controlling boost

[baby6]

Ok, so here is the scenario:

mods are in my sig. as of right now it is stock downpipe, adjustable actuator, and stock wastegate.

When I unscrew the actuator out almost all the way (I believe it is a HD actuator) I can get the car to build boost to 15 and keep it around that area (14-16) but it spools slow and isn't as powerful. The reason I think this may be and if I interpreted correctly a couple gentlemen on the board were discussing this: when the actuator is fully extended, it releases all of the exhaust gas sooner, thus spooling slower and decreasing the turbos velocity capabilities? If I tighten up the actuator some (went out last night) it boosted 16-19 pounds depending on load, but at 15 pounds the car SEEMED to pull MUCH harder with it tightened than with it extended, at the same boost level. Can someone please explain this to me? I am running the wastegate with OUT a boost controller, seeing as I have not had very good luck with the bleeder-style controllers.

With that being said, would a bigger internal gate help me with this issue at all, or do I absolutely HAVE to get a boost controller to make this work? I have an RJC 3" DP with internal gate on the way.

 

[pacecarta]

a hd actuator is normally only used when desired boost is 18 or more

unless the puck is making contact the spool will suffer ,it like having a header leak
, normal wastegate rod adjustment is to set the rod so it takes 1/8" to pull the rod to hook onto the DP arm

are you hooked up tuner style , that means with a hose from turbo run direct to wastegate actuator
try it this tuner style with rod hooked on with 1/8" pull and you will get the lowest boost possible , if boost is not low enough you may need to port the turbo housing,too low you can add a bleeder or tighten the rod a little

did you port the exhaust housing.
porting means open the hole so there is no more than 1/8" coverage of the puck all around opening
if boost wont run low enough or creeps up as rpm rises you should port match the turbo exhaust housing opening to the larger rjc puck

 

[baby6]

I put my stock wastegate back on, have my boost now at 15, fuel pressure rises 1:1 but still getting detonation so i pulled some timing out. It is extremely humid and hot out in Florida and I am not running Alky. Car pulls hard until it hits around 4600-5000 rpms and then starts to pop, almost like its leaning out but it is not. I thought I fixed this with the new turbo but apparently I was wrong, Wideband just arrived, so I am waiting for my Downpipe and hood mount FP Gauge to come and hopefully will get this thing to run the way it should.

 

[pacecarta]

running too rich an a/f with alky can knock as well

and the 49 could be operating in surge around 15psi part throttle depending on the intercooler
the surge will cause erratic fueling on maf

 

[baby6]

Not running alky just yet, Ive played with my fueling and timing, boost, I have changed everything to no avail. The last thing I will try is the crank sensor, which hopefully will my problem. Want to get the car running good first before I strap alky to it. I need a set of headers first though, as I have a driver side leak for the 4th or 5th time now. What can a pre-turbo leak cause? Ive heard multiple answers but would like to hear from you.

 

[pacecarta]

preturbo can cause the o2 sensor at idle to see oxygen and add fuel when running closed loop idle
turbo tweak uses open loop idle so little leaks at idle dont have as much effect

off idle depending on the severety of the leak it will have less effect as engine rpm rises and the exhasut builds pressure
when running too rich you could get detonation from the excess fuel igniting in the exhaust headers because it will have o2 availble from the leak
once in in boost it really doenst matter as the exhaust pressure could be twice as high as boost and its just air getting out
but leaks before turbo can and will affect the spool up time since its the same as having a wastegate cracked open

 

[baby6]

That's what I thought, thanks for the input. Can't wait to see how this ta-49 spools with new headers, it already spools wicket fast even with the leak! crazy stuff.

 

[Pronto]

Popping, try tightening your sparkplug gap...

 

[baby6]

Pronto, they are already at .030. Nothin.

 

[Pronto]

Try 28

 

[blue-t]

valve spring pressure

 

[forcefed3.8's]

How much boost is the chip burned for? It might be flooding out.

 

[baby6]

Chip is burned for 15-17 psi. I ported the wastegate hole but now I have the stock actuator adjusted too tightly, I am going to put the hd actuator on and see how it goes...one day in the near future.
Really just havent been trying to beat on the car lately, I drive it every day and would rather not push it to the limit.