hello fellow H-t'er haven't posted much. Been lurking and cars been on standstill due to purchasing a home pass year 1/2.. glad to be back.

before. I start I know that my boost levels are. not optimal for this turbo nor. the gate sizing.. Lol. but who the heck welds a 38mm flange to a. t4 manifold anyways.. lol
-I have a SFP (old school mini ram) T4 manifold.
- 6265. 81ar t4
-tial 38mm with 5s
psi spring
-hondata boost by gear / pwm controller. (currently not using, I'm on fixed duty cycle and running off the spring only)

having a small issue. re turbo'd the hatch a couple. Weeks back. and it's spiking hard.. (thank God. for my s300 and my overboost protection)

now before I took kit off the car I held 5psi and creeped to 7 at high rpm..
And since the reinstall it has been getting worst.. Its like the gate isn't even holding any pressures

I've inspected the gate internally to see if spring broke or diaphragm was torn.. all looks as it should be.

what would cause this recent over boosting?
has anyone hurd of springs just getting weak?

I have a 7psi spring was going to swap in tonight to see if it has that..

any input would be great

 

That's because you're using WAY too small a gate for the size turbo you're using and Too little boost for you to use it with. You need a larger wastegate with a higher spring.. period.

That amount of Lbs/min at that pressure just can't be handled by that small of a gate. There's nothing physically wrong with the gate, it just can't bypass enough.

 

Big turbo, low boost = big wastegate

you need a TiAL 44 at least. you're having to bypass so much flow around the turbine wheel that you're choking the 38. it simply can't flow anymore and that results in a boost increase.

also the sfp manifold didn't have the best wastegate placement in the first place

 

then why did it hold 5psi before

 

same turbo and everything?

 

I love when I can predict a thread just by its title alone.

 

These gents speak the truth, op. I went through the same thing trying to run low boost on a large-ish turbo. And my manifold (like most) gave priority to the turbo rather than the wastegate. End result, I went from a single 38 to dual 44s just to be able to run 4 lb. springs without having creep issues. I'm glad I did though because even at 4 psi, 2nd gear cuts loose up top a bit unless the asphalt is damn near perfect! I've got a pretty good foundation to build some boost by gear upon now.

 

iknorite?

 

Ahhh ignorance is bliss is it not...

@wantboost yes the exact same setup was on car drove for over 2000 miles.. held 5psi (spring) creeped to 7psi

I'm aware of my faults and my weaknesses the manifold is not the best design but it did work.. the wastegate is not the best for application.. But did work.

as we were hanging around in shop lastnight discussing this issue my buddy reminded me on the fist hell ride after install we hurd a whistle comming from top port off gate. we removed gate. inspected spring and diaphragm.. all looked ok as it did before. we swaped the diaphragm and a 7psi spring.. Test drive still same.. Going to swap gates tonight..

I really hate throwing things into the parts cannon and see what sticks.. But when in Rome.. lol

 

The seal around the shaft in the gate body leaks a bit, you can hear air rushing past if you charge the wastegate with pressurized air.

something has to have changed if this setup was working fine. either the diaphragm is pinched or torn, the shaft seal has failed, a pressure signal line to the gate is clogged or punctured or your boost controller solenoid has taken a dump

so you haven't changed cams, intake manifold, downpipe and exhaust size, dumptube size and length, etc. any changes that allow the engine to operate more efficiently can cause boost control issues to suddenly

 

I grabed a gate from my buddys shop..I immediately saw a diffrence the fire ring. Had pressure behind it. my Tial gate, the ring sat flush in the body of the gate.. the replacement gate was installed and no more issue.

:-D I'm super happy.. I can tune the creep in lol. no more dangerous over boosting. thank you for the help wantaboost

 

anytime, that's what i'm here for

So the issue with your original gate was that the fire ring wasn't sealing against the valve properly?