing up. Then do the same for your friends car and compare the two. See if maybe the tension is different and then you can go from there. Just an idea

 

[paddlenbike]

Depending on settings it has nothing to do with the wastegate spring...

It does when the boost controller is turned off. I only pull about 6 psi WITH the Defcon DP and 3" exhaust and Profec OFF.

Good idea Trent. My actuator was so easy to pull back (when I shimmed it) that I am sure the spring (or whatever) has fatiqued.

 

[Silver88Turbo]

I plan on shimming the wastegate before I put my turbo back on even though I have an EBC just for that reason.

 

[ma71supraturbo]

It does when the boost controller is turned off. I only pull about 6 psi WITH the Defcon DP and 3" exhaust and Profec OFF.

boost leak? Do you guys hit fuel cut at the same level?

 

[ZaZZn]

if the spring was weak you would get less then stock boost because it would open ealier then it shoud.

 

[MrBoost]

paddlenbike, if you need a new stock one, I have one free with shipping, just collecting dust in my shed.

 

[paddlenbike]

paddlenbike, if you need a new stock one, I have one free with shipping, just collecting dust in my shed.

OH my, that's great! I will PM you my mailing address. Just let me know what I owe you for shipping.

And thanks!

Zazzn--stock boost is about 6.8 psi and most people pull 7-8 psi when running the Defcon DP. I'm pulling 6 psi or less WITH my wastegate shimmed one washer. That is less than stock.

 

[MK3Brent]

I plan on shimming the wastegate before I put my turbo back on even though I have an EBC just for that reason.

Can you have an accurate boost setting with the WG already shimmed?

Seems to me.... I thought the EBC would act as a solenoid stepping motor, and with the washers in there, the solenoid would start to act up, and not function properly..

But, if the washers simply hold the gate shut.. then, it should help the EBC... I DON'T KNOW


Tell me what you think.

 

[paddlenbike]

boost leak? Do you guys hit fuel cut at the same level?

I hit fuel cut at about 11.5 psi.

 

[Shawndude]

Originally posted by paddlenbike
I drove another forum member's car last night and his boost seemed to come on a lot sharper than mine....

Were the cars the same years (rear end gear ratios?).

Apart from the things already mentioned, an exhaust manifold leak will also reduce your spool up greatly. It can be so small you can't even hear it.

Jam a wet rag up your exhaust pipe to seal it off, and the car should die at idle. If it doesn't, you have a leak somewhere.

But comparing two different cars is always a tough thing to do. Why don't you guys do a 4th gear pull, side by side from 3K and see what is really going on.

 

[paddlenbike]

Re: Re: Replacement CT26 wastegate spring?

Shawndude, the cars are both '88s, but mine is a 5 speed and his is an auto. We both have full 3" exhausts (including elbow), so the cars are "somewhat similar." But I noticed it while driving yet a 3rd Supra that the boost sort of "hit" rather than fading in like mine. I realize this is not a scientific analysis, rather just an observation.

Even though I have an EBC, I decided to leave the WG shimmed because it took at least one washer just to take up the slack and put pressure on the spring. I say "spring" but I can't even find one in the TSRM. But something is putting pressure on the door keeping it closed.

I can't hear a manifold leak, but I wouldn't rule it out. As always, thanks for the tips!

Ken

 

[Silver88Turbo]

Can you have an accurate boost setting with the WG already shimmed?

Seems to me.... I thought the EBC would act as a solenoid stepping motor, and with the washers in there, the solenoid would start to act up, and not function properly..

But, if the washers simply hold the gate shut.. then, it should help the EBC... I DON'T KNOW


Tell me what you think.

Basically, when you shim the wastegate actuator, it essentially stiffens the spring inside. I will not be able to use the same settings on the EBC but the wastegate will not open as easily, so it should hold more boost and hopefully provide better response. My only concern is boost spikes since the wastegate will not open as easily. I hope that answers your question and I will let ya know how it works (it will be a while though).