20g boosting issue

[Bluefire16]

Hey guys, just got my 20g installed. Was running stock wastegate pressure (like 9 psi) it would spike to like 14 then settle at 9psi. Well i put my boost controller on, and just went up a few pounds.

Now it spikes to like 20 and drops. This turbo feels great when its hitting around 16(i no thats not even much) but sometimes the turbo feels sluggish like its just holding out. Then after a split second cuts in.

Thats the first issue, the second one. If i am driving slowly and gradually get on it, it will boost fine and hard to 15psi. But if i step on it, it spikes really hard to 20 and then drops to 11 and is real sluggish.

Any ideas?

And i have done 3 BLTS.

 

[brian9397gsx]

Is your wastegate arm (if its internally gated) adjustable it almost sounds like its to tight. What kind of 20g are we talking about?

 

[95tsiemad]

Are you still running a stock clutch

 

[Bluefire16]

Im an auto....

And its a internally gated. Wastegate arm is tight but seems fine. Its non adjustable...Maybe ill try and use another wastegate actuator.

And its a bastard 20g with a 7cm housing and its ported with a ported o2 housing

 

[brian9397gsx]

How is your boost sourced to the wastegate? what kind of mbc are you using and if you take it off and run straight to the wastegate does it still spike? I have heard of cases were bleeder type mbcs and cheaper ball and spring mbcs will cause spike. Of course having to many things t eed into your boost ref for your wastegate can slow it down to causing spike

if its an authentic mhi unit chances are good the wastegate actuator itself is fine, I wasn't sure if you had an eBay special or not or if you just had an adjustable wastegate.

 

[Bluefire16]

^^ I would not run a ebay turbo, its a legit MHI bastard 20g, just rebuilt and balanced. All fresh, thing is pure sex haha.

Wastegate is actually a little dented (i had experience with bad ones in the past, so i might change it out) I have like 3 extra ones laying around.

And im running a NXS boost controller. Ball and spring...never had issues with it in the past when running my 14b and small 16g

 

[brian9397gsx]

If its dented give it a shot they are not to bad to change. Didn't mean to offend about the eBay thing just when you hear about a 20g spiking you think of the evo dsm 20g with the faulty waste-gates

 

[Bluefire16]

^^ Ha no worries...i wasnt taking it serious. Its just the wastegate doesnt seem like it would be the problem (not like i have had in the past).

Im just not sure what it could be....

Now if i could figure out my heating issue...

 

[JusMX141]

Definitely sounds like an issue with the actuator. This is what will happen if you're running too much tension on the actuator arm....the additional tension on the actuator arm causes there to be a delay in the response time from when the actuator head sees boost pressure to when it actually opens the flapper.

 

[Bluefire16]

Ah.... hmm, it just seems that the boost is EVERYWHERE. Like not consistent at all, always different.

 

[brute]

I'm not totally familiar with your boost controller; does it have a bleeder hole? Which part of your actuator is dented (diaphragm housing, arm bent, etc.)?

If you remove your boost controller and just run vacuum line straight from your compressor housing to the wastegate, does it still exhibit this behavior?

 

[Bluefire16]

Well i put new spark plugs and fixed a few things today, shes running a bit better. Boost seemed a lot better today, my old plugs were pretty bad and fouled.

And yes my diaphragm is "crushed" a bit. My boost controller is this one... NXS BOOST CONTROL BLEED VALVE TURBO SOLENOID CONTROLLER - eBay (item 260356025810 end time Dec-24-10 03:30:00 PST)

And today after i put in the new plugs i ran the wastegate right off the turbo.

Boost seemed better, just a little off still

 

[brute]

Well i put new spark plugs and fixed a few things today, shes running a bit better. Boost seemed a lot better today, my old plugs were pretty bad and fouled.

Make sure you're running stock gap for now - once you get this problem ironed out, you can increase gap if you need to. While you're at it, make sure your wires are in good shape. Spark issues have a funny way of disguising themselves as boost issues.

And yes my diaphragm is "crushed" a bit.

Based on this, I would highly suggest swapping in a 'good' one (you mentioned you have numerous, so it can't hurt to try). I'm thinking that if the diaphragm was crushed it would behave quite erratically, which seems to be what your problem is.

Boost seemed better, just a little off still

So it is still spiking randomly? Does it always spike to the same boost, then settle at the same boost? Does it vary from run to run? And I assume you have confirmed the lack of boost leaks by now?

 

[Bluefire16]

Ha yes i have check like my OP i did 3 BLTs already. Im running normal gap of .028, and the wires are good.

It seems to be spiking to around 17psi. Maybe its just ### this thing is ported? And i mean really ported out. Also im running my stock exhaust atm.