AM performance downpipe issues.

[Kansei240sx]

Alright guys, for those of you that have bought the AM performance downpipe ( PLUMB BACK ), its a lovely peice and it fits flawlessly around the steering shaft and matches up with my cat back perfectly, but im having a serious problem with it.

Im am having horrible boost creep since i've had it on. Im thinking either A. the wg arm on the actuator is hitting the flange, or there is a slight back pressure causing the WG not to vent off enough giving me boost creep.

My response on the turbo is off the walls and holds solid 10 psi or so up to about 4670 and then it just starts going to 15 or past, untill the MAF maxes out or i lean out and the car bucks.

Its and RB25DET , i have a straight shot from my hot pipe, to my WG actuator, no boost solenoid and no, i didnt have any problems like this with my stock downpipe and elbow. Anyone else have suggestions?

I have had a few of my car buddies and even myself thought that, what i should do is pressurize the wg actuator with the air compressor, see how far it travels with the DP ON, and then the same off. if there is a difference in measurement and the WG flap is hitting the DP then i may have some grinding to do, if not, i need to dump the WG tube, which i wanted to do anyways.

[cdorhout]

I've had no problems at all with the downpipe. Zero boost creep.

I had no boost creep with the stock turbo at 12psi, and I still don't have any at 19psi with the new turbo.

You may have another problem.

Disconnect the WG arm, and see if the flap opens and closes easily.

[blurrbosi]

Damn internal gates. Use the compressor trick like you are saying. That normally tests the functionality of the little guys.

[Carl H]

you can always try porting out the wg outlet on the turbine housing...

[Kansei240sx]

i took the arm off the flap, and it opens the complete + or - 90 or so degree's.

With the actuator it only opens about half that, which is normal, or so i figure. I took the downpipe off and noticed that the two middle bolts had actually rattled out and i only had the two bottom nuts, and and two top bolts in.

I took the DP off, and cut off the recirculation to where its dumped, and im having the bend welded up tomorrow.

Ill just put all new hardware in it tomorrow, and try to find another WG. Im going to see if a i can get or use a friends RB20 actuator if the same problem occurs.

[Kansei240sx]

Well the pipe is dumped now, and..... it sounds...kinda akward, but i love it. It doesnt sound like a RB thats been dumped, in fact, it sounds like my friends NA-T 2JZ with a dump.

Either way, I can get her up to about 5500 before the boost goes south on me again, so im going to replace the wg and see if that fixes it, if not, i have no idea whats going on.

[Kansei240sx]

Ok.... so i swapped wastegates, did a leakdown test of my intercooler piping and turbo, and still the same problem, with it dumped...and it sounds wierd compared to any other dumped RB ive ever heard.. Anyways, the pipe was cut off RIGHT before it bends back into the downpipe.

I can get up to about 4800 before it goes from 10 psi to 10+ and fuel cut, WHICH i dont go to, i just know it'll happen because the car starts to slow down.

WG arm opens and closes fine, both WG's work fine, No leaks out of the outlet pipe or anything.

Im going to put the stock downpipe and elbow back on. If everything works i suppose the dump tube is too restrictive, if it doesnt does anyone have any ideas? Im at a loss as to what it'd be if doesnt work this time.

[Kansei240sx]

So i put the stock downpipe back on, and what do you know, no problems with boost and the car flat out hauls some ***.

I really want the AM performance dp on the car due to it clearing the steering shaft.

When i turn to the left, its normal, and when i turn to the right its stiffer than one side so steering feels abnormal.

[ripracer]

I have a chance to get one of these, but with this post I'm kinda weiry of buying one now. Has anyone else had problems with there's. Anybody running one of the elbow downpipe combos you can get off ebay.

[Kansei240sx]

The ones off ebay are peices of ****, and dont fit our cars.... From what it seems, no one has had a problem with this pipe except for me.

[Bronze MFP]

I had an open WG pipe, then converted it to a closed pipe, either way I have no boost creep. this is on a stock(ish) rb20 running 1bar of boost. if anything, it boosts to 1 bar, then falls off to about .9bar as rpms increase

[JerryRigRB240]

Kansei, if you're still having problems with the downpipe email me. I'm sure Andrew will do what he can to fix the problem.

It sounds like the wastegate valve is not working properly when the AM Performance downpipe is not bolted on. It could be the wastegate gas being restricted, but the 1 1/2" wastegate tube should not be too restrictive unless you're running a lot more boost than you say.

It could be as easy of a fix as porting the turbo side of the flange out a little. Pictures might help diagnose the problem too.

[l0nestar]

*post removed*
Modified by l0nestar at 3:29 PM 7/8/2007