40mm wastegate overrun?

[TurboAnything]

I have run into a problem with a hks 40mm gate on a evoIII mani. I have been getting real bad creep. It is a 17psi spring and it will climb to there by 3500rpm but by 4100 im at 22. It gets even better by 8000rpm im at 32-33psi. There is no boost controller just a straight line to the gate. Also there is no wastegate dump tube. But i think that would help by not have one? Anyone have a problem like this the only thing i can think of is that just the 1 runner is not enough to keep the S258 under control and the gasses can not revert back through the mani to expel enough?

 

[slowgsr]

First off, why are you not running a dumtube off that wastegate?

 

[BrokenTsi]

You dont HAVE to have a dump tube. It wont hurt anything.

There's no way you're 'overrunning' a 40mm wastegate. I run a tial 40mm wastegate, and I hold 35+psi just fine on my t67. I would say that hks wastegate is just junk or something. I had a buddy who ran an hks wastegate, and his did the same thing. Now he runs a tial 40mm, and all is good.

 

[Burnett03]

Sounds to me like the gate is messing up. Maybe it's not staying open, or not fully opening.

 

[Mr Peepers]

Does it have two reference ports? If so, do you have the line running to the bottom/side port?

I can't seem to find any info on them to tell if they are two port designs like Tials.

 

[illeffekt vr-4]

How is it mounted? Is it on one of the runners or at the collector on the manifold?

 

[99gst_racer]

Are you kidding me no one has had this issue! I very rarely ask for help and no one has a opinion.

Don't bump threads here. Be patient and wait for a response.


Also, we need more details. Where is the gate mounted? What is it's pressure source? how do you know it's a 17psi spring (IE: are you 100% sure)?


EDIT: Just check your gallery. Your pressure line to the gate is way too long. Shorten it up to less than a third of what it is now.

 

[92awddsm]

Also, plumb it to the port on the top of the gate. By plumbing the lower port and leaving the upper vented, you are unintentionally holding the valve closed when hitting boost. If you make these two changes, it will act totally different.

Actually, the pressure source goes to the lower port and the top port is either used by an ebc or left open without. The hookup is correct but I do agree the the long vacuum line is probably the cause. The best option is to run the line directly to a pressure port on the turbo if it has one. If not, run directly over the vc to a port on the intake manifold.

Used to have an HKS 40mm wg on my old setup and it was junk when it would actually hold boost, it would creep. I will never run anything other than tial again.

 

[99gst_racer]

Shit, nevermind, you're right Keith. I have it backwards. I had just woken up before I posted that. [puts foot in mouth]

 

[Burnett03]

EDIT: Your pressure line to the gate is way too long. Shorten it up to less than a third of what it is now.

The pressure source length would not cause the problems he is describing.

 

[99gst_racer]

The pressure source length would not cause the problems he is describing.

Sure it could. An overly long pressure line could cause a delay in the wastegates response to open; resulting in a boost spike and/or creep. As could a tear or leak in the pressure line.

 

[TurboAnything]

The gate was working no problem with my old turbo. Now i have this 58mmX83mm compressor and everything changed. The car has gotten sick fast and i have issues watching the gauges but i noticed that the car pulled harder and harder as the rpms climb so i made a attempt to watch the gauge and saw over 30psi. So the only change was the turbo this year. I have removed the gate and inspected the diaphragm and found no tears or pinholes. The valve moves freely and i removed the base and sealed it with copper spray there is no boost leaks at the gate. I am going to attempt to relocate my gate to the O2 housing since its a block off style. I have no funs for a tial i am knee deep in 240sx issues.

 

[Burnett03]

Sure it could. An overly long pressure line could cause a delay in the wastegates response to open; resulting in a boost spike and/or creep. As could a tear or leak in the pressure line.

I'm not buying it.. I can see a tear causing the problem, but not the length.. It's not like he has over 8 feet of hose. Even with the length he has the amount of time it takes to reach the gate is less than a second. He said it's creeping as the rpm's rise. Thus the gate already has pressure to it so the length of the hose has no effect.

 

[Slippi84]

That thing is crazy long. Sure it can effect wastaget response time and effectiveness. Put a nippl on the compressor outlet and run it there I bet you control boost a lot better. Only other thing that would cause that is a huge exhaust leak.

 

[NewTurboTuner]

You dont HAVE to have a dump tube. It wont hurt anything.

I beleive you're mistaken about this. Running no dump tube (or a super short dump tube) CAN hurt something.... the WG!

Theres too much fast heating/cooling when you don't use a proper dump tube.
A Waste Gate can glow red hot on boost, and then (without a proper dump tube) when you're off boost, the WG cools too quickly.... sometimes it causes cracks in the WG flang/valve, then it won't work.

That might be your case. I hope not bet you better check.
Take the WG off and look to see if you cracked it.

If it's not cracked yet, then get a dump tube on there asap, before you do crack it.

~~~~~~~~~~~~~~~~~~~~~~~~~~~

The shorter the hoses the better.
Keep them as short as possible for the best response.

 

[DECODER22]

im running a 60-1 with a tial 38mm set at 18 psi the MBC is set at 24 and creeps to 28+ so im not sure if this is a wasegate issue since its brand new or what it could be,is something else causing the creep besides the wastegate?

 

[DECODER22]

also the tial is running off the manifold it seems like a few people are having these creep issues