My '91 turbo has been acting wierd for the past couple of months. little things keep popping up nothing serious but baffling. so here I am -again looking to you guys for some answers.
My O2 sensor came off a couple of weeks ago. no prob, got 2 new bolts, put it back on. no problems. now my Greddy Profec II EBC is telling me I'm hitting 18, 19,even 20 psi? is that even possible with a stock(as far as I know) CT26?.I've had the same boost settings/gain values on the EBC for a year and now this.I've been turning down the boost gain settings but still hitting those boost #'s ...everything seems fine. car is running great. I'm hoping it's not the EBC on it's way out and giving me false info.... I'm puzzled...any thoughts????
The turbo will make as much boost as you allow it to. That is the point of a boost controller. The boost controller doesn't push the boost up.... it holds the boost back. Sounds like you are having boost controller issues.
at lower boost levels everything seems fine and right on the money. maybe these are just spikes and i just need to readjust the gain. I think the whole time before my O2 sensor popped out , there must have beena leak there and maybe thats why i never boosted that high before... i'll just keep an eye on it...
Like I was saying.... the turbo can take as much air as you can push into it. Doesn't mean that it is going to be useful though. I push 20psi on my "CT26" and it doesn't show any signs of power loss. Not your average ct26 though.
I thought you were running a CT27?
anyway, I went riding tonight and adjusted the gain/boost some more. tuned it way lower. and now i'm peaking @15.8. . so i guess everything's OK. I must have my FCD on the wrong setting cuz I should have hit fuel cut at 17 psi... I can't remeber off ahnd whta the instrucions said to set it at. but one raises fuel cut and the othe turns it off. it.s an HKS FCD. it's either on 7 or 9.. does you know which setting does what?
Yeah, I know what a CT27 is, but i thought they were capable of significant more boost than the CT26?
You're right. the Greddy Profec II is suppose to reduce the boost when going over set values...hhhmmm? need to get out the little manual that came with it and read it again.
will 17 -20 psi from the CT26 damgage my engine? I've heard fro a reliable source that the CT26 will not out run the stock fuel system..but I'm concerned..
will 17 -20 psi from the CT26 damgage my engine? I've heard fro a reliable source that the CT26 will not out run the stock fuel system..but I'm concerned..
A leak at the O2 sensor would not affect your boost level.
Only a leak before the turbo would affect your boost and that would lower it.
Your boost is controlled by a wastegate that bleeds off exhaust before it gets to the turbine. If you are overboosting either the wategate is not opening or you have a boost control issue.
All your boost controller is doing is putting a restriction in the line to the wastegate actuator until you reach the "set" boost level and then it removes the restriction and lets your wastegate open. That is the basic concept of what is going on.
The OEM fuel system is more than adequate to supply anything the CT26 can dish out, that does not mean that you can't blow up your engine with a CT26. All that means is you will not run lean. You can still blow up from running to much boost causing too much heat resulting in deadly detonation.
If you were hitting 18-20 psi on the Ct26, I can gaurantee you that you were seeing incredibly high pressure/heat in your turbine which would be backing up into your engine.
The HKS FCD has a setting that will rasie the FC to 17.2 psi and another setting to eliminate it. The only real reason to use the FCD is to raise fuel cut since you can eliminate fuel cut for free. If you want to raise it, the max you can raise it to is 17.2 psi. You can't raise it higher than that. If you want more than 17.2 psi of boost, you need to eliminate FC completely.
well i have adjusted the EBC over and over and it hasn't made any difference. still hitting the high boost levels. no matter what the setting. the boost limiter is not stopping the excess boost. so how do i determine if it's the EBC or the wastegate thats malfunctioning?
Pull the two hoses off of your wastegate and compressor housing that lead to the boost controller. Plug them together with a single vac line. That should give you minimum wastegate boost (7psi). You might want to hook the stock boost controller up too.... that is the 2nd nipple off of the actuator.
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