Whats wrong with my wastegate?
 

I have a d16a1 with an IHI RHB5. Everything runs great exceptt it overboosts, big time.
The boost will steadily climb to 10 psi in 4th gear.
Not suprising you say?


I have the wastegate disconnected. Thats right, the wastegate arm has been removed. I am suprised it even build boost. but 10 psi?
Any ideas? Clogged wastegate port?
I want to run 5 psi.
Another thing is, the boost guage gose up liek a tach, I thought boost was suposed to hit at a certain psi and stay there throughout the rev range?


Any help appreciated.

Dan

Re:Whats wrong with my wastegate?
 

ttt

Re:Whats wrong with my wastegate?
 

if the wastgate arm was gone (assuming you are talking about the rod) then WG stated close and u WILL kept on building boost
what the WG does is when certain amount of boost is present, it pushes on the rod and the rod push open the flapper, hence release the excess pressure and control boost level.
now u took it off, flapper stay closed annd pressure kept on goin up = boost kept on going up

Re:Whats wrong with my wastegate?
 

Umm, woudlnt the exhaust pressure push the wastegate flapper open? siince there is nothing holding it back now?

Re:Whats wrong with my wastegate?
 

yeah, if you take the wastegate arm off of the flapper it shouldn't boost much at all, maybe 1psi if you've got a small turbo. Check and see if the flapper is free to open up completely. If not, then check the passage like you said.

Re:Whats wrong with my wastegate?
 

duh...

Re:Whats wrong with my wastegate?
 

actually, if you take the wg actuator off the flapper, it will be like having an open wg, the actuator holds the flapper closed, if they're not attached, the flapper will....... well....... flap, creating no boost. so, you're flapper must be stuck shut or some ----. internal wg's are ghey :P

Re:Whats wrong with my wastegate?
 

One word...
TIAL!

Re:Whats wrong with my wastegate?
 

When you disconnect the actuator arm from the flapper - how far can you open the flapper? Its like a door. Can you open it 90 degrees? 40 degrees? 10 degrees? If you can't open it that much then that could be the problem. If you can open it a good amount then you should probably make sure the dump tube is clear. What kind of downpipe are you using - is the wg dump open or does it return to the downpipe?

Re:Whats wrong with my wastegate?
 

Im using a stock IHI RHB5 exhasut downpipe.
I can open the wastegate fully, when I take off the downpipe I see it is fully open (liek 180 degrees)
The only thing I can see right now is that the passage is blocked. I am goign to check it right now and well see how it goes.

Thanks for the help!

Re:Whats wrong with my wastegate?
 

What kind of boost guage are you using? Maybe its not a turbo/wg issue at all and simply a fubar guage.

Re:Whats wrong with my wastegate?
 

OK, I checked thw Wg, it works fine, no obstruction to flow. But this is what I think may be the problem. The flange's outlet that ive welded to the exhaust manifold is 4-5mm smaller than the ihi RHB5's inlet. So what I am thinking is that small outlet is restricitng flow to the Wastegate. I tried porting it a bit, it took 20 mins to take of 1mm, but I noticed the boost wont climb past 7 psi. Still alot considering the WG is fully open, but maybe if I completley port match it it will boost 2-3 pounds? Have any of u guys had this problem before?

Re:Whats wrong with my wastegate?
 

I havent read everything.....I had the same problem with my first turbo..
Small turbine and small wastegate hole...the exhaust gasses will be so much that it can't all go thru the wastegate hole....min boosted to 15 psi with the wastegate open, but it only happened at 6K+ rpm's. get an external wastegate...right now I have a T3/T4 and I just bought an ex wastegate, cause the internal one of mine isn't working very well,

Re:Whats wrong with my wastegate?
 

Ok guys, I am really stumped on this.
I bought a new boost guage and it shows 9 psi in 4th gear at 5500rpm.
Has anyone else here used a IHI RHB5 and had the same problem? What If I enlarge the WG port? anything?

Re:Whats wrong with my wastegate?
 

ttt